chore(release): bump package versions to 1.14.2 (#382)

Ship the extractor resource bounds and layout fixes that landed since 1.14.1.

Co-authored-by: Cursor <cursoragent@cursor.com>

.github/workflows/ci.yml

@@ -24,6 +24,9 @@ jobs:
       - name: Cache cargo
         uses: Swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4 # v2.9.1
 
+      - name: Check package version sync
+        run: python3 scripts/version.py --check
+
       - name: Run tests
         run: cargo test --verbose
 

.github/workflows/publish-crate.yml

@@ -31,6 +31,9 @@ jobs:
         with:
           fetch-depth: 2
 
+      - name: Check package version sync
+        run: python3 scripts/version.py --check
+
       - name: Check if version changed
         id: check
         run: |

.github/workflows/publish-pypi.yml

@@ -28,6 +28,9 @@ jobs:
         with:
           fetch-depth: 2
 
+      - name: Check package version sync
+        run: python3 scripts/version.py --check
+
       - name: Check if version changed
         id: check
         run: |

.github/workflows/publish-wasm.yml

@@ -28,6 +28,9 @@ jobs:
         with:
           fetch-depth: 2
 
+      - name: Check package version sync
+        run: python3 scripts/version.py --check
+
       - name: Check package version
         id: check
         run: |

.github/workflows/publish.yml

@@ -28,6 +28,9 @@ jobs:
         with:
           fetch-depth: 2
 
+      - name: Check package version sync
+        run: python3 scripts/version.py --check
+
       - name: Check if version changed
         id: check
         run: |

.gitignore

@@ -31,9 +31,8 @@ Thumbs.db
 napi/index.js
 napi/index.d.ts
 
-# Local samples and scripts
+# Local samples
 samples/
-scripts/
 
 # Test output
 test_output/

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pdf-inspector"
-version = "0.1.7"
+version = "1.14.2"
 edition = "2021"
 autobins = false
 authors = ["Firecrawl Team"]

README.md

@@ -110,7 +110,7 @@ Or add it manually:
 
 ```toml
 [dependencies]
-pdf-inspector = "0.1"
+pdf-inspector = "1"
 ```
 
 ```rust

SECURITY.md

@@ -5,14 +5,15 @@
 If you believe you've found a security vulnerability in pdf-inspector, please
 report it privately so we can fix it before public disclosure.
 
-**Preferred:** Email **help@firecrawl.dev** with:
+**Preferred:** Submit through Firecrawl's Bugcrowd vulnerability disclosure
+program at <https://bugcrowd.com/engagements/firecrawl-vdp-ess>. Please include:
 
 - A description of the issue and its impact
 - Steps to reproduce (a minimal PDF or input that triggers the bug is ideal)
 - The version or commit hash of pdf-inspector you tested against
 
-**Alternative:** Use GitHub's private vulnerability reporting under the
-[Security tab](https://github.com/firecrawl/pdf-inspector/security/advisories/new).
+**Alternative:** If you'd rather not use Bugcrowd, email
+**help@firecrawl.dev** with the same details.
 
 We'll acknowledge your report in a timely manner and keep you updated on
 remediation progress. Please do not open a public GitHub issue for security

docs/publishing.md

@@ -1,38 +1,57 @@
 # Publishing
 
-The Rust crate is published to [crates.io](https://crates.io/crates/pdf-inspector) with trusted publishing from GitHub Actions. The first release was published manually; future releases publish from `.github/workflows/publish-crate.yml` when a `Cargo.toml` version change lands on `main`.
+Every pdf-inspector distribution uses one shared semantic version:
 
-## crates.io Trusted Publisher
+- Rust crate: `pdf-inspector`
+- Python package: `pdf-inspector`
+- Node package: `@firecrawl/pdf-inspector` and its platform packages
+- Browser package: `@firecrawl/pdf-inspector-wasm`
+- Internal NAPI and WASM Rust crates
 
-Configure the trusted publisher for the `pdf-inspector` crate with:
+`Cargo.toml` is the canonical version source. Update every manifest and lockfile
+with:
 
-- Repository: `firecrawl/pdf-inspector`
-- Workflow: `publish-crate.yml`
-- Environment: `crates-io`
+```bash
+python3 scripts/version.py <version>
+```
 
-The workflow uses `rust-lang/crates-io-auth-action@v1` to exchange GitHub's OIDC token for a short-lived crates.io token, then passes it to `cargo publish`.
+Verify that nothing has diverged with:
 
-## Release Steps
+```bash
+python3 scripts/version.py --check
+```
 
-1. Update `version` in `Cargo.toml`.
-2. Merge the version bump to `main`.
-3. The publish workflow compares the new `Cargo.toml` version with `HEAD~1`, runs `cargo publish --dry-run`, then publishes if that version is not already on crates.io.
+CI and every publishing workflow run this check before building or publishing.
 
-If `Cargo.toml` changes without a package version bump, the workflow exits without publishing.
+## Release steps
 
-## Browser WebAssembly package
+1. Choose the next shared semantic version and run `scripts/version.py`.
+2. Review the manifest and lockfile changes in the version-bump pull request.
+3. Merge the pull request to `main`.
+4. The crates.io, PyPI, Node, and WASM workflows independently build and
+   publish that version from the same commit.
+5. After all registries succeed, create one `v<version>` GitHub release that
+   links to each package and describes changes since the previous shared tag.
 
-The browser package is published as `@firecrawl/pdf-inspector-wasm`. Its version lives in `wasm/Cargo.toml`, and `.github/workflows/publish-wasm.yml` builds the `web` target with `wasm-pack` before publishing the generated package.
+The independent workflows are intentionally idempotent. A manual dispatch from
+`main` can repair a partial release, and already-published artifacts are skipped.
 
-The npm package must exist before a trusted publisher can be configured. For the first release only:
+## Trusted publishers
 
-1. Build with `wasm-pack build wasm --target web --scope firecrawl --out-dir pkg --release`.
-2. Inspect with `npm pack --dry-run ./wasm/pkg`.
-3. Publish with `npm publish ./wasm/pkg --access public` from an authorized maintainer session.
-4. In the package settings on npm, configure the GitHub Actions trusted publisher:
-   - Organization: `firecrawl`
-   - Repository: `pdf-inspector`
-   - Workflow: `publish-wasm.yml`
-   - Allowed action: `npm publish`
+The repositories use GitHub Actions OIDC instead of long-lived registry tokens.
+Configure each registry's trusted publisher for `firecrawl/pdf-inspector` and
+its corresponding workflow:
 
-After that one-time bootstrap, bumping the version in `wasm/Cargo.toml` and merging it to `main` publishes through OIDC. Until the package exists, the workflow exits cleanly without attempting an unauthenticated first publish. See npm's [trusted publishing documentation](https://docs.npmjs.com/trusted-publishers/) for the registry-side setup.
+- crates.io: `publish-crate.yml`, environment `crates-io`
+- PyPI: `publish-pypi.yml`, environment `pypi`
+- npm Node package: `publish.yml`
+- npm WASM package: `publish-wasm.yml`
+
+The WASM package must exist before npm trusted publishing can be configured. If
+it ever needs to be bootstrapped again, build and inspect it before publishing:
+
+```bash
+wasm-pack build wasm --target web --scope firecrawl --out-dir pkg --release
+npm pack --dry-run ./wasm/pkg
+npm publish ./wasm/pkg --access public
+```

docs/python.md

@@ -80,6 +80,17 @@ for page in result.pages:
 
 # Restrict to specific 0-indexed pages (preserves caller order)
 result = pdf_inspector.extract_pages_markdown("document.pdf", pages=[0, 2])
+
+# Structure-tree elements from tagged PDFs (empty list when untagged).
+# Pages are 1-indexed to match TextItem.page, so (page, mcid) joins directly
+# against extract_text_with_positions — e.g. to recover real heading levels:
+elements = pdf_inspector.extract_structure_elements("tagged.pdf")
+roles = {(e.page, e.mcid): e.role for e in elements}
+headings = [
+    item.text
+    for item in pdf_inspector.extract_text_with_positions("tagged.pdf")
+    if item.mcid is not None and roles.get((item.page, item.mcid), "").startswith("H")
+]
 ```
 
 ## API reference
@@ -100,6 +111,8 @@ result = pdf_inspector.extract_pages_markdown("document.pdf", pages=[0, 2])
 | `extract_text_in_regions_bytes(data, page_regions)` | Region extraction from bytes |
 | `extract_pages_markdown(path, pages=None)` | Per-page Markdown + layout metadata (all pages by default) |
 | `extract_pages_markdown_bytes(data, pages=None)` | Per-page Markdown from bytes |
+| `extract_structure_elements(path, pages=None)` | Structure-tree elements from tagged PDFs (page, mcid, role) |
+| `extract_structure_elements_bytes(data, pages=None)` | Structure-tree elements from bytes |
 
 ## Types
 
@@ -144,6 +157,12 @@ class TextItem:                      # extract_text_with_positions
     is_underline: bool
     is_strikeout: bool
     item_type: str
+    mcid: int | None                 # marked-content ID for tagged PDFs (None otherwise)
+
+class StructureElement:              # extract_structure_elements
+    page: int                        # 1-indexed (matches TextItem.page)
+    mcid: int
+    role: str                        # "H1".."H6", "P", "Table", ... (resolved via /RoleMap)
 
 class RegionText:                    # extract_text_in_regions
     text: str

docs/rust-api.md

@@ -138,6 +138,34 @@ for page in &result.pages {
 println!("Complex layout? {}", result.is_complex);
 ```
 
+Extract structure-tree elements from tagged PDFs, and join them against
+`extract_text_with_positions` to attach semantic roles (heading levels,
+paragraphs, table cells) to extracted text:
+
+```rust
+use pdf_inspector::{extract_structure_elements, extract_text_with_positions};
+use std::collections::HashMap;
+
+// One entry per marked-content reference, sorted by (page, mcid); empty for
+// untagged PDFs. Pages are 1-indexed to match `TextItem::page`, so the
+// (page, mcid) pair is a direct join key.
+let elements = extract_structure_elements("tagged.pdf", None)?;
+let roles: HashMap<(u32, i64), &str> = elements
+    .iter()
+    .map(|e| ((e.page, e.mcid), e.role.as_str()))
+    .collect();
+
+for item in extract_text_with_positions("tagged.pdf")? {
+    if let Some(mcid) = item.mcid {
+        if let Some(role) = roles.get(&(item.page, mcid)) {
+            if role.starts_with('H') {
+                println!("{}: {}", role, item.text);
+            }
+        }
+    }
+}
+```
+
 ## Processing modes
 
 | Mode | What it does | Returns |
@@ -163,6 +191,8 @@ println!("Complex layout? {}", result.is_complex);
 | `to_markdown_from_items_with_rects(items, options, rects)` | Markdown with rectangle-based table detection |
 | `extract_pages_markdown(path, pages)` | Per-page Markdown + layout metadata (file) |
 | `extract_pages_markdown_mem(bytes, pages)` | Per-page Markdown from bytes |
+| `extract_structure_elements(path, pages)` | Structure-tree elements from tagged PDFs (page, mcid, role) |
+| `extract_structure_elements_mem(bytes, pages)` | Structure-tree elements from bytes |
 
 Low-level detection functions are also available via the `detector` module (`detect_pdf_type`, `detect_pdf_type_with_config`, etc.) for callers who need `PdfTypeResult` instead of `PdfProcessResult`.
 
@@ -178,7 +208,8 @@ Low-level detection functions are also available via the `detector` module (`det
 | `DetectionConfig` | Configuration for detection: scan strategy, thresholds |
 | `ScanStrategy` | `EarlyExit`, `Full`, `Sample(n)`, `Pages(vec)` |
 | `LayoutComplexity` | Layout analysis: is_complex, pages_with_tables, pages_with_columns |
-| `TextItem` | Text with position, font info, and page number |
+| `TextItem` | Text with position, font info, page number, and optional structure-tree `mcid` |
+| `StructureElement` | Tagged-PDF structure reference: page (1-indexed), mcid, role (`"H1"`..`"H6"`, `"P"`, …) |
 | `MarkdownOptions` | Configuration for Markdown formatting (page numbers, etc.) |
 | `PageMarkdown` | Per-page result: page (0-indexed), markdown, needs_ocr |
 | `PagesExtractionResult` | Per-page output + 1-indexed pages_with_tables / pages_with_columns / pages_needing_ocr, is_complex |

napi/Cargo.lock

@@ -851,7 +851,7 @@ checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
 
 [[package]]
 name = "pdf-inspector"
-version = "0.1.7"
+version = "1.14.2"
 dependencies = [
  "env_logger",
  "include_dir",
@@ -867,7 +867,7 @@ dependencies = [
 
 [[package]]
 name = "pdf-inspector-napi"
-version = "0.2.2"
+version = "1.14.2"
 dependencies = [
  "napi",
  "napi-build",

napi/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pdf-inspector-napi"
-version = "0.2.2"
+version = "1.14.2"
 edition = "2021"
 
 [lib]

napi/README.md

@@ -83,6 +83,22 @@ for (const region of result[0].regions) {
 }
 ```
 
+### Async variants
+
+`processPdf`, `classifyPdf`, and `extractPagesMarkdown` are synchronous and parse on the calling thread — in Node, that's the event loop. For a one-off call in a script that's fine, but in a server a large document can hold the loop for tens to hundreds of milliseconds.
+
+`processPdfAsync`, `classifyPdfAsync`, and `extractPagesMarkdownAsync` take the same arguments and produce the same results, but run the parse on the libuv thread pool and return a promise, keeping the event loop free. The input buffer is copied before the call returns, so it's safe to reuse or mutate immediately:
+
+```typescript
+import { classifyPdfAsync, extractPagesMarkdownAsync } from '@firecrawl/pdf-inspector'
+
+const classification = await classifyPdfAsync(pdf)
+if (classification.pdfType === 'TextBased') {
+  const { pages } = await extractPagesMarkdownAsync(pdf)
+  // ...
+}
+```
+
 ## Types
 
 ```typescript

napi/bun.lock

@@ -8,12 +8,12 @@
         "@napi-rs/cli": "^3.4.1",
       },
       "optionalDependencies": {
-        "@firecrawl/pdf-inspector-darwin-arm64": "1.12.0",
-        "@firecrawl/pdf-inspector-linux-arm64-gnu": "1.12.0",
-        "@firecrawl/pdf-inspector-linux-arm64-musl": "1.12.0",
-        "@firecrawl/pdf-inspector-linux-x64-gnu": "1.12.0",
-        "@firecrawl/pdf-inspector-linux-x64-musl": "1.12.0",
-        "@firecrawl/pdf-inspector-win32-x64-msvc": "1.12.0",
+        "@firecrawl/pdf-inspector-darwin-arm64": "1.14.2",
+        "@firecrawl/pdf-inspector-linux-arm64-gnu": "1.14.2",
+        "@firecrawl/pdf-inspector-linux-arm64-musl": "1.14.2",
+        "@firecrawl/pdf-inspector-linux-x64-gnu": "1.14.2",
+        "@firecrawl/pdf-inspector-linux-x64-musl": "1.14.2",
+        "@firecrawl/pdf-inspector-win32-x64-msvc": "1.14.2",
       },
     },
   },

napi/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@firecrawl/pdf-inspector",
-  "version": "1.12.0",
+  "version": "1.14.2",
   "description": "Fast PDF classification and text extraction. Detect text-based vs scanned PDFs, extract text by region with quality checks. Native Rust performance via napi-rs.",
   "main": "index.js",
   "types": "index.d.ts",
@@ -52,11 +52,11 @@
     "@napi-rs/cli": "^3.4.1"
   },
   "optionalDependencies": {
-    "@firecrawl/pdf-inspector-linux-x64-gnu": "1.12.0",
-    "@firecrawl/pdf-inspector-linux-x64-musl": "1.12.0",
-    "@firecrawl/pdf-inspector-linux-arm64-gnu": "1.12.0",
-    "@firecrawl/pdf-inspector-linux-arm64-musl": "1.12.0",
-    "@firecrawl/pdf-inspector-darwin-arm64": "1.12.0",
-    "@firecrawl/pdf-inspector-win32-x64-msvc": "1.12.0"
+    "@firecrawl/pdf-inspector-linux-x64-gnu": "1.14.2",
+    "@firecrawl/pdf-inspector-linux-x64-musl": "1.14.2",
+    "@firecrawl/pdf-inspector-linux-arm64-gnu": "1.14.2",
+    "@firecrawl/pdf-inspector-linux-arm64-musl": "1.14.2",
+    "@firecrawl/pdf-inspector-darwin-arm64": "1.14.2",
+    "@firecrawl/pdf-inspector-win32-x64-msvc": "1.14.2"
   }
 }

napi/src/lib.rs

@@ -89,6 +89,11 @@ pub struct TextItem {
     pub item_type: ItemType,
     /// URL for link items, `None` for other types.
     pub link_url: Option<String>,
+    /// Marked Content ID from the content stream's BDC/BMC operator, `None`
+    /// when the text is not part of marked content. Join with the
+    /// `page`/`mcid` pairs from [`extractStructureElements`] to attach
+    /// structure-tree roles (headings, paragraphs, …) in tagged PDFs.
+    pub mcid: Option<i64>,
 }
 
 /// A page's regions for text extraction: (page_index_0based, bboxes).
@@ -153,9 +158,7 @@ fn to_napi_result(r: pdf_inspector::PdfProcessResult) -> PdfResult {
     }
 }
 
-fn to_napi_page_ocr_reasons(
-    reasons: Vec<pdf_inspector::PageOcrReasons>,
-) -> Vec<PageOcrReasons> {
+fn to_napi_page_ocr_reasons(reasons: Vec<pdf_inspector::PageOcrReasons>) -> Vec<PageOcrReasons> {
     reasons
         .into_iter()
         .map(|reason| PageOcrReasons {
@@ -202,6 +205,31 @@ where
     }
 }
 
+// ---------------------------------------------------------------------------
+// Shared implementations (single body behind sync and async entry points)
+// ---------------------------------------------------------------------------
+
+fn process_pdf_impl(bytes: &[u8], pages: Option<Vec<u32>>) -> Result<PdfResult> {
+    let mut opts = pdf_inspector::PdfOptions::new();
+    if let Some(p) = pages {
+        opts = opts.pages(p);
+    }
+    let result = pdf_inspector::process_pdf_mem_with_options(bytes, opts)
+        .map_err(|e| to_napi_err(e, "process_pdf"))?;
+    Ok(to_napi_result(result))
+}
+
+fn classify_pdf_impl(bytes: &[u8]) -> Result<PdfClassification> {
+    let result =
+        pdf_inspector::classify_pdf_mem(bytes).map_err(|e| to_napi_err(e, "classify_pdf"))?;
+    Ok(PdfClassification {
+        pdf_type: convert_pdf_type(result.pdf_type),
+        page_count: result.page_count,
+        pages_needing_ocr: result.pages_needing_ocr,
+        confidence: result.confidence as f64,
+    })
+}
+
 // ---------------------------------------------------------------------------
 // Public NAPI API
 // ---------------------------------------------------------------------------
@@ -210,15 +238,7 @@ where
 #[napi]
 pub fn process_pdf(buffer: Buffer, pages: Option<Vec<u32>>) -> Result<PdfResult> {
     let bytes: Vec<u8> = buffer.to_vec();
-    catch_panic("process_pdf", move || {
-        let mut opts = pdf_inspector::PdfOptions::new();
-        if let Some(p) = pages {
-            opts = opts.pages(p);
-        }
-        let result = pdf_inspector::process_pdf_mem_with_options(&bytes, opts)
-            .map_err(|e| to_napi_err(e, "process_pdf"))?;
-        Ok(to_napi_result(result))
-    })
+    catch_panic("process_pdf", move || process_pdf_impl(&bytes, pages))
 }
 
 /// Fast detection only — no text extraction or markdown.
@@ -238,16 +258,7 @@ pub fn detect_pdf(buffer: Buffer) -> Result<PdfResult> {
 #[napi]
 pub fn classify_pdf(buffer: Buffer) -> Result<PdfClassification> {
     let bytes: Vec<u8> = buffer.to_vec();
-    catch_panic("classify_pdf", move || {
-        let result =
-            pdf_inspector::classify_pdf_mem(&bytes).map_err(|e| to_napi_err(e, "classify_pdf"))?;
-        Ok(PdfClassification {
-            pdf_type: convert_pdf_type(result.pdf_type),
-            page_count: result.page_count,
-            pages_needing_ocr: result.pages_needing_ocr,
-            confidence: result.confidence as f64,
-        })
-    })
+    catch_panic("classify_pdf", move || classify_pdf_impl(&bytes))
 }
 
 /// Extract plain text from a PDF Buffer.
@@ -300,12 +311,61 @@ pub fn extract_text_with_positions(
                     is_strikeout: item.is_strikeout,
                     item_type,
                     link_url,
+                    mcid: item.mcid,
                 }
             })
             .collect())
     })
 }
 
+/// One structure-tree element reference from a tagged PDF.
+#[napi(object)]
+pub struct StructureElementJs {
+    /// 1-indexed page number (matches `TextItem.page`).
+    pub page: u32,
+    /// Marked Content ID from the page's content stream (matches
+    /// `TextItem.mcid`).
+    pub mcid: i64,
+    /// Standard structure type name ("H1".."H6", "P", "Table", "TD", …).
+    /// Custom tags are resolved through the document's role map; tags with
+    /// no standard mapping are returned verbatim.
+    pub role: String,
+}
+
+/// Extract structure-tree element references from a tagged PDF.
+///
+/// Parses the document's structure tree (when present) and returns one
+/// entry per marked-content reference, resolved to its 1-indexed page,
+/// MCID, and structure type name. Returns an empty array when the PDF is
+/// not tagged.
+///
+/// Join `(page, mcid)` against the `page`/`mcid` fields from
+/// [`extractTextWithPositions`] to attach heading levels (H1..H6) and other
+/// semantic roles to extracted text.
+///
+/// Pass 1-indexed page numbers (matching `TextItem.page`) to restrict
+/// output; omit `pages` for the whole document. Entries are sorted by
+/// `(page, mcid)`.
+#[napi]
+pub fn extract_structure_elements(
+    buffer: Buffer,
+    pages: Option<Vec<u32>>,
+) -> Result<Vec<StructureElementJs>> {
+    let bytes: Vec<u8> = buffer.to_vec();
+    catch_panic("extract_structure_elements", move || {
+        let elements = pdf_inspector::extract_structure_elements_mem(&bytes, pages.as_deref())
+            .map_err(|e| to_napi_err(e, "extract_structure_elements"))?;
+        Ok(elements
+            .into_iter()
+            .map(|e| StructureElementJs {
+                page: e.page,
+                mcid: e.mcid,
+                role: e.role,
+            })
+            .collect())
+    })
+}
+
 /// Extract text within bounding-box regions from a PDF.
 ///
 /// For hybrid OCR: layout model detects regions in rendered images,
@@ -633,25 +693,32 @@ pub fn extract_pages_markdown(
 ) -> Result<PagesExtractionResult> {
     let bytes: Vec<u8> = buffer.to_vec();
     catch_panic("extract_pages_markdown", move || {
-        let result = pdf_inspector::extract_pages_markdown_mem(&bytes, pages.as_deref())
-            .map_err(|e| to_napi_err(e, "extract_pages_markdown"))?;
-        Ok(PagesExtractionResult {
-            pages: result
-                .pages
-                .into_iter()
-                .map(|r| PageMarkdownResult {
-                    page: r.page,
-                    markdown: r.markdown,
-                    needs_ocr: r.needs_ocr,
-                    ocr_reason: r.ocr_reason,
-                })
-                .collect(),
-            pages_with_tables: result.pages_with_tables,
-            pages_with_columns: result.pages_with_columns,
-            pages_needing_ocr: result.pages_needing_ocr,
-            ocr_reasons_by_page: to_napi_page_ocr_reasons(result.ocr_reasons_by_page),
-            is_complex: result.is_complex,
-        })
+        extract_pages_markdown_impl(&bytes, pages.as_deref())
+    })
+}
+
+fn extract_pages_markdown_impl(
+    bytes: &[u8],
+    pages: Option<&[u32]>,
+) -> Result<PagesExtractionResult> {
+    let result = pdf_inspector::extract_pages_markdown_mem(bytes, pages)
+        .map_err(|e| to_napi_err(e, "extract_pages_markdown"))?;
+    Ok(PagesExtractionResult {
+        pages: result
+            .pages
+            .into_iter()
+            .map(|r| PageMarkdownResult {
+                page: r.page,
+                markdown: r.markdown,
+                needs_ocr: r.needs_ocr,
+                ocr_reason: r.ocr_reason,
+            })
+            .collect(),
+        pages_with_tables: result.pages_with_tables,
+        pages_with_columns: result.pages_with_columns,
+        pages_needing_ocr: result.pages_needing_ocr,
+        ocr_reasons_by_page: to_napi_page_ocr_reasons(result.ocr_reasons_by_page),
+        is_complex: result.is_complex,
     })
 }
 
@@ -692,3 +759,131 @@ fn to_page_region_texts(results: Vec<pdf_inspector::PageRegionResult>) -> Vec<Pa
         })
         .collect()
 }
+
+// ---------------------------------------------------------------------------
+// Async variants (libuv thread pool via AsyncTask)
+//
+// The synchronous exports above parse on the calling thread, which in Node is
+// the event loop. These `*Async` variants run the same shared implementations
+// on the libuv thread pool and hand JavaScript a promise, so servers under
+// concurrent load keep answering requests while a document parses. The sync
+// exports keep their names, signatures, and behaviour.
+//
+// Each factory copies the input Buffer to an owned `Vec<u8>` on the calling
+// (JS) thread — deliberately. JS execution is single-threaded, so no JS code
+// can mutate the buffer while the synchronous part of the call copies it.
+// Holding the napi `Buffer` and reading it from the worker instead would be
+// zero-copy, but a caller mutating the buffer before the promise settles
+// would then race the worker's reads — undefined behavior, not a recoverable
+// error (a known napi-rs soundness hazard with cross-thread Buffer access).
+// The copy is a one-time memcpy, negligible next to the parse it unblocks.
+// ---------------------------------------------------------------------------
+
+pub struct ProcessPdfTask {
+    bytes: Vec<u8>,
+    pages: Option<Vec<u32>>,
+}
+
+impl Task for ProcessPdfTask {
+    type Output = PdfResult;
+    type JsValue = PdfResult;
+
+    fn compute(&mut self) -> Result<Self::Output> {
+        let bytes = std::mem::take(&mut self.bytes);
+        let pages = self.pages.take();
+        // AssertUnwindSafe: `bytes`/`pages` are moved into the closure and
+        // dropped on unwind — no shared state can be observed broken.
+        catch_panic(
+            "process_pdf",
+            panic::AssertUnwindSafe(move || process_pdf_impl(&bytes, pages)),
+        )
+    }
+
+    fn resolve(&mut self, _env: Env, output: Self::Output) -> Result<Self::JsValue> {
+        Ok(output)
+    }
+}
+
+/// Async variant of [`processPdf`]: same result, but the parse runs on the
+/// libuv thread pool instead of the event loop and the call returns a
+/// promise. The buffer is copied before the call returns, so it may be
+/// reused or mutated immediately.
+// ts_return_type is required: napi-rs emits `Promise<unknown>` for
+// `AsyncTask<T>` returns without it.
+#[napi(ts_return_type = "Promise<PdfResult>")]
+pub fn process_pdf_async(buffer: Buffer, pages: Option<Vec<u32>>) -> AsyncTask<ProcessPdfTask> {
+    AsyncTask::new(ProcessPdfTask {
+        bytes: buffer.to_vec(),
+        pages,
+    })
+}
+
+pub struct ClassifyPdfTask {
+    bytes: Vec<u8>,
+}
+
+impl Task for ClassifyPdfTask {
+    type Output = PdfClassification;
+    type JsValue = PdfClassification;
+
+    fn compute(&mut self) -> Result<Self::Output> {
+        let bytes = std::mem::take(&mut self.bytes);
+        catch_panic(
+            "classify_pdf",
+            panic::AssertUnwindSafe(move || classify_pdf_impl(&bytes)),
+        )
+    }
+
+    fn resolve(&mut self, _env: Env, output: Self::Output) -> Result<Self::JsValue> {
+        Ok(output)
+    }
+}
+
+/// Async variant of [`classifyPdf`]: same result, but the classification runs
+/// on the libuv thread pool instead of the event loop and the call returns a
+/// promise. The buffer is copied before the call returns, so it may be
+/// reused or mutated immediately.
+#[napi(ts_return_type = "Promise<PdfClassification>")]
+pub fn classify_pdf_async(buffer: Buffer) -> AsyncTask<ClassifyPdfTask> {
+    AsyncTask::new(ClassifyPdfTask {
+        bytes: buffer.to_vec(),
+    })
+}
+
+pub struct ExtractPagesMarkdownTask {
+    bytes: Vec<u8>,
+    pages: Option<Vec<u32>>,
+}
+
+impl Task for ExtractPagesMarkdownTask {
+    type Output = PagesExtractionResult;
+    type JsValue = PagesExtractionResult;
+
+    fn compute(&mut self) -> Result<Self::Output> {
+        let bytes = std::mem::take(&mut self.bytes);
+        let pages = self.pages.take();
+        catch_panic(
+            "extract_pages_markdown",
+            panic::AssertUnwindSafe(move || extract_pages_markdown_impl(&bytes, pages.as_deref())),
+        )
+    }
+
+    fn resolve(&mut self, _env: Env, output: Self::Output) -> Result<Self::JsValue> {
+        Ok(output)
+    }
+}
+
+/// Async variant of [`extractPagesMarkdown`]: same result, but the extraction
+/// runs on the libuv thread pool instead of the event loop and the call
+/// returns a promise. The buffer is copied before the call returns, so it
+/// may be reused or mutated immediately.
+#[napi(ts_return_type = "Promise<PagesExtractionResult>")]
+pub fn extract_pages_markdown_async(
+    buffer: Buffer,
+    pages: Option<Vec<u32>>,
+) -> AsyncTask<ExtractPagesMarkdownTask> {
+    AsyncTask::new(ExtractPagesMarkdownTask {
+        bytes: buffer.to_vec(),
+        pages,
+    })
+}

napi/test.mjs

@@ -2,16 +2,21 @@ import { readFileSync } from 'fs';
 import { strict as assert } from 'assert';
 import {
   processPdf,
+  processPdfAsync,
   detectPdf,
   classifyPdf,
+  classifyPdfAsync,
   extractText,
   extractTextWithPositions,
+  extractStructureElements,
   extractTextInRegions,
   detectVectorGridInRegion,
   extractPagesMarkdown,
+  extractPagesMarkdownAsync,
 } from './index.js';
 
 const fixture = readFileSync('../tests/fixtures/thermo-freon12.pdf');
+const taggedFixture = readFileSync('../tests/fixtures/firecrawl_docs_tagged.pdf');
 
 // --- processPdf ---
 console.log('Testing processPdf...');
@@ -79,6 +84,46 @@ assert.ok(page1Items.length > 0);
 assert.ok(page1Items.every(i => i.page === 1));
 console.log('  extractTextWithPositions with pages: OK');
 
+// mcid: undefined on untagged PDFs, numeric on tagged marked content
+assert.ok(items.every(i => i.mcid === undefined || typeof i.mcid === 'number'));
+const taggedItems = extractTextWithPositions(taggedFixture);
+assert.ok(
+  taggedItems.some(i => typeof i.mcid === 'number'),
+  'tagged PDF text items should carry Marked Content IDs',
+);
+console.log('  extractTextWithPositions mcid: OK');
+
+// --- extractStructureElements ---
+console.log('Testing extractStructureElements...');
+const structureElements = extractStructureElements(taggedFixture);
+assert.ok(structureElements.length > 0);
+assert.ok(structureElements.every(e => typeof e.page === 'number'));
+assert.ok(structureElements.every(e => typeof e.mcid === 'number'));
+assert.ok(structureElements.every(e => typeof e.role === 'string' && e.role.length > 0));
+assert.ok(
+  structureElements.some(e => e.role === 'H1'),
+  'tagged fixture should surface H1 heading roles',
+);
+
+// (page, mcid) joins against extractTextWithPositions to recover heading text
+const h1Refs = new Set(
+  structureElements.filter(e => e.role === 'H1').map(e => `${e.page}:${e.mcid}`),
+);
+const h1Text = taggedItems
+  .filter(i => typeof i.mcid === 'number' && h1Refs.has(`${i.page}:${i.mcid}`))
+  .map(i => i.text)
+  .join('');
+assert.ok(h1Text.trim().length > 0, 'H1 join should recover heading text');
+
+// pages filter is 1-indexed, matching TextItem.page
+const page1Elements = extractStructureElements(taggedFixture, [1]);
+assert.ok(page1Elements.length > 0);
+assert.ok(page1Elements.every(e => e.page === 1));
+
+// untagged PDFs yield an empty array
+assert.deepEqual(extractStructureElements(fixture), []);
+console.log('  extractStructureElements: OK');
+
 // --- extractTextInRegions ---
 console.log('Testing extractTextInRegions...');
 const regionResults = extractTextInRegions(fixture, [
@@ -124,10 +169,75 @@ assert.equal(picked.pages[0].page, 2);
 assert.equal(picked.pages[1].page, 0);
 console.log('  extractPagesMarkdown with pages: OK');
 
+// --- Async variants ---
+console.log('Testing async variants...');
+
+// processPdfAsync returns a promise and matches the sync result
+const asyncResultPromise = processPdfAsync(fixture);
+assert.ok(asyncResultPromise instanceof Promise);
+const asyncResult = await asyncResultPromise;
+assert.equal(asyncResult.pdfType, result.pdfType);
+assert.equal(asyncResult.pageCount, result.pageCount);
+assert.equal(asyncResult.markdown, result.markdown);
+console.log('  processPdfAsync: OK');
+
+// processPdfAsync with pages
+const asyncResult2 = await processPdfAsync(fixture, [1]);
+assert.equal(asyncResult2.markdown, result2.markdown);
+console.log('  processPdfAsync with pages: OK');
+
+// classifyPdfAsync matches the sync result
+const asyncClassified = await classifyPdfAsync(fixture);
+assert.equal(asyncClassified.pdfType, classified.pdfType);
+assert.equal(asyncClassified.pageCount, classified.pageCount);
+assert.equal(asyncClassified.confidence, classified.confidence);
+assert.deepEqual(asyncClassified.pagesNeedingOcr, classified.pagesNeedingOcr);
+console.log('  classifyPdfAsync: OK');
+
+// extractPagesMarkdownAsync matches the sync result
+const asyncAllPages = await extractPagesMarkdownAsync(fixture);
+assert.equal(asyncAllPages.pages.length, allPages.pages.length);
+assert.deepEqual(
+  asyncAllPages.pages.map(p => p.markdown),
+  allPages.pages.map(p => p.markdown),
+);
+assert.equal(asyncAllPages.isComplex, allPages.isComplex);
+console.log('  extractPagesMarkdownAsync: OK');
+
+// selected pages preserve caller order
+const asyncPicked = await extractPagesMarkdownAsync(fixture, [2, 0]);
+assert.equal(asyncPicked.pages.length, 2);
+assert.equal(asyncPicked.pages[0].page, 2);
+assert.equal(asyncPicked.pages[1].page, 0);
+console.log('  extractPagesMarkdownAsync with pages: OK');
+
+// input buffer is copied at call time: mutating it immediately after the
+// call must not affect the in-flight parse
+const scratch = Buffer.from(fixture);
+const inFlight = processPdfAsync(scratch);
+scratch.fill(0);
+const fromMutated = await inFlight;
+assert.equal(fromMutated.markdown, result.markdown);
+console.log('  processPdfAsync input copied at call time: OK');
+
+// concurrent async calls all settle
+const [c1, c2, c3] = await Promise.all([
+  processPdfAsync(fixture),
+  classifyPdfAsync(fixture),
+  extractPagesMarkdownAsync(fixture),
+]);
+assert.equal(c1.pdfType, 'TextBased');
+assert.equal(c2.pdfType, 'TextBased');
+assert.equal(c3.pages.length, 3);
+console.log('  concurrent async calls: OK');
+
 // --- Error handling ---
 console.log('Testing error handling...');
 assert.throws(() => processPdf(Buffer.from('not a pdf')), /process_pdf/);
 assert.throws(() => classifyPdf(Buffer.from('')), /classify_pdf/);
+await assert.rejects(processPdfAsync(Buffer.from('not a pdf')), /process_pdf/);
+await assert.rejects(classifyPdfAsync(Buffer.from('')), /classify_pdf/);
+await assert.rejects(extractPagesMarkdownAsync(Buffer.from('')), /extract_pages_markdown/);
 console.log('  error handling: OK');
 
 console.log('\nAll NAPI tests passed!');

pdf_inspector.pyi

@@ -51,6 +51,20 @@ class TextItem:
     is_underline: bool
     is_strikeout: bool
     item_type: str
+    mcid: Optional[int]
+    """Marked Content ID from the content stream's BDC/BMC operator, None when
+    the text is not part of marked content. Join with the (page, mcid) pairs
+    from extract_structure_elements to attach structure-tree roles in tagged
+    PDFs."""
+
+class StructureElement:
+    """One structure-tree element reference from a tagged PDF."""
+    page: int
+    """1-indexed page number (matches TextItem.page)."""
+    mcid: int
+    """Marked Content ID from the page's content stream (matches TextItem.mcid)."""
+    role: str
+    """Standard structure type name ("H1".."H6", "P", "Table", "TD", ...)."""
 
 class RegionText:
     """Extracted text for a single region."""
@@ -132,6 +146,27 @@ def extract_text_with_positions_bytes(data: bytes, pages: Optional[list[int]] =
     """Extract text with position information from bytes."""
     ...
 
+def extract_structure_elements(path: str, pages: Optional[list[int]] = None) -> list[StructureElement]:
+    """Extract structure-tree element references from a tagged PDF file.
+
+    Returns one entry per marked-content reference, resolved to its 1-indexed
+    page, MCID, and structure type name ("H1".."H6", "P", "Table", ...), sorted
+    by (page, mcid). Returns an empty list when the PDF is not tagged.
+
+    Args:
+        path: Path to the PDF file.
+        pages: Optional list of 1-indexed pages (matching ``TextItem.page``).
+            When ``None`` (default), the whole document is returned.
+    """
+    ...
+
+def extract_structure_elements_bytes(data: bytes, pages: Optional[list[int]] = None) -> list[StructureElement]:
+    """Extract structure-tree element references from tagged PDF bytes.
+
+    See :func:`extract_structure_elements` for details.
+    """
+    ...
+
 def extract_text_in_regions(
     path: str,
     page_regions: list[tuple[int, list[list[float]]]],

pyproject.toml

@@ -4,9 +4,9 @@ build-backend = "maturin"
 
 [project]
 name = "pdf-inspector"
-# Bump this to publish to PyPI — CI publishes automatically when the version
-# changes on main (same flow as napi/package.json for npm).
-version = "0.2.6"
+# Keep package versions in sync with `python3 scripts/version.py <version>`.
+# CI publishes automatically when the synchronized change lands on main.
+version = "1.14.2"
 description = "Fast PDF inspection, classification, and text extraction with smart scanned vs text-based detection"
 readme = "docs/python.md"
 license = { text = "MIT" }

scripts/tests/test_version.py

@@ -0,0 +1,111 @@
+import json
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+
+from version import PLATFORM_PACKAGES, check_versions, set_versions
+
+
+class VersionTests(unittest.TestCase):
+    def setUp(self):
+        self.temporary = tempfile.TemporaryDirectory()
+        self.root = Path(self.temporary.name)
+        (self.root / "napi").mkdir()
+        (self.root / "site").mkdir()
+        (self.root / "wasm").mkdir()
+
+        self._write_manifest("Cargo.toml", "package", "0.1.0")
+        self._write_manifest("pyproject.toml", "project", "0.1.0")
+        self._write_manifest("napi/Cargo.toml", "package", "0.1.0")
+        self._write_manifest("wasm/Cargo.toml", "package", "0.1.0")
+
+        package = {
+            "name": "@firecrawl/pdf-inspector",
+            "version": "0.1.0",
+            "optionalDependencies": {
+                dependency: "0.1.0" for dependency in PLATFORM_PACKAGES
+            },
+        }
+        (self.root / "napi/package.json").write_text(
+            json.dumps(package), encoding="utf-8"
+        )
+        (self.root / "napi/bun.lock").write_text(
+            "\n".join(
+                f'        "{dependency}": "0.1.0",'
+                for dependency in PLATFORM_PACKAGES
+            )
+            + "\n",
+            encoding="utf-8",
+        )
+        (self.root / "site/index.html").write_text(
+            'https://cdn.jsdelivr.net/npm/@firecrawl/pdf-inspector-wasm@0.1.0/'
+            'pdf_inspector_wasm.js\n',
+            encoding="utf-8",
+        )
+        self._write_lock(
+            "napi/Cargo.lock", ("pdf-inspector", "pdf-inspector-napi")
+        )
+        self._write_lock(
+            "wasm/Cargo.lock", ("pdf-inspector", "pdf-inspector-wasm")
+        )
+
+    def tearDown(self):
+        self.temporary.cleanup()
+
+    def _write_manifest(self, relative, section, version):
+        (self.root / relative).write_text(
+            f'[{section}]\nname = "fixture"\nversion = "{version}"\n',
+            encoding="utf-8",
+        )
+
+    def _write_lock(self, relative, packages):
+        content = "\n".join(
+            f'[[package]]\nname = "{package}"\nversion = "0.1.0"\n'
+            for package in packages
+        )
+        (self.root / relative).write_text(content, encoding="utf-8")
+
+    def test_updates_every_version_location(self):
+        set_versions("1.14.0", self.root)
+
+        self.assertEqual(check_versions(self.root), "1.14.0")
+
+    def test_reports_a_divergent_package(self):
+        self._write_manifest("wasm/Cargo.toml", "package", "0.2.0")
+
+        with self.assertRaisesRegex(ValueError, "WASM package: 0.2.0"):
+            check_versions(self.root)
+
+    def test_rejects_an_invalid_version(self):
+        with self.assertRaisesRegex(ValueError, "Invalid semantic version"):
+            set_versions("next", self.root)
+
+    def test_rejects_numeric_prerelease_with_leading_zero(self):
+        before = (self.root / "Cargo.toml").read_text(encoding="utf-8")
+
+        with self.assertRaisesRegex(ValueError, "Invalid semantic version"):
+            set_versions("1.2.3-01", self.root)
+
+        self.assertEqual(
+            (self.root / "Cargo.toml").read_text(encoding="utf-8"), before
+        )
+
+    def test_preflight_failure_does_not_partially_update(self):
+        before = (self.root / "Cargo.toml").read_text(encoding="utf-8")
+        (self.root / "site/index.html").write_text(
+            "missing module URL\n", encoding="utf-8"
+        )
+
+        with self.assertRaisesRegex(ValueError, "Missing pinned WASM package URL"):
+            set_versions("1.14.0", self.root)
+
+        self.assertEqual(
+            (self.root / "Cargo.toml").read_text(encoding="utf-8"), before
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()

scripts/version.py

@@ -0,0 +1,262 @@
+#!/usr/bin/env python3
+"""Keep every pdf-inspector package on one release version."""
+
+from __future__ import annotations
+
+import argparse
+import json
+import re
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+PRERELEASE_IDENTIFIER = (
+    r"(?:0|[1-9]\d*|[0-9A-Za-z-]*[A-Za-z-][0-9A-Za-z-]*)"
+)
+SEMVER = re.compile(
+    r"^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)"
+    rf"(?:-{PRERELEASE_IDENTIFIER}(?:\.{PRERELEASE_IDENTIFIER})*)?"
+    r"(?:\+[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*)?$"
+)
+VERSION_LINE = re.compile(r'^(\s*version\s*=\s*")[^"]+(".*)$')
+SECTION_LINE = re.compile(r"^\s*\[([^]]+)]\s*$")
+PLATFORM_PACKAGES = (
+    "@firecrawl/pdf-inspector-linux-x64-gnu",
+    "@firecrawl/pdf-inspector-linux-x64-musl",
+    "@firecrawl/pdf-inspector-linux-arm64-gnu",
+    "@firecrawl/pdf-inspector-linux-arm64-musl",
+    "@firecrawl/pdf-inspector-darwin-arm64",
+    "@firecrawl/pdf-inspector-win32-x64-msvc",
+)
+TOML_VERSIONS = (
+    ("Rust crate", Path("Cargo.toml"), "package"),
+    ("Python package", Path("pyproject.toml"), "project"),
+    ("NAPI crate", Path("napi/Cargo.toml"), "package"),
+    ("WASM package", Path("wasm/Cargo.toml"), "package"),
+)
+LOCK_VERSIONS = (
+    ("NAPI lock: core", Path("napi/Cargo.lock"), "pdf-inspector"),
+    ("NAPI lock: binding", Path("napi/Cargo.lock"), "pdf-inspector-napi"),
+    ("WASM lock: core", Path("wasm/Cargo.lock"), "pdf-inspector"),
+    ("WASM lock: binding", Path("wasm/Cargo.lock"), "pdf-inspector-wasm"),
+)
+SITE_WASM_VERSION = re.compile(
+    r"(@firecrawl/pdf-inspector-wasm@)([^/\"]+)(/pdf_inspector_wasm\.js)"
+)
+
+
+def _read_section_version(path: Path, section: str) -> str:
+    active = False
+    for line in path.read_text(encoding="utf-8").splitlines():
+        section_match = SECTION_LINE.match(line)
+        if section_match:
+            active = section_match.group(1) == section
+        elif active:
+            version_match = VERSION_LINE.match(line)
+            if version_match:
+                return line.split('"', 2)[1]
+    raise ValueError(f"No version found in [{section}] of {path}")
+
+
+def _write_section_version(path: Path, section: str, version: str) -> None:
+    lines = path.read_text(encoding="utf-8").splitlines(keepends=True)
+    active = False
+    for index, line in enumerate(lines):
+        section_match = SECTION_LINE.match(line)
+        if section_match:
+            active = section_match.group(1) == section
+        elif active:
+            version_match = VERSION_LINE.match(line)
+            if version_match:
+                newline = "\n" if line.endswith("\n") else ""
+                replacement = (
+                    f"{version_match.group(1)}{version}"
+                    f"{version_match.group(2).rstrip()}"
+                )
+                lines[index] = (
+                    f"{replacement}{newline}"
+                )
+                path.write_text("".join(lines), encoding="utf-8")
+                return
+    raise ValueError(f"No version found in [{section}] of {path}")
+
+
+def _package_block(lines: list[str], package: str) -> tuple[int, int]:
+    for start, line in enumerate(lines):
+        if line.strip() != "[[package]]":
+            continue
+        end = next(
+            (
+                index
+                for index in range(start + 1, len(lines))
+                if lines[index].strip() == "[[package]]"
+            ),
+            len(lines),
+        )
+        if any(line.strip() == f'name = "{package}"' for line in lines[start:end]):
+            return start, end
+    raise ValueError(f"No lockfile entry found for {package}")
+
+
+def _read_lock_version(path: Path, package: str) -> str:
+    lines = path.read_text(encoding="utf-8").splitlines()
+    start, end = _package_block(lines, package)
+    for line in lines[start:end]:
+        version_match = VERSION_LINE.match(line)
+        if version_match:
+            return line.split('"', 2)[1]
+    raise ValueError(f"No version found for {package} in {path}")
+
+
+def _write_lock_version(path: Path, package: str, version: str) -> None:
+    lines = path.read_text(encoding="utf-8").splitlines(keepends=True)
+    start, end = _package_block(lines, package)
+    for index in range(start, end):
+        version_match = VERSION_LINE.match(lines[index])
+        if version_match:
+            newline = "\n" if lines[index].endswith("\n") else ""
+            lines[index] = (
+                f'{version_match.group(1)}{version}{version_match.group(2).rstrip()}'
+                f"{newline}"
+            )
+            path.write_text("".join(lines), encoding="utf-8")
+            return
+    raise ValueError(f"No version found for {package} in {path}")
+
+
+def _node_versions(root: Path) -> dict[str, str]:
+    package = json.loads((root / "napi/package.json").read_text(encoding="utf-8"))
+    versions = {"Node package": package["version"]}
+    optional = package.get("optionalDependencies", {})
+    for dependency in PLATFORM_PACKAGES:
+        if dependency not in optional:
+            raise ValueError(f"Missing Node optional dependency: {dependency}")
+        versions[f"Node optional dependency: {dependency}"] = optional[dependency]
+    return versions
+
+
+def _bun_versions(root: Path) -> dict[str, str]:
+    text = (root / "napi/bun.lock").read_text(encoding="utf-8")
+    versions = {}
+    for dependency in PLATFORM_PACKAGES:
+        match = re.search(
+            rf'"{re.escape(dependency)}": "([^"]+)"[,]', text
+        )
+        if not match:
+            raise ValueError(f"Missing Bun lock dependency: {dependency}")
+        versions[f"Bun lock: {dependency}"] = match.group(1)
+    return versions
+
+
+def _site_wasm_version(root: Path) -> str:
+    text = (root / "site/index.html").read_text(encoding="utf-8")
+    match = SITE_WASM_VERSION.search(text)
+    if not match:
+        raise ValueError("Missing pinned WASM package URL in site/index.html")
+    return match.group(2)
+
+
+def package_versions(root: Path = ROOT) -> dict[str, str]:
+    versions = {
+        label: _read_section_version(root / relative, section)
+        for label, relative, section in TOML_VERSIONS
+    }
+    versions.update(_node_versions(root))
+    versions.update(_bun_versions(root))
+    versions["Website WASM module"] = _site_wasm_version(root)
+    versions.update(
+        {
+            label: _read_lock_version(root / relative, package)
+            for label, relative, package in LOCK_VERSIONS
+        }
+    )
+    return versions
+
+
+def check_versions(root: Path = ROOT) -> str:
+    versions = package_versions(root)
+    expected = versions["Rust crate"]
+    if not SEMVER.fullmatch(expected):
+        raise ValueError(f"Rust crate has an invalid semantic version: {expected}")
+    mismatches = {
+        label: version for label, version in versions.items() if version != expected
+    }
+    if mismatches:
+        details = "\n".join(
+            f"  - {label}: {version}" for label, version in mismatches.items()
+        )
+        raise ValueError(f"Expected every package to use {expected}:\n{details}")
+    return expected
+
+
+def set_versions(version: str, root: Path = ROOT) -> None:
+    if not SEMVER.fullmatch(version):
+        raise ValueError(f"Invalid semantic version: {version}")
+
+    # Validate every expected location before writing the first file. This
+    # prevents a stale manifest or generated file from leaving a partial bump.
+    package_versions(root)
+
+    for _, relative, section in TOML_VERSIONS:
+        _write_section_version(root / relative, section, version)
+
+    package_path = root / "napi/package.json"
+    package = json.loads(package_path.read_text(encoding="utf-8"))
+    package["version"] = version
+    optional = package.get("optionalDependencies", {})
+    for dependency in PLATFORM_PACKAGES:
+        if dependency not in optional:
+            raise ValueError(f"Missing Node optional dependency: {dependency}")
+        optional[dependency] = version
+    package_path.write_text(json.dumps(package, indent=2) + "\n", encoding="utf-8")
+
+    bun_path = root / "napi/bun.lock"
+    bun_text = bun_path.read_text(encoding="utf-8")
+    for dependency in PLATFORM_PACKAGES:
+        pattern = rf'("{re.escape(dependency)}": ")[^"]+("[,])'
+        bun_text, count = re.subn(
+            pattern, rf"\g<1>{version}\g<2>", bun_text, count=1
+        )
+        if count != 1:
+            raise ValueError(f"Missing Bun lock dependency: {dependency}")
+    bun_path.write_text(bun_text, encoding="utf-8")
+
+    site_path = root / "site/index.html"
+    site_text = site_path.read_text(encoding="utf-8")
+    site_text, count = SITE_WASM_VERSION.subn(
+        rf"\g<1>{version}\g<3>", site_text, count=1
+    )
+    if count != 1:
+        raise ValueError("Missing pinned WASM package URL in site/index.html")
+    site_path.write_text(site_text, encoding="utf-8")
+
+    for _, relative, package_name in LOCK_VERSIONS:
+        _write_lock_version(root / relative, package_name, version)
+
+    check_versions(root)
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("version", nargs="?", help="new shared semantic version")
+    parser.add_argument(
+        "--check", action="store_true", help="fail if package versions have diverged"
+    )
+    arguments = parser.parse_args()
+    if arguments.check == bool(arguments.version):
+        parser.error("provide either a version or --check")
+
+    try:
+        if arguments.check:
+            version = check_versions()
+            print(f"All packages use {version}")
+        else:
+            set_versions(arguments.version)
+            print(f"Updated all packages to {arguments.version}")
+    except ValueError as error:
+        parser.exit(1, f"{error}\n")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

site/index.html

@@ -975,7 +975,7 @@ result = pdf_inspector.<span class="fn">process_pdf</span>(<span class="str">"do
 <script>
   (() => {
     const MAX_FILE_SIZE = 25 * 1024 * 1024;
-    const WASM_MODULE_URL = "https://cdn.jsdelivr.net/npm/@firecrawl/pdf-inspector-wasm@0.1.1/pdf_inspector_wasm.js";
+    const WASM_MODULE_URL = "https://cdn.jsdelivr.net/npm/@firecrawl/pdf-inspector-wasm@1.14.2/pdf_inspector_wasm.js";
     const input = document.querySelector("#pdf-input");
     const dropZone = document.querySelector("#drop-zone");
     const filePanel = document.querySelector("#demo-file");

src/detector.rs

@@ -1382,7 +1382,13 @@ fn scan_content_for_text_operators(
     let is_word_end =
         |pos: usize| -> bool { pos + 1 >= content.len() || content[pos + 1].is_ascii_whitespace() };
 
-    // Simple state machine to find operators
+    // Simple state machine to find operators.
+    // Each Tj/TJ/Tf lookback stops at the previous text/font operator so a
+    // malformed `] TJ` (no `[`) cannot rescan the entire prefix — that was
+    // quadratic in the number of operators.
+    // `Tj`/`TJ` are only counted when the preceding token closes a string or
+    // array (')', '>', ']'), so `Tj` inside `(Hello Tj World)` cannot pin the floor.
+    let mut operand_floor = 0usize;
     let mut i = 0;
     while i < content.len() {
         let b = content[i];
@@ -1392,14 +1398,15 @@ fn scan_content_for_text_operators(
             let next = content[i + 1];
             if next == b'j' || next == b'J' {
                 // Verify it's an operator (followed by whitespace or newline)
-                if i + 2 >= content.len()
+                if (i + 2 >= content.len()
                     || content[i + 2].is_ascii_whitespace()
                     || content[i + 2] == b'\n'
-                    || content[i + 2] == b'\r'
+                    || content[i + 2] == b'\r')
+                    && preceding_operand_closer(content, i, operand_floor)
                 {
                     text_ops += 1;
-                    // Scan backward for text string operand to collect unique chars
-                    collect_text_chars_before(content, i, unique_chars);
+                    collect_text_chars_before(content, i, unique_chars, operand_floor);
+                    operand_floor = i;
                 }
             } else if next == b'f' {
                 // Tf = set font operator
@@ -1415,12 +1422,10 @@ fn scan_content_for_text_operators(
                     || content[i + 2] == b'<'
                     || content[i + 2] == b'/'
                 {
-                    font_changes += 1;
-                    // Extract the font name operand preceding the size + Tf.
-                    // Pattern: /FontName <size> Tf
-                    // Scan backward past the size number and whitespace to find /Name.
-                    if let Some(name) = extract_font_name_before_tf(content, i) {
+                    if let Some(name) = extract_font_name_before_tf(content, i, operand_floor) {
                         used_font_names.insert(name);
+                        font_changes += 1;
+                        operand_floor = i;
                     }
                 }
             }
@@ -1466,6 +1471,20 @@ fn scan_content_for_text_operators(
     (text_ops, image_count, path_ops, font_changes)
 }
 
+/// True when the token before `op_pos` (skipping whitespace, not crossing
+/// `floor`) is a string/array closer. Used so `Tj` inside `(Hello Tj World)`
+/// is not treated as an operator.
+fn preceding_operand_closer(content: &[u8], op_pos: usize, floor: usize) -> bool {
+    let mut j = op_pos;
+    while j > floor {
+        j -= 1;
+        if !content[j].is_ascii_whitespace() {
+            return matches!(content[j], b')' | b'>' | b']');
+        }
+    }
+    false
+}
+
 /// Extract the font name operand from content stream bytes preceding a Tf operator.
 ///
 /// The Tf operator syntax is: `/FontName size Tf`
@@ -1473,25 +1492,27 @@ fn scan_content_for_text_operators(
 /// whitespace to find the `/Name` token.
 ///
 /// Returns the font name bytes (without the leading `/`), e.g. `b"F1"` for `/F1`.
-fn extract_font_name_before_tf(content: &[u8], tf_pos: usize) -> Option<Vec<u8>> {
+/// `floor` is the start of the previous text/font operator (or 0); lookback
+/// must not cross it.
+fn extract_font_name_before_tf(content: &[u8], tf_pos: usize, floor: usize) -> Option<Vec<u8>> {
     // Scan backward past whitespace before "Tf"
     let mut j = tf_pos;
-    while j > 0 && content[j - 1].is_ascii_whitespace() {
+    while j > floor && content[j - 1].is_ascii_whitespace() {
         j -= 1;
     }
     // Scan backward past the size number (digits, '.', '-')
-    while j > 0
+    while j > floor
         && (content[j - 1].is_ascii_digit() || content[j - 1] == b'.' || content[j - 1] == b'-')
     {
         j -= 1;
     }
     // Scan backward past whitespace between font name and size
-    while j > 0 && content[j - 1].is_ascii_whitespace() {
+    while j > floor && content[j - 1].is_ascii_whitespace() {
         j -= 1;
     }
     // Now j should point just after the font name. Scan backward to find '/'.
     let name_end = j;
-    while j > 0 && content[j - 1] != b'/' {
+    while j > floor && content[j - 1] != b'/' {
         // Font names consist of regular characters (not whitespace, not delimiters)
         if content[j - 1].is_ascii_whitespace() || content[j - 1] == b'(' || content[j - 1] == b')'
         {
@@ -1499,7 +1520,7 @@ fn extract_font_name_before_tf(content: &[u8], tf_pos: usize) -> Option<Vec<u8>>
         }
         j -= 1;
     }
-    if j == 0 || content[j - 1] != b'/' {
+    if j <= floor || content[j - 1] != b'/' {
         return None;
     }
     // j-1 is the '/', font name is content[j..name_end]
@@ -1514,16 +1535,24 @@ fn extract_font_name_before_tf(content: &[u8], tf_pos: usize) -> Option<Vec<u8>>
 /// and collect unique non-whitespace bytes from it.
 ///
 /// Handles both literal strings `(...)` and hex strings `<...>`.
-fn collect_text_chars_before(content: &[u8], op_pos: usize, unique_chars: &mut HashSet<u8>) {
+/// `floor` is the start of the previous text/font operator (or 0); lookback
+/// must not cross it, or a missing `[` before `TJ` rescans the whole prefix.
+fn collect_text_chars_before(
+    content: &[u8],
+    op_pos: usize,
+    unique_chars: &mut HashSet<u8>,
+    floor: usize,
+) {
     // Walk backward past whitespace to find the closing delimiter
     let mut j = op_pos;
-    while j > 0 {
+    while j > floor {
         j -= 1;
         if !content[j].is_ascii_whitespace() {
             break;
         }
     }
-    if j == 0 {
+    // All whitespace, or we landed on the previous operator token.
+    if j == floor {
         return;
     }
 
@@ -1533,7 +1562,7 @@ fn collect_text_chars_before(content: &[u8], op_pos: usize, unique_chars: &mut H
         // Literal string: scan backward for matching '('
         let mut depth = 1i32;
         let mut k = j;
-        while k > 0 && depth > 0 {
+        while k > floor && depth > 0 {
             k -= 1;
             match content[k] {
                 b')' if k == 0 || content[k - 1] != b'\\' => depth += 1,
@@ -1552,7 +1581,7 @@ fn collect_text_chars_before(content: &[u8], op_pos: usize, unique_chars: &mut H
     } else if closing == b'>' {
         // Hex string: scan backward for '<'
         let mut k = j;
-        while k > 0 {
+        while k > floor {
             k -= 1;
             if content[k] == b'<' {
                 break;
@@ -1582,7 +1611,7 @@ fn collect_text_chars_before(content: &[u8], op_pos: usize, unique_chars: &mut H
     } else if closing == b']' {
         // TJ array: scan backward for '[' and collect from all strings inside
         let mut k = j;
-        while k > 0 {
+        while k > floor {
             k -= 1;
             if content[k] == b'[' {
                 break;
@@ -2014,6 +2043,51 @@ mod tests {
         assert_eq!(imgs3, 0);
     }
 
+    #[test]
+    fn test_scan_content_successive_tj_collects_each_operand() {
+        // Lookback is floored at the previous Tj/TJ/Tf so later operators must
+        // still see their own operands.
+        let content = b"[(Hello)] TJ [(World)] TJ (More) Tj";
+        let mut uchars = HashSet::new();
+        let (ops, _, _, _) =
+            scan_content_for_text_operators(content, &mut uchars, &mut HashSet::new());
+        assert_eq!(ops, 3);
+        for &ch in b"HeloWrdM" {
+            assert!(uchars.contains(&ch), "missing char {}", ch as char);
+        }
+    }
+
+    #[test]
+    fn test_scan_content_tj_inside_literal_is_not_an_operator() {
+        // `Tj` followed by space inside a literal must not count as an operator
+        // or pin the lookback floor; the real `Tj` still collects the string.
+        let content = b"BT (Hello Tj World) Tj ET";
+        let mut uchars = HashSet::new();
+        let (ops, _, _, _) =
+            scan_content_for_text_operators(content, &mut uchars, &mut HashSet::new());
+        assert_eq!(ops, 1);
+        for &ch in b"HeloTjWrd" {
+            assert!(uchars.contains(&ch), "missing char {}", ch as char);
+        }
+    }
+
+    #[test]
+    fn test_scan_content_malformed_tj_lookback_stays_linear() {
+        // `] TJ` with no `[` used to walk the entire prefix for every operator
+        // (quadratic). 30k repeats is enough that a prefix rescan would dominate
+        // the test runtime; with the floor it is a single linear pass.
+        let n = 30_000usize;
+        let mut content = Vec::with_capacity(n * 5);
+        for _ in 0..n {
+            content.extend_from_slice(b"] TJ\n");
+        }
+        let mut uchars = HashSet::new();
+        let (ops, _, _, _) =
+            scan_content_for_text_operators(&content, &mut uchars, &mut HashSet::new());
+        assert_eq!(ops, n as u32);
+        assert!(uchars.is_empty());
+    }
+
     #[test]
     fn test_image_dominated_detection() {
         // Do operators are no longer counted as images by scan_content_for_text_operators.
@@ -2772,14 +2846,14 @@ mod tests {
     fn test_extract_font_name_basic() {
         // Standard pattern: /F1 12 Tf
         let content = b"/F1 12 Tf";
-        let name = extract_font_name_before_tf(content, 6); // 'T' is at index 6
+        let name = extract_font_name_before_tf(content, 6, 0); // 'T' is at index 6
         assert_eq!(name, Some(b"F1".to_vec()));
     }
 
     #[test]
     fn test_extract_font_name_long_name() {
         let content = b"/ArialMT-Bold 9.5 Tf";
-        let name = extract_font_name_before_tf(content, 18);
+        let name = extract_font_name_before_tf(content, 18, 0);
         assert_eq!(name, Some(b"ArialMT-Bold".to_vec()));
     }
 

src/extractor/content_decode.rs

@@ -0,0 +1,328 @@
+//! Bounded content-stream decoding.
+//!
+//! `lopdf::content::Content::decode` materializes every operator before any
+//! caller can apply a limit. A compact page of `q Q` pairs can therefore
+//! allocate hundreds of megabytes and abort. Count operators first (without
+//! allocating `Operation` objects) and skip decode when the cap is exceeded.
+
+use crate::PdfError;
+use lopdf::content::Content;
+
+/// Maximum content-stream operators decoded for a page or a single Form
+/// XObject. Matches the previous post-decode skip threshold.
+pub(crate) const MAX_PAGE_OPERATIONS: usize = 1_000_000;
+
+/// Decode `data` unless it contains more than `max_operations` operators.
+///
+/// Returns `Ok(None)` when the stream exceeds the cap, so callers can skip
+/// extraction without first allocating the operation vector.
+pub(crate) fn decode_content_bounded(
+    data: &[u8],
+    max_operations: usize,
+) -> Result<Option<Content>, PdfError> {
+    if content_exceeds_operation_limit(data, max_operations) {
+        return Ok(None);
+    }
+    Content::decode(data)
+        .map(Some)
+        .map_err(|e| PdfError::Parse(e.to_string()))
+}
+
+fn content_exceeds_operation_limit(data: &[u8], max_operations: usize) -> bool {
+    count_content_operators(data, max_operations.saturating_add(1)) > max_operations
+}
+
+/// Count operators using the same token rules as lopdf's content parser,
+/// stopping at `limit`. Does not allocate `Operation` / `Object` values.
+fn count_content_operators(data: &[u8], limit: usize) -> usize {
+    let mut i = 0;
+    let mut count = 0;
+    while i < data.len() && count < limit {
+        skip_content_space(data, &mut i);
+        if i >= data.len() {
+            break;
+        }
+        if data[i] == b'%' {
+            skip_comment(data, &mut i);
+            continue;
+        }
+        match data[i] {
+            b'(' => i = skip_literal_string(data, i),
+            b'<' => {
+                if data.get(i + 1) == Some(&b'<') {
+                    i += 2;
+                } else {
+                    i = skip_hex_string(data, i);
+                }
+            }
+            b'>' => {
+                i += 1;
+                if data.get(i) == Some(&b'>') {
+                    i += 1;
+                }
+            }
+            b'[' | b']' => i += 1,
+            b'/' => skip_name(data, &mut i),
+            b'+' | b'-' | b'.' => skip_number(data, &mut i),
+            b if b.is_ascii_digit() => skip_number(data, &mut i),
+            b if is_operator_byte(b) => {
+                let start = i;
+                i += 1;
+                while i < data.len() && is_operator_byte(data[i]) {
+                    i += 1;
+                }
+                let token = &data[start..i];
+                if token == b"true" || token == b"false" || token == b"null" {
+                    continue;
+                }
+                count += 1;
+                if token == b"BI" && (i >= data.len() || is_content_space(data[i])) {
+                    i = skip_inline_image_after_bi(data, i);
+                }
+            }
+            _ => i += 1,
+        }
+    }
+    count
+}
+
+fn is_content_space(b: u8) -> bool {
+    // PDF whitespace (ISO 32000): NUL, tab, LF, FF, CR, space. Names must
+    // stop on these so a following operator is not absorbed into `/Name`.
+    matches!(b, b'\0' | b'\t' | b'\n' | b'\x0c' | b'\r' | b' ')
+}
+
+fn is_operator_byte(b: u8) -> bool {
+    b.is_ascii_alphabetic() || matches!(b, b'*' | b'\'' | b'"')
+}
+
+fn is_delimiter(b: u8) -> bool {
+    matches!(
+        b,
+        b'(' | b')' | b'<' | b'>' | b'[' | b']' | b'{' | b'}' | b'/' | b'%'
+    )
+}
+
+fn skip_content_space(data: &[u8], i: &mut usize) {
+    while *i < data.len() && is_content_space(data[*i]) {
+        *i += 1;
+    }
+}
+
+fn skip_comment(data: &[u8], i: &mut usize) {
+    while *i < data.len() && data[*i] != b'\n' && data[*i] != b'\r' {
+        *i += 1;
+    }
+}
+
+fn skip_literal_string(data: &[u8], mut i: usize) -> usize {
+    let mut depth = 1i32;
+    i += 1;
+    while i < data.len() && depth > 0 {
+        match data[i] {
+            b'\\' => {
+                i += 1;
+                if i < data.len() {
+                    i += 1;
+                }
+            }
+            b'(' => {
+                depth += 1;
+                i += 1;
+            }
+            b')' => {
+                depth -= 1;
+                i += 1;
+            }
+            _ => i += 1,
+        }
+    }
+    i
+}
+
+fn skip_hex_string(data: &[u8], mut i: usize) -> usize {
+    i += 1;
+    while i < data.len() && data[i] != b'>' {
+        i += 1;
+    }
+    if i < data.len() {
+        i += 1;
+    }
+    i
+}
+
+fn skip_name(data: &[u8], i: &mut usize) {
+    *i += 1;
+    while *i < data.len() && !is_content_space(data[*i]) && !is_delimiter(data[*i]) {
+        *i += 1;
+    }
+}
+
+fn skip_number(data: &[u8], i: &mut usize) {
+    if *i < data.len() && matches!(data[*i], b'+' | b'-') {
+        *i += 1;
+    }
+    while *i < data.len() && data[*i].is_ascii_digit() {
+        *i += 1;
+    }
+    if *i < data.len() && data[*i] == b'.' {
+        *i += 1;
+        while *i < data.len() && data[*i].is_ascii_digit() {
+            *i += 1;
+        }
+    }
+}
+
+/// After a `BI` operator, skip inline-image data through `EI`.
+/// Uses the same PDF whitespace set as `is_content_space`. If `EI` is not
+/// found, leave the cursor in place so later operators are still counted
+/// (undercounting would let decode allocate the full vector).
+fn skip_inline_image_after_bi(data: &[u8], mut i: usize) -> usize {
+    skip_content_space(data, &mut i);
+    let rest = &data[i..];
+    if let Some(pos) = rest.windows(4).position(|w| {
+        is_content_space(w[0]) && w[1] == b'E' && w[2] == b'I' && is_content_space(w[3])
+    }) {
+        return i + pos + 3;
+    }
+    i
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn lopdf_op_count(data: &[u8]) -> usize {
+        Content::decode(data)
+            .map(|c| c.operations.len())
+            .unwrap_or(0)
+    }
+
+    /// DoS safety: never report fewer operators than lopdf would allocate.
+    /// Overcount is acceptable (skip a page); undercount would re-open decode.
+    fn assert_count_does_not_undercount(data: &[u8]) {
+        let ours = count_content_operators(data, usize::MAX);
+        match Content::decode(data) {
+            Ok(content) => assert!(
+                ours >= content.operations.len(),
+                "undercount: ours={ours} lopdf={} for {:?}",
+                content.operations.len(),
+                String::from_utf8_lossy(data)
+            ),
+            Err(_) => {}
+        }
+    }
+
+    #[test]
+    fn operator_count_matches_lopdf_for_typical_streams() {
+        let samples: &[&[u8]] = &[
+            b"q 1 0 0 1 0 0 cm BT /F1 12 Tf 72 720 Td (Hello) Tj ET Q",
+            b"q Q q Q",
+            b"BT /F1 12 Tf 12 TL 1 0 0 1 100 512 Tm (first) Tj (struck) ' ET",
+            b"1 0 0 rg 0 0 10 10 re f",
+            b"true false null q",
+            b"% comment\nq Q\n",
+            b"[ (a) 1 (b) ] TJ",
+            b"1 0 0 1 0 0 cm /Im0 Do",
+        ];
+        for data in samples {
+            assert_eq!(
+                count_content_operators(data, usize::MAX),
+                lopdf_op_count(data),
+                "count mismatch for {}",
+                String::from_utf8_lossy(data)
+            );
+        }
+    }
+
+    #[test]
+    fn strings_and_comments_are_not_operators() {
+        let data = b"(q Q Tj) Tj % q Q\nET";
+        assert_eq!(
+            count_content_operators(data, usize::MAX),
+            lopdf_op_count(data)
+        );
+        assert_eq!(count_content_operators(data, usize::MAX), 2); // Tj, ET
+    }
+
+    #[test]
+    fn inline_image_counts_as_one_operator() {
+        let data = b"BI /W 2 /H 2 /CS /RGB /BPC 8 ID \x00\x01\x02\x03 EI q";
+        assert_eq!(
+            count_content_operators(data, usize::MAX),
+            lopdf_op_count(data)
+        );
+        assert_eq!(count_content_operators(data, usize::MAX), 2); // BI, q
+    }
+
+    #[test]
+    fn inline_image_ei_accepts_pdf_whitespace() {
+        let tab = b"BI /W 1 /H 1 ID \xff\tEI\t q Q";
+        let nul = b"BI /W 1 /H 1 ID \xff\x00EI\x00 q Q";
+        let ff = b"BI /W 1 /H 1 ID \xff\x0cEI\x0c q Q";
+        for data in [tab.as_slice(), nul.as_slice(), ff.as_slice()] {
+            assert_count_does_not_undercount(data);
+            assert!(
+                count_content_operators(data, usize::MAX) >= 3,
+                "BI plus following q Q must remain visible after EI, got {} for {:?}",
+                count_content_operators(data, usize::MAX),
+                String::from_utf8_lossy(data)
+            );
+        }
+    }
+
+    #[test]
+    fn decode_is_skipped_when_operator_cap_is_exceeded() {
+        let mut data = Vec::new();
+        for _ in 0..20 {
+            data.extend_from_slice(b"q Q\n");
+        }
+        assert!(decode_content_bounded(&data, 10).unwrap().is_none());
+        let decoded = decode_content_bounded(&data, 50).unwrap().unwrap();
+        assert_eq!(decoded.operations.len(), 40);
+    }
+
+    #[test]
+    fn name_whitespace_does_not_swallow_following_operator() {
+        // NUL / form-feed end a name (PDF whitespace). Absorbing `q` into
+        // `/x` would undercount and let decode allocate the operator vector.
+        let mut nul_sep = Vec::new();
+        let mut ff_sep = Vec::new();
+        for _ in 0..8_000 {
+            nul_sep.extend_from_slice(b"/x\x00q");
+            ff_sep.extend_from_slice(b"/x\x0cq");
+        }
+        assert_count_does_not_undercount(&nul_sep);
+        assert_count_does_not_undercount(&ff_sep);
+        assert!(count_content_operators(&ff_sep, usize::MAX) >= 8_000);
+    }
+
+    #[test]
+    fn edge_streams_do_not_undercount_vs_lopdf() {
+        let samples: &[&[u8]] = &[
+            b".5 0 0 .5 0 0 cm",
+            b"+1 -2 3.0 rg",
+            b"<0041> Tj",
+            b"(unbalanced",
+            b"BI /W 1 /H 1 ID \xff\xff no EI here q Q q Q",
+            b"q\x00Q\x00q\x00Q",
+            b"/F1\x0c12 Tf (Hi) Tj",
+            b"{ 1 2 add } cvx",
+        ];
+        for data in samples {
+            assert_count_does_not_undercount(data);
+        }
+    }
+
+    #[test]
+    fn million_q_pairs_are_rejected_without_decode() {
+        let mut data = Vec::with_capacity((MAX_PAGE_OPERATIONS + 1) * 2);
+        for _ in 0..=MAX_PAGE_OPERATIONS {
+            data.extend_from_slice(b"q\n");
+        }
+        assert!(content_exceeds_operation_limit(&data, MAX_PAGE_OPERATIONS));
+        assert!(decode_content_bounded(&data, MAX_PAGE_OPERATIONS)
+            .unwrap()
+            .is_none());
+    }
+}

src/extractor/content_stream.rs

@@ -19,7 +19,7 @@ use super::fonts::{
     CMapDecisionCache, FontStyleCache,
 };
 use super::underline::UnderlineLine;
-use super::xobjects::{extract_form_xobject_text, get_page_xobjects, XObjectType};
+use super::xobjects::{extract_form_xobject_text, get_page_xobjects, FormWalkBudget, XObjectType};
 use super::{get_number, image_bbox_from_ctm, multiply_matrices};
 
 /// Strip PDF comments (% to end of line) from content stream bytes.
@@ -137,8 +137,11 @@ fn rise_adjusted(tm: &[f32; 6], rise: f32) -> [f32; 6] {
     ]
 }
 
-/// Returns `(page_extraction, has_gid_fonts)` where `has_gid_fonts` indicates
-/// the page uses fonts with unresolvable gid-encoded glyphs.
+/// Returns `(page_extraction, has_gid_fonts, coords_rotated, skipped_invisible)`
+/// where `has_gid_fonts` indicates the page uses fonts with unresolvable
+/// gid-encoded glyphs and `skipped_invisible` reports that invisible (Tr 3)
+/// text was present but suppressed — callers can use it to decide whether an
+/// `include_invisible` retry could recover anything at all.
 pub(crate) fn extract_page_text_items(
     doc: &Document,
     page_id: ObjectId,
@@ -146,9 +149,8 @@ pub(crate) fn extract_page_text_items(
     font_cmaps: &FontCMaps,
     include_invisible: bool,
     style_cache: &mut FontStyleCache,
-) -> Result<(PageExtraction, bool, bool), PdfError> {
-    use lopdf::content::Content;
-
+    form_budget: &mut FormWalkBudget,
+) -> Result<(PageExtraction, bool, bool, bool), PdfError> {
     let mut items = Vec::new();
     let mut rects: Vec<PdfRect> = Vec::new();
     let mut clip_rects: Vec<PdfRect> = Vec::new();
@@ -252,22 +254,27 @@ pub(crate) fn extract_page_text_items(
     // Content::decode parser, causing it to skip operators like ET and Q.
     let content_data = strip_pdf_comments(&content_data);
 
-    let content = Content::decode(&content_data).map_err(|e| PdfError::Parse(e.to_string()))?;
-
-    const MAX_OPERATIONS: usize = 1_000_000;
-    if content.operations.len() > MAX_OPERATIONS {
-        log::warn!(
-            "page {}: skipping extraction — {} operations exceeds limit ({})",
-            page_num,
-            content.operations.len(),
-            MAX_OPERATIONS
-        );
-        return Ok(((Vec::new(), Vec::new(), Vec::new()), false, false));
-    }
+    let content = match super::content_decode::decode_content_bounded(
+        &content_data,
+        super::content_decode::MAX_PAGE_OPERATIONS,
+    )? {
+        Some(content) => content,
+        None => {
+            log::warn!(
+                "page {}: skipping extraction — content stream exceeds {} operations",
+                page_num,
+                super::content_decode::MAX_PAGE_OPERATIONS
+            );
+            return Ok(((Vec::new(), Vec::new(), Vec::new()), false, false, false));
+        }
+    };
 
     // Graphics state tracking
     let mut ctm = [1.0f32, 0.0, 0.0, 1.0, 0.0, 0.0]; // Current Transformation Matrix
     let mut text_rendering_mode: i32 = 0; // 0=fill, 1=stroke, 2=fill+stroke, 3=invisible
+                                          // Invisible (Tr 3) text was present but suppressed — reported to callers
+                                          // so an include_invisible retry is attempted only when it can recover.
+    let mut skipped_invisible = false;
     let mut line_width: f32 = 1.0;
     #[derive(Clone)]
     struct SavedGraphicsState {
@@ -494,6 +501,14 @@ pub(crate) fn extract_page_text_items(
                     // For Mixed/template PDFs, include_invisible=true extracts
                     // the OCR text layer that sits behind scanned images.
                     if text_rendering_mode == 3 && !include_invisible {
+                        if op
+                            .operands
+                            .first()
+                            .and_then(get_operand_bytes)
+                            .is_some_and(|raw| !raw.is_empty())
+                        {
+                            skipped_invisible = true;
+                        }
                         if let Some(w_ts) = w_ts_opt {
                             text_matrix[4] += w_ts * text_matrix[0];
                             text_matrix[5] += w_ts * text_matrix[1];
@@ -565,6 +580,16 @@ pub(crate) fn extract_page_text_items(
                 if in_text_block && !op.operands.is_empty() {
                     if let Ok(array) = op.operands[0].as_array() {
                         let font_info = font_widths.get(&current_font);
+                        // Numeric-only TJ arrays (pure kerning) show no
+                        // text — they must not trigger the invisible retry.
+                        if text_rendering_mode == 3
+                            && !include_invisible
+                            && array
+                                .iter()
+                                .any(|el| get_operand_bytes(el).is_some_and(|raw| !raw.is_empty()))
+                        {
+                            skipped_invisible = true;
+                        }
                         let is_invisible = (text_rendering_mode == 3 && !include_invisible)
                             || suppress_glyph_extraction;
                         // Capture first-glyph position for ActualText
@@ -770,6 +795,16 @@ pub(crate) fn extract_page_text_items(
                         )
                     })
                 });
+                if text_rendering_mode == 3
+                    && !include_invisible
+                    && op
+                        .operands
+                        .first()
+                        .and_then(get_operand_bytes)
+                        .is_some_and(|raw| !raw.is_empty())
+                {
+                    skipped_invisible = true;
+                }
                 if !((text_rendering_mode == 3 && !include_invisible)
                     || suppress_glyph_extraction
                     || op.operands.is_empty())
@@ -882,6 +917,7 @@ pub(crate) fn extract_page_text_items(
                                         &ctm,
                                         &mut cmap_decisions,
                                         style_cache,
+                                        form_budget,
                                     );
                                     items.extend(form_items);
                                 }
@@ -1251,6 +1287,12 @@ pub(crate) fn extract_page_text_items(
         }
     }
 
+    if form_budget.was_truncated() {
+        log::warn!(
+            "page {page_num}: Form XObject expansion truncated (invocation or operation budget reached); nested form text may be incomplete"
+        );
+    }
+
     // Underline detection reads only painted ink: `re` rects confirmed by
     // a paint operator plus filled-subpath rects — never clip-only rects,
     // which draw nothing.
@@ -1300,7 +1342,12 @@ pub(crate) fn extract_page_text_items(
 
     let items = super::merge_text_items(items);
     let items = super::merge_subscript_items(items);
-    Ok(((items, rects, lines), has_gid_fonts, coords_rotated))
+    Ok((
+        (items, rects, lines),
+        has_gid_fonts,
+        coords_rotated,
+        skipped_invisible,
+    ))
 }
 
 /// Counts of text operators with horizontal vs rotated combined matrices.
@@ -1498,13 +1545,14 @@ mod tests {
 
         let (doc, page_id) = simple_doc_with_content(content);
         let font_cmaps = FontCMaps::from_doc(&doc);
-        let ((items, _, _), _, _) = extract_page_text_items(
+        let ((items, _, _), _, _, _) = extract_page_text_items(
             &doc,
             page_id,
             1,
             &font_cmaps,
             false,
             &mut FontStyleCache::new(),
+            &mut FormWalkBudget::new(),
         )
         .unwrap();
         items
@@ -1734,9 +1782,10 @@ BT /F1 12 Tf 0 1 -1 0 240 100 Tm (WORLD) Tj ET
             &font_cmaps,
             false,
             &mut FontStyleCache::new(),
+            &mut FormWalkBudget::new(),
         )
         .unwrap();
-        let ((items, rects, lines), _has_gid, _coords_rotated) = result;
+        let ((items, rects, lines), _has_gid, _coords_rotated, _skipped_invisible) = result;
         assert!(items.is_empty());
         assert!(rects.is_empty());
         assert!(lines.is_empty());
@@ -1817,13 +1866,14 @@ BT 30 700 Tm <41> Tj ET";
         doc.trailer.set("Root", Object::Reference(catalog_id));
 
         let font_cmaps = FontCMaps::from_doc(&doc);
-        let ((items, _, _), _, _) = extract_page_text_items(
+        let ((items, _, _), _, _, _) = extract_page_text_items(
             &doc,
             page_id,
             1,
             &font_cmaps,
             false,
             &mut FontStyleCache::new(),
+            &mut FormWalkBudget::new(),
         )
         .unwrap();
         let text = items
@@ -1887,4 +1937,19 @@ BT 30 700 Tm <41> Tj ET";
         let output = strip_pdf_comments(input);
         assert_eq!(output, b"(x\\\\) Tj  \nET\n");
     }
+
+    #[test]
+    fn oversized_content_stream_skips_extraction() {
+        let mut content =
+            Vec::with_capacity((super::super::content_decode::MAX_PAGE_OPERATIONS + 1) * 2);
+        for _ in 0..=super::super::content_decode::MAX_PAGE_OPERATIONS {
+            content.extend_from_slice(b"q\n");
+        }
+        content.extend_from_slice(b"BT /F1 12 Tf 72 720 Td (Hello) Tj ET\n");
+        let items = extract_simple_items(&content);
+        assert!(
+            items.is_empty(),
+            "pages over the operator cap must not be decoded"
+        );
+    }
 }

src/extractor/fonts.rs

@@ -482,7 +482,11 @@ pub(crate) fn parse_cid_w_array(
     widths: &mut HashMap<u16, u16>,
 ) {
     let mut i = 0;
+    let mut assigned = 0usize;
     while i < w_array.len() {
+        if assigned >= crate::tounicode::MAX_CID_W_EXPANSION {
+            return;
+        }
         let start_cid = match &w_array[i] {
             Object::Integer(n) => *n as u16,
             Object::Real(n) => *n as u16,
@@ -501,12 +505,14 @@ pub(crate) fn parse_cid_w_array(
             Object::Array(arr) => {
                 // [c [w1 w2 ...]] — consecutive widths starting at c
                 for (j, w_obj) in arr.iter().enumerate() {
-                    let w = match w_obj {
-                        Object::Integer(n) => *n as u16,
-                        Object::Real(n) => *n as u16,
-                        _ => continue,
-                    };
-                    widths.insert(start_cid + j as u16, w);
+                    if !assign_cid_width(
+                        widths,
+                        start_cid.wrapping_add(j as u16),
+                        w_obj,
+                        &mut assigned,
+                    ) {
+                        return;
+                    }
                 }
                 i += 1;
             }
@@ -514,12 +520,14 @@ pub(crate) fn parse_cid_w_array(
                 // Could be a reference to an array
                 if let Ok(Object::Array(arr)) = doc.get_object(*r) {
                     for (j, w_obj) in arr.iter().enumerate() {
-                        let w = match w_obj {
-                            Object::Integer(n) => *n as u16,
-                            Object::Real(n) => *n as u16,
-                            _ => continue,
-                        };
-                        widths.insert(start_cid + j as u16, w);
+                        if !assign_cid_width(
+                            widths,
+                            start_cid.wrapping_add(j as u16),
+                            w_obj,
+                            &mut assigned,
+                        ) {
+                            return;
+                        }
                     }
                     i += 1;
                 } else {
@@ -542,8 +550,8 @@ pub(crate) fn parse_cid_w_array(
                         continue;
                     }
                 };
-                for cid in start_cid..=end {
-                    widths.insert(cid, w);
+                if !assign_cid_width_range(widths, start_cid, end, w, &mut assigned) {
+                    return;
                 }
                 i += 1;
             }
@@ -561,8 +569,8 @@ pub(crate) fn parse_cid_w_array(
                         continue;
                     }
                 };
-                for cid in start_cid..=end {
-                    widths.insert(cid, w);
+                if !assign_cid_width_range(widths, start_cid, end, w, &mut assigned) {
+                    return;
                 }
                 i += 1;
             }
@@ -573,6 +581,45 @@ pub(crate) fn parse_cid_w_array(
     }
 }
 
+fn assign_cid_width(
+    widths: &mut HashMap<u16, u16>,
+    cid: u16,
+    w_obj: &Object,
+    assigned: &mut usize,
+) -> bool {
+    let w = match w_obj {
+        Object::Integer(n) => *n as u16,
+        Object::Real(n) => *n as u16,
+        _ => return true,
+    };
+    if *assigned >= crate::tounicode::MAX_CID_W_EXPANSION {
+        return false;
+    }
+    widths.insert(cid, w);
+    *assigned += 1;
+    true
+}
+
+fn assign_cid_width_range(
+    widths: &mut HashMap<u16, u16>,
+    start: u16,
+    end: u16,
+    w: u16,
+    assigned: &mut usize,
+) -> bool {
+    if start > end {
+        return true;
+    }
+    for cid in start..=end {
+        if *assigned >= crate::tounicode::MAX_CID_W_EXPANSION {
+            return false;
+        }
+        widths.insert(cid, w);
+        *assigned += 1;
+    }
+    true
+}
+
 /// Compute the width of a string in text space units,
 /// given raw bytes and font width info.
 /// Returns width in text space units (font_units * units_scale * font_size).
@@ -2313,4 +2360,48 @@ end",
         // invalid CMap result — so it must not clear the gid flag.
         assert!(gid_flagged(Some("<01> <FFFD>\n<02> <FFFD>")));
     }
+
+    #[test]
+    fn parse_cid_w_array_range_and_consecutive() {
+        use super::parse_cid_w_array;
+        use lopdf::{Document, Object};
+        use std::collections::HashMap;
+
+        let doc = Document::new();
+        let mut widths = HashMap::new();
+        let w = vec![
+            Object::Integer(10),
+            Object::Integer(12),
+            Object::Integer(500),
+            Object::Integer(20),
+            Object::Array(vec![Object::Integer(100), Object::Integer(200)]),
+        ];
+        parse_cid_w_array(&doc, &w, &mut widths);
+        assert_eq!(widths.get(&10), Some(&500));
+        assert_eq!(widths.get(&11), Some(&500));
+        assert_eq!(widths.get(&12), Some(&500));
+        assert_eq!(widths.get(&20), Some(&100));
+        assert_eq!(widths.get(&21), Some(&200));
+    }
+
+    #[test]
+    fn parse_cid_w_array_repeated_full_ranges_stay_bounded() {
+        use super::parse_cid_w_array;
+        use crate::tounicode::MAX_CID_W_EXPANSION;
+        use lopdf::{Document, Object};
+        use std::collections::HashMap;
+
+        let doc = Document::new();
+        let mut widths = HashMap::new();
+        let mut w = Vec::new();
+        for _ in 0..5_000 {
+            w.push(Object::Integer(0));
+            w.push(Object::Integer(65535));
+            w.push(Object::Integer(500));
+        }
+        parse_cid_w_array(&doc, &w, &mut widths);
+        assert!(widths.len() <= MAX_CID_W_EXPANSION);
+        assert_eq!(widths.get(&0), Some(&500));
+        assert_eq!(widths.get(&65535), Some(&500));
+    }
 }

src/extractor/layout.rs

@@ -41,15 +41,110 @@ pub(crate) fn detect_columns(
     }
     debug!("page {}: detect_columns: {} items", page, page_items.len());
 
-    // Find page bounds
-    let x_min = page_items.iter().map(|i| i.x).fold(f32::INFINITY, f32::min);
-    let x_max = page_items
-        .iter()
-        .map(|i| i.x + effective_width(i))
-        .fold(f32::NEG_INFINITY, f32::max);
+    // The width of one ordinary page, used three ways below: as the largest
+    // credible width for a single text run, as the size of empty gap that marks
+    // content as detached, and as the span past which those checks run at all.
+    // This is a heuristic, not a format rule: PDF 2.0 sets no page-size limit,
+    // and since PDF 1.6 `UserUnit` scales a page's physical size independently
+    // of its coordinates. 14_400 units (200in at the default 1/72in unit) is
+    // the traditional Acrobat architectural limit, which makes it a reasonable
+    // "wider than any ordinary page" mark in coordinate space.
+    const MAX_PAGE_EXTENT: f32 = 14_400.0;
+    // A detached cluster is only dropped if it also holds a small minority of
+    // the items, so a genuine two-part layout keeps its full bounds even when
+    // the halves are far apart.
+    const MAX_TRIM_FRACTION: f32 = 0.10;
+
+    // Position and width of each item, skipping only non-finite geometry.
+    let finite_span = |i: &&TextItem| -> Option<(f32, f32)> {
+        let (left, width) = (i.x, effective_width(i));
+        (left.is_finite() && (left + width).is_finite()).then_some((left, width))
+    };
+
+    let (min_left, max_right, total) = page_items.iter().filter_map(finite_span).fold(
+        (f32::INFINITY, f32::NEG_INFINITY, 0usize),
+        |(lo, hi, n), (left, width)| (lo.min(left), hi.max(left + width), n + 1),
+    );
+
+    // No item had usable geometry, so there is no layout to report.
+    if total == 0 {
+        return vec![];
+    }
+
+    // Every threshold below (gutter margins, spanning-item width, the XY-cut
+    // margin) is a fraction of the page width, so a far item can set the scale
+    // for the whole page and shrink the effective detection window to a
+    // rounding error — real gutters then fall inside the margin band and a
+    // genuine multi-column page collapses to one region.
+    //
+    // Anything inside one page extent is ordinary, so the common case keeps the
+    // plain bounds and skips the work below entirely.
+    let (x_min, x_max) = if max_right - min_left <= MAX_PAGE_EXTENT {
+        (min_left, max_right)
+    } else {
+        // Discarding content needs positive evidence that it is not part of the
+        // layout, because a count-based rule alone cannot tell a stray from a
+        // sparse far sidebar. The evidence is geometric: positions are grouped
+        // into clusters separated by more than a whole page of continuous
+        // emptiness. Real content, however sparse, does not leave a void that
+        // large; a malformed coordinate sits alone beyond one.
+        let mut spans: Vec<(f32, f32)> = page_items.iter().filter_map(finite_span).collect();
+        spans.sort_by(|a, b| a.0.total_cmp(&b.0));
+
+        let mut core: Option<std::ops::Range<usize>> = None;
+        let mut start = 0usize;
+        for i in 1..=spans.len() {
+            if i < spans.len() && spans[i].0 - spans[i - 1].0 <= MAX_PAGE_EXTENT {
+                continue;
+            }
+            if core.as_ref().is_none_or(|best| i - start > best.len()) {
+                core = Some(start..i);
+            }
+            start = i;
+        }
+        let mut core = core.unwrap_or(0..spans.len());
+
+        // Only drop the detached clusters when they are a small minority, so a
+        // genuine two-part layout keeps its full bounds.
+        let dropped = spans.len() - core.len();
+        if dropped as f32 > spans.len() as f32 * MAX_TRIM_FRACTION {
+            core = 0..spans.len();
+        }
+        let core = &spans[core];
+
+        // Positions cannot be inflated by a bogus width, so the spread of the
+        // content is a sound scale for judging one. A run much wider than the
+        // page's own content is a malformed width — the test is relative, so a
+        // genuinely large page keeps its genuinely long runs.
+        let (lo, widest_left) = (core[0].0, core[core.len() - 1].0);
+        let max_run_width = (widest_left - lo) + MAX_PAGE_EXTENT;
+        let hi = core
+            .iter()
+            .filter(|&&(_, width)| width <= max_run_width)
+            .map(|&(left, width)| left + width)
+            .fold(widest_left, f32::max);
+
+        if lo != min_left || hi != max_right {
+            debug!(
+                "page {page}: bounds {min_left}..{max_right} exceed one page; \
+                 dropped {dropped}/{} detached item(s), using {lo}..{hi}",
+                spans.len()
+            );
+        }
+        (lo, hi)
+    };
+
+    // Hard ceiling on the histogram size, independent of the trimming above:
+    // the bounds are attacker-influenced, so an unclamped
+    // `page_width / BIN_WIDTH` lets a crafted PDF force an arbitrarily large
+    // `vec![0u32; num_bins]` allocation. 65_536 bins covers ~128k points at
+    // BIN_WIDTH 2.0 — roughly 9x the largest legal page — so this never binds
+    // on a real layout. Kept as a bound that does not depend on the outlier
+    // heuristic staying correct.
+    const MAX_BINS: usize = 65_536;
 
     let page_width = x_max - x_min;
-    if page_width < 200.0 {
+    if !page_width.is_finite() || page_width < 200.0 {
         return vec![ColumnRegion { x_min, x_max }];
     }
 
@@ -57,13 +152,20 @@ pub(crate) fn detect_columns(
         return vec![ColumnRegion { x_min, x_max }];
     }
 
+    // Widen the bins rather than dropping the tail of the page. Clamping the
+    // count alone would leave anything past MAX_BINS * BIN_WIDTH outside the
+    // histogram, folded into the last bin, which places gutters at the wrong
+    // coordinates. Scaling keeps full coverage under the same allocation
+    // ceiling; only the resolution degrades, and only beyond ~131k points.
+    let bin_width = BIN_WIDTH.max(page_width / MAX_BINS as f32);
+
     // Build occupancy histogram.
     // Exclude items wider than 60% of page width — these are spanning items
     // (titles, full-width paragraphs) that would fill the gutter and prevent
     // detection of partial-page column layouts (e.g. two-column abstracts on
     // a page that also has single-column introduction text).
     let wide_threshold = page_width * 0.6;
-    let num_bins = ((page_width / BIN_WIDTH).ceil() as usize).max(1);
+    let num_bins = ((page_width / bin_width).ceil() as usize).clamp(1, MAX_BINS);
     let mut histogram = vec![0u32; num_bins];
 
     for item in &page_items {
@@ -71,8 +173,8 @@ pub(crate) fn detect_columns(
         if w > wide_threshold {
             continue;
         }
-        let left = ((item.x - x_min) / BIN_WIDTH).floor() as usize;
-        let right = (((item.x + w) - x_min) / BIN_WIDTH).ceil() as usize;
+        let left = ((item.x - x_min) / bin_width).floor() as usize;
+        let right = (((item.x + w) - x_min) / bin_width).ceil() as usize;
         let left = left.min(num_bins);
         let right = right.min(num_bins);
         for count in histogram.iter_mut().take(right).skip(left) {
@@ -109,12 +211,12 @@ pub(crate) fn detect_columns(
     let valleys: Vec<(usize, usize)> = valleys
         .into_iter()
         .filter(|&(start, end)| {
-            let width_pts = (end - start) as f32 * BIN_WIDTH;
+            let width_pts = (end - start) as f32 * bin_width;
             if width_pts < MIN_GUTTER_WIDTH {
                 return false;
             }
             // Valley center must not be within 5% of page edges
-            let center_pts = ((start + end) as f32 / 2.0) * BIN_WIDTH;
+            let center_pts = ((start + end) as f32 / 2.0) * bin_width;
             center_pts > margin_threshold && center_pts < (page_width - margin_threshold)
         })
         .collect();
@@ -132,7 +234,7 @@ pub(crate) fn detect_columns(
             &histogram,
             num_bins,
             x_min,
-            BIN_WIDTH,
+            bin_width,
             page_width,
             margin_threshold,
         );
@@ -141,7 +243,7 @@ pub(crate) fn detect_columns(
                 &rel_valleys,
                 &page_items,
                 x_min,
-                BIN_WIDTH,
+                bin_width,
                 x_max,
                 MIN_ITEMS_PER_COLUMN,
                 MIN_VERTICAL_SPAN_RATIO,
@@ -182,7 +284,7 @@ pub(crate) fn detect_columns(
         &valleys,
         &page_items,
         x_min,
-        BIN_WIDTH,
+        bin_width,
         x_max,
         MIN_ITEMS_PER_COLUMN,
         MIN_VERTICAL_SPAN_RATIO,
@@ -196,7 +298,7 @@ pub(crate) fn detect_columns(
         &valleys,
         &page_items,
         x_min,
-        BIN_WIDTH,
+        bin_width,
         x_max,
         MIN_ITEMS_PER_COLUMN,
         MIN_VERTICAL_SPAN_RATIO,
@@ -1827,7 +1929,7 @@ fn split_column_stragglers(lines: Vec<TextLine>) -> (Vec<TextLine>, Vec<TextLine
         .unwrap();
 
     let (cs, ce) = segments[core_seg];
-    let mut core = Vec::with_capacity(ce - cs);
+    let mut core = Vec::with_capacity(ce.saturating_sub(cs));
     let mut stragglers = Vec::new();
     for (i, line) in lines.into_iter().enumerate() {
         if i >= cs && i < ce {
@@ -2533,6 +2635,214 @@ mod tests {
         );
     }
 
+    #[test]
+    fn extreme_far_coordinate_does_not_allocate_unboundedly() {
+        // A crafted PDF can place a text run at an arbitrary coordinate via the
+        // text matrix. The derived page width must not drive an unbounded
+        // histogram allocation (previously `page_width / BIN_WIDTH` bins with no
+        // upper bound would try to reserve terabytes and abort the process).
+        let mut items = Vec::new();
+        for i in 0..24 {
+            items.push(make_item(1, i as f32 * 10.0, 700.0 - i as f32 * 5.0, "A"));
+        }
+        // Item placed 1e12 points away — 5e11 bins if left unclamped.
+        items.push(make_item(1, 1e12, 700.0, "Z"));
+
+        // Must return without aborting; content is preserved as a single region.
+        let cols = detect_columns(&items, 1, false);
+        assert!(!cols.is_empty());
+    }
+
+    #[test]
+    fn non_finite_coordinates_never_leak_into_region_bounds() {
+        // An inf/NaN coordinate must not escape as a column boundary: callers
+        // treat these as page/column edges.
+        for bad_x in [f32::INFINITY, f32::NEG_INFINITY, f32::NAN] {
+            let mut items = Vec::new();
+            for i in 0..24 {
+                items.push(make_item(1, i as f32 * 10.0, 700.0 - i as f32 * 5.0, "A"));
+            }
+            items.push(make_item(1, bad_x, 700.0, "Z"));
+
+            for col in detect_columns(&items, 1, false) {
+                assert!(
+                    col.x_min.is_finite() && col.x_max.is_finite(),
+                    "bad_x {bad_x} leaked bounds {}..{}",
+                    col.x_min,
+                    col.x_max
+                );
+            }
+        }
+    }
+
+    #[test]
+    fn all_non_finite_coordinates_yield_no_columns() {
+        let items: Vec<TextItem> = (0..24)
+            .map(|i| make_item(1, f32::NAN, 700.0 - i as f32 * 5.0, "A"))
+            .collect();
+
+        assert!(detect_columns(&items, 1, false).is_empty());
+    }
+
+    #[test]
+    fn one_bad_item_does_not_disable_column_detection() {
+        // A single stray item should not collapse a clean two-column page to
+        // one region. Every gutter threshold is a fraction of the page width,
+        // so an untrimmed outlier pushes real gutters inside the rejected
+        // margin band. A malformed *width* at an ordinary position poisons the
+        // bounds just as a malformed position does.
+        for (label, bad_x, bad_width) in [
+            ("nan position", f32::NAN, 0.0),
+            ("inf position", f32::INFINITY, 0.0),
+            ("far position", 50_000.0, 0.0),
+            ("very far position", 1e12, 0.0),
+            ("huge width", 100.0, 1e12),
+            ("inf width", 100.0, f32::INFINITY),
+        ] {
+            let mut items = Vec::new();
+            items.extend(fill_zone(1, 30.0, 280.0, 750.0, 50.0));
+            items.extend(fill_zone(1, 320.0, 570.0, 750.0, 50.0));
+            let mut bad = make_item(1, bad_x, 400.0, "Z");
+            bad.width = bad_width;
+            items.push(bad);
+
+            let cols = detect_columns(&items, 1, false);
+            assert_eq!(
+                cols.len(),
+                2,
+                "{label}: expected 2 columns, got {}",
+                cols.len()
+            );
+            for col in &cols {
+                assert!(
+                    col.x_max - col.x_min <= MAX_PAGE_EXTENT_FOR_TEST,
+                    "{label}: region {}..{} exceeds one page",
+                    col.x_min,
+                    col.x_max
+                );
+            }
+        }
+    }
+
+    /// Mirrors `MAX_PAGE_EXTENT` in `detect_columns`.
+    const MAX_PAGE_EXTENT_FOR_TEST: f32 = 14_400.0;
+
+    #[test]
+    fn very_wide_page_keeps_full_histogram_coverage() {
+        // Beyond MAX_BINS * BIN_WIDTH (~131k points) the bins must widen rather
+        // than stop covering the page. Three zones: the first gutter is inside
+        // the old coverage limit, the second is past it. Because the first
+        // gutter is found, the XY-cut fallback never runs, so a truncated
+        // histogram silently reports two columns instead of three.
+        let mut items = Vec::new();
+        items.extend(fill_zone(1, 0.0, 60_000.0, 750.0, 700.0));
+        items.extend(fill_zone(1, 70_000.0, 140_000.0, 750.0, 700.0));
+        items.extend(fill_zone(1, 160_000.0, 200_000.0, 750.0, 700.0));
+
+        let cols = detect_columns(&items, 1, false);
+        assert_eq!(
+            cols.len(),
+            3,
+            "Expected 3 columns across a 200k-wide page, got {}",
+            cols.len()
+        );
+        assert!(
+            (140_000.0..=160_000.0).contains(&cols[1].x_max),
+            "second gutter at {}, expected inside the real 140k..160k gap",
+            cols[1].x_max
+        );
+    }
+
+    #[test]
+    fn large_page_with_legitimately_long_runs_is_kept() {
+        // On a very large page, individual runs can exceed one ordinary page's
+        // width. They are real content, so they must not be judged malformed:
+        // the page keeps its columns and its full right edge.
+        let mut items = Vec::new();
+        for row in 0..30 {
+            let y = 750.0 - row as f32 * 14.0;
+            let mut left = make_item(1, 0.0, y, "Left run");
+            left.width = 20_000.0;
+            let mut right = make_item(1, 25_000.0, y, "Right run");
+            right.width = 20_000.0;
+            items.extend([left, right]);
+        }
+
+        let cols = detect_columns(&items, 1, false);
+        assert!(
+            !cols.is_empty(),
+            "a page of long-but-valid runs must still report a layout"
+        );
+        let right_edge = cols
+            .iter()
+            .map(|c| c.x_max)
+            .fold(f32::NEG_INFINITY, f32::max);
+        assert!(
+            right_edge > 44_000.0,
+            "long runs were treated as malformed: right edge {right_edge}, expected ~45_000"
+        );
+    }
+
+    #[test]
+    fn sparse_far_sidebar_on_a_large_page_is_kept() {
+        // A large-format page with a thin, sparsely-populated sidebar far from
+        // the main block. The sidebar is a small minority of the items, so an
+        // item-count rule alone would discard it — but nothing about its
+        // geometry says it is invalid, so its bounds must survive.
+        let mut items = Vec::new();
+        items.extend(fill_zone(1, 0.0, 12_000.0, 750.0, 500.0));
+        for i in 0..12 {
+            items.push(make_item(1, 24_000.0, 750.0 - i as f32 * 14.0, "Sidebar"));
+        }
+
+        let cols = detect_columns(&items, 1, false);
+        let right_edge = cols
+            .iter()
+            .map(|c| c.x_max)
+            .fold(f32::NEG_INFINITY, f32::max);
+        assert!(
+            right_edge > 24_000.0,
+            "sidebar was trimmed away: right edge {right_edge}, expected >24_000"
+        );
+    }
+
+    #[test]
+    fn genuinely_wide_layout_keeps_its_true_bounds() {
+        // A large-format page whose content really is spread beyond one
+        // ordinary page must not be trimmed to the median cluster: its far
+        // items are the majority, not strays.
+        let mut items = Vec::new();
+        items.extend(fill_zone(1, 100.0, 20_000.0, 750.0, 600.0));
+        items.extend(fill_zone(1, 22_000.0, 40_000.0, 750.0, 600.0));
+
+        let cols = detect_columns(&items, 1, false);
+        let widest = cols
+            .iter()
+            .map(|c| c.x_max)
+            .fold(f32::NEG_INFINITY, f32::max);
+        assert!(
+            widest > 35_000.0,
+            "wide layout was trimmed: right edge {widest}, expected ~40_000"
+        );
+    }
+
+    #[test]
+    fn oversized_but_legal_page_is_not_trimmed() {
+        // A wide-format page well inside the 14_400pt spec limit must keep its
+        // real bounds — outlier trimming is only for spans beyond a legal page.
+        let mut items = Vec::new();
+        items.extend(fill_zone(1, 100.0, 4_000.0, 750.0, 400.0));
+        items.extend(fill_zone(1, 4_400.0, 8_000.0, 750.0, 400.0));
+
+        let cols = detect_columns(&items, 1, false);
+        assert_eq!(cols.len(), 2, "Expected 2 columns, got {}", cols.len());
+        assert!(
+            cols[1].x_max > 7_000.0,
+            "right column should keep its true extent, got {}",
+            cols[1].x_max
+        );
+    }
+
     #[test]
     fn two_column_regression_guard() {
         // Standard 2-column layout with clear gutter at center

src/extractor/links.rs

@@ -2,11 +2,51 @@
 
 use crate::types::{ItemType, TextItem};
 use lopdf::{Document, Object, ObjectId};
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 
 use super::fonts::{resolve_array, resolve_dict};
 use super::get_number;
 
+/// Upper bound on the number of form-field nodes visited during a single
+/// `extract_form_fields` pass. A crafted PDF can chain thousands of distinct
+/// `/Kids` fields to blow the stack even without an outright reference cycle,
+/// so we cap total traversal work in addition to detecting cycles.
+const MAX_FORM_FIELD_NODES: usize = 100_000;
+
+/// Upper bound on `/Kids` recursion depth. Real AcroForm hierarchies are only
+/// a few levels deep (fields → child fields → widgets); a crafted PDF can chain
+/// tens of thousands of distinct fields into a linear `/Kids` list that would
+/// overflow the stack via depth-first recursion long before the node budget is
+/// reached. This depth cap bounds the stack independently of total node count.
+const MAX_FORM_FIELD_DEPTH: usize = 100;
+
+/// Traversal budget for the AcroForm field walk. Bounds both the number of
+/// distinct nodes visited *and* the total number of `/Fields`/`/Kids` entries
+/// examined.
+///
+/// Counting `visited` alone is not enough: invalid entries (non-references) and
+/// duplicate references never grow `visited`, so an oversized array full of them
+/// would iterate to completion no matter how large. Charging every examined
+/// entry against the same budget makes it a real cap on traversal work.
+pub(crate) struct FieldWalkBudget {
+    visited: HashSet<ObjectId>,
+    examined: usize,
+}
+
+impl FieldWalkBudget {
+    fn new() -> Self {
+        Self {
+            visited: HashSet::new(),
+            examined: 0,
+        }
+    }
+
+    /// True once the budget is spent; callers must stop iterating and recursing.
+    fn exhausted(&self) -> bool {
+        self.visited.len() >= MAX_FORM_FIELD_NODES || self.examined >= MAX_FORM_FIELD_NODES
+    }
+}
+
 pub fn extract_page_links(doc: &Document, page_id: ObjectId, page_num: u32) -> Vec<TextItem> {
     let mut links = Vec::new();
 
@@ -146,9 +186,12 @@ pub(crate) fn extract_form_fields(
         Err(_) => return items,
     };
 
+    // Borrow the array rather than cloning it: a crafted `/Fields` can be huge,
+    // and cloning would pay an O(n) allocation/copy before the budget check
+    // below can stop the work.
     let fields = match acroform.get(b"Fields") {
         Ok(obj) => match resolve_array(doc, obj) {
-            Some(arr) => arr.clone(),
+            Some(arr) => arr,
             None => return items,
         },
         Err(_) => return items,
@@ -158,7 +201,19 @@ pub(crate) fn extract_form_fields(
     }
     let annotation_pages = annotation_page_map(doc, page_map);
 
-    for field_obj in &fields {
+    // Bound the walk so a crafted PDF cannot send us into unbounded recursion
+    // via a `/Kids` cycle, a deep chain, or an oversized array of invalid or
+    // duplicate entries.
+    let mut budget = FieldWalkBudget::new();
+
+    for field_obj in fields {
+        // Stop once the budget is spent so a `/Fields` array wider than the
+        // budget can't burn CPU iterating entries whose walk would no-op. Charge
+        // every entry (including invalid ones) against the budget.
+        if budget.exhausted() {
+            break;
+        }
+        budget.examined += 1;
         if let Ok(field_ref) = field_obj.as_reference() {
             walk_form_fields(
                 doc,
@@ -168,6 +223,8 @@ pub(crate) fn extract_form_fields(
                 page_map,
                 &annotation_pages,
                 &mut items,
+                &mut budget,
+                0,
             );
         }
     }
@@ -202,6 +259,7 @@ fn annotation_page_map(
 }
 
 /// Recursively walk the form field tree, extracting leaf field values.
+#[allow(clippy::too_many_arguments)]
 pub(crate) fn walk_form_fields(
     doc: &Document,
     field_id: ObjectId,
@@ -210,7 +268,22 @@ pub(crate) fn walk_form_fields(
     page_map: &HashMap<ObjectId, u32>,
     annotation_pages: &HashMap<ObjectId, u32>,
     items: &mut Vec<TextItem>,
+    budget: &mut FieldWalkBudget,
+    depth: usize,
 ) {
+    // Guard against `/Kids` cycles and pathologically large field trees.
+    // Exceeding the depth cap means the chain is too deep to be a legitimate
+    // form (and would overflow the stack); an exhausted budget means the tree is
+    // too large. Both checks run *before* inserting so the visited set can never
+    // grow past the budget.
+    if depth > MAX_FORM_FIELD_DEPTH || budget.exhausted() {
+        return;
+    }
+    // Revisiting an object ID means we hit a `/Kids` cycle.
+    if !budget.visited.insert(field_id) {
+        return;
+    }
+
     let field_dict = match doc.get_dictionary(field_id) {
         Ok(d) => d,
         Err(_) => return,
@@ -241,9 +314,19 @@ pub(crate) fn walk_form_fields(
 
     // Check for /Kids — if present, recurse into children
     if let Ok(kids_obj) = field_dict.get(b"Kids") {
+        // Iterate the borrowed array directly — cloning a crafted, oversized
+        // `/Kids` would allocate and copy every entry before the budget check
+        // below could stop the work.
         if let Some(kids) = resolve_array(doc, kids_obj) {
-            let kids = kids.clone();
-            for kid in &kids {
+            for kid in kids {
+                // Stop once the budget is spent so a `/Kids` array wider than the
+                // budget can't burn CPU iterating entries whose walk would no-op.
+                // Charge every entry (including invalid/duplicate ones) against
+                // the budget so this is a true traversal-work cap.
+                if budget.exhausted() {
+                    break;
+                }
+                budget.examined += 1;
                 if let Ok(kid_ref) = kid.as_reference() {
                     walk_form_fields(
                         doc,
@@ -253,6 +336,8 @@ pub(crate) fn walk_form_fields(
                         page_map,
                         annotation_pages,
                         items,
+                        budget,
+                        depth + 1,
                     );
                 }
             }
@@ -411,4 +496,225 @@ mod tests {
         assert_eq!(items[0].page, 2);
         assert_eq!(items[0].text, "customer: Alice");
     }
+
+    #[test]
+    fn kids_self_cycle_does_not_overflow_stack() {
+        // A crafted AcroForm field that lists itself in `/Kids` must not send
+        // the traversal into unbounded recursion.
+        let mut doc = Document::new();
+        let field_id = doc.new_object_id();
+        doc.set_object(
+            field_id,
+            dictionary! {
+                "FT" => "Tx",
+                "T" => Object::string_literal("loop"),
+                "Kids" => vec![Object::Reference(field_id)],
+            },
+        );
+        let catalog_id = doc.add_object(dictionary! {
+            "Type" => "Catalog",
+            "AcroForm" => dictionary! {
+                "Fields" => vec![Object::Reference(field_id)],
+            },
+        });
+        doc.trailer.set("Root", Object::Reference(catalog_id));
+
+        let page_map = HashMap::new();
+        // Completes (rather than overflowing the stack) and yields no items.
+        let items = extract_form_fields(&doc, &page_map);
+        assert!(items.is_empty());
+    }
+
+    #[test]
+    fn kids_mutual_cycle_terminates() {
+        // Two fields that reference each other via `/Kids` form a cycle that
+        // must also terminate.
+        let mut doc = Document::new();
+        let field_a = doc.new_object_id();
+        let field_b = doc.new_object_id();
+        doc.set_object(
+            field_a,
+            dictionary! {
+                "T" => Object::string_literal("a"),
+                "Kids" => vec![Object::Reference(field_b)],
+            },
+        );
+        doc.set_object(
+            field_b,
+            dictionary! {
+                "T" => Object::string_literal("b"),
+                "Kids" => vec![Object::Reference(field_a)],
+            },
+        );
+        let catalog_id = doc.add_object(dictionary! {
+            "Type" => "Catalog",
+            "AcroForm" => dictionary! {
+                "Fields" => vec![Object::Reference(field_a)],
+            },
+        });
+        doc.trailer.set("Root", Object::Reference(catalog_id));
+
+        let page_map = HashMap::new();
+        let items = extract_form_fields(&doc, &page_map);
+        assert!(items.is_empty());
+    }
+
+    #[test]
+    fn deep_acyclic_kids_chain_does_not_overflow_stack() {
+        // A long chain of *distinct* fields (no cycle) must also terminate:
+        // the visited set alone would still recurse to the chain length, so
+        // the depth cap is what prevents a stack overflow here.
+        let mut doc = Document::new();
+        let n = MAX_FORM_FIELD_DEPTH * 500;
+        let ids: Vec<ObjectId> = (0..=n).map(|_| doc.new_object_id()).collect();
+        for i in 0..n {
+            doc.set_object(
+                ids[i],
+                dictionary! {
+                    "FT" => "Tx",
+                    "Kids" => vec![Object::Reference(ids[i + 1])],
+                },
+            );
+        }
+        // Leaf carries a value; it sits far below the depth cap so it is never
+        // reached, proving traversal stops early rather than crashing.
+        doc.set_object(
+            ids[n],
+            dictionary! {
+                "FT" => "Tx",
+                "T" => Object::string_literal("leaf"),
+                "V" => Object::string_literal("x"),
+                "Rect" => vec![10.into(), 20.into(), 110.into(), 40.into()],
+            },
+        );
+        let catalog_id = doc.add_object(dictionary! {
+            "Type" => "Catalog",
+            "AcroForm" => dictionary! {
+                "Fields" => vec![Object::Reference(ids[0])],
+            },
+        });
+        doc.trailer.set("Root", Object::Reference(catalog_id));
+
+        let page_map = HashMap::new();
+        let items = extract_form_fields(&doc, &page_map);
+        assert!(items.is_empty());
+    }
+
+    #[test]
+    fn wide_tree_traversal_stops_at_node_budget() {
+        // A single field with a `/Kids` array wider than the node budget must
+        // stop traversal at the cap rather than growing `visited` (and the work)
+        // without bound. Each processed leaf emits one item, so the item count
+        // is bounded by the budget and reaches right up to it (a couple of
+        // slots go to the root and the boundary node charged against the cap).
+        let mut doc = Document::new();
+        let fanout = MAX_FORM_FIELD_NODES + 50;
+        let leaf_ids: Vec<ObjectId> = (0..fanout).map(|_| doc.new_object_id()).collect();
+        for &leaf in &leaf_ids {
+            doc.set_object(
+                leaf,
+                dictionary! {
+                    "FT" => "Tx",
+                    "V" => Object::string_literal("v"),
+                    "Rect" => vec![10.into(), 20.into(), 110.into(), 40.into()],
+                },
+            );
+        }
+        let kids: Vec<Object> = leaf_ids.iter().map(|&id| Object::Reference(id)).collect();
+        let root_id = doc.add_object(dictionary! {
+            "T" => Object::string_literal("root"),
+            "Kids" => kids,
+        });
+        let catalog_id = doc.add_object(dictionary! {
+            "Type" => "Catalog",
+            "AcroForm" => dictionary! {
+                "Fields" => vec![Object::Reference(root_id)],
+            },
+        });
+        doc.trailer.set("Root", Object::Reference(catalog_id));
+
+        let page_map = HashMap::new();
+        let items = extract_form_fields(&doc, &page_map);
+        // Extraction stops at the budget: bounded above by the cap, and it gets
+        // right up to it (allowing a small delta for the root/boundary nodes
+        // charged against the budget).
+        assert!(items.len() <= MAX_FORM_FIELD_NODES);
+        assert!(items.len() >= MAX_FORM_FIELD_NODES - 3);
+    }
+
+    #[test]
+    fn wide_top_level_fields_stop_at_node_budget() {
+        // A top-level `/Fields` array wider than the budget must also stop at
+        // the cap: the item count is bounded by the budget and reaches right up
+        // to it.
+        let mut doc = Document::new();
+        let fanout = MAX_FORM_FIELD_NODES + 50;
+        let leaf_ids: Vec<ObjectId> = (0..fanout).map(|_| doc.new_object_id()).collect();
+        for &leaf in &leaf_ids {
+            doc.set_object(
+                leaf,
+                dictionary! {
+                    "FT" => "Tx",
+                    "V" => Object::string_literal("v"),
+                    "Rect" => vec![10.into(), 20.into(), 110.into(), 40.into()],
+                },
+            );
+        }
+        let fields: Vec<Object> = leaf_ids.iter().map(|&id| Object::Reference(id)).collect();
+        let catalog_id = doc.add_object(dictionary! {
+            "Type" => "Catalog",
+            "AcroForm" => dictionary! {
+                "Fields" => fields,
+            },
+        });
+        doc.trailer.set("Root", Object::Reference(catalog_id));
+
+        let page_map = HashMap::new();
+        let items = extract_form_fields(&doc, &page_map);
+        assert!(items.len() <= MAX_FORM_FIELD_NODES);
+        assert!(items.len() >= MAX_FORM_FIELD_NODES - 3);
+    }
+
+    #[test]
+    fn duplicate_and_invalid_kids_entries_stop_at_budget() {
+        // Duplicate references and non-reference junk never grow `visited`, so
+        // without charging examined entries against the budget an oversized
+        // array of them would iterate to completion. The walk must still
+        // terminate and extract the single real leaf exactly once.
+        let mut doc = Document::new();
+        let leaf_id = doc.new_object_id();
+        doc.set_object(
+            leaf_id,
+            dictionary! {
+                "FT" => "Tx",
+                "V" => Object::string_literal("v"),
+                "Rect" => vec![10.into(), 20.into(), 110.into(), 40.into()],
+            },
+        );
+        // A `/Kids` array far wider than the budget: half duplicate references
+        // to the same leaf, half invalid (null) entries.
+        let mut kids: Vec<Object> = Vec::new();
+        for i in 0..(MAX_FORM_FIELD_NODES * 2) {
+            if i % 2 == 0 {
+                kids.push(Object::Reference(leaf_id));
+            } else {
+                kids.push(Object::Null);
+            }
+        }
+        let root_id = doc.add_object(dictionary! {
+            "T" => Object::string_literal("root"),
+            "Kids" => kids,
+        });
+        let catalog_id = doc.add_object(dictionary! {
+            "Type" => "Catalog",
+            "AcroForm" => dictionary! {
+                "Fields" => vec![Object::Reference(root_id)],
+            },
+        });
+        doc.trailer.set("Root", Object::Reference(catalog_id));
+
+        let page_map = HashMap::new();
+        let items = extract_form_fields(&doc, &page_map);
+        assert_eq!(items.len(), 1);
+    }
 }

src/extractor/mod.rs

@@ -3,6 +3,7 @@
 //! This module extracts text with position information for structure detection.
 
 mod base14;
+mod content_decode;
 pub(crate) mod content_stream;
 mod fonts;
 mod layout;
@@ -37,6 +38,7 @@ pub(crate) use layout::group_prefiltered_items_into_lines_with_thresholds_and_re
 pub(crate) use layout::is_newspaper_layout;
 pub(crate) use layout::ColumnRegion;
 pub use layout::{group_into_lines, group_into_lines_preserving_all_text};
+pub(crate) use xobjects::FormWalkBudget;
 
 // ---------------------------------------------------------------------------
 // Public API
@@ -282,18 +284,22 @@ fn extract_positioned_text_impl(
             font_cmaps,
             include_invisible,
             &mut style_cache,
+            &mut FormWalkBudget::new(),
         );
-        let ((mut items, mut rects, mut lines), has_gid_fonts, coords_rotated) = match page_result {
-            Ok(extraction) => extraction,
-            Err(error) if required_pages.is_some_and(|required| !required.contains(page_num)) => {
-                debug!(
-                    "page {}: skipping context-only extraction error: {}",
-                    page_num, error
-                );
-                continue;
-            }
-            Err(error) => return Err(error),
-        };
+        let ((mut items, mut rects, mut lines), has_gid_fonts, coords_rotated, _skipped_invisible) =
+            match page_result {
+                Ok(extraction) => extraction,
+                Err(error)
+                    if required_pages.is_some_and(|required| !required.contains(page_num)) =>
+                {
+                    debug!(
+                        "page {}: skipping context-only extraction error: {}",
+                        page_num, error
+                    );
+                    continue;
+                }
+                Err(error) => return Err(error),
+            };
         // Clip to the visible page box: single-page extracts and imposed
         // spreads keep neighboring pages' content in the stream, positioned
         // outside the CropBox. Extracting it interleaves invisible text into
@@ -884,6 +890,92 @@ fn tracked_run_space_floor(group: &[&TextItem], start: usize) -> Option<(usize,
     Some((end, floor * fs))
 }
 
+/// Fractional font-size band within which `merge_text_items` treats two runs as
+/// the same size. Shared with `is_small_caps_continuation`, which exists only to
+/// rescue junctions this band would otherwise break.
+const MERGE_FONT_SIZE_BAND: f32 = 0.20;
+
+/// Detect a small-caps continuation: typesetters render small caps as a
+/// full-size capital immediately followed by shrunken capitals in the same
+/// font (`(R) Tj` at 9.98pt, then `(OLANDO) Tj` at 6.74pt). Those runs are one
+/// word, but the font-size band in `merge_text_items` would split them,
+/// leaving "R" and "OLANDO" as separate items — which then read as separate
+/// table columns, since column boundaries cluster on item start positions.
+///
+/// Gated tightly so it cannot absorb the other reasons a smaller run follows a
+/// larger one:
+///   - runs the size band already accepts — excluded by requiring the junction
+///     to *cross* the band, so within-band pairs keep the normal word-spacing
+///     logic instead of having their space suppressed
+///   - superscripts / footnote markers — excluded by requiring an uppercase
+///     *letter* on both sides, so digits never qualify
+///   - drop caps — excluded because the body text that follows is mixed case
+///   - adjacent table cells or separate words — excluded by requiring the runs
+///     to be visually contiguous (essentially no gap)
+fn is_small_caps_continuation(
+    text_so_far: &str,
+    first: &TextItem,
+    next: &TextItem,
+    gap: f32,
+) -> bool {
+    // Must shrink. Real small caps sit near 0.7-0.8 of the full cap height;
+    // anything smaller is a superscript or a different run entirely.
+    if first.font_size <= 0.0 || next.font_size >= first.font_size {
+        return false;
+    }
+    // Only rescue junctions the size band would have broken. Within-band pairs
+    // merge on their own, and suppressing their space would swallow real word
+    // gaps between two similarly-sized uppercase words.
+    if (next.font_size - first.font_size).abs() <= first.font_size * MERGE_FONT_SIZE_BAND {
+        return false;
+    }
+    if next.font_size / first.font_size < 0.55 {
+        return false;
+    }
+    // Visually contiguous: the capital and its small caps touch. A real word
+    // space or a column gap disqualifies.
+    if !(-first.font_size * 0.2..=first.font_size * 0.15).contains(&gap) {
+        return false;
+    }
+    // The continuation must be all-uppercase letters (digits and lowercase
+    // both disqualify), and must contain at least one letter.
+    let mut saw_letter = false;
+    for ch in next.text.chars() {
+        if ch.is_alphabetic() {
+            saw_letter = true;
+            if !ch.is_uppercase() {
+                return false;
+            }
+        } else if ch.is_numeric() {
+            return false;
+        }
+    }
+    if !saw_letter {
+        return false;
+    }
+    // What we are continuing must itself end in a capital. Check the actual
+    // trailing character rather than skipping back to the nearest letter: after
+    // "ANGELA M. MAZZARELLI1" the run to continue is the footnote marker, not
+    // the "I" before it.
+    let trimmed = text_so_far.trim_end();
+    if trimmed.chars().last().is_some_and(|c| c.is_numeric()) {
+        // One legitimate exception: an ordinal suffix set as a smaller run,
+        // e.g. "JULY 4" + "TH". Only the four English suffixes qualify —
+        // anything else after a digit is a footnote marker or numeric suffix.
+        return matches!(trimmed_suffix(next), "TH" | "ST" | "ND" | "RD");
+    }
+    trimmed
+        .chars()
+        .rev()
+        .find(|c| c.is_alphabetic())
+        .is_some_and(|c| c.is_uppercase())
+}
+
+/// The continuation run's text, trimmed — used to spot ordinal suffixes.
+fn trimmed_suffix(next: &TextItem) -> &str {
+    next.text.trim()
+}
+
 pub(crate) fn merge_text_items(items: Vec<TextItem>) -> Vec<TextItem> {
     if items.is_empty() {
         return items;
@@ -942,8 +1034,16 @@ pub(crate) fn merge_text_items(items: Vec<TextItem>) -> Vec<TextItem> {
             let mut j = i + 1;
             while j < group.len() {
                 let next = group[j];
-                // Must be similar font size (within 20%)
-                if (next.font_size - first.font_size).abs() > first.font_size * 0.20 {
+                // A small-caps junction is mid-word: it both survives the
+                // font-size band below and must never take a space.
+                let small_caps_join =
+                    is_small_caps_continuation(&text, first, next, next.x - end_x);
+                // Must be similar font size, except for genuine small-caps
+                // runs, where the shrunken capitals are the same word as the
+                // full-size initial (see helper).
+                if (next.font_size - first.font_size).abs() > first.font_size * MERGE_FONT_SIZE_BAND
+                    && !small_caps_join
+                {
                     break;
                 }
                 // Never merge across style boundaries: the merged item
@@ -997,7 +1097,7 @@ pub(crate) fn merge_text_items(items: Vec<TextItem>) -> Vec<TextItem> {
                     Some((run_end, floor)) if j <= run_end => floor,
                     _ => threshold,
                 };
-                if needs_bullet_space || gap > effective_threshold {
+                if !small_caps_join && (needs_bullet_space || gap > effective_threshold) {
                     text.push(' ');
                 }
                 text.push_str(&next.text);
@@ -3001,6 +3101,145 @@ mod tests {
         }
     }
 
+    /// Small caps as typesetters emit them: a full-size capital at 9.98pt
+    /// immediately followed by shrunken capitals at 6.74pt, touching.
+    /// Modelled on `199AD3d.pdf` p.5 ("ROLANDO T. ACOSTA, P.J.").
+    #[test]
+    fn small_caps_run_merges_into_one_word() {
+        let items = vec![
+            make_item_fs("R", 144.36, 581.84, 7.20, 9.98),
+            make_item_fs("OLANDO", 151.56, 581.84, 30.56, 6.74),
+            make_item_fs("T. A", 185.45, 581.84, 17.58, 9.98),
+            make_item_fs("COSTA", 203.94, 581.84, 23.15, 6.74),
+            make_item_fs(", P.J.", 227.09, 581.84, 22.56, 9.98),
+        ];
+        let merged = merge_text_items(items);
+        assert_eq!(merged.len(), 1, "got {:?}", merged);
+        assert_eq!(merged[0].text, "ROLANDO T. ACOSTA, P.J.");
+    }
+
+    /// The full two-column row: both names must merge independently and the
+    /// 72pt column gap between them must survive as an item boundary.
+    #[test]
+    fn small_caps_merge_does_not_swallow_a_second_column() {
+        let items = vec![
+            // Column 1: "ROLANDO T. ACOSTA, P.J." ending at x=249.65
+            make_item_fs("R", 144.36, 581.84, 7.20, 9.98),
+            make_item_fs("OLANDO", 151.56, 581.84, 30.56, 6.74),
+            make_item_fs("T. A", 185.45, 581.84, 17.58, 9.98),
+            make_item_fs("COSTA", 203.94, 581.84, 23.15, 6.74),
+            make_item_fs(", P.J.", 227.09, 581.84, 22.56, 9.98),
+            // Column 2 starts at x=321.96 — a 72pt gap.
+            make_item_fs("A", 321.96, 581.84, 7.20, 9.98),
+            make_item_fs("NIL", 329.17, 581.84, 12.72, 6.74),
+            make_item_fs("C. S", 345.04, 581.84, 19.59, 9.98),
+            make_item_fs("INGH", 364.62, 581.84, 19.08, 6.74),
+        ];
+        let merged = merge_text_items(items);
+        let texts: Vec<&str> = merged.iter().map(|i| i.text.as_str()).collect();
+        assert_eq!(
+            texts,
+            vec!["ROLANDO T. ACOSTA, P.J.", "ANIL C. SINGH"],
+            "column gap should keep the two names apart"
+        );
+    }
+
+    #[test]
+    fn small_caps_merge_keeps_word_space_between_same_size_capitals() {
+        // Two uppercase words at sizes the merge band already accepts (9.98 and
+        // 9.0, a 10% drop) separated by a real word gap. The small-caps path
+        // must not claim this junction and swallow the space.
+        let items = vec![
+            make_item_fs("SEE", 100.0, 500.0, 18.0, 9.98),
+            make_item_fs("ALSO", 119.2, 500.0, 24.0, 9.0),
+        ];
+        let merged = merge_text_items(items);
+        assert_eq!(merged.len(), 1, "got {:?}", merged);
+        assert_eq!(merged[0].text, "SEE ALSO");
+    }
+
+    #[test]
+    fn trailing_digit_is_not_a_capital_awaiting_small_caps() {
+        // "...MAZZARELLI1" ends in a footnote marker; the backward search for an
+        // uppercase letter must not skip the digit and glue the next run.
+        assert!(!is_small_caps_continuation(
+            "ANGELA M. MAZZARELLI1",
+            &make_item_fs("ANGELA", 100.0, 500.0, 40.0, 9.98),
+            &make_item_fs("SHULMAN", 140.0, 500.0, 30.0, 6.74),
+            0.0,
+        ));
+    }
+
+    #[test]
+    fn ordinal_suffix_after_a_digit_still_merges() {
+        // "TUESDAY, JULY 4" + "TH" is one word in the source; the digit guard
+        // must not block the four English ordinal suffixes.
+        for suffix in ["TH", "ST", "ND", "RD"] {
+            assert!(
+                is_small_caps_continuation(
+                    "TUESDAY, JULY 4",
+                    &make_item_fs("JULY", 100.0, 500.0, 30.0, 12.0),
+                    &make_item_fs(suffix, 130.0, 500.0, 8.0, 8.0),
+                    0.0,
+                ),
+                "{suffix} should merge after a digit"
+            );
+        }
+    }
+
+    #[test]
+    fn superscript_footnote_marker_is_not_a_small_caps_continuation() {
+        // A digit must never qualify — otherwise footnote markers get glued on
+        // without the superscript handling.
+        assert!(!is_small_caps_continuation(
+            "MAZZARELLI",
+            &make_item_fs("MAZZARELLI", 100.0, 500.0, 50.0, 9.98),
+            &make_item_fs("1", 150.0, 503.0, 3.0, 6.74),
+            0.0,
+        ));
+    }
+
+    #[test]
+    fn drop_cap_is_not_a_small_caps_continuation() {
+        // Mixed-case body text after a large initial is a drop cap, not small
+        // caps.
+        assert!(!is_small_caps_continuation(
+            "T",
+            &make_item_fs("T", 100.0, 500.0, 20.0, 30.0),
+            &make_item_fs("he court held", 120.0, 500.0, 60.0, 10.0),
+            0.0,
+        ));
+    }
+
+    #[test]
+    fn separate_word_is_not_a_small_caps_continuation() {
+        // A real word space disqualifies even when both runs are uppercase.
+        let first = make_item_fs("SEE", 100.0, 500.0, 20.0, 9.98);
+        let next = make_item_fs("ALSO", 128.0, 500.0, 25.0, 6.74);
+        assert!(!is_small_caps_continuation("SEE", &first, &next, 8.0));
+    }
+
+    #[test]
+    fn lowercase_continuation_is_not_small_caps() {
+        assert!(!is_small_caps_continuation(
+            "SMALL",
+            &make_item_fs("SMALL", 100.0, 500.0, 30.0, 9.98),
+            &make_item_fs("caps", 130.0, 500.0, 20.0, 6.74),
+            0.0,
+        ));
+    }
+
+    #[test]
+    fn too_small_a_ratio_is_not_small_caps() {
+        // 0.4 ratio is a superscript/sub-run, outside the small-caps band.
+        assert!(!is_small_caps_continuation(
+            "A",
+            &make_item_fs("A", 100.0, 500.0, 7.0, 10.0),
+            &make_item_fs("BC", 107.0, 500.0, 8.0, 4.0),
+            0.0,
+        ));
+    }
+
     #[test]
     fn test_merge_subscript_items_chemical_formula() {
         // NH₃: "NH" at fs=8 followed by subscript "3" at fs=4.7

src/extractor/xobjects.rs

@@ -16,6 +16,76 @@ use super::{get_number, image_bbox_from_ctm, multiply_matrices};
 
 const MAX_FORM_XOBJECT_DEPTH: u8 = 5;
 
+/// Upper bound on Form XObject invocations during a single page extraction.
+/// Depth alone is not enough: an acyclic DAG where each form invokes the next
+/// N times expands to N^depth work before the depth cap is reached.
+const MAX_FORM_XOBJECT_INVOCATIONS: usize = 10_000;
+
+/// Upper bound on content-stream operations walked across all Form XObject
+/// expansions for a page. Nested forms are decoded independently of the
+/// page-level operation cap, so this keeps total form work in the same
+/// ballpark as that page cap.
+const MAX_FORM_XOBJECT_OPERATIONS: usize = 1_000_000;
+
+/// Shared budget for Form XObject expansion on a page. Bounds both nested DAG
+/// expansion and repeated sibling `/Do` invocations of the same form.
+pub(crate) struct FormWalkBudget {
+    invocations: usize,
+    operations: usize,
+    max_invocations: usize,
+    max_operations: usize,
+    truncated: bool,
+}
+
+impl FormWalkBudget {
+    pub(crate) fn new() -> Self {
+        Self::with_limits(MAX_FORM_XOBJECT_INVOCATIONS, MAX_FORM_XOBJECT_OPERATIONS)
+    }
+
+    fn with_limits(max_invocations: usize, max_operations: usize) -> Self {
+        Self {
+            invocations: 0,
+            operations: 0,
+            max_invocations,
+            max_operations,
+            truncated: false,
+        }
+    }
+
+    fn exhausted(&mut self) -> bool {
+        if self.invocations >= self.max_invocations || self.operations >= self.max_operations {
+            self.truncated = true;
+            true
+        } else {
+            false
+        }
+    }
+
+    fn charge_invocation(&mut self) -> bool {
+        if self.exhausted() {
+            return false;
+        }
+        self.invocations += 1;
+        true
+    }
+
+    /// Charge one walked content-stream operator. Independent of the
+    /// invocation cap so a form that was already admitted can finish its
+    /// stream (up to the operation cap).
+    fn charge_operation(&mut self) -> bool {
+        if self.operations >= self.max_operations {
+            self.truncated = true;
+            return false;
+        }
+        self.operations += 1;
+        true
+    }
+
+    pub(crate) fn was_truncated(&self) -> bool {
+        self.truncated
+    }
+}
+
 pub(crate) enum XObjectType {
     Image,
     Form(ObjectId),
@@ -109,6 +179,7 @@ fn collect_xobjects_from_dict(
 }
 
 /// Extract text items from a Form XObject
+#[allow(clippy::too_many_arguments)]
 pub(crate) fn extract_form_xobject_text(
     doc: &Document,
     form_id: ObjectId,
@@ -117,6 +188,7 @@ pub(crate) fn extract_form_xobject_text(
     parent_ctm: &[f32; 6],
     cmap_decisions: &mut CMapDecisionCache,
     style_cache: &mut FontStyleCache,
+    budget: &mut FormWalkBudget,
 ) -> Vec<TextItem> {
     extract_form_xobject_text_inner(
         doc,
@@ -127,6 +199,7 @@ pub(crate) fn extract_form_xobject_text(
         cmap_decisions,
         style_cache,
         0,
+        budget,
     )
 }
 
@@ -140,11 +213,14 @@ fn extract_form_xobject_text_inner(
     cmap_decisions: &mut CMapDecisionCache,
     style_cache: &mut FontStyleCache,
     depth: u8,
+    budget: &mut FormWalkBudget,
 ) -> Vec<TextItem> {
-    use lopdf::content::Content;
-
     let mut items = Vec::new();
 
+    if !budget.charge_invocation() {
+        return items;
+    }
+
     // Get the Form XObject stream
     let Ok(Object::Stream(stream)) = doc.get_object(form_id) else {
         return items;
@@ -156,8 +232,12 @@ fn extract_form_xobject_text_inner(
         Err(_) => stream.content.clone(),
     };
 
-    // Decode the content stream
-    let Ok(content) = Content::decode(&content_data) else {
+    // Decode the content stream. Cap before lopdf materializes the operator
+    // vector — the walk budget cannot help if decode itself allocates first.
+    let Ok(Some(content)) = super::content_decode::decode_content_bounded(
+        &content_data,
+        super::content_decode::MAX_PAGE_OPERATIONS,
+    ) else {
         return items;
     };
 
@@ -246,19 +326,55 @@ fn extract_form_xobject_text_inner(
     let mut current_font = String::new();
     let mut current_font_size: f32 = 12.0;
     let mut text_matrix = [1.0f32, 0.0, 0.0, 1.0, 0.0, 0.0];
+    // Text line matrix (TLM) — Td/TD/T* move relative to the start of the
+    // current line, not to the position left by the last show operator.
+    let mut line_matrix = [1.0f32, 0.0, 0.0, 1.0, 0.0, 0.0];
+    let mut text_leading: f32 = 0.0; // TL parameter (text-space units)
+    let mut char_spacing: f32 = 0.0; // Tc parameter
+    let mut word_spacing: f32 = 0.0; // Tw parameter
     let mut in_text_block = false;
     let mut fill_is_white = false;
     let mut ctm = base_ctm;
-    let mut ctm_stack: Vec<[f32; 6]> = Vec::new();
+
+    // Text state (Tc/Tw/TL/Tf) and the fill colour are part of the graphics
+    // state and must be saved/restored by q/Q alongside the CTM.
+    #[derive(Clone)]
+    struct GraphicsState {
+        ctm: [f32; 6],
+        char_spacing: f32,
+        word_spacing: f32,
+        text_leading: f32,
+        current_font: String,
+        current_font_size: f32,
+        fill_is_white: bool,
+    }
+    let mut ctm_stack: Vec<GraphicsState> = Vec::new();
 
     for op in &content.operations {
+        if !budget.charge_operation() {
+            break;
+        }
         match op.operator.as_str() {
             "q" => {
-                ctm_stack.push(ctm);
+                ctm_stack.push(GraphicsState {
+                    ctm,
+                    char_spacing,
+                    word_spacing,
+                    text_leading,
+                    current_font: current_font.clone(),
+                    current_font_size,
+                    fill_is_white,
+                });
             }
             "Q" => {
                 if let Some(saved) = ctm_stack.pop() {
-                    ctm = saved;
+                    ctm = saved.ctm;
+                    char_spacing = saved.char_spacing;
+                    word_spacing = saved.word_spacing;
+                    text_leading = saved.text_leading;
+                    current_font = saved.current_font;
+                    current_font_size = saved.current_font_size;
+                    fill_is_white = saved.fill_is_white;
                 }
             }
             "cm" => {
@@ -276,7 +392,7 @@ fn extract_form_xobject_text_inner(
                         let xobj_name = String::from_utf8_lossy(name).to_string();
                         match form_xobjects.get(&xobj_name) {
                             Some(XObjectType::Form(nested_id)) => {
-                                if depth < MAX_FORM_XOBJECT_DEPTH {
+                                if depth < MAX_FORM_XOBJECT_DEPTH && !budget.exhausted() {
                                     let nested_items = extract_form_xobject_text_inner(
                                         doc,
                                         *nested_id,
@@ -286,6 +402,7 @@ fn extract_form_xobject_text_inner(
                                         cmap_decisions,
                                         style_cache,
                                         depth + 1,
+                                        budget,
                                     );
                                     items.extend(nested_items);
                                 }
@@ -321,6 +438,7 @@ fn extract_form_xobject_text_inner(
             "BT" => {
                 in_text_block = true;
                 text_matrix = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0];
+                line_matrix = text_matrix;
             }
             "ET" => {
                 in_text_block = false;
@@ -333,12 +451,33 @@ fn extract_form_xobject_text_inner(
                     current_font_size = get_number(&op.operands[1]).unwrap_or(12.0);
                 }
             }
+            "TL" => {
+                // Set text leading (used by T*, ', and ")
+                if let Some(tl) = op.operands.first().and_then(get_number) {
+                    text_leading = tl;
+                }
+            }
+            "Tc" => {
+                if let Some(tc) = op.operands.first().and_then(get_number) {
+                    char_spacing = tc;
+                }
+            }
+            "Tw" => {
+                if let Some(tw) = op.operands.first().and_then(get_number) {
+                    word_spacing = tw;
+                }
+            }
             "Td" | "TD" => {
+                // Move text position: TLM = T(tx,ty) x TLM; Tm = TLM
                 if op.operands.len() >= 2 {
                     let tx = get_number(&op.operands[0]).unwrap_or(0.0);
                     let ty = get_number(&op.operands[1]).unwrap_or(0.0);
-                    text_matrix[4] += tx * text_matrix[0] + ty * text_matrix[2];
-                    text_matrix[5] += tx * text_matrix[1] + ty * text_matrix[3];
+                    line_matrix[4] += tx * line_matrix[0] + ty * line_matrix[2];
+                    line_matrix[5] += tx * line_matrix[1] + ty * line_matrix[3];
+                    text_matrix = line_matrix;
+                    if op.operator == "TD" {
+                        text_leading = -ty;
+                    }
                 }
             }
             "Tm" => {
@@ -347,8 +486,20 @@ fn extract_form_xobject_text_inner(
                         text_matrix[i] =
                             get_number(operand).unwrap_or(if i == 0 || i == 3 { 1.0 } else { 0.0 });
                     }
+                    line_matrix = text_matrix;
                 }
             }
+            "T*" => {
+                // Move to start of next line: equivalent to `0 -TL Td`
+                let tl = if text_leading != 0.0 {
+                    text_leading
+                } else {
+                    current_font_size * 1.2
+                };
+                line_matrix[4] += (-tl) * line_matrix[2];
+                line_matrix[5] += (-tl) * line_matrix[3];
+                text_matrix = line_matrix;
+            }
             "g" => {
                 if let Some(gray) = op.operands.first().and_then(get_number) {
                     fill_is_white = gray > 0.95;
@@ -384,17 +535,33 @@ fn extract_form_xobject_text_inner(
                     _ => fill_is_white = false,
                 }
             }
-            "Tj" => {
-                if in_text_block && !op.operands.is_empty() {
+            "Tj" | "'" | "\"" => {
+                // `'` = move to next line then show; `"` = set word/char spacing,
+                // move to next line, then show (string is the last operand).
+                if op.operator != "Tj" {
+                    if op.operator == "\"" && op.operands.len() >= 3 {
+                        word_spacing = get_number(&op.operands[0]).unwrap_or(word_spacing);
+                        char_spacing = get_number(&op.operands[1]).unwrap_or(char_spacing);
+                    }
+                    let tl = if text_leading != 0.0 {
+                        text_leading
+                    } else {
+                        current_font_size * 1.2
+                    };
+                    line_matrix[4] += (-tl) * line_matrix[2];
+                    line_matrix[5] += (-tl) * line_matrix[3];
+                    text_matrix = line_matrix;
+                }
+                if let (true, Some(show_operand)) = (in_text_block, op.operands.last()) {
                     if fill_is_white {
                         if let Some(font_info) = font_widths.get(&current_font) {
-                            if let Some(raw_bytes) = get_operand_bytes(&op.operands[0]) {
+                            if let Some(raw_bytes) = get_operand_bytes(show_operand) {
                                 let w_ts = compute_string_width_ts(
                                     raw_bytes,
                                     font_info,
                                     current_font_size,
-                                    0.0,
-                                    0.0,
+                                    char_spacing,
+                                    word_spacing,
                                 );
                                 text_matrix[4] += w_ts * text_matrix[0];
                                 text_matrix[5] += w_ts * text_matrix[1];
@@ -403,7 +570,7 @@ fn extract_form_xobject_text_inner(
                         continue;
                     }
                     if let Some(text) = extract_text_from_operand(
-                        &op.operands[0],
+                        show_operand,
                         &current_font,
                         font_base_names.get(&current_font).map(|s| s.as_str()),
                         font_cmaps,
@@ -419,13 +586,13 @@ fn extract_form_xobject_text_inner(
                             * type3_scales.get(&current_font).copied().unwrap_or(1.0);
                         let (x, y) = (combined[4], combined[5]);
                         let width = if let Some(font_info) = font_widths.get(&current_font) {
-                            if let Some(raw_bytes) = get_operand_bytes(&op.operands[0]) {
+                            if let Some(raw_bytes) = get_operand_bytes(show_operand) {
                                 let w_ts = compute_string_width_ts(
                                     raw_bytes,
                                     font_info,
                                     current_font_size,
-                                    0.0,
-                                    0.0,
+                                    char_spacing,
+                                    word_spacing,
                                 );
                                 text_matrix[4] += w_ts * text_matrix[0];
                                 text_matrix[5] += w_ts * text_matrix[1];
@@ -548,8 +715,8 @@ fn extract_form_xobject_text_inner(
                                         raw_bytes,
                                         fi,
                                         current_font_size,
-                                        0.0,
-                                        0.0,
+                                        char_spacing,
+                                        word_spacing,
                                     );
                                 }
                             }
@@ -683,3 +850,415 @@ pub(crate) fn get_form_fonts<'a>(
 
     fonts
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::extractor::content_stream::extract_page_text_items;
+    use lopdf::{dictionary, Dictionary, Stream};
+
+    /// Build an acyclic Form XObject DAG: `levels` form objects, each non-leaf
+    /// invoking the next form `branches` times. The leaf draws a single `(X)`.
+    /// Returns `(doc, root_form_id)`.
+    fn form_dag(branches: usize, levels: usize) -> (Document, ObjectId) {
+        assert!(levels >= 2);
+        let mut doc = Document::new();
+        let font_id = doc.add_object(dictionary! {
+            "Type" => "Font",
+            "Subtype" => "Type1",
+            "BaseFont" => "Helvetica",
+        });
+        let ids: Vec<ObjectId> = (0..levels).map(|_| doc.new_object_id()).collect();
+        for level in 0..levels {
+            let stream = if level + 1 == levels {
+                Stream::new(
+                    dictionary! {
+                        "Type" => "XObject",
+                        "Subtype" => "Form",
+                        "BBox" => vec![0.into(), 0.into(), 100.into(), 100.into()],
+                        "Resources" => dictionary! {
+                            "Font" => dictionary! {
+                                "F1" => Object::Reference(font_id),
+                            },
+                        },
+                    },
+                    b"BT /F1 10 Tf 10 10 Td (X) Tj ET\n".to_vec(),
+                )
+            } else {
+                let next_name = format!("Fm{}", level + 1);
+                let content = format!("/{next_name} Do\n").repeat(branches);
+                let mut xobjects = Dictionary::new();
+                xobjects.set(next_name, Object::Reference(ids[level + 1]));
+                let mut resources = Dictionary::new();
+                resources.set("XObject", Object::Dictionary(xobjects));
+                let mut dict = dictionary! {
+                    "Type" => "XObject",
+                    "Subtype" => "Form",
+                    "BBox" => vec![0.into(), 0.into(), 100.into(), 100.into()],
+                };
+                dict.set("Resources", Object::Dictionary(resources));
+                Stream::new(dict, content.into_bytes())
+            };
+            doc.set_object(ids[level], Object::Stream(stream));
+        }
+        (doc, ids[0])
+    }
+
+    fn page_invoking_form(mut doc: Document, form_id: ObjectId) -> (Document, ObjectId) {
+        let content_id = doc.add_object(Object::Stream(Stream::new(
+            dictionary! {},
+            b"/Fm0 Do\n".to_vec(),
+        )));
+        let page_id = doc.add_object(dictionary! {
+            "Type" => "Page",
+            "Contents" => Object::Reference(content_id),
+            "Resources" => dictionary! {
+                "XObject" => dictionary! {
+                    "Fm0" => Object::Reference(form_id),
+                },
+            },
+            "MediaBox" => vec![0.into(), 0.into(), 612.into(), 792.into()],
+        });
+        let pages_id = doc.add_object(dictionary! {
+            "Type" => "Pages",
+            "Count" => Object::Integer(1),
+            "Kids" => vec![Object::Reference(page_id)],
+        });
+        let catalog_id = doc.add_object(dictionary! {
+            "Type" => "Catalog",
+            "Pages" => Object::Reference(pages_id),
+        });
+        doc.trailer.set("Root", Object::Reference(catalog_id));
+        (doc, page_id)
+    }
+
+    fn extract_form(
+        doc: &Document,
+        form_id: ObjectId,
+        budget: &mut FormWalkBudget,
+    ) -> Vec<TextItem> {
+        extract_form_xobject_text(
+            doc,
+            form_id,
+            1,
+            &FontCMaps::from_doc(doc),
+            &[1.0, 0.0, 0.0, 1.0, 0.0, 0.0],
+            &mut CMapDecisionCache::new(),
+            &mut FontStyleCache::new(),
+            budget,
+        )
+    }
+
+    #[test]
+    fn nested_form_still_extracts_leaf_text() {
+        let (doc, root) = form_dag(1, 3);
+        let items = extract_form(&doc, root, &mut FormWalkBudget::new());
+        assert_eq!(items.len(), 1);
+        assert_eq!(items[0].text, "X");
+    }
+
+    #[test]
+    fn acyclic_form_dag_within_budget_keeps_all_leaves() {
+        // 4 sibling invocations across 4 nested levels → 4^4 leaf drawings.
+        // Default budgets are far above 256, so legitimate nesting is intact.
+        let (doc, root) = form_dag(4, 5);
+        let items = extract_form(&doc, root, &mut FormWalkBudget::new());
+        assert_eq!(items.len(), 4usize.pow(4));
+        assert!(items.iter().all(|item| item.text == "X"));
+    }
+
+    #[test]
+    fn acyclic_form_dag_stops_at_invocation_budget() {
+        // Same DAG as above would draw 256 leaves; a tiny invocation cap must
+        // stop expansion rather than walking the full tree.
+        let (doc, root) = form_dag(4, 5);
+        let mut budget = FormWalkBudget::with_limits(20, MAX_FORM_XOBJECT_OPERATIONS);
+        let items = extract_form(&doc, root, &mut budget);
+        assert!(
+            items.len() < 4usize.pow(4),
+            "invocation budget must truncate DAG expansion; got {} items",
+            items.len()
+        );
+        assert!(budget.was_truncated());
+    }
+
+    #[test]
+    fn form_operations_stop_at_budget() {
+        let mut doc = Document::new();
+        let font_id = doc.add_object(dictionary! {
+            "Type" => "Font",
+            "Subtype" => "Type1",
+            "BaseFont" => "Helvetica",
+        });
+        let mut content = b"q Q\n".repeat(50);
+        content.extend_from_slice(b"BT /F1 10 Tf 10 10 Td (X) Tj ET\n");
+        let form_id = doc.add_object(Object::Stream(Stream::new(
+            dictionary! {
+                "Type" => "XObject",
+                "Subtype" => "Form",
+                "BBox" => vec![0.into(), 0.into(), 100.into(), 100.into()],
+                "Resources" => dictionary! {
+                    "Font" => dictionary! {
+                        "F1" => Object::Reference(font_id),
+                    },
+                },
+            },
+            content,
+        )));
+
+        let mut budget = FormWalkBudget::with_limits(MAX_FORM_XOBJECT_INVOCATIONS, 10);
+        let items = extract_form(&doc, form_id, &mut budget);
+        assert!(
+            items.is_empty(),
+            "operation budget must stop before the trailing text show"
+        );
+        assert!(budget.was_truncated());
+    }
+
+    #[test]
+    fn page_level_form_dag_stays_within_production_budget() {
+        // A page-level `/Do` of an 8-wide, 6-level Form DAG would expand to
+        // 8^5 = 32_768 leaf drawings without a budget. The production
+        // invocation cap must keep extraction bounded.
+        let (doc, root) = form_dag(8, 6);
+        let (doc, page_id) = page_invoking_form(doc, root);
+
+        let font_cmaps = FontCMaps::from_doc(&doc);
+        let ((items, _, _), _, _, _) = extract_page_text_items(
+            &doc,
+            page_id,
+            1,
+            &font_cmaps,
+            false,
+            &mut FontStyleCache::new(),
+            &mut FormWalkBudget::new(),
+        )
+        .unwrap();
+        assert!(
+            items.len() <= MAX_FORM_XOBJECT_INVOCATIONS,
+            "page-level Form expansion must stay within the invocation cap; got {}",
+            items.len()
+        );
+        assert!(
+            !items.is_empty(),
+            "budget must still allow some nested form text through"
+        );
+    }
+
+    #[test]
+    fn shared_form_budget_spans_two_extraction_passes() {
+        // The invisible-layer retry calls extract_page_text_items twice for
+        // the same page; both passes must share one budget.
+        let (doc, root) = form_dag(1, 2);
+        let (doc, page_id) = page_invoking_form(doc, root);
+        let font_cmaps = FontCMaps::from_doc(&doc);
+        // Root + leaf = 2 invocations on the first pass.
+        let mut budget = FormWalkBudget::with_limits(2, MAX_FORM_XOBJECT_OPERATIONS);
+        let ((first, _, _), _, _, _) = extract_page_text_items(
+            &doc,
+            page_id,
+            1,
+            &font_cmaps,
+            false,
+            &mut FontStyleCache::new(),
+            &mut budget,
+        )
+        .unwrap();
+        assert_eq!(first.iter().filter(|item| item.text == "X").count(), 1);
+        assert!(!budget.was_truncated());
+
+        let ((second, _, _), _, _, _) = extract_page_text_items(
+            &doc,
+            page_id,
+            1,
+            &font_cmaps,
+            true,
+            &mut FontStyleCache::new(),
+            &mut budget,
+        )
+        .unwrap();
+        assert!(
+            second.iter().all(|item| item.text != "X"),
+            "second pass must not get a fresh invocation budget"
+        );
+        assert!(budget.was_truncated());
+    }
+
+    /// Build a document whose page draws *all* of its content through a single
+    /// Form XObject — the shape emitted by print-to-PDF producers like PDFlib,
+    /// where the page stream itself is only `q /X1 Do Q`.
+    fn doc_with_form_content(form_content: &[u8]) -> (Document, ObjectId) {
+        let mut doc = Document::new();
+        let widths: Vec<Object> = (0..=255).map(|_| 600.into()).collect();
+        let font_id = doc.add_object(dictionary! {
+            "Type" => "Font",
+            "Subtype" => "Type1",
+            "BaseFont" => "Helvetica",
+            "FirstChar" => 0,
+            "LastChar" => 255,
+            "Widths" => Object::Array(widths),
+        });
+        let form_id = doc.add_object(Object::Stream(Stream::new(
+            dictionary! {
+                "Type" => "XObject",
+                "Subtype" => "Form",
+                "BBox" => vec![0.into(), 0.into(), 612.into(), 792.into()],
+                "Resources" => dictionary! {
+                    "Font" => dictionary! { "F1" => Object::Reference(font_id) },
+                },
+            },
+            form_content.to_vec(),
+        )));
+        let content_id = doc.add_object(Object::Stream(Stream::new(
+            dictionary! {},
+            b"q /X1 Do Q".to_vec(),
+        )));
+        let page_id = doc.add_object(dictionary! {
+            "Type" => "Page",
+            "Contents" => Object::Reference(content_id),
+            "Resources" => dictionary! {
+                "XObject" => dictionary! { "X1" => Object::Reference(form_id) },
+            },
+            "MediaBox" => vec![0.into(), 0.into(), 612.into(), 792.into()],
+        });
+        let pages_id = doc.add_object(dictionary! {
+            "Type" => "Pages",
+            "Count" => Object::Integer(1),
+            "Kids" => vec![Object::Reference(page_id)],
+        });
+        let catalog_id = doc.add_object(dictionary! {
+            "Type" => "Catalog",
+            "Pages" => Object::Reference(pages_id),
+        });
+        doc.trailer.set("Root", Object::Reference(catalog_id));
+        (doc, page_id)
+    }
+
+    fn form_items(form_content: &[u8]) -> Vec<TextItem> {
+        let (doc, page_id) = doc_with_form_content(form_content);
+        let font_cmaps = FontCMaps::from_doc(&doc);
+        let ((items, _, _), _, _, _) = extract_page_text_items(
+            &doc,
+            page_id,
+            1,
+            &font_cmaps,
+            false,
+            &mut FontStyleCache::new(),
+            &mut FormWalkBudget::new(),
+        )
+        .unwrap();
+        items
+    }
+
+    fn find<'a>(items: &'a [TextItem], text: &str) -> &'a TextItem {
+        items
+            .iter()
+            .find(|item| item.text == text)
+            .unwrap_or_else(|| {
+                let found: Vec<&String> = items.iter().map(|i| &i.text).collect();
+                panic!("no item {text:?} in {found:?}")
+            })
+    }
+
+    #[test]
+    fn t_star_inside_form_moves_to_next_line() {
+        // T* was previously unhandled inside Form XObjects, so every line after
+        // the first piled onto the preceding baseline and drifted right.
+        let items =
+            form_items(b"BT /F1 12 Tf 12 TL 1 0 0 1 100 700 Tm (first) Tj T* (second) Tj ET");
+
+        let first = find(&items, "first");
+        let second = find(&items, "second");
+        assert!((first.y - 700.0).abs() < 0.1, "first y = {}", first.y);
+        assert!((second.y - 688.0).abs() < 0.1, "second y = {}", second.y);
+        assert!((second.x - 100.0).abs() < 0.1, "second x = {}", second.x);
+    }
+
+    #[test]
+    fn td_inside_form_is_relative_to_line_start_not_shown_text() {
+        // Td moves relative to the text *line* matrix. Applying it to the
+        // matrix already advanced by Tj marched each line off the right edge.
+        let items = form_items(b"BT /F1 12 Tf 1 0 0 1 100 700 Tm (AAAAA) Tj 0 -12 Td (B) Tj ET");
+
+        let b = find(&items, "B");
+        assert!((b.x - 100.0).abs() < 0.1, "B x = {} (expected 100)", b.x);
+        assert!((b.y - 688.0).abs() < 0.1, "B y = {}", b.y);
+    }
+
+    #[test]
+    fn td_inside_form_sets_leading_for_later_t_star() {
+        // `TD` sets the leading to -ty as a side effect; a following T* must
+        // reuse it.
+        let items = form_items(
+            b"BT /F1 12 Tf 1 0 0 1 100 700 Tm (one) Tj 0 -15 TD (two) Tj T* (three) Tj ET",
+        );
+
+        assert!((find(&items, "two").y - 685.0).abs() < 0.1);
+        let three = find(&items, "three");
+        assert!((three.y - 670.0).abs() < 0.1, "three y = {}", three.y);
+        assert!((three.x - 100.0).abs() < 0.1, "three x = {}", three.x);
+    }
+
+    #[test]
+    fn quote_operator_inside_form_moves_to_next_line() {
+        let items = form_items(b"BT /F1 12 Tf 12 TL 1 0 0 1 100 700 Tm (first) Tj (second) ' ET");
+
+        let second = find(&items, "second");
+        assert!((second.y - 688.0).abs() < 0.1, "second y = {}", second.y);
+        assert!((second.x - 100.0).abs() < 0.1, "second x = {}", second.x);
+    }
+
+    #[test]
+    fn double_quote_operator_inside_form_sets_spacing_and_moves() {
+        // `aw ac (string) "` — set word spacing and char spacing, then T* and show.
+        let items =
+            form_items(b"BT /F1 12 Tf 12 TL 1 0 0 1 100 700 Tm (first) Tj 0 0 (second) \" ET");
+
+        let second = find(&items, "second");
+        assert!((second.y - 688.0).abs() < 0.1, "second y = {}", second.y);
+        assert!((second.x - 100.0).abs() < 0.1, "second x = {}", second.x);
+    }
+
+    #[test]
+    fn char_spacing_inside_form_widens_advance() {
+        // Tc was hardcoded to 0 in the form parser, so advance widths drifted.
+        // 2 glyphs x 600/1000 x 12pt = 14.4, plus 2 x Tc(2.0) = 18.4.
+        let items = form_items(b"BT /F1 12 Tf 1 0 0 1 100 700 Tm 2 Tc (AB) Tj ET");
+
+        let ab = find(&items, "AB");
+        assert!((ab.width - 18.4).abs() < 0.1, "AB width = {}", ab.width);
+    }
+
+    #[test]
+    fn q_restores_fill_colour_inside_form() {
+        // A white fill set inside q/Q must not leak past the Q — otherwise the
+        // following black text is treated as invisible and dropped entirely.
+        let items = form_items(
+            b"BT /F1 12 Tf 12 TL 1 0 0 1 100 700 Tm q 1 g (hidden) Tj Q T* (visible) Tj ET",
+        );
+
+        assert!(
+            items.iter().any(|item| item.text == "visible"),
+            "text after Q was dropped: {:?}",
+            items.iter().map(|i| &i.text).collect::<Vec<_>>()
+        );
+        assert!(
+            !items.iter().any(|item| item.text == "hidden"),
+            "white-filled text should still be suppressed"
+        );
+    }
+
+    #[test]
+    fn q_restores_text_state_inside_form() {
+        // Tc/TL live in the graphics state; `Q` must roll them back.
+        let items =
+            form_items(b"BT /F1 12 Tf 12 TL 1 0 0 1 100 700 Tm q 30 TL (a) Tj Q T* (b) Tj ET");
+
+        let b = find(&items, "b");
+        assert!(
+            (b.y - 688.0).abs() < 0.1,
+            "b y = {} (leading should restore to 12)",
+            b.y
+        );
+    }
+}

src/glyph_names.rs

@@ -4566,9 +4566,13 @@ pub fn glyph_to_char(name: &str) -> Option<char> {
         }
     }
 
-    // Try to parse uniXXXX format
-    if name.starts_with("uni") && name.len() >= 7 {
-        if let Ok(code) = u32::from_str_radix(&name[3..7], 16) {
+    // Try to parse uniXXXX format.
+    // Use `get` rather than a byte-length check + slice: `name` can contain
+    // non-ASCII bytes (e.g. U+FFFD from lossy UTF-8 decoding of an attacker
+    // controlled /Differences name), so byte index 7 may not be a char
+    // boundary and `&name[3..7]` would panic.
+    if let Some(hex) = name.strip_prefix("uni").and_then(|rest| rest.get(..4)) {
+        if let Ok(code) = u32::from_str_radix(hex, 16) {
             // Strip PUA F000 offset: uniF0XX → U+00XX (Windows Symbol encoding convention)
             let code = if (0xF000..=0xF0FF).contains(&code) {
                 code - 0xF000
@@ -4588,3 +4592,36 @@ pub fn glyph_to_char(name: &str) -> Option<char> {
 
     None
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn uni_hex_parsing() {
+        assert_eq!(glyph_to_char("uni0041"), Some('A'));
+        assert_eq!(glyph_to_char("uni00e9"), Some('\u{00e9}'));
+        // PUA F0xx symbol-encoding offset is stripped.
+        assert_eq!(glyph_to_char("uniF041"), Some('A'));
+    }
+
+    #[test]
+    fn u_hex_parsing() {
+        assert_eq!(glyph_to_char("u0041"), Some('A'));
+        assert_eq!(glyph_to_char("u1F600"), Some('\u{1F600}'));
+    }
+
+    #[test]
+    fn non_ascii_uni_name_does_not_panic() {
+        // A crafted /Differences name like `/uni#80#80#80#80` decodes via
+        // from_utf8_lossy into "uni" followed by four U+FFFD replacements.
+        // Byte index 7 lands mid-character, so a naive `&name[3..7]` slice
+        // would panic. It must be handled gracefully instead.
+        let crafted = format!("uni{0}{0}{0}{0}", '\u{FFFD}');
+        assert_eq!(glyph_to_char(&crafted), None);
+
+        // Assorted non-ASCII bytes right after the "uni" prefix.
+        assert_eq!(glyph_to_char("uni\u{FFFD}bc"), None);
+        assert_eq!(glyph_to_char("uni\u{00e9}00"), None);
+    }
+}

src/lib.rs

@@ -657,6 +657,80 @@ pub fn extract_pages_markdown<P: AsRef<Path>>(
     extract_pages_markdown_mem(&buffer, pages)
 }
 
+// =========================================================================
+// Structure-tree element extraction (tagged PDFs)
+// =========================================================================
+
+/// One structure-tree element reference from a tagged PDF, resolved to a
+/// page and Marked Content ID.
+///
+/// Join `(page, mcid)` against [`TextItem::page`] / [`TextItem::mcid`] from
+/// [`extract_text_with_positions`] to attach semantic roles (heading levels,
+/// paragraphs, table cells, …) to extracted text.
+#[derive(Debug, Clone)]
+pub struct StructureElement {
+    /// 1-indexed page number (matches [`TextItem::page`]).
+    pub page: u32,
+    /// Marked Content ID from the page's content stream (matches
+    /// [`TextItem::mcid`]).
+    pub mcid: i64,
+    /// Standard structure type name ("H1".."H6", "P", "Table", "TD", …).
+    /// Custom tags are resolved through the document's `/RoleMap`; tags
+    /// with no standard mapping are returned verbatim.
+    pub role: String,
+}
+
+/// Extract structure-tree element references from a tagged PDF in memory.
+///
+/// Parses `/StructTreeRoot` (when present) and returns one entry per
+/// marked-content reference, resolved to its 1-indexed page, MCID, and
+/// structure type name. Returns an empty list when the PDF is not tagged.
+///
+/// Pass `Some(&[...])` with 1-indexed page numbers (matching
+/// [`TextItem::page`]) to restrict output to those pages; pass `None` for
+/// the whole document. Entries are sorted by `(page, mcid)`.
+pub fn extract_structure_elements_mem(
+    buffer: &[u8],
+    pages: Option<&[u32]>,
+) -> Result<Vec<StructureElement>, PdfError> {
+    validate_pdf_bytes(buffer)?;
+    let (doc, _page_count) = load_document_from_mem(buffer)?;
+    let Some(tree) = structure_tree::StructTree::from_doc(&doc) else {
+        return Ok(Vec::new());
+    };
+    let page_ids = doc.get_pages();
+    let roles = tree.mcid_to_roles(&page_ids);
+
+    let page_filter: Option<HashSet<u32>> = pages.map(|p| p.iter().copied().collect());
+    let mut elements: Vec<StructureElement> = roles
+        .into_iter()
+        .filter(|(page, _)| page_filter.as_ref().is_none_or(|f| f.contains(page)))
+        .flat_map(|(page, mcids)| {
+            mcids.into_iter().map(move |(mcid, role)| StructureElement {
+                page,
+                mcid,
+                role: role.name().to_string(),
+            })
+        })
+        .collect();
+    elements.sort_unstable_by_key(|e| (e.page, e.mcid));
+    Ok(elements)
+}
+
+/// Path-based wrapper for [`extract_structure_elements_mem`].
+///
+/// Reads the PDF from disk and extracts structure-tree element references.
+/// Pass `None` for `pages` to return the whole document, or `Some(&[...])`
+/// to restrict to specific 1-indexed pages.
+pub fn extract_structure_elements<P: AsRef<Path>>(
+    path: P,
+    pages: Option<&[u32]>,
+) -> Result<Vec<StructureElement>, PdfError> {
+    validate_pdf_file(&path)?;
+    let buffer = std::fs::read(path.as_ref())?;
+    extract_structure_elements_mem(&buffer, pages)
+}
+
 // =========================================================================
 // Region-based text extraction (for hybrid OCR pipelines)
 // =========================================================================
@@ -683,6 +757,23 @@ pub struct PageRegionResult {
     pub regions: Vec<RegionText>,
 }
 
+/// Minimum alphanumeric mass an invisible (Tr 3) text layer must carry for
+/// the OCR-layer fallback in [`extract_text_in_regions_mem`] to adopt it. A
+/// real OCR layer carries far more; a stray watermark or artifact does not.
+const OCR_LAYER_MIN_ALNUM: usize = 40;
+
+/// Alphanumeric mass of extracted items, ignoring raster placeholders.
+/// `[Image: ...]` items (ItemType::Image) are synthesized for image
+/// XObjects — they mark that pixels exist, not that text was read, so they
+/// must not count as coverage.
+fn non_placeholder_alnum(items: &[TextItem]) -> usize {
+    items
+        .iter()
+        .filter(|it| !matches!(it.item_type, types::ItemType::Image))
+        .map(|it| it.text.chars().filter(|c| c.is_alphanumeric()).count())
+        .sum()
+}
+
 /// Extract text within bounding-box regions from a PDF in memory.
 ///
 /// This is designed for hybrid OCR pipelines: a layout model detects regions
@@ -735,8 +826,11 @@ pub fn extract_text_in_regions_mem(
         let height = get_page_height(&doc, page_id).unwrap_or(792.0);
         page_heights.insert(*page_num, height);
 
-        // Extract text items for this page
-        let ((mut items, _rects, _lines), has_gid, coords_rotated) =
+        // Extract text items for this page. The Form XObject budget is shared
+        // with the invisible-layer retry below so one page cannot consume two
+        // full expansion budgets.
+        let mut form_budget = extractor::FormWalkBudget::new();
+        let ((mut items, _rects, _lines), mut has_gid, mut coords_rotated, skipped_invisible) =
             extractor::content_stream::extract_page_text_items(
                 &doc,
                 page_id,
@@ -744,7 +838,54 @@ pub fn extract_text_in_regions_mem(
                 &font_cmaps,
                 false,
                 &mut style_cache,
+                &mut form_budget,
             )?;
+        // OCR-layer fallback: scanned pages often carry their text as an
+        // invisible (Tr 3) layer behind the page raster. The visible-only
+        // pass sees nothing there but `[Image: ...]` placeholders, so every
+        // region on the page reports needs_ocr even though the exact text is
+        // embedded in the PDF — and this extractor then disagrees with the
+        // markdown path, which already retries Mixed PDFs with the invisible
+        // layer included. Retry page-scoped, and only when (a) the first
+        // pass actually SKIPPED invisible text — blank pages and image-only
+        // scans without an OCR layer must not pay a second content-stream
+        // parse (review catch) — and (b) the page has NO visible text item
+        // at all (punctuation counts, whitespace-only artifacts don't): an
+        // invisible OCR layer transcribes the raster, so any visible glyph
+        // has an invisible twin there and adoption would duplicate it
+        // (review catches — strict gate, no fuzzy dedupe). Adopt the retry
+        // only when it contributes real, non-garbage text.
+        let has_visible_text = items.iter().any(|it| {
+            !matches!(it.item_type, types::ItemType::Image) && !it.text.trim().is_empty()
+        });
+        if skipped_invisible && !has_visible_text {
+            if let Ok(((inv_items, _inv_rects, _inv_lines), inv_gid, inv_rotated, _)) =
+                extractor::content_stream::extract_page_text_items(
+                    &doc,
+                    page_id,
+                    *page_num,
+                    &font_cmaps,
+                    true,
+                    &mut style_cache,
+                    &mut form_budget,
+                )
+            {
+                let inv_alnum = non_placeholder_alnum(&inv_items);
+                // Judge the WHOLE recovered layer, not a prefix — a broken
+                // OCR layer can hide its garbage past any fixed sample size
+                // (review catch).
+                let sample: String = inv_items
+                    .iter()
+                    .filter(|it| !matches!(it.item_type, types::ItemType::Image))
+                    .map(|it| it.text.as_str())
+                    .collect();
+                if inv_alnum >= OCR_LAYER_MIN_ALNUM && !is_garbage_text(&sample) {
+                    items = inv_items;
+                    has_gid = inv_gid;
+                    coords_rotated = inv_rotated;
+                }
+            }
+        }
         let threshold = text_utils::fix_letterspaced_items(&mut items);
         if threshold > 0.10 {
             page_thresholds.insert(*page_num, threshold);
@@ -901,7 +1042,7 @@ pub fn extract_tables_in_regions_mem(
         let height = get_page_height(&doc, page_id).unwrap_or(792.0);
         page_heights.insert(*page_num, height);
 
-        let ((mut items, rects, lines), has_gid, coords_rotated) =
+        let ((mut items, rects, lines), has_gid, coords_rotated, _skipped_invisible) =
             extractor::content_stream::extract_page_text_items(
                 &doc,
                 page_id,
@@ -909,6 +1050,7 @@ pub fn extract_tables_in_regions_mem(
                 &font_cmaps,
                 false,
                 &mut style_cache,
+                &mut extractor::FormWalkBudget::new(),
             )?;
         let threshold = text_utils::fix_letterspaced_items(&mut items);
         if threshold > 0.10 {
@@ -1212,7 +1354,7 @@ pub fn detect_vector_grid_in_region_mem(
     let needed_pages = HashSet::from([page_1idx]);
     let font_cmaps = FontCMaps::from_doc_pages_fast(&doc, Some(&needed_pages));
     let page_h = get_page_height(&doc, page_id).unwrap_or(792.0);
-    let ((mut items, rects, lines), _has_gid, coords_rotated) =
+    let ((mut items, rects, lines), _has_gid, coords_rotated, _skipped_invisible) =
         extractor::content_stream::extract_page_text_items(
             &doc,
             page_id,
@@ -1220,6 +1362,7 @@ pub fn detect_vector_grid_in_region_mem(
             &font_cmaps,
             false,
             &mut extractor::FontStyleCache::new(),
+            &mut extractor::FormWalkBudget::new(),
         )?;
     text_utils::fix_letterspaced_items(&mut items);
 
@@ -1406,15 +1549,17 @@ mod vector_grid_tests {
         let &page_id = pages.get(&1).unwrap();
         let needed: HashSet<u32> = HashSet::from([1]);
         let cmaps = FontCMaps::from_doc_pages_fast(&doc, Some(&needed));
-        let ((items, rects, _lines), _has_gid, _rotated) = extract_page_text_items(
-            &doc,
-            page_id,
-            1,
-            &cmaps,
-            false,
-            &mut crate::extractor::FontStyleCache::new(),
-        )
-        .unwrap();
+        let ((items, rects, _lines), _has_gid, _rotated, _skipped_invisible) =
+            extract_page_text_items(
+                &doc,
+                page_id,
+                1,
+                &cmaps,
+                false,
+                &mut crate::extractor::FontStyleCache::new(),
+                &mut crate::extractor::FormWalkBudget::new(),
+            )
+            .unwrap();
 
         let (rect_tables, _) = detect_tables_from_rects(&items, &rects, 1);
         assert_eq!(rect_tables.len(), 1, "expected one rect-detected table");
@@ -1448,15 +1593,17 @@ mod vector_grid_tests {
         let &page_id = pages.get(&page_num).unwrap();
         let needed: HashSet<u32> = HashSet::from([page_num]);
         let cmaps = FontCMaps::from_doc_pages_fast(&doc, Some(&needed));
-        let ((items, rects, _lines), _has_gid, _rotated) = extract_page_text_items(
-            &doc,
-            page_id,
-            page_num,
-            &cmaps,
-            false,
-            &mut crate::extractor::FontStyleCache::new(),
-        )
-        .unwrap();
+        let ((items, rects, _lines), _has_gid, _rotated, _skipped_invisible) =
+            extract_page_text_items(
+                &doc,
+                page_id,
+                page_num,
+                &cmaps,
+                false,
+                &mut crate::extractor::FontStyleCache::new(),
+                &mut crate::extractor::FormWalkBudget::new(),
+            )
+            .unwrap();
 
         let (rect_tables, _) = detect_tables_from_rects(&items, &rects, page_num);
         rect_tables
@@ -2184,7 +2331,7 @@ pub fn extract_tables_with_structure_cells_mem(
         let height = get_page_height(&doc, page_id).unwrap_or(792.0);
         page_heights.insert(*page_num, height);
 
-        let ((mut items, _rects, _lines), _has_gid, coords_rotated) =
+        let ((mut items, _rects, _lines), _has_gid, coords_rotated, _skipped_invisible) =
             extractor::content_stream::extract_page_text_items(
                 &doc,
                 page_id,
@@ -2192,6 +2339,7 @@ pub fn extract_tables_with_structure_cells_mem(
                 &font_cmaps,
                 false,
                 &mut style_cache,
+                &mut extractor::FormWalkBudget::new(),
             )?;
         let threshold = text_utils::fix_letterspaced_items(&mut items);
         if threshold > 0.10 {
@@ -2986,7 +3134,7 @@ fn detect_tsr_quality_issue(
     let mut needed: HashSet<u32> = HashSet::new();
     needed.insert(page_1idx);
     let font_cmaps = FontCMaps::from_doc_pages_fast(&doc, Some(&needed));
-    let ((mut items, _rects, _lines), _has_gid, coords_rotated) =
+    let ((mut items, _rects, _lines), _has_gid, coords_rotated, _skipped_invisible) =
         extractor::content_stream::extract_page_text_items(
             &doc,
             page_id,
@@ -2994,6 +3142,7 @@ fn detect_tsr_quality_issue(
             &font_cmaps,
             false,
             &mut extractor::FontStyleCache::new(),
+            &mut extractor::FormWalkBudget::new(),
         )?;
     let adaptive_threshold = text_utils::fix_letterspaced_items(&mut items);
     let coords = if coords_rotated {

src/markdown/analysis.rs

@@ -171,6 +171,74 @@ pub(crate) fn is_toc_marker_heading(text: &str) -> bool {
 /// equation and absent from name-plus-number headings. A bare trailing colon
 /// is NOT a fragment signal either: real headings frequently end with colons
 /// ("Procedure:", "Steps for Using the Microscope:").
+/// True when the line opens with a section number ("3.", "2.1.4", "IV)").
+///
+/// Mirrors the acceptance of `heading::parse_numbering` rather than the
+/// stricter `convert::starts_with_section_number`, which deliberately
+/// requires two components because it bypasses isolation checks. Here a
+/// single "1." counts: numbering is independent evidence of a heading, and
+/// `heading.rs` applies its numbered-prefix allowance *after* consulting
+/// `is_heading_fragment`, so without this exemption a numbered
+/// sentence-case heading would be vetoed before that allowance can run.
+fn starts_with_numbering_prefix(t: &str) -> bool {
+    let Some(first) = t.split_whitespace().next() else {
+        return false;
+    };
+    let has_delimiter = first.ends_with(['.', ')', ':']);
+    let token = first.trim_end_matches(['.', ')', ':']);
+    if token.is_empty() {
+        return false;
+    }
+    let parts: Vec<&str> = token.split('.').collect();
+    let decimal = parts
+        .iter()
+        .all(|p| !p.is_empty() && p.len() <= 3 && p.chars().all(|c| c.is_ascii_digit()));
+    if decimal {
+        // "1." / "2.1." carry a delimiter; "2.3 Title" is written without
+        // one, so a multi-component number is accepted bare. A bare single
+        // number ("3 apples") is not — that is ordinary prose.
+        return has_delimiter || parts.len() >= 2;
+    }
+    // Roman numerals go through the heading parser's own grammar so the two
+    // agree: uppercase I/V/X/L/C only, at most 8 characters. A looser rule
+    // here would exempt markers the parser rejects — "iv)" or "d)" from an
+    // alphabetical list — letting an ordinary list item bypass the veto and
+    // reach heading promotion.
+    //
+    // A delimiter is also required: a bare leading "I" is the pronoun far
+    // more often than a section number.
+    has_delimiter && crate::markdown::heading::roman_value(token).is_some()
+}
+
+/// True when the line reads as a title rather than a sentence: every
+/// content word (ignoring minor words) starts uppercase. Used to spare real
+/// headings from the dangling-verb veto — "Bond Yields" is a section title,
+/// "the method yields" is a stranded clause, and only the casing tells them
+/// apart.
+fn looks_title_case(t: &str) -> bool {
+    const MINOR: &[&str] = &[
+        "a", "an", "the", "of", "and", "or", "for", "to", "in", "on", "at", "by", "with", "from",
+        "as", "is", "are", "that", "than", "into",
+    ];
+    let mut content = 0usize;
+    let mut capitalized = 0usize;
+    for w in t.split_whitespace() {
+        let cleaned: String = w.chars().filter(|c| c.is_alphabetic()).collect();
+        if cleaned.is_empty() {
+            continue;
+        }
+        if MINOR.contains(&cleaned.to_lowercase().as_str()) {
+            continue;
+        }
+        content += 1;
+        if cleaned.chars().next().is_some_and(char::is_uppercase) {
+            capitalized += 1;
+        }
+    }
+    // A single content word ("Yields") is a title by default.
+    content == 0 || capitalized == content
+}
+
 pub(crate) fn is_heading_fragment(text: &str) -> bool {
     let t = text.trim_end();
 
@@ -244,9 +312,133 @@ pub(crate) fn is_heading_fragment(text: &str) -> bool {
     if t.ends_with(':') && t.split_whitespace().any(is_equation_number) {
         return true;
     }
+
+    // Dangling clause: a stranded sentence lead-in ends on a relational
+    // verb with no terminal punctuation — "Note that the exact error equals"
+    // left ahead of its formula when a phantom table dissolved.
+    //
+    // Gated on the line reading as prose rather than a title. Case is the
+    // discriminator the trailing word alone cannot provide: a heading is
+    // title case ("Bond Yields", "The Method Yields") while a stranded
+    // lead-in is sentence case ("the method yields"). Without this gate the
+    // veto eats real headings — "Bond Yields", "Crop Yields" and any wrapped
+    // title-case heading the preprocessor failed to merge.
+    if !t.ends_with(['.', '!', '?', ':', ';', ')', ']'])
+        && !looks_title_case(t)
+        && !starts_with_numbering_prefix(t)
+    {
+        if let Some(last) = t.split_whitespace().next_back() {
+            let word: String = last
+                .trim_matches(|c: char| !c.is_alphanumeric())
+                .to_lowercase();
+            // Relational verbs only, and only those with no common noun
+            // sense. "yields" was dropped for exactly that reason: "Bond
+            // Yields" is a real section title. Function words, copulas and
+            // auxiliaries were measured and rejected outright — a heading
+            // that wraps across lines ends on those, and suppressing them
+            // destroyed real IRS Publication 17 headings.
+            const DANGLING_TAIL: &[&str] =
+                &["equals", "denotes", "implies", "satisfies", "signifies"];
+            if DANGLING_TAIL.contains(&word.as_str()) {
+                return true;
+            }
+        }
+    }
     false
 }
 
+#[cfg(test)]
+mod fragment_heading_tests {
+    use super::is_heading_fragment;
+
+    #[test]
+    fn dangling_tail_marks_stranded_clause() {
+        // opendataloader 01030000000144: left behind when a phantom table
+        // dissolved, ahead of its formula on the next line.
+        assert!(is_heading_fragment("Note that the exact error equals"));
+        assert!(is_heading_fragment("The remainder term satisfies"));
+        assert!(is_heading_fragment("we conclude that the sum equals"));
+    }
+
+    #[test]
+    fn real_headings_survive() {
+        assert!(!is_heading_fragment("Introduction"));
+        assert!(!is_heading_fragment("Error Analysis"));
+        assert!(!is_heading_fragment("Materials and Methods"));
+        assert!(!is_heading_fragment("Results"));
+        assert!(!is_heading_fragment("3.2 Richardson Extrapolation"));
+        assert!(!is_heading_fragment("Discussion and Conclusions"));
+        // Terminal punctuation means the clause is complete.
+        assert!(!is_heading_fragment("What is a Derivative?"));
+        assert!(!is_heading_fragment("Procedure:"));
+        assert!(!is_heading_fragment("Note that this is important."));
+    }
+
+    #[test]
+    fn title_case_headings_ending_in_a_verb_survive() {
+        // "yields" is also a plural noun; these are real section titles.
+        assert!(!is_heading_fragment("Bond Yields"));
+        assert!(!is_heading_fragment("Crop Yields"));
+        assert!(!is_heading_fragment("Dividend Yields"));
+        assert!(!is_heading_fragment("Yields"));
+        // A wrapped title-case heading whose first line ends on a listed
+        // verb must survive even if the preprocessor failed to merge it.
+        assert!(!is_heading_fragment("The Theorem Implies"));
+        assert!(!is_heading_fragment("What This Denotes"));
+    }
+
+    #[test]
+    fn numbered_sentence_case_headings_survive() {
+        // heading.rs consults is_heading_fragment BEFORE applying its
+        // numbered-prefix allowance, so the veto must not pre-empt it.
+        assert!(!is_heading_fragment("1. What the model implies"));
+        assert!(!is_heading_fragment("2.3 How the estimator satisfies"));
+        assert!(!is_heading_fragment("IV) What this denotes"));
+        // Without numbering the same wording is still a stranded clause.
+        assert!(is_heading_fragment("What the model implies"));
+        // A bare leading number or pronoun is prose, not numbering.
+        assert!(is_heading_fragment("3 apples and what that implies"));
+        assert!(is_heading_fragment("I think the model implies"));
+        // Markers heading::parse_numbering rejects must not be exempted
+        // either, or an ordinary list item bypasses the veto: lowercase
+        // roman, alphabetical markers, and over-long tokens.
+        assert!(is_heading_fragment("iv) the estimator satisfies"));
+        assert!(is_heading_fragment("d) the value implies"));
+        // Unsupported character (M is outside the parser's I/V/X/L/C set).
+        assert!(is_heading_fragment("MMMM. the value implies"));
+        // Over-long token: nine valid characters, so this exercises the
+        // 8-character bound rather than the character set.
+        assert!(is_heading_fragment("IIIIIIIII. the value implies"));
+        // Eight is still within the bound and stays exempt.
+        assert!(!is_heading_fragment("IIIIIIII. What this implies"));
+        // Uppercase roman within the parser's grammar is still exempt.
+        assert!(!is_heading_fragment("IV. What this denotes"));
+        assert!(!is_heading_fragment("XII) What this implies"));
+    }
+
+    #[test]
+    fn wrapped_headings_are_not_fragments() {
+        // A heading that wraps across lines ends on a function word. These
+        // are real headings from IRS Publication 17 and must survive.
+        assert!(!is_heading_fragment("Casualty and"));
+        assert!(!is_heading_fragment("Rule 10. You Must Be at"));
+        assert!(!is_heading_fragment("Higher Standard Deduction for"));
+        assert!(!is_heading_fragment("Qualifying Child of"));
+        assert!(!is_heading_fragment("When Can I Withdraw or"));
+        // Copulas and auxiliaries also end real wrapped headings.
+        assert!(!is_heading_fragment("Rule 15. Your AGI Must Be"));
+        assert!(!is_heading_fragment("What Medical Expenses Are"));
+        assert!(!is_heading_fragment("Rule 13. You Must Have"));
+        assert!(!is_heading_fragment("When Can a Roth IRA Be"));
+    }
+
+    #[test]
+    fn dangling_check_is_case_insensitive() {
+        // All-caps is not sentence case, so the veto must not fire there.
+        assert!(!is_heading_fragment("THE REMAINDER EQUALS"));
+    }
+}
+
 /// Compute the Y-gap threshold for paragraph break detection.
 ///
 /// Instead of using a fixed multiple of base_size (which fails for double-spaced

src/markdown/heading.rs

@@ -127,7 +127,9 @@ fn visual_style(line: &TextLine) -> Option<VisualStyle> {
     })
 }
 
-fn roman_value(token: &str) -> Option<u32> {
+/// Shared with `analysis::starts_with_numbering_prefix` so the veto
+/// exemption and the heading parser agree on what a roman numeral is.
+pub(super) fn roman_value(token: &str) -> Option<u32> {
     if token.is_empty() || token.len() > 8 {
         return None;
     }

src/python.rs

@@ -271,6 +271,12 @@ pub struct PyTextItem {
     pub is_strikeout: bool,
     #[pyo3(get)]
     pub item_type: String,
+    /// Marked Content ID from the content stream's BDC/BMC operator, None
+    /// when the text is not part of marked content. Join with the
+    /// (page, mcid) pairs from extract_structure_elements to attach
+    /// structure-tree roles (headings, paragraphs, ...) in tagged PDFs.
+    #[pyo3(get)]
+    pub mcid: Option<i64>,
 }
 
 #[pymethods]
@@ -286,6 +292,32 @@ impl PyTextItem {
     }
 }
 
+/// One structure-tree element reference from a tagged PDF.
+#[pyclass(name = "StructureElement")]
+#[derive(Clone)]
+pub struct PyStructureElement {
+    /// 1-indexed page number (matches TextItem.page).
+    #[pyo3(get)]
+    pub page: u32,
+    /// Marked Content ID from the page's content stream (matches
+    /// TextItem.mcid).
+    #[pyo3(get)]
+    pub mcid: i64,
+    /// Standard structure type name ("H1".."H6", "P", "Table", "TD", ...).
+    #[pyo3(get)]
+    pub role: String,
+}
+
+#[pymethods]
+impl PyStructureElement {
+    fn __repr__(&self) -> String {
+        format!(
+            "StructureElement(page={}, mcid={}, role='{}')",
+            self.page, self.mcid, self.role
+        )
+    }
+}
+
 // ---------------------------------------------------------------------------
 // Helpers
 // ---------------------------------------------------------------------------
@@ -356,6 +388,18 @@ fn convert_text_items(items: Vec<crate::TextItem>) -> Vec<PyTextItem> {
             is_underline: item.is_underline,
             is_strikeout: item.is_strikeout,
             item_type: item_type_str(&item.item_type),
+            mcid: item.mcid,
+        })
+        .collect()
+}
+
+fn convert_structure_elements(elements: Vec<crate::StructureElement>) -> Vec<PyStructureElement> {
+    elements
+        .into_iter()
+        .map(|e| PyStructureElement {
+            page: e.page,
+            mcid: e.mcid,
+            role: e.role,
         })
         .collect()
 }
@@ -613,6 +657,48 @@ fn extract_pages_markdown_bytes(
     Ok(to_py_pages_result(result))
 }
 
+/// Extract structure-tree element references from a tagged PDF file.
+///
+/// Parses the document's structure tree (when present) and returns one
+/// entry per marked-content reference, resolved to its 1-indexed page,
+/// MCID, and structure type name ("H1".."H6", "P", "Table", ...). Returns
+/// an empty list when the PDF is not tagged.
+///
+/// Join (page, mcid) against the page/mcid attributes from
+/// [`extract_text_with_positions`] to attach heading levels and other
+/// semantic roles to extracted text.
+///
+/// Args:
+///     path: Path to the PDF file.
+///     pages: Optional list of 1-indexed pages (matching TextItem.page).
+///         When None (default), the whole document is returned.
+///
+/// Returns:
+///     List of StructureElement sorted by (page, mcid).
+#[pyfunction]
+#[pyo3(signature = (path, pages=None))]
+fn extract_structure_elements(
+    path: &str,
+    pages: Option<Vec<u32>>,
+) -> PyResult<Vec<PyStructureElement>> {
+    let elements = crate::extract_structure_elements(path, pages.as_deref()).map_err(to_py_err)?;
+    Ok(convert_structure_elements(elements))
+}
+
+/// Extract structure-tree element references from tagged PDF bytes.
+///
+/// See [`extract_structure_elements`] for details.
+#[pyfunction]
+#[pyo3(signature = (data, pages=None))]
+fn extract_structure_elements_bytes(
+    data: &[u8],
+    pages: Option<Vec<u32>>,
+) -> PyResult<Vec<PyStructureElement>> {
+    let elements =
+        crate::extract_structure_elements_mem(data, pages.as_deref()).map_err(to_py_err)?;
+    Ok(convert_structure_elements(elements))
+}
+
 /// Python module definition.
 #[pymodule]
 fn pdf_inspector(m: &Bound<'_, PyModule>) -> PyResult<()> {
@@ -620,6 +706,7 @@ fn pdf_inspector(m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_class::<PyPageOcrReasons>()?;
     m.add_class::<PyPdfClassification>()?;
     m.add_class::<PyTextItem>()?;
+    m.add_class::<PyStructureElement>()?;
     m.add_class::<PyRegionText>()?;
     m.add_class::<PyPageRegionTexts>()?;
     m.add_class::<PyPageMarkdown>()?;
@@ -634,6 +721,8 @@ fn pdf_inspector(m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_function(wrap_pyfunction!(extract_text_bytes, m)?)?;
     m.add_function(wrap_pyfunction!(extract_text_with_positions, m)?)?;
     m.add_function(wrap_pyfunction!(extract_text_with_positions_bytes, m)?)?;
+    m.add_function(wrap_pyfunction!(extract_structure_elements, m)?)?;
+    m.add_function(wrap_pyfunction!(extract_structure_elements_bytes, m)?)?;
     m.add_function(wrap_pyfunction!(extract_text_in_regions, m)?)?;
     m.add_function(wrap_pyfunction!(extract_text_in_regions_bytes, m)?)?;
     m.add_function(wrap_pyfunction!(extract_pages_markdown, m)?)?;

src/tables/detect_heuristic.rs

@@ -435,6 +435,72 @@ fn revised_table_cell_indices(
         .collect()
 }
 
+/// Index of candidate "body" items (larger-font attachment targets) sorted by
+/// Y, so script-attachment checks scan a narrow Y window instead of the whole
+/// page per candidate.
+struct ScriptBodyIndex<'a> {
+    /// (y, item), sorted ascending by y
+    by_y: Vec<(f32, &'a TextItem)>,
+    /// widest vertical attachment window any body item can produce
+    max_window: f32,
+}
+
+impl<'a> ScriptBodyIndex<'a> {
+    fn new(items: &'a [TextItem]) -> Self {
+        // Smallest table-candidate font is 6pt, so any possible attachment
+        // target is at least 6 x 1.2 pt.
+        let mut by_y: Vec<(f32, &TextItem)> = items
+            .iter()
+            .filter(|i| i.font_size >= 6.0 * 1.2)
+            .map(|i| (i.y, i))
+            .collect();
+        by_y.sort_by(|a, b| a.0.total_cmp(&b.0));
+        let max_window = by_y
+            .iter()
+            .map(|(_, i)| i.font_size * 0.8)
+            .fold(0.0f32, f32::max);
+        Self { by_y, max_window }
+    }
+
+    /// True when a small-font item is horizontally attached to a larger-font
+    /// item at a script baseline offset — a sub/superscript in running text
+    /// or math (equation subscripts, footnote markers). Script attachments
+    /// are not table cells; without this filter, display equations with
+    /// sub/superscripts form phantom small-font table regions (e.g. TeX
+    /// papers where log subscripts cluster with footnote lines into a fake
+    /// 3-column table). A genuine baseline offset is required so same-line
+    /// table neighbours (a small cell beside a larger label cell) are never
+    /// classified as scripts.
+    ///
+    /// `min_anchor_size` additionally constrains what counts as an
+    /// attachment target: the small-font pass accepts any sufficiently
+    /// larger item (0.0), while the body-font pass requires a heading-sized
+    /// anchor so a body-size table cell beside a slightly larger label with
+    /// baseline jitter is never treated as a script.
+    fn is_script_attachment(&self, small: &TextItem, min_anchor_size: f32) -> bool {
+        let attach_gap = small.font_size.max(4.0) * 0.6;
+        let lo = self
+            .by_y
+            .partition_point(|(y, _)| *y < small.y - self.max_window);
+        self.by_y[lo..]
+            .iter()
+            .take_while(|(y, _)| *y <= small.y + self.max_window)
+            .any(|(_, body)| {
+                let dy = (small.y - body.y).abs();
+                body.font_size >= small.font_size * 1.2
+                    && body.font_size >= min_anchor_size
+                    && dy > body.font_size * 0.05
+                    && dy <= body.font_size * 0.8
+                    && {
+                        let gap_after_body = small.x - (body.x + body.width);
+                        let gap_before_body = body.x - (small.x + small.width);
+                        (-attach_gap..=attach_gap).contains(&gap_after_body)
+                            || (-attach_gap..=attach_gap).contains(&gap_before_body)
+                    }
+            })
+    }
+}
+
 /// Detect tables in a set of text items from a single page
 pub fn detect_tables(items: &[TextItem], base_font_size: f32, skip_body_font: bool) -> Vec<Table> {
     detect_tables_with_page_width(items, base_font_size, skip_body_font, content_width(items))
@@ -483,6 +549,27 @@ pub(crate) fn detect_tables_with_page_width(
     // === Pass 1: Small-font tables (existing behavior) ===
     let table_font_threshold = base_font_size * 0.90;
 
+    // Mark sub/superscript attachments once per pass. They stay candidates —
+    // the masks only remove them from region qualification and column/row
+    // geometry.
+    //
+    // The two passes need different anchor thresholds. In the small-font pass
+    // any sufficiently larger neighbour is a plausible base for a script. In
+    // the body-font pass the candidates are themselves body-sized
+    // (0.85..1.05x), so a merely "slightly larger" neighbour is usually a bold
+    // label or an adjacent column header, not the base of a superscript —
+    // treating it as one would strip real cells out of the geometry and lose
+    // the table. Requiring a heading-sized anchor (>= 1.15x base) keeps the
+    // body pass to genuine scripts hanging off headings.
+    let script_index = ScriptBodyIndex::new(items);
+    let script_flags: Vec<bool> = items
+        .iter()
+        .map(|item| script_index.is_script_attachment(item, 0.0))
+        .collect();
+    let body_script_flags: Vec<bool> = items
+        .iter()
+        .map(|item| script_index.is_script_attachment(item, base_font_size * 1.15))
+        .collect();
     let table_candidates: Vec<(usize, &TextItem)> = items
         .iter()
         .enumerate()
@@ -494,7 +581,14 @@ pub(crate) fn detect_tables_with_page_width(
         .collect();
 
     if table_candidates.len() >= 6 {
-        let regions = find_table_regions(&table_candidates);
+        // Qualify regions from non-script items: a cluster of sub/superscripts
+        // must not, on its own, mark out a table region.
+        let region_evidence: Vec<(usize, &TextItem)> = table_candidates
+            .iter()
+            .filter(|(idx, _)| !script_flags[*idx])
+            .cloned()
+            .collect();
+        let regions = find_table_regions(&region_evidence);
 
         for (y_min, y_max) in regions {
             let region_items: Vec<(usize, &TextItem)> = table_candidates
@@ -508,7 +602,9 @@ pub(crate) fn detect_tables_with_page_width(
             }
 
             if let Some(mut table) =
-                detect_table_in_region(&region_items, TableDetectionMode::SmallFont)
+                detect_table_in_region(&region_items, TableDetectionMode::SmallFont, &|i| {
+                    script_flags[i]
+                })
             {
                 // Try to recover body-font header row above the small-font table
                 recover_header_row(&mut table, items, table_font_threshold);
@@ -553,8 +649,20 @@ pub(crate) fn detect_tables_with_page_width(
             body_font_low,
             body_font_high,
         );
+        // Scripts are NOT filtered out of the candidate set here, mirroring
+        // the small-font pass: they must stay eligible for cell assignment so
+        // a sub/superscript that belongs inside a table cell keeps its text.
+        // The heading-anchored `body_script_flags` mask removes them from
+        // geometry only.
         if body_candidates.len() >= 6 {
-            let regions = find_table_regions_strict(&body_candidates);
+            // Same reasoning as the small-font pass: scripts do not qualify
+            // regions, but remain available for cell assignment within one.
+            let region_evidence: Vec<(usize, &TextItem)> = body_candidates
+                .iter()
+                .filter(|(idx, _)| !body_script_flags[*idx])
+                .cloned()
+                .collect();
+            let regions = find_table_regions_strict(&region_evidence);
             log::debug!("body-font: {} strict regions found", regions.len());
 
             for (y_min, y_max, _x_min, _x_max) in &regions {
@@ -580,7 +688,9 @@ pub(crate) fn detect_tables_with_page_width(
                 }
 
                 if let Some(table) =
-                    detect_table_in_region(&region_items, TableDetectionMode::BodyFont)
+                    detect_table_in_region(&region_items, TableDetectionMode::BodyFont, &|i| {
+                        body_script_flags[i]
+                    })
                 {
                     tables.push(table);
                 }
@@ -808,10 +918,30 @@ fn find_table_regions_strict(items: &[(usize, &TextItem)]) -> Vec<(f32, f32, f32
     regions
 }
 
-/// Detect a table within a specific region
-fn detect_table_in_region(items: &[(usize, &TextItem)], mode: TableDetectionMode) -> Option<Table> {
-    // Find column boundaries
-    let columns = find_column_boundaries(items, mode);
+/// Detect a table within a specific region.
+///
+/// `is_script` marks items that are sub/superscript attachments. Those are
+/// excluded from the *geometry* — they must not be able to create a column,
+/// which is how equation subscript clusters used to fabricate phantom grids —
+/// but they remain eligible for cell assignment, so legitimate cell content
+/// (exponents in an engineering-notation table, footnote markers) stays in
+/// the cell it belongs to instead of leaking out into the reading order.
+fn detect_table_in_region(
+    items: &[(usize, &TextItem)],
+    mode: TableDetectionMode,
+    is_script: &dyn Fn(usize) -> bool,
+) -> Option<Table> {
+    // Column geometry from non-script items only.
+    let geometry_items: Vec<(usize, &TextItem)> = items
+        .iter()
+        .filter(|(idx, _)| !is_script(*idx))
+        .cloned()
+        .collect();
+    // A region that is *entirely* scripts has no table structure at all.
+    if geometry_items.is_empty() {
+        return None;
+    }
+    let columns = find_column_boundaries(&geometry_items, mode);
     let min_cols = 2;
     if columns.len() < min_cols || columns.len() > 25 {
         log::debug!(
@@ -822,8 +952,8 @@ fn detect_table_in_region(items: &[(usize, &TextItem)], mode: TableDetectionMode
         return None;
     }
 
-    // Find row boundaries
-    let rows = find_row_boundaries(items);
+    // Find row boundaries (geometry items only, same reasoning)
+    let rows = find_row_boundaries(&geometry_items);
     let min_rows = 2;
     if rows.len() < min_rows {
         log::debug!(
@@ -842,6 +972,11 @@ fn detect_table_in_region(items: &[(usize, &TextItem)], mode: TableDetectionMode
     );
 
     // Verify this looks like a table: multiple items should align to columns
+    // Validate against ALL items, including scripts. Columns are derived from
+    // non-script geometry so scripts cannot *create* a column, but excluding
+    // them from validation too would let a region manufacture alignment: drop
+    // the awkward items and whatever remains looks like a tidy grid. Block
+    // diagrams did exactly that. Everything in the region must fit.
     let col_alignment = check_column_alignment(items, &columns, mode);
     let min_alignment = match mode {
         TableDetectionMode::SmallFont => 0.5,
@@ -912,6 +1047,29 @@ fn detect_table_in_region(items: &[(usize, &TextItem)], mode: TableDetectionMode
         cells.push(row_cells);
     }
 
+    // Validation 0 (small-font pass only): reject tiny all-numeric
+    // fragments. A <=2-row grid whose every cell is a bare 1-2 digit number
+    // carries no tabular information — in practice these are
+    // exponent/subscript clusters from display math that happen to align.
+    // Body-font tables are not subject to this veto: their cells cannot be
+    // script glyphs.
+    if matches!(mode, TableDetectionMode::SmallFont) {
+        let nonempty_cells: Vec<&String> =
+            cells.iter().flatten().filter(|c| !c.is_empty()).collect();
+        if rows.len() <= 2
+            && !nonempty_cells.is_empty()
+            && nonempty_cells
+                .iter()
+                .all(|c| c.len() <= 2 && c.chars().all(|ch| ch.is_ascii_digit()))
+        {
+            log::debug!(
+                "  validation 0 fail: tiny all-numeric fragment ({} cells)",
+                nonempty_cells.len()
+            );
+            return None;
+        }
+    }
+
     // Validation 1: some rows should have content in first column.
     // Use a lower threshold (25%) for tables with wrapped cells where
     // continuation lines leave the first column empty.
@@ -1977,6 +2135,146 @@ fn try_add_label_column(
 
 #[cfg(test)]
 mod tests {
+
+    fn make_item(text: &str, x: f32, y: f32, font_size: f32, width: f32) -> TextItem {
+        TextItem {
+            text: text.to_string(),
+            x,
+            y,
+            width,
+            height: font_size,
+            font: "TestFont".to_string(),
+            font_size,
+            page: 1,
+            is_bold: false,
+            is_italic: false,
+            is_underline: false,
+            is_strikeout: false,
+            item_type: ItemType::Text,
+            mcid: None,
+        }
+    }
+
+    #[test]
+    fn script_attachment_detects_subscript_after_body_text() {
+        let body = make_item("log", 100.0, 500.0, 10.0, 15.0);
+        let sub = make_item("10", 115.5, 497.0, 7.0, 7.0);
+        let items = vec![body, sub.clone()];
+        assert!(ScriptBodyIndex::new(&items).is_script_attachment(&sub, 0.0));
+    }
+
+    #[test]
+    fn script_attachment_detects_superscript_footnote_marker() {
+        let body = make_item("Hartley", 200.0, 500.0, 10.0, 35.0);
+        let sup = make_item("2", 235.8, 504.0, 6.6, 3.5);
+        let items = vec![body, sup.clone()];
+        assert!(ScriptBodyIndex::new(&items).is_script_attachment(&sup, 0.0));
+    }
+
+    #[test]
+    fn script_attachment_ignores_small_cell_far_from_body_text() {
+        let body = make_item("Revenue", 100.0, 500.0, 10.0, 40.0);
+        let cell = make_item("1,234", 180.0, 500.0, 7.0, 20.0);
+        let items = vec![body, cell.clone()];
+        assert!(!ScriptBodyIndex::new(&items).is_script_attachment(&cell, 0.0));
+    }
+
+    #[test]
+    fn body_pass_anchor_spares_cells_beside_slightly_larger_labels() {
+        // A body-font table cell (10pt) sitting beside a slightly larger,
+        // NON-heading label (12.5pt) with a little baseline jitter. The
+        // small-font pass treats any larger neighbour as a possible script
+        // base, but the body pass must not: at body sizes a slightly larger
+        // neighbour is a bold label or column header, and flagging the cell
+        // would strip it out of the table geometry and lose the table.
+        // Cell at the low end of the body band (0.85x base) beside a 10.5pt
+        // label. 10.5 clears the inherent 1.2x-of-cell rule (10.2) but falls
+        // below the body pass's heading anchor (11.5), which is exactly the
+        // band where the two masks must disagree.
+        let label = make_item("Revenue", 100.0, 500.0, 10.5, 40.0);
+        let cell = make_item("1,234", 141.0, 496.5, 8.5, 22.0);
+        let items = vec![label, cell.clone()];
+        let index = ScriptBodyIndex::new(&items);
+        let base = 10.0;
+        assert!(
+            index.is_script_attachment(&cell, 0.0),
+            "small-font pass anchor should still see this as an attachment"
+        );
+        assert!(
+            !index.is_script_attachment(&cell, base * 1.15),
+            "body pass must not treat a cell beside a slightly larger label \
+             as a script — that removes real cells from the geometry"
+        );
+        // A genuine heading-sized anchor still qualifies in the body pass.
+        let heading = make_item("Section", 100.0, 500.0, 20.0, 60.0);
+        let sup = make_item("3", 161.0, 508.0, 10.0, 5.0);
+        let h_items = vec![heading, sup.clone()];
+        assert!(
+            ScriptBodyIndex::new(&h_items).is_script_attachment(&sup, base * 1.15),
+            "script hanging off a heading must still be excluded in the body pass"
+        );
+    }
+
+    #[test]
+    fn script_attachment_ignores_same_baseline_neighbor_cell() {
+        // A small cell beside a larger label on the SAME baseline is a table
+        // layout, not a subscript — a genuine baseline offset is required.
+        let label = make_item("Total", 100.0, 500.0, 10.0, 25.0);
+        let cell = make_item("42", 127.0, 500.0, 7.5, 9.0);
+        let items = vec![label, cell.clone()];
+        assert!(!ScriptBodyIndex::new(&items).is_script_attachment(&cell, 0.0));
+    }
+
+    #[test]
+    fn script_attachment_ignores_neighbor_on_different_line() {
+        let body = make_item("Header", 100.0, 500.0, 10.0, 30.0);
+        let cell = make_item("42", 131.0, 486.0, 7.0, 10.0);
+        let items = vec![body, cell.clone()];
+        assert!(!ScriptBodyIndex::new(&items).is_script_attachment(&cell, 0.0));
+    }
+
+    /// Equation-subscript + footnote layout from Shannon entropy.pdf page 1,
+    /// with real coordinates. Without the larger-font anchors the small items
+    /// alone DO form a phantom table — proving the layout reaches detection —
+    /// and adding the anchors must suppress it.
+    fn shannon_page1_small_items() -> Vec<TextItem> {
+        vec![
+            make_item("2", 267.4, 133.9, 7.4, 3.7),
+            make_item("10", 306.2, 133.9, 7.4, 7.4),
+            make_item("10", 342.7, 133.9, 7.4, 7.4),
+            make_item("10", 325.0, 118.9, 7.4, 7.4),
+            make_item("Bell System Technical Journal,", 295.7, 101.9, 8.0, 95.0),
+            make_item(
+                "April 1924, p. 324; Certain Topics in",
+                396.7,
+                101.9,
+                8.0,
+                130.0,
+            ),
+            make_item("v. 47, April 1928, p. 617.", 250.9, 92.5, 8.0, 90.0),
+            make_item("Bell System Technical Journal,", 264.2, 82.6, 8.0, 95.0),
+            make_item("July 1928, p. 535.", 364.3, 82.6, 8.0, 65.0),
+        ]
+    }
+
+    #[test]
+    fn equation_scripts_do_not_form_phantom_table() {
+        let bare = shannon_page1_small_items();
+        assert!(
+            !detect_tables(&bare, 10.0, false).is_empty(),
+            "test layout must form a phantom table when the filter cannot fire"
+        );
+        let mut items = shannon_page1_small_items();
+        items.push(make_item("log", 253.0, 137.0, 10.0, 13.5));
+        items.push(make_item("log", 291.5, 137.0, 10.0, 13.5));
+        items.push(make_item("log", 328.0, 137.0, 10.0, 13.5));
+        items.push(make_item("log", 310.3, 122.0, 10.0, 13.5));
+        let tables = detect_tables(&items, 10.0, false);
+        assert!(
+            tables.is_empty(),
+            "equation scripts + footnotes must not become a table: {tables:?}"
+        );
+    }
     use super::*;
     use crate::types::ItemType;
 

src/tables/detect_rects.rs

@@ -1,6 +1,6 @@
 //! Rectangle-based table detection using union-find clustering.
 
-use std::collections::HashMap;
+use std::collections::{BTreeMap, HashMap, HashSet};
 
 use log::debug;
 
@@ -78,19 +78,111 @@ pub(crate) fn rects_overlap(a: &(f32, f32, f32, f32), b: &(f32, f32, f32, f32),
     !(a_right < b_left || b_right < a_left || a_top < b_bottom || b_top < a_bottom)
 }
 
+fn grid_coord(value: f32, cell: f32) -> i32 {
+    (value / cell).floor().clamp(-1_000_000.0, 1_000_000.0) as i32
+}
+
+/// Inclusive grid range. `None` if the rect covers more cells than we will
+/// materialize — those rects are clustered via a bounded fallback.
+fn grid_span(lo: f32, hi: f32, cell: f32) -> Option<std::ops::RangeInclusive<i32>> {
+    let a = grid_coord(lo.min(hi), cell);
+    let b = grid_coord(lo.max(hi), cell);
+    let span = b.saturating_sub(a);
+    if span > 64 {
+        return None;
+    }
+    Some(a..=b)
+}
+
+fn union_bucket_pairs(
+    uf: &mut UnionFind,
+    rects: &[(f32, f32, f32, f32)],
+    bucket: &[usize],
+    tolerance: f32,
+) {
+    let m = bucket.len();
+    let mut pairs = 0usize;
+    'cell: for a in 0..m {
+        let i = bucket[a];
+        if uf.component_size(i) >= MAX_CLUSTER_RECTS {
+            continue;
+        }
+        for &j in &bucket[a + 1..] {
+            if pairs >= MAX_CLUSTER_PAIRS_PER_CELL {
+                break 'cell;
+            }
+            if uf.component_size(j) >= MAX_CLUSTER_RECTS {
+                continue;
+            }
+            pairs += 1;
+            if rects_overlap(&rects[i], &rects[j], tolerance) {
+                uf.union(i, j);
+                if uf.component_size(i) >= MAX_CLUSTER_RECTS {
+                    break;
+                }
+            }
+        }
+    }
+}
+
+fn union_rect_against_bands(
+    uf: &mut UnionFind,
+    rects: &[(f32, f32, f32, f32)],
+    i: usize,
+    bands: &BTreeMap<i32, Vec<usize>>,
+    lo: i32,
+    hi: i32,
+    tolerance: f32,
+) {
+    if uf.component_size(i) >= MAX_CLUSTER_RECTS {
+        return;
+    }
+    let mut pairs = 0usize;
+    let mut seen = HashSet::new();
+    for (_, bucket) in bands.range(lo..=hi) {
+        for &j in bucket {
+            if !seen.insert(j) {
+                continue;
+            }
+            if pairs >= MAX_CLUSTER_PAIRS_PER_CELL {
+                return;
+            }
+            if i == j || uf.component_size(j) >= MAX_CLUSTER_RECTS {
+                continue;
+            }
+            pairs += 1;
+            if rects_overlap(&rects[i], &rects[j], tolerance) {
+                uf.union(i, j);
+                if uf.component_size(i) >= MAX_CLUSTER_RECTS {
+                    return;
+                }
+            }
+        }
+    }
+}
+
 /// Maximum component size for rect clustering.  No real table has thousands
 /// of cell rects — once a component exceeds this, it is a vector drawing or
 /// page-spanning clipping path.  We skip overlap checks for rects already in
-/// an oversized component, keeping the original O(n²) loop but making it
-/// effectively O(n) for pathological pages.
+/// an oversized component.
 const MAX_CLUSTER_RECTS: usize = 2000;
 
+/// Pairwise-disjoint rects never merge, so a component-size cap does not
+/// stop an all-pairs loop. Rects are hashed into this many points of grid
+/// and compared only against others in the same cell.
+const CLUSTER_GRID_CELL: f32 = 64.0;
+
+/// All-pairs AABB tests allowed inside one grid cell. A real table cell is
+/// tens of points wide, so a 64-pt cell holds a handful of neighbors — not
+/// thousands of stacked drawings.
+const MAX_CLUSTER_PAIRS_PER_CELL: usize = 16_384;
+
 /// Cluster rects by spatial overlap using union-find.
 /// Returns groups of rect indices; only groups with ≥ `min_size` rects are returned.
 ///
-/// Skips overlap checks for rects whose component has already exceeded
-/// [`MAX_CLUSTER_RECTS`], so pages with tens of thousands of vector-drawing
-/// rects complete in milliseconds instead of minutes.
+/// Overlap tests run inside a uniform grid so far-apart rects are never
+/// compared, and each cell is pair-capped so a dense stack cannot go
+/// quadratic or starve an independent table in another cell.
 pub(crate) fn cluster_rects(
     rects: &[(f32, f32, f32, f32)],
     tolerance: f32,
@@ -98,23 +190,144 @@ pub(crate) fn cluster_rects(
 ) -> Vec<Vec<usize>> {
     let n = rects.len();
     let mut uf = UnionFind::new(n);
+    let cell = CLUSTER_GRID_CELL.max(tolerance * 4.0);
 
-    for i in 0..n {
-        // If rect i is already in an oversized component, no point comparing
-        // it against further rects — the component won't be used for table
-        // detection anyway.
+    let mut grid: HashMap<(i32, i32), Vec<usize>> = HashMap::new();
+    let mut large: Vec<usize> = Vec::new();
+    for (idx, &(x, y, w, h)) in rects.iter().enumerate() {
+        match (
+            grid_span(x - tolerance, x + w + tolerance, cell),
+            grid_span(y - tolerance, y + h + tolerance, cell),
+        ) {
+            (Some(xs), Some(ys)) => {
+                for gx in xs {
+                    for gy in ys.clone() {
+                        grid.entry((gx, gy)).or_default().push(idx);
+                    }
+                }
+            }
+            _ => large.push(idx),
+        }
+    }
+
+    let mut keys: Vec<_> = grid.keys().copied().collect();
+    keys.sort_unstable();
+    let mut keys_by_y: BTreeMap<i32, Vec<i32>> = BTreeMap::new();
+    for &key in &keys {
+        union_bucket_pairs(&mut uf, rects, &grid[&key], tolerance);
+        keys_by_y.entry(key.1).or_default().push(key.0);
+    }
+
+    // Oversized spans skip insert. Range-query occupied cells they cover so
+    // later X-ranges are not starved and we do not scan unrelated rows.
+    for &i in &large {
         if uf.component_size(i) >= MAX_CLUSTER_RECTS {
             continue;
         }
-        for j in (i + 1)..n {
-            if rects_overlap(&rects[i], &rects[j], tolerance) {
-                uf.union(i, j);
-                // Check if the merged component just exceeded the cap —
-                // if so, no need to test more pairs for rect i.
+        let (x, y, w, h) = rects[i];
+        let x_lo = grid_coord(x - tolerance, cell);
+        let x_hi = grid_coord(x + w + tolerance, cell);
+        let y_lo = grid_coord(y - tolerance, cell);
+        let y_hi = grid_coord(y + h + tolerance, cell);
+        for (&gy, gxs) in keys_by_y.range(y_lo..=y_hi) {
+            let start = gxs.partition_point(|&gx| gx < x_lo);
+            for &gx in &gxs[start..] {
+                if gx > x_hi {
+                    break;
+                }
+                let bucket = &grid[&(gx, gy)];
+                let mut pairs = 0usize;
+                for &j in bucket {
+                    if pairs >= MAX_CLUSTER_PAIRS_PER_CELL {
+                        break;
+                    }
+                    if uf.component_size(j) >= MAX_CLUSTER_RECTS {
+                        continue;
+                    }
+                    pairs += 1;
+                    if rects_overlap(&rects[i], &rects[j], tolerance) {
+                        uf.union(i, j);
+                        if uf.component_size(i) >= MAX_CLUSTER_RECTS {
+                            break;
+                        }
+                    }
+                }
                 if uf.component_size(i) >= MAX_CLUSTER_RECTS {
                     break;
                 }
             }
+            if uf.component_size(i) >= MAX_CLUSTER_RECTS {
+                break;
+            }
+        }
+    }
+
+    // Oversized-vs-oversized: band on the short axis so stacked or side-by-side
+    // page-spanning rules stay linear. Wide vs tall pairs are matched by
+    // querying the tall X-index; dual-oversized rects occupy every coarse-Y
+    // cell they span.
+    let mut large_x: BTreeMap<i32, Vec<usize>> = BTreeMap::new();
+    let mut large_y: BTreeMap<i32, Vec<usize>> = BTreeMap::new();
+    let mut large_coarse_y: BTreeMap<i32, Vec<usize>> = BTreeMap::new();
+    let mut wide: Vec<usize> = Vec::new();
+    let mut dual: Vec<usize> = Vec::new();
+    for &i in &large {
+        let (x, y, w, h) = rects[i];
+        let xs = grid_span(x - tolerance, x + w + tolerance, cell);
+        let ys = grid_span(y - tolerance, y + h + tolerance, cell);
+        match (xs, ys) {
+            (Some(xs), _) => {
+                for gx in xs {
+                    large_x.entry(gx).or_default().push(i);
+                }
+            }
+            (_, Some(ys)) => {
+                wide.push(i);
+                for gy in ys {
+                    large_y.entry(gy).or_default().push(i);
+                }
+            }
+            _ => {
+                dual.push(i);
+                let coarse = cell * 64.0;
+                match grid_span(y - tolerance, y + h + tolerance, coarse) {
+                    Some(ys) => {
+                        for gy in ys {
+                            large_coarse_y.entry(gy).or_default().push(i);
+                        }
+                    }
+                    None => {
+                        large_coarse_y.entry(i32::MIN).or_default().push(i);
+                    }
+                }
+            }
+        }
+    }
+    for bands in [&large_x, &large_y, &large_coarse_y] {
+        for bucket in bands.values() {
+            union_bucket_pairs(&mut uf, rects, bucket, tolerance);
+        }
+    }
+    // Cross-orientation is |wide|×|tall| if every wide rule spans the page.
+    // Skip that pass when the product cannot be a table (a few rules).
+    let tall_n = large
+        .len()
+        .saturating_sub(wide.len())
+        .saturating_sub(dual.len());
+    let cross_n =
+        (wide.len() + dual.len()).saturating_mul(tall_n) + dual.len().saturating_mul(wide.len());
+    if cross_n > 0 && cross_n <= MAX_CLUSTER_PAIRS_PER_CELL {
+        for &i in wide.iter().chain(&dual) {
+            let (x, _, w, _) = rects[i];
+            let x_lo = grid_coord(x - tolerance, cell);
+            let x_hi = grid_coord(x + w + tolerance, cell);
+            union_rect_against_bands(&mut uf, rects, i, &large_x, x_lo, x_hi, tolerance);
+        }
+        for &i in &dual {
+            let (_, y, _, h) = rects[i];
+            let y_lo = grid_coord(y - tolerance, cell);
+            let y_hi = grid_coord(y + h + tolerance, cell);
+            union_rect_against_bands(&mut uf, rects, i, &large_y, y_lo, y_hi, tolerance);
         }
     }
 
@@ -3810,6 +4023,113 @@ mod tests {
         assert_eq!(groups[0].len(), 2);
     }
 
+    #[test]
+    fn test_cluster_rects_overlapping_grid_still_clusters() {
+        // Neighboring cells overlap; the grid must still union the whole table.
+        let mut rects = Vec::new();
+        for row in 0..4 {
+            for col in 0..4 {
+                rects.push((col as f32 * 9.0, row as f32 * 9.0, 10.0, 10.0));
+            }
+        }
+        let groups = cluster_rects(&rects, 0.0, 1);
+        assert_eq!(groups.len(), 1);
+        assert_eq!(groups[0].len(), 16);
+    }
+
+    #[test]
+    fn test_cluster_rects_many_disjoint_stays_subquadratic() {
+        // Pairwise-disjoint rects never merge, so a component-size cap does
+        // not stop all-pairs overlap tests. Spread in X so they land in
+        // different grid cells; 8k is enough that n² tests would dominate.
+        let n = 8_000usize;
+        let rects: Vec<(f32, f32, f32, f32)> =
+            (0..n).map(|i| (i as f32 * 20.0, 0.0, 10.0, 10.0)).collect();
+        let groups = cluster_rects(&rects, 0.0, 2);
+        assert!(groups.is_empty());
+    }
+
+    #[test]
+    fn test_cluster_rects_stacked_disjoint_does_not_starve_later_table() {
+        // Same X, spread in Y: a spatial grid must still union an overlapping
+        // pair in another region of the page.
+        let n = 8_000usize;
+        let mut rects: Vec<(f32, f32, f32, f32)> =
+            (0..n).map(|i| (0.0, i as f32 * 20.0, 10.0, 10.0)).collect();
+        rects.push((500.0, 0.0, 10.0, 10.0));
+        rects.push((508.0, 0.0, 10.0, 10.0));
+        let groups = cluster_rects(&rects, 0.0, 2);
+        assert_eq!(groups.len(), 1);
+        assert_eq!(groups[0].len(), 2);
+    }
+
+    #[test]
+    fn test_cluster_rects_oversized_span_still_unions() {
+        // Wider than 64 grid cells; must still union the small overlapping rect.
+        let rects = vec![(0.0, 0.0, 5000.0, 10.0), (4900.0, 0.0, 10.0, 10.0)];
+        let groups = cluster_rects(&rects, 0.0, 1);
+        assert_eq!(groups.len(), 1);
+        assert_eq!(groups[0].len(), 2);
+    }
+
+    #[test]
+    fn test_cluster_rects_many_oversized_spans_all_get_a_pass() {
+        // More than 32 huge rects: the last one must still union its overlap.
+        let mut rects: Vec<(f32, f32, f32, f32)> = (0..40)
+            .map(|i| (0.0, i as f32 * 20.0, 5000.0, 10.0))
+            .collect();
+        rects.push((4900.0, 39.0 * 20.0, 10.0, 10.0));
+        let groups = cluster_rects(&rects, 0.0, 2);
+        assert_eq!(groups.len(), 1);
+        assert_eq!(groups[0].len(), 2);
+    }
+
+    #[test]
+    fn test_cluster_rects_oversized_not_starved_by_earlier_disjoint() {
+        // 9k earlier disjoint drawings would exhaust an index-order cap of
+        // 8,192 before the overlapping cell is visited.
+        let mut rects: Vec<(f32, f32, f32, f32)> = (0..9_000)
+            .map(|i| (10_000.0, i as f32 * 20.0, 10.0, 10.0))
+            .collect();
+        let wide = rects.len();
+        rects.push((0.0, 0.0, 5000.0, 10.0));
+        let target = rects.len();
+        rects.push((4900.0, 0.0, 10.0, 10.0));
+        let groups = cluster_rects(&rects, 0.0, 2);
+        assert!(
+            groups
+                .iter()
+                .any(|g| g.contains(&wide) && g.contains(&target)),
+            "wide rule and far-end cell must share a cluster"
+        );
+    }
+
+    #[test]
+    fn test_cluster_rects_wide_and_tall_oversized_union() {
+        let rects = vec![(0.0, 0.0, 5000.0, 10.0), (0.0, 0.0, 10.0, 5000.0)];
+        let groups = cluster_rects(&rects, 0.0, 2);
+        assert_eq!(groups.len(), 1);
+        assert_eq!(groups[0].len(), 2);
+    }
+
+    #[test]
+    fn test_cluster_rects_dual_oversized_spans_coarse_y() {
+        let rects = vec![(0.0, 0.0, 5000.0, 5000.0), (0.0, 4500.0, 5000.0, 5000.0)];
+        let groups = cluster_rects(&rects, 0.0, 2);
+        assert_eq!(groups.len(), 1);
+        assert_eq!(groups[0].len(), 2);
+    }
+
+    #[test]
+    fn test_cluster_rects_many_wide_and_tall_stays_subquadratic() {
+        let mut rects = Vec::with_capacity(4_000);
+        for i in 0..2_000 {
+            rects.push((0.0, i as f32 * 20.0, 5000.0, 10.0));
+            rects.push((i as f32 * 20.0, 0.0, 10.0, 5000.0));
+        }
+        let _groups = cluster_rects(&rects, 0.0, 2);
+    }
+
     // --- snap_edges ---
 
     #[test]

src/tounicode.rs

@@ -540,18 +540,14 @@ impl ToUnicodeCMap {
 
     /// Remap a CMap that references pre-subsetting GIDs to sequential post-subsetting GIDs.
     /// Collects all source CIDs, sorts them, and reassigns to 1, 2, 3, ...
+    ///
+    /// Range expansion stops after `MAX_CID_W_EXPANSION` CID visits, counting
+    /// overwrites, so repeated full-width `bfrange`s cannot re-expand the
+    /// 16-bit domain. Later overlapping ranges that would have introduced new
+    /// CIDs after that many visits are truncated.
     pub fn remap_to_sequential(&self) -> ToUnicodeCMap {
         let mut cid_to_unicode: HashMap<u16, String> = HashMap::new();
-
-        // Expand ranges first
-        for &(start, end, base) in &self.ranges {
-            for cid in start..=end {
-                let unicode_cp = base + (cid - start) as u32;
-                if let Some(ch) = char::from_u32(unicode_cp) {
-                    cid_to_unicode.insert(cid, ch.to_string());
-                }
-            }
-        }
+        expand_bfranges_for_remap(&self.ranges, &mut cid_to_unicode, MAX_CID_W_EXPANSION);
 
         // char_map entries override range entries
         for (&cid, unicode) in &self.char_map {
@@ -576,6 +572,33 @@ impl ToUnicodeCMap {
     }
 }
 
+/// Expand `bfrange` entries into individual CID→Unicode inserts.
+/// Returns how many CIDs were visited. Counts overwrites so a repeated
+/// full-width range cannot keep working after `max_assignments`.
+fn expand_bfranges_for_remap(
+    ranges: &[(u16, u16, u32)],
+    cid_to_unicode: &mut HashMap<u16, String>,
+    max_assignments: usize,
+) -> usize {
+    let mut assigned = 0usize;
+    'ranges: for &(start, end, base) in ranges {
+        if start > end {
+            continue;
+        }
+        for cid in start..=end {
+            if assigned >= max_assignments {
+                break 'ranges;
+            }
+            assigned += 1;
+            let unicode_cp = base + (cid - start) as u32;
+            if let Some(ch) = char::from_u32(unicode_cp) {
+                cid_to_unicode.insert(cid, ch.to_string());
+            }
+        }
+    }
+    assigned
+}
+
 /// Parse a hex string to u16
 fn parse_hex_u16(hex: &str) -> Option<u16> {
     u16::from_str_radix(hex.trim(), 16).ok()
@@ -594,7 +617,7 @@ fn hex_to_unicode_string(hex: &str) -> Option<String> {
 
     let bytes: Option<Vec<u8>> = (0..hex.len())
         .step_by(2)
-        .map(|i| u8::from_str_radix(&hex[i..i + 2], 16).ok())
+        .map(|i| u8::from_str_radix(hex.get(i..i + 2)?, 16).ok())
         .collect();
     let bytes = bytes?;
 
@@ -1561,23 +1584,31 @@ fn parse_encoding_cmap_stream(data: &[u8]) -> Option<EncodingCMap> {
     }
 
     let mut map = HashMap::new();
+    let mut assigned = 0usize;
     let mut pos = 0;
     while let Some(start) = text[pos..].find("begincidchar") {
         let section_start = pos + start + "begincidchar".len();
         if let Some(end) = text[section_start..].find("endcidchar") {
             let section = &text[section_start..section_start + end];
-            parse_cidchar_section(section, &mut map, &mut src_hex_lengths);
+            if !parse_cidchar_section(section, &mut map, &mut src_hex_lengths, &mut assigned) {
+                break;
+            }
             pos = section_start + end;
         } else {
             break;
         }
     }
     pos = 0;
-    while let Some(start) = text[pos..].find("begincidrange") {
+    while assigned < MAX_CID_W_EXPANSION {
+        let Some(start) = text[pos..].find("begincidrange") else {
+            break;
+        };
         let section_start = pos + start + "begincidrange".len();
         if let Some(end) = text[section_start..].find("endcidrange") {
             let section = &text[section_start..section_start + end];
-            parse_cidrange_section(section, &mut map, &mut src_hex_lengths);
+            if !parse_cidrange_section(section, &mut map, &mut src_hex_lengths, &mut assigned) {
+                break;
+            }
             pos = section_start + end;
         } else {
             break;
@@ -1612,7 +1643,8 @@ fn parse_cidchar_section(
     section: &str,
     map: &mut HashMap<u16, u16>,
     src_hex_lengths: &mut Vec<usize>,
-) {
+    assigned: &mut usize,
+) -> bool {
     let mut chars = section.chars().peekable();
     loop {
         while chars.peek().is_some_and(|c| c.is_whitespace()) {
@@ -1643,16 +1675,20 @@ fn parse_cidchar_section(
             }
         }
         if let (Some(code), Ok(cid)) = (parse_hex_u16(&src_hex), cid_str.parse::<u16>()) {
-            map.insert(code, cid);
+            if !assign_encoding_cid(map, code, cid, assigned) {
+                return false;
+            }
         }
     }
+    true
 }
 
 fn parse_cidrange_section(
     section: &str,
     map: &mut HashMap<u16, u16>,
     src_hex_lengths: &mut Vec<usize>,
-) {
+    assigned: &mut usize,
+) -> bool {
     let mut chars = section.chars().peekable();
     loop {
         while chars.peek().is_some_and(|c| c.is_whitespace()) {
@@ -1703,12 +1739,34 @@ fn parse_cidrange_section(
         ) else {
             continue;
         };
+        if start > end {
+            continue;
+        }
         let mut cid = start_cid;
         for code in start..=end {
-            map.insert(code, cid);
+            if !assign_encoding_cid(map, code, cid, assigned) {
+                return false;
+            }
             cid = cid.saturating_add(1);
         }
     }
+    true
+}
+
+fn assign_encoding_cid(
+    map: &mut HashMap<u16, u16>,
+    code: u16,
+    cid: u16,
+    assigned: &mut usize,
+) -> bool {
+    // Count overwrites: unique-key coverage alone would not stop a repeated
+    // full-width range from re-inserting all 65,536 codes.
+    if *assigned >= MAX_CID_W_EXPANSION {
+        return false;
+    }
+    map.insert(code, cid);
+    *assigned += 1;
+    true
 }
 
 fn parse_binary_cmap_encoding(data: &[u8]) -> Result<EncodingCMap, String> {
@@ -1832,6 +1890,13 @@ fn merge_cmaps(mut base: ToUnicodeCMap, overlay: ToUnicodeCMap) -> ToUnicodeCMap
     base
 }
 
+/// Shared 16-bit CID expansion cap (65,536).
+/// Encoding `begincidrange`, `/W` width assignment, and ToUnicode sequential
+/// remap count every insert, including overwrites, so a repeated full-width
+/// range cannot keep working after the domain is filled. The `/W` unicode
+/// heuristic caps unique CIDs with the same number.
+pub(crate) const MAX_CID_W_EXPANSION: usize = 65_536;
+
 /// Check if a CIDFont's /W (widths) array contains CID values that look like
 /// Unicode codepoints rather than low-value GIDs.
 ///
@@ -1843,20 +1908,23 @@ pub(crate) fn cid_values_look_like_unicode(cid_font_dict: &lopdf::Dictionary) ->
         _ => return false,
     };
 
-    // The /W array format: [cid [w1 w2 ...]] or [cid_start cid_end w]
-    // We extract all CID values (the first element of each group).
-    let mut cids: Vec<u16> = Vec::new();
+    // The /W array format: [cid [w1 w2 ...]] or [cid_start cid_end w].
+    // Collect unique CIDs only: repeating a full-width range must not grow a
+    // temporary vector (or the sort) with the range length on every copy.
+    let mut seen = HashSet::new();
     let mut i = 0;
-    while i < w_arr.len() {
+    while i < w_arr.len() && seen.len() < MAX_CID_W_EXPANSION {
         if let Ok(cid) = w_arr[i].as_i64() {
-            cids.push(cid as u16);
-            // Skip the width data
+            let start = cid as u16;
             if i + 1 < w_arr.len() {
                 match &w_arr[i + 1] {
                     Object::Array(widths) => {
                         // [cid [w1 w2 ...]] — CIDs are cid, cid+1, ..., cid+len-1
-                        for j in 1..widths.len() {
-                            cids.push((cid as u16).wrapping_add(j as u16));
+                        for j in 0..widths.len() {
+                            if seen.len() >= MAX_CID_W_EXPANSION {
+                                break;
+                            }
+                            seen.insert(start.wrapping_add(j as u16));
                         }
                         i += 2;
                     }
@@ -1864,9 +1932,7 @@ pub(crate) fn cid_values_look_like_unicode(cid_font_dict: &lopdf::Dictionary) ->
                         // [cid_start cid_end w] — range of CIDs
                         if i + 2 < w_arr.len() {
                             if let Ok(cid_end) = w_arr[i + 1].as_i64() {
-                                for c in (cid as u16)..=(cid_end as u16) {
-                                    cids.push(c);
-                                }
+                                record_unique_cid_range(start, cid_end as u16, &mut seen);
                             }
                             i += 3;
                         } else {
@@ -1875,6 +1941,7 @@ pub(crate) fn cid_values_look_like_unicode(cid_font_dict: &lopdf::Dictionary) ->
                     }
                 }
             } else {
+                seen.insert(start);
                 i += 1;
             }
         } else {
@@ -1882,10 +1949,11 @@ pub(crate) fn cid_values_look_like_unicode(cid_font_dict: &lopdf::Dictionary) ->
         }
     }
 
-    if cids.is_empty() {
+    if seen.is_empty() {
         return false;
     }
 
+    let mut cids: Vec<u16> = seen.into_iter().collect();
     cids.sort_unstable();
     let median = cids[cids.len() / 2];
     // Unicode text CIDs are typically >= 0x20 (space) with letters at 0x41+.
@@ -1894,6 +1962,18 @@ pub(crate) fn cid_values_look_like_unicode(cid_font_dict: &lopdf::Dictionary) ->
     median >= 0x41
 }
 
+fn record_unique_cid_range(start: u16, end: u16, seen: &mut HashSet<u16>) {
+    if start > end {
+        return;
+    }
+    for cid in start..=end {
+        if seen.len() >= MAX_CID_W_EXPANSION {
+            return;
+        }
+        seen.insert(cid);
+    }
+}
+
 /// Build a ToUnicodeCMap from predefined CID→Unicode mapping based on CIDSystemInfo.
 ///
 /// Supports Adobe-Korea1 (Korean) character collection. Can be extended for
@@ -2606,6 +2686,24 @@ endcmap
         assert_eq!(cmap.lookup(0x0025), Some("B".to_string()));
     }
 
+    #[test]
+    fn test_hex_to_unicode_non_ascii_no_panic() {
+        // A destination containing a multi-byte char makes the byte length even
+        // while a byte offset can land inside a char. Slicing must not panic;
+        // it should be rejected gracefully.
+        assert_eq!(hex_to_unicode_string("XéY"), None);
+        assert_eq!(hex_to_unicode_string("\u{fffd}0"), None);
+    }
+
+    #[test]
+    fn test_parse_bfchar_non_ascii_destination_no_panic() {
+        // Crafted /ToUnicode CMap: a non-hex, non-ASCII destination previously
+        // triggered a char-boundary panic in hex_to_unicode_string.
+        let cmap_content = "beginbfchar <0041> <XéY> endbfchar";
+        // Must not panic; the malformed entry is simply skipped.
+        let _ = ToUnicodeCMap::parse(cmap_content.as_bytes());
+    }
+
     #[test]
     fn test_parse_bfchar_1byte() {
         // This is the pattern that caused the CJK bug: codespace is <0000><FFFF>
@@ -2849,6 +2947,33 @@ endbfrange
         assert!(remapped.ranges.is_empty());
     }
 
+    #[test]
+    fn remap_to_sequential_repeated_full_bfranges_stay_bounded() {
+        // 5,000 copies of `<0003> <ffff>` must stop after 65,536 CID visits,
+        // not 5,000 × ~65,533 expansions.
+        let ranges = vec![(3u16, 65535u16, 0x41u32); 5_000];
+        let mut map = std::collections::HashMap::new();
+        let assigned = expand_bfranges_for_remap(&ranges, &mut map, MAX_CID_W_EXPANSION);
+        assert_eq!(assigned, MAX_CID_W_EXPANSION);
+        assert!(map.len() <= MAX_CID_W_EXPANSION);
+
+        let mut body = String::new();
+        let mut remaining = 5_000usize;
+        while remaining > 0 {
+            let n = remaining.min(100);
+            body.push_str(&format!("{n} beginbfrange\n"));
+            for _ in 0..n {
+                body.push_str("<0003> <ffff> <0041>\n");
+            }
+            body.push_str("endbfrange\n");
+            remaining -= n;
+        }
+        let data = format!("1 begincodespacerange\n<0000> <ffff>\nendcodespacerange\n{body}");
+        let cmap = ToUnicodeCMap::parse(data.as_bytes()).unwrap();
+        let remapped = cmap.remap_to_sequential();
+        assert_eq!(remapped.lookup(1), Some("A".to_string()));
+    }
+
     #[test]
     fn test_min_source_cid() {
         let cmap_content = r#"
@@ -3280,4 +3405,79 @@ endbfrange
             "An indirect /Subtype naming CIDFontType2 must still reach the remap"
         );
     }
+
+    #[test]
+    fn cid_values_look_like_unicode_letter_range() {
+        let mut dict = lopdf::Dictionary::new();
+        dict.set(
+            "W",
+            Object::Array(vec![
+                Object::Integer(0x41),
+                Object::Integer(0x5A),
+                Object::Integer(500),
+            ]),
+        );
+        assert!(cid_values_look_like_unicode(&dict));
+    }
+
+    #[test]
+    fn cid_values_look_like_unicode_low_gids() {
+        let mut dict = lopdf::Dictionary::new();
+        dict.set(
+            "W",
+            Object::Array(vec![
+                Object::Integer(0),
+                Object::Array(vec![Object::Integer(500); 10]),
+            ]),
+        );
+        assert!(!cid_values_look_like_unicode(&dict));
+    }
+
+    #[test]
+    fn cid_values_look_like_unicode_repeated_full_ranges_stay_bounded() {
+        // Repeating `[0 65535 w]` must not materialize 65,536 CIDs per copy.
+        let mut w = Vec::new();
+        for _ in 0..5_000 {
+            w.push(Object::Integer(0));
+            w.push(Object::Integer(65535));
+            w.push(Object::Integer(500));
+        }
+        let mut dict = lopdf::Dictionary::new();
+        dict.set("W", Object::Array(w));
+        assert!(cid_values_look_like_unicode(&dict));
+    }
+
+    #[test]
+    fn encoding_cidrange_maps_a_normal_range() {
+        let data = b"1 begincodespacerange\n<0000> <FFFF>\nendcodespacerange\n\
+1 begincidrange\n<0041> <0043> 65\nendcidrange\n";
+        let enc = parse_encoding_cmap_stream(data).unwrap();
+        assert_eq!(enc.map.get(&0x41), Some(&65));
+        assert_eq!(enc.map.get(&0x42), Some(&66));
+        assert_eq!(enc.map.get(&0x43), Some(&67));
+        assert_eq!(enc.map.len(), 3);
+        assert_eq!(enc.code_byte_length, 2);
+    }
+
+    #[test]
+    fn encoding_cidrange_repeated_full_ranges_stay_bounded() {
+        // 5,000 copies of `<0000> <ffff> 0` must not re-expand the 16-bit
+        // domain on every declaration.
+        let mut body = String::new();
+        let mut remaining = 5_000usize;
+        while remaining > 0 {
+            let n = remaining.min(100);
+            body.push_str(&format!("{n} begincidrange\n"));
+            for _ in 0..n {
+                body.push_str("<0000> <ffff> 0\n");
+            }
+            body.push_str("endcidrange\n");
+            remaining -= n;
+        }
+        let data = format!("1 begincodespacerange\n<0000> <FFFF>\nendcodespacerange\n{body}");
+        let enc = parse_encoding_cmap_stream(data.as_bytes()).unwrap();
+        assert!(enc.map.len() <= MAX_CID_W_EXPANSION);
+        assert_eq!(enc.map.get(&0), Some(&0));
+        assert_eq!(enc.map.get(&65535), Some(&65535));
+    }
 }

tests/integration_tests.rs

@@ -1429,6 +1429,77 @@ fn test_firecrawl_tagged_pdf_struct_tree() {
     assert_eq!(fence_count % 2, 0, "Code fences should be balanced");
 }
 
+#[test]
+fn test_tagged_pdf_text_items_carry_mcid() {
+    let buf = std::fs::read("tests/fixtures/firecrawl_docs_tagged.pdf").unwrap();
+    let items = pdf_inspector::extractor::extract_text_with_positions_mem(&buf).unwrap();
+    assert!(
+        items.iter().any(|i| i.mcid.is_some()),
+        "Tagged PDF text items should carry Marked Content IDs"
+    );
+}
+
+#[test]
+fn test_extract_structure_elements_tagged_pdf() {
+    let buf = std::fs::read("tests/fixtures/firecrawl_docs_tagged.pdf").unwrap();
+    let elements = pdf_inspector::extract_structure_elements_mem(&buf, None).unwrap();
+    assert!(!elements.is_empty(), "Tagged PDF should yield elements");
+    assert!(
+        elements.iter().any(|e| e.role == "H1"),
+        "Should surface H1 heading roles"
+    );
+    assert!(
+        elements.iter().all(|e| !e.role.is_empty()),
+        "Every element should carry a role name"
+    );
+
+    // Sorted by (page, mcid) for deterministic output
+    assert!(
+        elements
+            .windows(2)
+            .all(|w| (w[0].page, w[0].mcid) <= (w[1].page, w[1].mcid)),
+        "Elements should be sorted by (page, mcid)"
+    );
+
+    // The advertised join: (page, mcid) pairs must line up with the
+    // mcid-carrying TextItems from positioned extraction, and joining the
+    // H1 entries must recover non-empty heading text.
+    let items = pdf_inspector::extractor::extract_text_with_positions_mem(&buf).unwrap();
+    let h1_refs: std::collections::HashSet<(u32, i64)> = elements
+        .iter()
+        .filter(|e| e.role == "H1")
+        .map(|e| (e.page, e.mcid))
+        .collect();
+    let h1_text: String = items
+        .iter()
+        .filter(|i| i.mcid.is_some_and(|mcid| h1_refs.contains(&(i.page, mcid))))
+        .map(|i| i.text.as_str())
+        .collect();
+    assert!(
+        !h1_text.trim().is_empty(),
+        "Joining H1 structure elements to text items should recover heading text"
+    );
+
+    // Page filter is 1-indexed (matching TextItem.page) and equals the
+    // corresponding subset of the full document result.
+    let page1 = pdf_inspector::extract_structure_elements_mem(&buf, Some(&[1])).unwrap();
+    assert!(!page1.is_empty(), "Page 1 should have elements");
+    assert!(page1.iter().all(|e| e.page == 1));
+    let full_page1_count = elements.iter().filter(|e| e.page == 1).count();
+    assert_eq!(page1.len(), full_page1_count);
+}
+
+#[test]
+fn test_extract_structure_elements_untagged_pdf_empty() {
+    let buf = std::fs::read("tests/fixtures/thermo-freon12.pdf").unwrap();
+    let elements = pdf_inspector::extract_structure_elements_mem(&buf, None).unwrap();
+    assert!(
+        elements.is_empty(),
+        "Untagged PDF should yield no structure elements, got {:?}",
+        elements
+    );
+}
+
 #[test]
 fn test_identity_h_no_tounicode_suppresses_garbage() {
     // shinagawa_identity_h.pdf uses YuGothic with Identity-H encoding and no
@@ -1583,6 +1654,282 @@ fn test_extract_regions_mem_basic_text_pdf() {
     assert_eq!(regions[0].page, 0);
 }
 
+/// Build a synthetic "scanned page" PDF: a full-page image XObject with a
+/// text layer drawn in the given render mode (3 = invisible OCR overlay,
+/// 0 = normal visible fill). `visible_extra` optionally adds a normally
+/// rendered line so double-layer behavior can be tested; `layer_lines`
+/// overrides the layer content (default: three pangram lines);
+/// `quote_ops` shows every layer line via the `'` operator instead of Tj
+/// (both are standard show-text encodings for OCR layers).
+fn make_pdf_with_custom_text_layer(
+    text_render_mode: i32,
+    visible_extra: Option<&str>,
+    layer_lines: Option<&[&str]>,
+    quote_ops: bool,
+) -> Vec<u8> {
+    let mut pdf = b"%PDF-1.4\n".to_vec();
+    let mut offsets = vec![0usize];
+
+    fn add_object(pdf: &mut Vec<u8>, offsets: &mut Vec<usize>, id: usize, body: &str) {
+        offsets.push(pdf.len());
+        pdf.extend_from_slice(format!("{id} 0 obj\n").as_bytes());
+        pdf.extend_from_slice(body.as_bytes());
+        pdf.extend_from_slice(b"\nendobj\n");
+    }
+    fn add_stream_object(
+        pdf: &mut Vec<u8>,
+        offsets: &mut Vec<usize>,
+        id: usize,
+        dict: &str,
+        stream_bytes: &[u8],
+    ) {
+        offsets.push(pdf.len());
+        pdf.extend_from_slice(format!("{id} 0 obj\n").as_bytes());
+        pdf.extend_from_slice(
+            format!("<< {} /Length {} >>\nstream\n", dict, stream_bytes.len()).as_bytes(),
+        );
+        pdf.extend_from_slice(stream_bytes);
+        pdf.extend_from_slice(b"\nendstream\nendobj\n");
+    }
+
+    add_object(
+        &mut pdf,
+        &mut offsets,
+        1,
+        "<< /Type /Catalog /Pages 2 0 R >>",
+    );
+    add_object(
+        &mut pdf,
+        &mut offsets,
+        2,
+        "<< /Type /Pages /Kids [3 0 R] /Count 1 >>",
+    );
+    add_object(
+        &mut pdf,
+        &mut offsets,
+        3,
+        "<< /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] \
+         /Resources << /Font << /F1 5 0 R >> /XObject << /Im0 6 0 R >> >> \
+         /Contents 4 0 R >>",
+    );
+    // Full-page raster, then the text layer in the requested render mode —
+    // several lines so the OCR-layer gate's alnum floor (40) is well cleared.
+    let mut content = String::from("q 612 0 0 792 0 0 cm /Im0 Do Q\n");
+    let default_layer = [
+        "The quick brown fox jumps over the lazy dog",
+        "Pack my box with five dozen liquor jugs tonight",
+        "Sphinx of black quartz judge my vow carefully",
+    ];
+    let layer: &[&str] = layer_lines.unwrap_or(&default_layer);
+    if quote_ops {
+        // Every line shown via `'` (move-to-next-line + show) — nothing on
+        // this layer goes through Tj, pinning the `'` suppression path.
+        content.push_str(&format!(
+            "BT /F1 12 Tf {text_render_mode} Tr 16 TL 72 716 Td "
+        ));
+        for line in layer {
+            content.push_str(&format!("({line}) ' "));
+        }
+    } else {
+        content.push_str(&format!("BT /F1 12 Tf {text_render_mode} Tr 72 700 Td "));
+        for (i, line) in layer.iter().enumerate() {
+            if i > 0 {
+                content.push_str("0 -16 Td ");
+            }
+            content.push_str(&format!("({line}) Tj "));
+        }
+    }
+    content.push_str("ET\n");
+    if let Some(extra) = visible_extra {
+        content.push_str(&format!("BT /F1 12 Tf 0 Tr 72 500 Td ({extra}) Tj ET\n"));
+    }
+    add_stream_object(&mut pdf, &mut offsets, 4, "", content.as_bytes());
+    add_object(
+        &mut pdf,
+        &mut offsets,
+        5,
+        "<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>",
+    );
+    let image_pixel = [128u8];
+    add_stream_object(
+        &mut pdf,
+        &mut offsets,
+        6,
+        "/Type /XObject /Subtype /Image /Width 1 /Height 1 \
+         /ColorSpace /DeviceGray /BitsPerComponent 8",
+        &image_pixel,
+    );
+
+    let xref_start = pdf.len();
+    pdf.extend_from_slice(format!("xref\n0 {}\n", offsets.len()).as_bytes());
+    pdf.extend_from_slice(b"0000000000 65535 f \n");
+    for offset in offsets.iter().skip(1) {
+        pdf.extend_from_slice(format!("{offset:010} 00000 n \n").as_bytes());
+    }
+    pdf.extend_from_slice(
+        format!(
+            "trailer\n<< /Size {} /Root 1 0 R >>\nstartxref\n{}\n%%EOF",
+            offsets.len(),
+            xref_start
+        )
+        .as_bytes(),
+    );
+    pdf
+}
+
+fn make_pdf_with_text_layer(text_render_mode: i32, visible_extra: Option<&str>) -> Vec<u8> {
+    make_pdf_with_custom_text_layer(text_render_mode, visible_extra, None, false)
+}
+
+/// A scanned page whose only text is an invisible (Tr 3) OCR layer behind
+/// the raster must serve that layer from the region extractor instead of
+/// reporting the region as needs_ocr — the exact text is already in the PDF.
+#[test]
+fn test_extract_regions_mem_recovers_invisible_ocr_layer() {
+    let buf = make_pdf_with_text_layer(3, None);
+    let regions = extract_text_in_regions_mem(&buf, &full_page_regions(1)).unwrap();
+    assert_eq!(regions.len(), 1);
+    let region = &regions[0].regions[0];
+    assert!(
+        region.text.contains("quick brown fox"),
+        "invisible OCR layer should be served as region text, got: {:?}",
+        region.text
+    );
+    assert!(
+        !region.needs_ocr,
+        "recovered OCR layer must not fall back to GPU OCR"
+    );
+}
+
+/// ANY visible text on the page — even a single short line — must block the
+/// invisible-layer adoption entirely: the invisible pass returns visible
+/// items too, so adopting it alongside visible text would duplicate the
+/// visible words. Strict zero-visible gate, no fuzzy dedupe.
+#[test]
+fn test_extract_regions_mem_visible_text_blocks_invisible_layer() {
+    let buf = make_pdf_with_text_layer(3, Some("Folio 142"));
+    let regions = extract_text_in_regions_mem(&buf, &full_page_regions(1)).unwrap();
+    let region = &regions[0].regions[0];
+    assert!(
+        region.text.contains("Folio 142"),
+        "visible text should be extracted, got: {:?}",
+        region.text
+    );
+    assert!(
+        !region.text.contains("quick brown fox"),
+        "invisible layer must not be adopted when any visible text exists, got: {:?}",
+        region.text
+    );
+    assert_eq!(
+        region.text.matches("Folio 142").count(),
+        1,
+        "visible text must appear exactly once, got: {:?}",
+        region.text
+    );
+}
+
+/// An invisible OCR layer shown entirely via the `'` show-text operator
+/// (move-to-next-line + show) must also be recovered — the skipped_invisible
+/// signal has to fire on every show-text path, not just Tj/TJ.
+#[test]
+fn test_extract_regions_mem_recovers_quote_operator_layer() {
+    let buf = make_pdf_with_custom_text_layer(3, None, None, true);
+    let regions = extract_text_in_regions_mem(&buf, &full_page_regions(1)).unwrap();
+    let region = &regions[0].regions[0];
+    assert!(
+        region.text.contains("quick brown fox"),
+        "'-operator OCR layer should be recovered, got: {:?}",
+        region.text
+    );
+    assert!(!region.needs_ocr);
+}
+
+/// An invisible layer below the 40-alnum floor (a stray watermark line)
+/// must NOT be adopted — the region keeps its needs_ocr fallback.
+#[test]
+fn test_extract_regions_mem_tiny_invisible_layer_not_adopted() {
+    let buf = make_pdf_with_custom_text_layer(3, None, Some(&["Scanned by ACME"]), false);
+    let regions = extract_text_in_regions_mem(&buf, &full_page_regions(1)).unwrap();
+    let region = &regions[0].regions[0];
+    assert!(
+        !region.text.contains("Scanned by ACME"),
+        "below-floor invisible layer must not be adopted, got: {:?}",
+        region.text
+    );
+    // Only the raster placeholder remains — needs_ocr stays whatever main
+    // reports for placeholder-only regions (false today; downstream
+    // pipelines route placeholder-only text to OCR themselves, and this PR
+    // deliberately does not change that contract).
+    assert!(
+        region.text.trim().starts_with("[Image:"),
+        "region should hold only the raster placeholder, got: {:?}",
+        region.text
+    );
+}
+
+/// An invisible layer that clears the alnum floor but is mostly symbol
+/// garbage (a broken OCR run) must be rejected by the garbage gate.
+#[test]
+fn test_extract_regions_mem_garbage_invisible_layer_not_adopted() {
+    // Each line: 5 alphanumerics among 15 symbol chars. Ten lines clear the
+    // 40-alnum floor (50 alnum) while staying well under the half-alnum
+    // ratio is_garbage_text requires.
+    let garbage_lines: Vec<&str> = vec!["a@@b%%c&&d==e~~"; 10];
+    let buf = make_pdf_with_custom_text_layer(3, None, Some(&garbage_lines), false);
+    let regions = extract_text_in_regions_mem(&buf, &full_page_regions(1)).unwrap();
+    let region = &regions[0].regions[0];
+    assert!(
+        !region.text.contains("a@@b"),
+        "garbage invisible layer must not be adopted, got: {:?}",
+        region.text
+    );
+    assert!(
+        region.text.trim().starts_with("[Image:"),
+        "region should hold only the raster placeholder, got: {:?}",
+        region.text
+    );
+}
+
+/// Punctuation-only visible text (zero alphanumerics) must ALSO block
+/// adoption — the gate is item-presence, not alphanumeric mass. (Real-world
+/// rationale: an invisible OCR layer transcribes the raster, so visible
+/// glyphs typically have invisible twins there; this fixture's layers are
+/// disjoint, so it pins the gate itself, not the duplication scenario.)
+#[test]
+fn test_extract_regions_mem_punctuation_visible_blocks_invisible_layer() {
+    let buf = make_pdf_with_text_layer(3, Some("... --- ..."));
+    let regions = extract_text_in_regions_mem(&buf, &full_page_regions(1)).unwrap();
+    let region = &regions[0].regions[0];
+    assert!(
+        !region.text.contains("quick brown fox"),
+        "invisible layer must not be adopted over punctuation-only visible text, got: {:?}",
+        region.text
+    );
+    assert_eq!(
+        region.text.matches("... --- ...").count(),
+        1,
+        "visible punctuation must be preserved exactly once, got: {:?}",
+        region.text
+    );
+}
+
+/// Regression guard: a normal visible-text page (render mode 0) is served
+/// once and only once — if the fallback ever mis-fired here and merged a
+/// second pass, the phrase would duplicate.
+#[test]
+fn test_extract_regions_mem_visible_layer_unchanged() {
+    let buf = make_pdf_with_text_layer(0, None);
+    let regions = extract_text_in_regions_mem(&buf, &full_page_regions(1)).unwrap();
+    let region = &regions[0].regions[0];
+    assert_eq!(
+        region.text.matches("quick brown fox").count(),
+        1,
+        "visible text must appear exactly once, got: {:?}",
+        region.text
+    );
+    assert!(!region.needs_ocr);
+}
+
 #[test]
 fn test_extract_regions_mem_identity_h_needs_ocr() {
     let buf = std::fs::read("tests/fixtures/shinagawa_identity_h.pdf").unwrap();

tests/test_python.py

@@ -203,6 +203,79 @@ class TestExtractTextWithPositions:
         assert len(items) > 0
         assert all(item.page == 1 for item in items)
 
+    def test_mcid(self):
+        # Untagged fixture: mcid is None or int, never anything else
+        items = pdf_inspector.extract_text_with_positions(
+            fixture_path("thermo-freon12.pdf")
+        )
+        assert all(item.mcid is None or isinstance(item.mcid, int) for item in items)
+        # Tagged fixture: marked content carries MCIDs
+        tagged = pdf_inspector.extract_text_with_positions(
+            fixture_path("firecrawl_docs_tagged.pdf")
+        )
+        assert any(item.mcid is not None for item in tagged)
+
+
+# ---------------------------------------------------------------------------
+# extract_structure_elements / extract_structure_elements_bytes
+# ---------------------------------------------------------------------------
+
+
+class TestExtractStructureElements:
+    def test_tagged_file(self):
+        elements = pdf_inspector.extract_structure_elements(
+            fixture_path("firecrawl_docs_tagged.pdf")
+        )
+        assert len(elements) > 0
+        assert all(isinstance(e.page, int) for e in elements)
+        assert all(isinstance(e.mcid, int) for e in elements)
+        assert all(isinstance(e.role, str) and len(e.role) > 0 for e in elements)
+        assert any(e.role == "H1" for e in elements)
+
+    def test_join_with_text_items(self):
+        # (page, mcid) joins against extract_text_with_positions to recover
+        # heading text
+        path = fixture_path("firecrawl_docs_tagged.pdf")
+        elements = pdf_inspector.extract_structure_elements(path)
+        items = pdf_inspector.extract_text_with_positions(path)
+        h1_refs = {(e.page, e.mcid) for e in elements if e.role == "H1"}
+        h1_text = "".join(
+            item.text
+            for item in items
+            if item.mcid is not None and (item.page, item.mcid) in h1_refs
+        )
+        assert len(h1_text.strip()) > 0
+
+    def test_with_pages(self):
+        # pages filter is 1-indexed, matching TextItem.page
+        elements = pdf_inspector.extract_structure_elements(
+            fixture_path("firecrawl_docs_tagged.pdf"), pages=[1]
+        )
+        assert len(elements) > 0
+        assert all(e.page == 1 for e in elements)
+
+    def test_bytes(self):
+        data = fixture_bytes("firecrawl_docs_tagged.pdf")
+        elements = pdf_inspector.extract_structure_elements_bytes(data)
+        assert len(elements) > 0
+        assert any(e.role == "H1" for e in elements)
+
+    def test_untagged_returns_empty(self):
+        elements = pdf_inspector.extract_structure_elements(
+            fixture_path("thermo-freon12.pdf")
+        )
+        assert elements == []
+
+    def test_repr(self):
+        elements = pdf_inspector.extract_structure_elements(
+            fixture_path("firecrawl_docs_tagged.pdf")
+        )
+        assert "StructureElement" in repr(elements[0])
+
+    def test_not_a_pdf(self):
+        with pytest.raises(ValueError):
+            pdf_inspector.extract_structure_elements_bytes(b"not a pdf")
+
 
 # ---------------------------------------------------------------------------
 # extract_text_in_regions / extract_text_in_regions_bytes

wasm/Cargo.lock

@@ -724,7 +724,7 @@ checksum = "d6790f58c7ff633d8771f42965289203411a5e5c68388703c06e14f24770b41e"
 
 [[package]]
 name = "pdf-inspector"
-version = "0.1.7"
+version = "1.14.2"
 dependencies = [
  "env_logger",
  "include_dir",
@@ -740,7 +740,7 @@ dependencies = [
 
 [[package]]
 name = "pdf-inspector-wasm"
-version = "0.1.3"
+version = "1.14.2"
 dependencies = [
  "console_error_panic_hook",
  "js-sys",

wasm/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pdf-inspector-wasm"
-version = "0.1.3"
+version = "1.14.2"
 edition = "2021"
 authors = ["Firecrawl Team"]
 description = "Browser WebAssembly bindings for pdf-inspector"