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/preprocess.rs

@@ -150,61 +150,6 @@ pub(crate) fn merge_heading_lines(
 /// Merge drop caps with the appropriate line.
 /// A drop cap is a single large letter at the start of a paragraph.
 /// Due to PDF coordinate sorting, the drop cap may appear AFTER the line it belongs to.
-/// True when the text ends a sentence, as opposed to merely ending in a
-/// period. An abbreviation or list marker ("e.g.", "Fig.", "Mr.", "1.")
-/// closes with a period mid-sentence, so treating those as paragraph
-/// boundaries would let a drop cap be prepended to a continuation.
-fn ends_sentence(text: &str) -> bool {
-    let t = text.trim_end();
-    if t.ends_with(['!', '?']) {
-        return true;
-    }
-    let Some(stripped) = t.strip_suffix('.') else {
-        return false;
-    };
-    let last = stripped.split_whitespace().next_back().unwrap_or("");
-    if last.is_empty() {
-        return false;
-    }
-
-    // Abbreviations carry an internal period between very short segments
-    // ("e.g.", "i.e.", "U.S."). Domains and decimals have the same shape but
-    // longer or numeric segments ("example.com.", "3.14."), and those end
-    // sentences perfectly well, so require every segment to be short and
-    // alphabetic before reading the internal period as an abbreviation.
-    if last.contains('.')
-        && last
-            .split('.')
-            .filter(|seg| !seg.is_empty())
-            // Characters, not bytes: a two-letter non-ASCII abbreviation
-            // ("т.е.", "ú.d.") measures four or more bytes and would
-            // otherwise be read as a completed sentence.
-            .all(|seg| seg.chars().count() <= 2 && seg.chars().all(char::is_alphabetic))
-    {
-        return false;
-    }
-
-    // Enumerators stand alone on their line ("1.", "ii.", "IV."). A number
-    // or numeral in the tail of a sentence does not — "published in 2020.",
-    // "He scored 5." and "after World War II." all end sentences, and
-    // treating them as markers would block a legitimate drop-cap merge.
-    if stripped.split_whitespace().count() == 1 {
-        let is_numeric = last.chars().all(|c| c.is_ascii_digit());
-        let is_roman = last
-            .chars()
-            .all(|c| matches!(c.to_ascii_uppercase(), 'I' | 'V' | 'X' | 'L' | 'C'));
-        if is_numeric || is_roman {
-            return false;
-        }
-    }
-
-    const ABBREVIATIONS: &[&str] = &[
-        "Fig", "No", "Mr", "Mrs", "Ms", "Dr", "St", "vs", "etc", "al", "Ed", "Eq", "Ch", "pp",
-        "Vol", "cf", "Prof", "Inc", "Ltd", "Jr", "Sr",
-    ];
-    !ABBREVIATIONS.iter().any(|a| a.eq_ignore_ascii_case(last))
-}
-
 pub(crate) fn merge_drop_caps(lines: Vec<TextLine>, base_size: f32) -> Vec<TextLine> {
     let mut result: Vec<TextLine> = Vec::with_capacity(lines.len());
 
@@ -224,169 +169,6 @@ pub(crate) fn merge_drop_caps(lines: Vec<TextLine>, base_size: f32) -> Vec<TextL
                 .map(|c| c.is_uppercase())
                 .unwrap_or(false);
 
-        // Embedded drop cap: a two-line cap's baseline aligns with the
-        // paragraph's SECOND line, so Y-grouping puts the glyph at the start
-        // of that line rather than on a line of its own. Left there it
-        // surfaces mid-sentence once the paragraph is joined — Shannon's
-        // "A Mathematical Theory of Communication" reads "...which exchange
-        // T bandwidth for signal-to-noise ratio...". Detect it, prepend the
-        // character to the paragraph's first line, and drop it from this one.
-        //
-        // The size gate is 1.8x rather than 2.5x because bitmap (Type3) caps
-        // report their glyph bbox rather than the em box, so a two-line cap
-        // can measure as little as ~1.9x the body size.
-        if line.items.len() > 1 {
-            let first = &line.items[0];
-            // The remainder must be a substantive body run: a lone label or
-            // math fragment beside a large glyph is not a drop-cap paragraph.
-            let rest_letters: usize = line.items[1..]
-                .iter()
-                .map(|i| i.text.chars().filter(|c| c.is_alphabetic()).count())
-                .sum();
-            let is_embedded_cap = first.font_size >= base_size * 1.8
-                && first.text.trim().chars().count() == 1
-                && first
-                    .text
-                    .trim()
-                    .chars()
-                    .next()
-                    .is_some_and(char::is_uppercase)
-                && line.items[1..]
-                    .iter()
-                    .all(|i| i.font_size < base_size * 1.5)
-                && line.items[1..].iter().any(|i| i.x > first.x)
-                && rest_letters >= 8;
-            if is_embedded_cap {
-                let drop_char = first.text.trim().chars().next().unwrap();
-                let cap_x = first.x;
-                let line_y = line.y;
-                // Text on the cap's own line, pushed right to clear the glyph.
-                let rest_x = line.items[1].x;
-
-                // Walk up the run of lines the cap has indented. A drop cap
-                // pushes every line it covers to the right of the glyph, so
-                // the paragraph's first line is the TOPMOST line sharing that
-                // indent — however many lines the cap spans. Using the indent
-                // rather than the cap's font size is what makes this work for
-                // three- and four-line initials as well as two-line ones;
-                // deriving a line count from the em size does not survive
-                // contact with real documents, where 36-47pt initials sit
-                // over 11-14pt leading.
-                //
-                // A cap in a different column has no such run (its neighbours
-                // sit at an unrelated x), so it is left alone — which is
-                // correct when the cap's own line already carries the rest of
-                // the word.
-                const INDENT_TOLERANCE: f32 = 2.0;
-                const MAX_CAP_LINES: usize = 8;
-                let max_step = base_size * 2.5;
-                let mut target_idx = result.len();
-                let mut expected_y = line_y;
-                while target_idx > 0 && result.len() - target_idx < MAX_CAP_LINES {
-                    let cand = &result[target_idx - 1];
-                    let step = cand.y - expected_y;
-                    let shares_indent = cand
-                        .items
-                        .first()
-                        .is_some_and(|i| (i.x - rest_x).abs() <= INDENT_TOLERANCE);
-                    if cand.page != line.page || step <= 0.0 || step > max_step || !shares_indent {
-                        break;
-                    }
-                    expected_y = cand.y;
-                    target_idx -= 1;
-                }
-
-                // The topmost line of the run is the paragraph's first line.
-                // The line above THAT tells us whether it starts a paragraph.
-                let before_target = target_idx
-                    .checked_sub(1)
-                    .and_then(|i| result.get(i))
-                    .filter(|l| l.page == line.page)
-                    .map(|l| (l.text().trim_end().to_string(), l.y));
-                // Leading within the run: the step from the target down to the
-                // next line of the paragraph, which is the cap's own line when
-                // the run is a single line.
-                let run_step = result
-                    .get(target_idx)
-                    .map(|t| {
-                        let below_y = result.get(target_idx + 1).map_or(line_y, |b| b.y);
-                        t.y - below_y
-                    })
-                    .unwrap_or(0.0);
-                let step_for_gap = if run_step > 0.0 {
-                    run_step
-                } else {
-                    base_size * 1.2
-                };
-
-                let target = (target_idx < result.len())
-                    .then(|| &mut result[target_idx])
-                    .filter(|prev| {
-                        let prev_text = prev.text();
-                        let prev_trimmed = prev_text.trim();
-                        // A hyphen on the line above means the target resumes
-                        // a split word, so it continues a paragraph rather
-                        // than starting one (polkuja_ylakoulu: "ylakou-" +
-                        // "lulaisten").
-                        //
-                        // Case cannot serve as a continuation signal here: the
-                        // target legitimately starts lowercase, because the
-                        // cap removes the word's first letter and leaves
-                        // "ver the course..." for "Over".
-                        let continues_previous = before_target
-                            .as_ref()
-                            .is_some_and(|(b, _)| b.ends_with('-'));
-                        // The target must START a paragraph: extra leading
-                        // above it, a completed sentence on the line above, or
-                        // nothing above it at all.
-                        let starts_paragraph = match before_target.as_ref() {
-                            None => true,
-                            Some((text, y)) => {
-                                y - prev.y > step_for_gap * 1.15 || ends_sentence(text)
-                            }
-                        };
-                        !continues_previous
-                            && starts_paragraph
-                            && prev.page == line.page
-                            && prev.y > line_y
-                            // Indented past the cap glyph, not merely to its
-                            // right by an arbitrary amount.
-                            && prev
-                                .items
-                                .first()
-                                .is_some_and(|i| i.x > cap_x && i.x - cap_x <= first.font_size * 2.0)
-                            // Body text, so headings, labels and table
-                            // fragments are never rewritten.
-                            && prev_trimmed
-                                .chars()
-                                .next()
-                                .is_some_and(char::is_alphabetic)
-                            && prev_trimmed.chars().filter(|c| c.is_alphabetic()).count() >= 8
-                    });
-                if let Some(prev_line) = target {
-                    if let Some(first_item) = prev_line.items.first_mut() {
-                        // A mid-word cap ("T" + "HE recent") joins directly.
-                        // Leading whitespace only marks a word boundary when
-                        // the cap is itself a single-letter word, since the
-                        // paragraph's indent can also arrive as whitespace.
-                        const SINGLE_LETTER_WORDS: &[char] = &['A', 'I', 'O', 'U', 'Y', 'E'];
-                        let had_leading_ws = first_item.text.starts_with(char::is_whitespace)
-                            && SINGLE_LETTER_WORDS.contains(&drop_char);
-                        let rest = first_item.text.trim_start().to_string();
-                        first_item.text = if had_leading_ws {
-                            format!("{} {}", drop_char, rest)
-                        } else {
-                            format!("{}{}", drop_char, rest)
-                        };
-                    }
-                    let mut line = line.clone();
-                    line.items.remove(0);
-                    result.push(line);
-                    continue;
-                }
-            }
-        }
-
         if is_drop_cap {
             let drop_char = trimmed.chars().next().unwrap();
 
@@ -816,314 +598,6 @@ mod tests {
         }
     }
 
-    fn make_item_at(text: &str, font_size: f32, x: f32) -> TextItem {
-        let mut item = make_item(text, font_size, None);
-        item.x = x;
-        item.width = text.len() as f32 * font_size * 0.5;
-        item
-    }
-
-    #[test]
-    fn embedded_drop_cap_moves_to_paragraph_start() {
-        // A two-line cap baseline-aligns with the paragraph's SECOND line,
-        // so it lands as that line's first item (Shannon entropy.pdf p.1).
-        let first_line = TextLine {
-            items: vec![make_item_at(
-                "HE recent development which exchange",
-                10.0,
-                90.0,
-            )],
-            // 16pt baseline step under a 25pt cap: a genuine two-line cap.
-            y: 716.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let second_line = TextLine {
-            items: vec![
-                make_item_at("T", 25.0, 72.0),
-                make_item_at("bandwidth for signal-to-noise ratio", 10.0, 90.0),
-            ],
-            y: 700.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let result = merge_drop_caps(vec![first_line, second_line], 10.0);
-        assert_eq!(result.len(), 2);
-        assert!(
-            result[0].text().starts_with("THE recent"),
-            "cap should prepend to the paragraph start: {}",
-            result[0].text()
-        );
-        assert!(
-            result[1].text().starts_with("bandwidth"),
-            "cap must be removed from the second line: {}",
-            result[1].text()
-        );
-    }
-
-    #[test]
-    fn embedded_drop_cap_walks_a_multi_line_initial_to_the_paragraph_start() {
-        // A 47pt initial over 13pt leading covers four lines, so the
-        // paragraph's first line is three lines above the cap rather than
-        // immediately above it (polkuja_ylakoulu). The indented run, not the
-        // cap's em size, is what locates it.
-        let mut lines = vec![TextLine {
-            items: vec![make_item_at("Previous paragraph ends here.", 10.0, 72.0)],
-            y: 766.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        }];
-        for (i, text) in [
-            "rilaiset mediasisallot ovat tarkea osa",
-            "useimpien ylakoululaisten elamaa ja",
-            "muuta tekstia jatkuu tassa viela",
-        ]
-        .iter()
-        .enumerate()
-        {
-            lines.push(TextLine {
-                items: vec![make_item_at(text, 10.0, 90.0)],
-                y: 753.0 - 13.0 * i as f32,
-                page: 1,
-                adaptive_threshold: 0.10,
-            });
-        }
-        lines.push(TextLine {
-            items: vec![
-                make_item_at("E", 47.0, 72.0),
-                make_item_at("loppuosa tekstista tassa", 10.0, 90.0),
-            ],
-            y: 714.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        });
-
-        let result = merge_drop_caps(lines, 10.0);
-        assert!(
-            result[1].text().starts_with("Erilaiset"),
-            "cap belongs on the topmost line of the indented run: {}",
-            result[1].text()
-        );
-        assert!(
-            result[2].text().starts_with("useimpien"),
-            "intervening run lines must be untouched: {}",
-            result[2].text()
-        );
-        assert!(
-            result[4].text().starts_with("loppuosa"),
-            "cap must be removed from its own line: {}",
-            result[4].text()
-        );
-    }
-
-    #[test]
-    fn embedded_drop_cap_ignores_non_paragraph_neighbours() {
-        // Same geometry, but the preceding line is a short label rather than
-        // body text, so it must not be rewritten.
-        let label = TextLine {
-            items: vec![make_item_at("Fig. 2", 10.0, 90.0)],
-            y: 716.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let second_line = TextLine {
-            items: vec![
-                make_item_at("T", 25.0, 72.0),
-                make_item_at("bandwidth for signal-to-noise ratio", 10.0, 90.0),
-            ],
-            y: 700.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let result = merge_drop_caps(vec![label, second_line], 10.0);
-        assert_eq!(result[0].text().trim(), "Fig. 2");
-        assert!(
-            result[1].text().starts_with('T'),
-            "cap stays put: {}",
-            result[1].text()
-        );
-    }
-
-    #[test]
-    fn embedded_drop_cap_keeps_a_space_for_standalone_word_caps() {
-        // Leading whitespace on the paragraph's first item marks the cap as
-        // a word of its own rather than the first letter of one.
-        let mut lead = make_item_at("long time ago in a galaxy far away", 10.0, 90.0);
-        lead.text = " long time ago in a galaxy far away".to_string();
-        let first_line = TextLine {
-            items: vec![lead],
-            y: 716.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let second_line = TextLine {
-            items: vec![
-                make_item_at("A", 25.0, 72.0),
-                make_item_at("continued here with more body text", 10.0, 90.0),
-            ],
-            y: 700.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let result = merge_drop_caps(vec![first_line, second_line], 10.0);
-        assert!(
-            result[0].text().starts_with("A long time ago"),
-            "standalone-word cap keeps one space: {}",
-            result[0].text()
-        );
-    }
-
-    #[test]
-    fn embedded_drop_cap_skips_hyphenation_continuation_targets() {
-        // The line above the RUN ends on a hyphen, so the run's topmost line
-        // resumes a split word rather than starting a paragraph. It sits at
-        // the paragraph margin (x=72), outside the cap's indent, so it is not
-        // part of the run itself.
-        let split_word = TextLine {
-            items: vec![make_item_at(
-                "mediasisallot ovat osa useimpien ylakou-",
-                10.0,
-                72.0,
-            )],
-            y: 728.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let run_top = TextLine {
-            items: vec![make_item_at(
-                "lulaisten elamaa ja muuta tekstia",
-                10.0,
-                90.0,
-            )],
-            y: 714.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let cap_line = TextLine {
-            items: vec![
-                make_item_at("E", 25.0, 72.0),
-                make_item_at("jatkuu tassa lisaa leipatekstia", 10.0, 90.0),
-            ],
-            y: 700.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let result = merge_drop_caps(vec![split_word, run_top, cap_line], 10.0);
-        assert!(
-            result[1].text().starts_with("lulaisten"),
-            "a run resuming a split word must not receive the cap: {}",
-            result[1].text()
-        );
-        assert!(
-            result[2].text().starts_with('E'),
-            "cap stays put when no valid target exists: {}",
-            result[2].text()
-        );
-    }
-
-    #[test]
-    fn embedded_drop_cap_indent_is_not_a_word_boundary() {
-        // The paragraph's first line is indented to clear the cap, and that
-        // indent can arrive as leading whitespace. A mid-word cap must still
-        // join directly — "T HE recent" would be the defect this fixes.
-        let mut lead = make_item_at("HE recent development and more body text", 10.0, 90.0);
-        lead.text = "  HE recent development and more body text".to_string();
-        let first_line = TextLine {
-            items: vec![lead],
-            y: 716.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let cap_line = TextLine {
-            items: vec![
-                make_item_at("T", 25.0, 72.0),
-                make_item_at("bandwidth for signal-to-noise ratio", 10.0, 90.0),
-            ],
-            y: 700.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let result = merge_drop_caps(vec![first_line, cap_line], 10.0);
-        assert!(
-            result[0].text().starts_with("THE recent"),
-            "indent must not be read as a word boundary: {}",
-            result[0].text()
-        );
-    }
-
-    #[test]
-    fn ends_sentence_rejects_abbreviations_and_markers() {
-        use super::ends_sentence;
-        assert!(ends_sentence("This completes the thought."));
-        assert!(ends_sentence("Is that so?"));
-        assert!(ends_sentence("Stop!"));
-        // Periods that do not end a sentence.
-        assert!(!ends_sentence("as shown in Fig."));
-        assert!(!ends_sentence("see e.g."));
-        // Non-ASCII abbreviations. The two-CHARACTER segment is the case
-        // that distinguishes a character count from a byte count: "пр" is
-        // 2 chars but 4 bytes, so a byte-based bound would reject it and
-        // read the line as a completed sentence.
-        assert!(!ends_sentence("и т.пр."));
-        assert!(!ends_sentence("см. т.е."));
-        assert!(!ends_sentence("napr. ú.d."));
-        assert!(!ends_sentence("reviewed by Dr."));
-        // Standalone enumerators, any case.
-        assert!(!ends_sentence("1."));
-        assert!(!ends_sentence("IV."));
-        assert!(!ends_sentence("ii."));
-        assert!(!ends_sentence("xii."));
-        // Numbers and numerals that genuinely end a sentence must count,
-        // or a legitimate drop-cap merge is blocked.
-        assert!(ends_sentence("The paper was published in 2020."));
-        assert!(ends_sentence("He scored 5."));
-        assert!(ends_sentence("after World War II."));
-        assert!(ends_sentence("the constant equals 3.14."));
-        assert!(ends_sentence("documented at example.com."));
-        assert!(!ends_sentence("a trailing clause with no period"));
-    }
-
-    #[test]
-    fn embedded_drop_cap_allows_first_paragraph_on_a_new_page() {
-        // The line two back is on the previous page, so its y is unrelated
-        // and must not be used as leading evidence.
-        let prev_page_tail = TextLine {
-            items: vec![make_item_at(
-                "tail of the previous page body text",
-                10.0,
-                90.0,
-            )],
-            y: 90.0,
-            page: 1,
-            adaptive_threshold: 0.10,
-        };
-        let first_line = TextLine {
-            items: vec![make_item_at(
-                "HE recent development which exchange",
-                10.0,
-                90.0,
-            )],
-            y: 716.0,
-            page: 2,
-            adaptive_threshold: 0.10,
-        };
-        let cap_line = TextLine {
-            items: vec![
-                make_item_at("T", 25.0, 72.0),
-                make_item_at("bandwidth for signal-to-noise ratio", 10.0, 90.0),
-            ],
-            y: 700.0,
-            page: 2,
-            adaptive_threshold: 0.10,
-        };
-        let result = merge_drop_caps(vec![prev_page_tail, first_line, cap_line], 10.0);
-        assert!(
-            result[1].text().starts_with("THE recent"),
-            "a page break must not suppress the merge: {}",
-            result[1].text()
-        );
-    }
-
     #[test]
     fn test_merge_struct_tree_headings() {
         // Two consecutive lines tagged as H2 via struct tree, same font size as body

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_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/snapshots/shannon-entropy-p1-2.md

@@ -1,12 +1,16 @@
 Reprinted with corrections from *The Bell System Technical Journal,* Vol. 27, pp. 379–423, 623–656, July, October, 1948.
 
-# A Mathematical Theory of Communication
+## A Mathematical Theory of Communication
 
-## By C. E. SHANNON
+### By C. E. SHANNON
 
 INTRODUCTION
 
-THE recent development of various methods of modulation such as PCM and PPM which exchange bandwidth for signal-to-noise ratio has intensified the interest in a general theory of communication. A basis for such a theory is contained in the important papers of Nyquist¹ and Hartley² on this subject. In the present paper we will extend the theory to include a number of new factors, in particular the effect of noise in the channel, and the savings possible due to the statistical structure of the original message and due to the nature of the final destination of the information. The fundamental problem of communication is that of reproducing at one point either exactly or ap- proximately a message selected at another point. Frequently the messages have *meaning*; that is they refer to or are correlated according to some system with certain physical or conceptual entities. These semantic aspects of communication are irrelevant to the engineering problem. The significant aspect is that the actual message is one *selected from a set* of possible messages. The system must be designed to operate for each possible selection, not just the one which will actually be chosen since this is unknown at the time of design. If the number of messages in the set is finite then this number or any monotonic function of this number can be regarded as a measure of the information produced when one message is chosen from the set, all choices being equally likely. As was pointed out by Hartley the most natural choice is the logarithmic function. Although this definition must be generalized considerably when we consider the influence of the statistics of the message and when we have a continuous range of messages, we will in all cases use an essentially logarithmic measure. The logarithmic measure is more convenient for various reasons:
+HE recent development of various methods of modulation such as PCM and PPM which exchange
+
+# Tbandwidth for signal-to-noise ratio has intensified the interest in a general theory of communication. A
+
+basis for such a theory is contained in the important papers of Nyquist¹ and Hartley² on this subject. In the present paper we will extend the theory to include a number of new factors, in particular the effect of noise in the channel, and the savings possible due to the statistical structure of the original message and due to the nature of the final destination of the information. The fundamental problem of communication is that of reproducing at one point either exactly or ap- proximately a message selected at another point. Frequently the messages have *meaning*; that is they refer to or are correlated according to some system with certain physical or conceptual entities. These semantic aspects of communication are irrelevant to the engineering problem. The significant aspect is that the actual message is one *selected from a set* of possible messages. The system must be designed to operate for each possible selection, not just the one which will actually be chosen since this is unknown at the time of design. If the number of messages in the set is finite then this number or any monotonic function of this number can be regarded as a measure of the information produced when one message is chosen from the set, all choices being equally likely. As was pointed out by Hartley the most natural choice is the logarithmic function. Although this definition must be generalized considerably when we consider the influence of the statistics of the message and when we have a continuous range of messages, we will in all cases use an essentially logarithmic measure. The logarithmic measure is more convenient for various reasons:
 
 1. It is practically more useful. Parameters of engineering importance such as time, bandwidth, number of relays, etc., tend to vary linearly with the logarithm of the number of possibilities. For example, adding one relay to a group doubles the number of possible states of the relays. It adds 1 to the base 2 logarithm of this number. Doubling the time roughly squares the number of possible messages, or doubles the logarithm, etc.
 2. It is nearer to our intuitive feeling as to the proper measure. This is closely related to (1) since we in- tuitively measures entities by linear comparison with common standards. One feels, for example, that two punched cards should have twice the capacity of one for information storage, and two identical channels twice the capacity of one for transmitting information.

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"