225f96c241
The extract_markdown stub was calling extract_text instead of extract_text_fn, causing a compilation error. This fixes the function name to match the exported function from extract_text.rs. This completes the extract_text PyO3 entry point implementation, which was already present in extract_text.rs and lib.rs. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
95 lines
3.5 KiB
Rust
95 lines
3.5 KiB
Rust
//! Example: Compute PDF structural fingerprint.
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//!
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//! Demonstrates fingerprint computation for PDF document identification.
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//! The fingerprint is a reproducible 256-bit hash that identifies the
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//! semantic content independent of metadata churn.
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//!
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//! Usage:
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//! cargo run --example hash -- tests/fixtures/sample.pdf
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use anyhow::Result;
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use pdftract_core::fingerprint::{
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compute_fingerprint, ContentStreamData, FingerprintInput, PageFingerprintData,
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};
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use pdftract_core::parser::catalog::parse_catalog;
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use pdftract_core::parser::pages::flatten_page_tree;
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use pdftract_core::parser::stream::{FileSource, PdfSource};
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use pdftract_core::parser::xref::{load_xref_with_prev_chain, XrefResolver};
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use std::env;
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use std::path::Path;
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fn main() -> Result<()> {
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// Get PDF path from command line, or use a default
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let args: Vec<String> = env::args().collect();
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let pdf_path = args.get(1).map(|s| s.as_str()).unwrap_or("tests/fixtures/sample.pdf");
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// Open the PDF
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let source = FileSource::open(Path::new(pdf_path))?;
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// Find the startxref offset
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let source_len = source.len()?;
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let tail_len = 1024.min(source_len as usize) as u64;
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let tail_start = source_len - tail_len;
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let tail_data = source.read_at(tail_start, tail_len as usize)?;
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let startxref_pos = tail_data
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.windows(9)
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.rposition(|w| w == b"startxref")
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.ok_or_else(|| anyhow::anyhow!("startxref not found"))?;
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let offset_str = std::str::from_utf8(&tail_data[startxref_pos + 9..])
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.map_err(|_| anyhow::anyhow!("Invalid UTF-8 in startxref"))?
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.split_whitespace()
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.next()
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.ok_or_else(|| anyhow::anyhow!("No offset after startxref"))?;
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let startxref_offset: u64 = offset_str
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.parse()
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.map_err(|_| anyhow::anyhow!("Invalid startxref offset"))?;
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// Load xref and parse catalog
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let xref_section = load_xref_with_prev_chain(&source, startxref_offset);
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let resolver = XrefResolver::from_section(xref_section.clone());
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let root_ref = xref_section
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.trailer
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.as_ref()
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.and_then(|t| t.get("Root"))
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.and_then(|o| o.as_ref())
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.ok_or_else(|| anyhow::anyhow!("No /Root in trailer"))?;
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let catalog = parse_catalog(&resolver, root_ref, Some(&source as &dyn PdfSource))
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.map_err(|d| anyhow::anyhow!("Catalog parse failed: {}", d.first().map(|d| d.message.as_ref()).unwrap_or("unknown")))?;
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// Flatten page tree
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let pages = flatten_page_tree(&resolver, catalog.pages_ref)
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.map_err(|d| anyhow::anyhow!("Page tree parse failed: {}", d.first().map(|d| d.message.as_ref()).unwrap_or("unknown")))?;
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// Build fingerprint input
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let page_count = pages.len() as u32;
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let fingerprint_pages = pages
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.iter()
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.map(|page| PageFingerprintData {
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content_streams: page.contents.iter().map(|&r| ContentStreamData::Indirect(r)).collect(),
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resources: None,
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media_box: page.media_box,
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crop_box: page.crop_box,
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rotate: page.rotate,
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})
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.collect();
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let fingerprint_input = FingerprintInput {
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page_count,
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pages: fingerprint_pages,
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struct_tree_root_ref: catalog.struct_tree_root_ref,
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is_tagged: catalog.mark_info.is_tagged,
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catalog_flags: Default::default(),
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};
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// Compute fingerprint
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let fingerprint = compute_fingerprint(&fingerprint_input, &resolver, Some(&source as &dyn PdfSource));
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println!("{}", fingerprint);
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Ok(())
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}
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