pdfrum-parser

The file layer (ISO 32000-1 §7.5). A PDF is %PDF-m.n, a body of objects, a cross-reference table or stream at the end, and a trailer pointing at both; an incremental update appends another body, xref and trailer in front of the last. [load] finds that chain, or gives up on it and rebuilds the table by scanning the whole file for N G obj.

use std::sync::Arc;
use pdfrum_parser::{LoadOptions, load};

let bytes = std::fs::read(concat!(env!("CARGO_MANIFEST_DIR"), "/tests/files/minimal.pdf"))?;
let doc = load(Arc::from(bytes), &LoadOptions::default())?;
assert_eq!(doc.page_count(), 1);
# Ok::<(), Box<dyn std::error::Error>>(())

A malformed file PDFium would open is not an error here. That is the whole design constraint: real PDFs have wrong /Length values, xref offsets off by a few bytes, tables that point at nothing, and generations that do not match. Every one of those is repaired and recorded in the document's diagnostics, and Err is reserved for a file that cannot be opened at all. A caller that wants strictness reads the diagnostics; a caller that wants the document gets the document.

Loading is lazy. [load] reads the header, the xref chain and the trailer, and leaves object bodies as byte offsets until something asks for them — so opening a thousand-page file to read its page count does not parse a thousand pages, and the object store is Arc-backed shared bytes rather than a parsed tree in memory.

The stages are separable on purpose and each is testable on values alone: the lexer turns bytes into tokens and owns the byte classifier everything else asks questions of, syntax turns tokens into Objects and is where stream /Length repair lives, and xref finds cross-reference information by every route a file can offer before rebuilding from scratch.

Part of pdfrum. #![forbid(unsafe_code)].

MIT OR Apache-2.0