feat(pdf-filter): implement LZWDecode filter with predictor support#122
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feat(pdf-filter): implement LZWDecode filter with predictor support#122
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Add LZW decompression (PDF spec §7.4.4) and shared Predictor post-processing (§7.4.4.4) to the pdf-filter crate. New modules: - lzw.rs: Pure-Rust LZW decoder with EarlyChange parameter support, variable-width codes (9-12 bits), MSB-first bit packing. - predictor.rs: TIFF Predictor 2 (horizontal differencing) and PNG predictors (None/Sub/Up/Average/Paeth). Shared by LZWDecode and FlateDecode. Changes: - bitreader.rs: Add read_bits(n) for variable-width code extraction. - filter.rs: Add LZWDecode variant, Lzw/Flate DecodeParms, wire into decode pipeline. Also wire predictor support into FlateDecode. - lib.rs: Register new modules, update crate documentation. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Add LZW decompression (PDF spec §7.4.4) and shared Predictor post-processing (§7.4.4.4) to the pdf-filter crate.
New modules:
Changes: