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Gzip Decompress — Header/Footer Validation + CRC32

June 23, 2026 · Sigil-Docs · sigil-apps b8cabe8
appsbrowsernetcompression0.7.0

gzip_decompress.sg is the T20 sprint — gzip decompressor stub with header/footer validation and CRC32 integrity check. Validates magic bytes (0x1f 0x8b), compression method (0x08 for deflate), gzip footer (CRC32 + ISIZE). Stores decompression flags (header_valid, footer_valid, crc_match) in decomp_buf @0x580000 (24 B). GZIP-DECOMPRESS-PASS 6/6. 5808 B arm-el0.

Gzip frame validator

gzip_decompress.sg
Header + footer + CRC32 validation — validates gzip header: magic bytes 0x1f 0x8b, compression method 0x08 (deflate). Parses gzip footer: CRC32 (4 bytes, IEEE polynomial) + ISIZE (4 bytes, original uncompressed size mod 2^32). Stores validation result in decomp_buf as flags struct (24 B): header_valid, footer_valid, crc_match. Test: minimal valid gzip frame with known CRC. Foundation for Content-Encoding: gzip HTTP response decompression in the browser pipeline. GZIP-DECOMPRESS-PASS 6/6.