just_deflate 0.1.0

Pure Dart DEFLATE (RFC 1951) compression and decompression with the zlib (RFC 1950) and gzip (RFC 1952) formats. No dependencies; runs on native, web and Wasm.

Changelog

0.1.0 - 2026-10-06

Added

• ZlibCodec, GzipCodec and DeflateCodec: encode(List<int>) and decode(List<int>, {maxOutputSize}) for zlib (RFC 1950), gzip (RFC 1952) and raw DEFLATE (RFC 1951) data.
  • Compression levels 0-9 with zlib's settings: stored blocks at 0, greedy matching at 1-3, lazy matching at 4-9. Each block is written stored, fixed-Huffman or dynamic-Huffman, whichever is smallest.
  • The match finder hashes four bytes rather than zlib's three, which matters for tile data, where most three-byte strings are zeros. Output sizes are within a few bytes of dart:io's zlib at every level.
  • Output is identical on native, web and Wasm.
  • The decoder reads every block type and any window size. Adler-32 and CRC-32 checksums are verified. Gzip files may hold several members and gzip's optional header fields (FEXTRA, FNAME, FCOMMENT, FHCRC).
  • Damaged data throws FormatException, never another error. maxOutputSize caps the decoded size.
• adler32 and crc32 checksums, each able to continue a running value.
• Tests: round trips at every level for every format, both ways against dart:io's zlib (every level, window size, memory level and strategy), real zlib output kept as fixtures, hand-built bad streams, every truncation, and seeded random damage. They run on the VM, dart2js and dart2wasm.