Compression Decoders

Compression decoders read from one input stream (an io_reader called src) and write to an output stream (an io_writer called dst). Wuffs' implementations have one key method: transform_io. It incrementally decompresses the source data.

This method is a coroutine, and does not require either all of the input or all of the output to fit in a single contiguous buffer. It can suspend with the $short_read or $short_write statuses when the src buffer needs re-filling or the dst buffer needs flushing. For an example, look at the example/zcat program, which uses fixed size buffers, but reads arbitrarily long compressed input from stdin and writes arbitrarily long decompressed output to stdout.

Dictionaries

TODO: standardize the various dictionary APIs, after Wuffs v0.2 is released.

API Listing

In Wuffs syntax, the base.io_transformer methods are:

• dst_history_retain_length() u64
• get_quirk(key: u32) u64
• set_quirk!(key: u32, value: u64) status
• transform_io?(dst: io_writer, src: io_reader, workbuf: slice u8)
• workbuf_len() range_ii_u64

Implementations

• std/bzip2
• std/deflate
• std/gzip
• std/lzip
• std/lzma
• std/lzw
• std/xz
• std/zlib

Examples

• example/mzcat
• example/toy-genlib
• example/zcat

Quirks

• LZMA decoder quirks
• LZW decoder quirks
• XZ decoder quirks
• Zlib decoder quirks

Related Documentation

• I/O (Input / Output)

See also the general remarks on Wuffs' standard library.