std/compress

Deflate (RFC 1951), zlib (RFC 1950), and gzip (RFC 1952), in one call and as streams that take and give a part at a time. The work is the system's zlib, which a program that imports std/compress links with (-lz).

import "std/compress"

bytes packed = gzip(read_bytes("log.txt"))
bytes back = gunzip(packed, 100_000_000)?

Compressor c = compressor("gzip")?
for part in parts do
    file_write(out, c.push(part))?
end
file_write(out, c.finish())?

Function	Result
`compress(format, data, level)`	`data` in one of `COMPRESSION_FORMATS`: `"deflate"` (raw, as ZIP and HTTP hold it), `"zlib"`, or `"gzip"`; `level` 0 (none) to 9 (smallest), -1 for zlib's 6
`decompress(format, data, limit)`	what `data` decompresses to; `"auto"` takes zlib or gzip, whichever it is
`gzip(data, level)`, `gunzip(data, limit)`	gzip; every member of data that has several, as `cat a.gz b.gz` makes, as `gzip -d` reads it
`zlib_compress`, `zlib_decompress`, `deflate`, `inflate`	the same for zlib and raw deflate
`compressor(format, level)`	a `Compressor`: `push(data)` gives what is ready, `finish()` the rest
`decompressor(format, limit)`	a `Decompressor`: `push(data)` and `finish()` give `Result`s, `finish` failing for data cut short
`gzip_file(path, target, level)`, `gunzip_file(path, target, limit)`	a file compressed into another a part at a time, and back

Data that is not of its format, is cut short, has other data after its end, or would decompress to more than limit bytes is an ERROR of kind "invalid_data". A limit of 0 takes any size; a program that decompresses what others send should give one, since a few kilobytes can decompress to gigabytes. Call finish once on every stream: it frees zlib's state.