# add deflate compression, simplify decompression · gitcafe/zig

[View on GitCafe](https://git.cafe/gitcafe/zig/commit/f50c6479774d49fc21c5652b39bcad3c2512867b)

Repository: [gitcafe/zig](https://git.cafe/gitcafe/zig)

Visibility: public

Requested revision: f50c6479774d49fc21c5652b39bcad3c2512867b

Requested commit: f50c6479774d49fc21c5652b39bcad3c2512867b

Commit: f50c6479774d49fc21c5652b39bcad3c2512867b

Tree: 4c27a9c71489f778323b2decccd9607007da4e19

Author: Kendall Condon

Committer: Andrew Kelley

## Message

```
add deflate compression, simplify decompression

Implements deflate compression from scratch. A history window is kept in
the writer's buffer for matching and a chained hash table is used to
find matches. Tokens are accumulated until a threshold is reached and
then outputted as a block. Flush is used to indicate end of stream.

Additionally, two other deflate writers are provided:
* `Raw` writes only in store blocks (the uncompressed bytes). It
  utilizes data vectors to efficiently send block headers and data.
* `Huffman` only performs Huffman compression on data and no matching.

The above are also able to take advantage of writer semantics since they
do not need to keep a history.

Literal and distance code parameters in `token` have also been reworked.
Their parameters are now derived mathematically, however the more
expensive ones are still obtained through a lookup table (expect on
ReleaseSmall).

Decompression bit reading has been greatly simplified, taking advantage
of the ability to peek on the underlying reader. Additionally, a few
bugs with limit handling have been fixed.

```

## Parents

- [e79a00adf664ef46b74da5ed2d620d342b9f8807](https://git.cafe/gitcafe/zig/commit/e79a00adf664ef46b74da5ed2d620d342b9f8807?format=markdown)

[Source at this commit](https://git.cafe/gitcafe/zig/tree/f50c6479774d49fc21c5652b39bcad3c2512867b?format=markdown)