class http\Encoding\Stream\Deflate
 extends http\Encoding\Stream

A deflate stream supporting deflate, zlib and gzip encodings.


A note on the compression strategy:

The strategy parameter is used to tune the compression algorithm.

Use the value DEFAULT_STRATEGY for normal data, FILTERED for data produced by a filter (or predictor), HUFFMAN_ONLY to force Huffman encoding only (no string match), or RLE to limit match distances to one (run-length encoding).

Filtered data consists mostly of small values with a somewhat random distribution. In this case, the compression algorithm is tuned to compress them better. The effect of FILTERED is to force more Huffman coding and less string matching; it is somewhat intermediate between DEFAULT_STRATEGY and HUFFMAN_ONLY.

RLE is designed to be almost as fast as HUFFMAN_ONLY, but give better compression for PNG image data.

FIXED prevents the use of dynamic Huffman codes, allowing for a simpler decoder for special applications.

The strategy parameter only affects the compression ratio but not the correctness of the compressed output even if it is not set appropriately.

Source: zlib Manual