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   1 # class http\Encoding\Stream\Deflate extends http\Encoding\Stream
   2
   3 A deflate stream supporting deflate, zlib and gzip encodings.
   4
   5 ## Constants:
   6
   7 * TYPE_GZIP
   8   Gzip encoding. RFC1952
   9 * TYPE_ZLIB
  10   Zlib encoding. RFC1950
  11 * TYPE_RAW
  12   Deflate encoding. RFC1951
  13 * LEVEL_DEF
  14   Default compression level.
  15 * LEVEL_MIN
  16   Least compression level.
  17 * LEVEL_MAX
  18   Greatest compression level.
  19 * STRATEGY_DEF
  20   Default compression strategy.
  21 * STRATEGY_FILT
  22   Filtered compression strategy.
  23 * STRATEGY_HUFF
  24   Huffman strategy only.
  25 * STRATEGY_RLE
  26   Run-length encoding strategy.
  27 * STRATEGY_FIXED
  28   Encoding with fixed Huffman codes only.
  29
  30 > **A note on the compression strategy:**
  31 >
  32 > The strategy parameter is used to tune the compression algorithm.
  33 >
  34 > 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).
  35 >
  36 > 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.
  37 >
  38 > RLE is designed to be almost as fast as HUFFMAN_ONLY, but give better compression for PNG image data.
  39 >
  40 > FIXED prevents the use of dynamic Huffman codes, allowing for a simpler decoder for special applications.
  41 >
  42 > The strategy parameter only affects the compression ratio but not the correctness of the compressed output even if it is not set appropriately.
  43 >
  44 >_Source: [zlib Manual](http://www.zlib.net/manual.html)_
  45
  46
  47 ## Properties:
  48
  49 None.