Commit Graph

12 Commits

Author SHA1 Message Date
Zoltan Szabadka 05b3775ecb Fix buffer overflow bug in the brotli encoder. 2014-03-27 16:38:07 +01:00
Zoltan Szabadka 0829e37293 Update the dictionary and the transforms. 2014-03-25 16:48:25 +01:00
Zoltan Szabadka 278b89484f Updates to Brotli compression format, decoder and encoder
This commit contains a batch of changes that were made to the Brotli
compression algorithm in the last month. Most important changes:

   * Format change: don't push distances representing static dictionary words to the distance cache.
   * Fix decoder invalid memory access bug caused by building a non-complete Huffman tree.
   * Add a mode parameter to the encoder interface.
   * Use different hashers for text and font mode.
   * Add a heuristics to the hasher for skipping non-compressible data.
   * Exhaustive search of static dictionary during backward reference search.
2014-03-20 14:32:35 +01:00
Zoltan Szabadka 2733d6c0c2 Add the initial version of the static dictionary and transforms to Brotli. 2014-02-17 14:25:36 +01:00
Zoltan Szabadka cbd5cb55f4 Updates to Brotli compression format, decoder and encoder
This commit contains a batch of changes that were made to the Brotli
compression algorithm in the last month. Most important changes:

   * Fixes to the spec.
   * Change of code length code order.
   * Use a 2-level Huffman lookup table in the decoder.
   * Faster uncompressed meta-block decoding.
   * Optimized encoding of the Huffman code.
   * Detection of UTF-8 input encoding.
   * UTF-8 based literal cost modeling for improved
     backward reference selection.
2014-02-14 15:04:23 +01:00
Zoltan Szabadka 4c8c7fd31c Brotli format change: small improvement to the encoding of Huffman codes
Combine the HSKIP and the simple/complex Huffman code type bits.
2014-01-08 12:28:28 +01:00
Zoltan Szabadka b89f3be40b Brotli format change: improved encoding of Huffman codes
This change removes the redundant HCLEN, HLENINC and HLEN
fields from the encoding of the complex Huffman codes and
derives these from an invariant of the code length sequence.
Based on a patch by Robert Obryk.
2013-12-17 17:17:57 +01:00
Zoltan Szabadka e70949119a Updates to Brotli compression format, decoder and encoder
This commit contains a batch of changes that were made to the Brotli
compression algorithm in the last month. Most important changes:

   * Updated spec
   * Changed Huffman code length alphabet to use run length codes more
     efficiently, based on a suggestion by Robert Obryk
   * Changed encoding of the number of Huffman code lengths (HLEN)
   * Changed encoding of the number of Huffman trees (NTREES)
   * Added support for uncompressed meta-blocks
2013-12-12 13:18:04 +01:00
Zoltan Szabadka fe79fac8da Add draft specification of the brotli format 2013-11-28 17:37:13 +01:00
Roderick Sheeter 437bbad370 Added Brotli compress/decompress utilities and makefiles 2013-11-19 14:32:56 -08:00
Zoltan Szabadka 1571db36a9 Updates to Brotli compression format, decoder and encoder
This commit contains a batch of changes that were made to the Brotli
compression algorithm in the last three weeks. Most important changes:

  * Added UTF8 context model for good text compression.
  * Simplified context modeling by having only 4 context modes.
  * Per-block context mode selection.
  * Faster backward copying and bit reading functions.
  * More efficient histogram coding.
  * Streaming support for the decoder and encoder.
2013-11-15 19:02:17 +01:00
Zoltan Szabadka 79e99afe46 Add brotli compressor
This commit is for the encoder for brotli compression format.
Brotli is a generic byte-level compression algorithm.
2013-10-23 13:06:13 +02:00