Commit Graph

7 Commits

Author SHA1 Message Date
Zoltan Szabadka
65f3fc55f5 Bug fixes for the brotli encoder.
* Fix an out-of-bounds access to depth_histo in the
    bit cost calculation function.

  * Change type of distance symbol to uint16_t in block
    splitter, because if all postfix bits are used, there
    can be 520 distance symbols.

  * Save the distance cache between meta-blocks at the
    correct place. This fixes a roundtrip failure that
    can occur when there is an uncompressed metablock
    between two compressed metablocks.

  * Fix a bug when setting lgwin to 24 in the encoder parameters
    It ended up making metablocks larger than 24 bits in size.

  * Fix out-of-bounds memory accesses in parallel encoder.
    CreateBackwardReferences can read up to 4 bytes past end of
    input if the end of input is before mask.

  * Add missing header for memcpy() in port.h
2015-06-12 16:11:50 +02:00
Zoltan Szabadka
98539223f5 Remove quality parameter from bitstream writing functions.
Fix a few crashes related to some quality and param combinations.
2015-04-23 16:20:29 +02:00
Zoltan Szabadka
d6d9fc60e1 Factor out serialization functions into their own file.
Create a brotli_bit_stream library that is responsible for writing
various structures (headers, Huffman codes, etc.) directly into the
bit-stream.
2014-10-15 14:01:36 +02:00
Zoltan Szabadka
0454ab4ec0 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
60c24c0c2d 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
c6b9c7c5c8 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
c66e4e3e4f 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