Adds functions to prepend such dictionary to the
encoder and decoder, and twiddles their internal
parameters to do as if that was a previous part of
the input. This dictionary is just a prefilled LZ77
window, it is not related to the built in transformable
brotli dictionary.
* Read data by 4-byte runs.
This resolves unaligned read (Bus error) on arm-android.
* Get rid of malloc/free in BrotliBuildHuffmanTable.
* Tweak order of instructions when reading Huffman codes.
* Change order of members of bit reader state structure.
* Remove unused includes for assert. Add BROTLI_DCHECK
macros and use it instead of assert.
* Do not calculate nbits in common case of ReadSymbol.
* Introduce and use PREDICT_TRUE / PREDICT_FALSE macros.
* Allocate less memory in the brotli decoder if it knows
the result size beforehand. Before this, the decoder
would always allocate 16MB if the encoder annotated the
window size as 22 bit (which is the default), even if the
file is only a few KB uncompressed. Now, it'll only
allocate a ringbuffer as large as needed for the result file.
But only if it can know the filesize, it's not possible
to know that if there are multiple metablocks or too large
uncompressed metablock.
- Reject brotli streams where the number of
nibbles is too large for the size of the
meta-block
- Reject brotli streams where the padding
bits after a meta-block are not all zero
- Reject brotli streams where the symbol
in the simple prefix code is not in
the symbol alphabet
1) Use a tighter upper bound on the Huffman table size.
2) Remove unused argument len in ToUpperCase.
3) Remove unused no-op assignment in BrotliDecompress.
4) Fix include guard name.
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.
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.
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.
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
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.
(1) Move all variable declarations to the beginning of the block.
(2) Remove 'z' printf modifiers.
(3) Fix 'comma at the end of enumeration list' warning.
