1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/toolkit/components/workerlz4/lz4.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,73 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#include "mozilla/Compression.h"
1.9 +
1.10 +/**
1.11 + * LZ4 is a very fast byte-wise compression algorithm.
1.12 + *
1.13 + * Compared to Google's Snappy it is faster to compress and decompress and
1.14 + * generally produces output of about the same size.
1.15 + *
1.16 + * Compared to zlib it compresses at about 10x the speed, decompresses at about
1.17 + * 4x the speed and produces output of about 1.5x the size.
1.18 + *
1.19 + */
1.20 +
1.21 +using namespace mozilla::Compression;
1.22 +
1.23 +/**
1.24 + * Compresses 'inputSize' bytes from 'source' into 'dest'.
1.25 + * Destination buffer must be already allocated,
1.26 + * and must be sized to handle worst cases situations (input data not compressible)
1.27 + * Worst case size evaluation is provided by function LZ4_compressBound()
1.28 + *
1.29 + * @param inputSize is the input size. Max supported value is ~1.9GB
1.30 + * @param return the number of bytes written in buffer dest
1.31 + */
1.32 +extern "C" MOZ_EXPORT size_t
1.33 +workerlz4_compress(const char* source, size_t inputSize, char* dest) {
1.34 + return LZ4::compress(source, inputSize, dest);
1.35 +}
1.36 +
1.37 +/**
1.38 + * If the source stream is malformed, the function will stop decoding
1.39 + * and return a negative result, indicating the byte position of the
1.40 + * faulty instruction
1.41 + *
1.42 + * This function never writes outside of provided buffers, and never
1.43 + * modifies input buffer.
1.44 + *
1.45 + * note : destination buffer must be already allocated.
1.46 + * its size must be a minimum of 'outputSize' bytes.
1.47 + * @param outputSize is the output size, therefore the original size
1.48 + * @return true/false
1.49 + */
1.50 +extern "C" MOZ_EXPORT int
1.51 +workerlz4_decompress(const char* source, size_t inputSize,
1.52 + char* dest, size_t maxOutputSize,
1.53 + size_t *bytesOutput) {
1.54 + return LZ4::decompress(source, inputSize,
1.55 + dest, maxOutputSize,
1.56 + bytesOutput);
1.57 +}
1.58 +
1.59 +
1.60 +/*
1.61 + Provides the maximum size that LZ4 may output in a "worst case"
1.62 + scenario (input data not compressible) primarily useful for memory
1.63 + allocation of output buffer.
1.64 + note : this function is limited by "int" range (2^31-1)
1.65 +
1.66 + @param inputSize is the input size. Max supported value is ~1.9GB
1.67 + @return maximum output size in a "worst case" scenario
1.68 +*/
1.69 +extern "C" MOZ_EXPORT size_t
1.70 +workerlz4_maxCompressedSize(size_t inputSize)
1.71 +{
1.72 + return LZ4::maxCompressedSize(inputSize);
1.73 +}
1.74 +
1.75 +
1.76 +
