Line data    Source code

       1             : /* This Source Code Form is subject to the terms of the Mozilla Public
       2             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       3             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       4             : 
       5             : #include "mozilla/Compression.h"
       6             : 
       7             : /**
       8             :  * LZ4 is a very fast byte-wise compression algorithm.
       9             :  *
      10             :  * Compared to Google's Snappy it is faster to compress and decompress and
      11             :  * generally produces output of about the same size.
      12             :  *
      13             :  * Compared to zlib it compresses at about 10x the speed, decompresses at about
      14             :  * 4x the speed and produces output of about 1.5x the size.
      15             :  *
      16             :  */
      17             : 
      18             : using namespace mozilla::Compression;
      19             : 
      20             : /**
      21             :  * Compresses 'inputSize' bytes from 'source' into 'dest'.
      22             :  * Destination buffer must be already allocated,
      23             :  * and must be sized to handle worst cases situations (input data not compressible)
      24             :  * Worst case size evaluation is provided by function LZ4_compressBound()
      25             :  *
      26             :  * @param inputSize is the input size. Max supported value is ~1.9GB
      27             :  * @param return the number of bytes written in buffer dest
      28             :  */
      29             : extern "C" MOZ_EXPORT size_t
      30           0 : workerlz4_compress(const char* source, size_t inputSize, char* dest) {
      31           0 :   return LZ4::compress(source, inputSize, dest);
      32             : }
      33             : 
      34             : /**
      35             :  * If the source stream is malformed, the function will stop decoding
      36             :  * and return a negative result, indicating the byte position of the
      37             :  * faulty instruction
      38             :  *
      39             :  * This function never writes outside of provided buffers, and never
      40             :  * modifies input buffer.
      41             :  *
      42             :  * note : destination buffer must be already allocated.
      43             :  *        its size must be a minimum of 'outputSize' bytes.
      44             :  * @param outputSize is the output size, therefore the original size
      45             :  * @return true/false
      46             :  */
      47             : extern "C" MOZ_EXPORT int
      48           0 : workerlz4_decompress(const char* source, size_t inputSize,
      49             :                      char* dest, size_t maxOutputSize,
      50             :                      size_t *bytesOutput) {
      51           0 :   return LZ4::decompress(source, inputSize,
      52             :                          dest, maxOutputSize,
      53           0 :                          bytesOutput);
      54             : }
      55             : 
      56             : 
      57             : /*
      58             :   Provides the maximum size that LZ4 may output in a "worst case"
      59             :   scenario (input data not compressible) primarily useful for memory
      60             :   allocation of output buffer.
      61             :   note : this function is limited by "int" range (2^31-1)
      62             : 
      63             :   @param inputSize is the input size. Max supported value is ~1.9GB
      64             :   @return maximum output size in a "worst case" scenario
      65             : */
      66             : extern "C" MOZ_EXPORT size_t
      67           0 : workerlz4_maxCompressedSize(size_t inputSize)
      68             : {
      69           0 :   return LZ4::maxCompressedSize(inputSize);
      70             : }
      71             : 
      72             : 
      73             :