The Tor Browser / file comparison
comparison: toolkit/components/workerlz4/lz4.cpp
toolkit/components/workerlz4/lz4.cpp
- branch
- TOR_BUG_9701
- changeset 14
- 925c144e1f1f
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| -1:000000000000 | 0:1ebc267b053a |
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| 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 workerlz4_compress(const char* source, size_t inputSize, char* dest) { | |
| 31 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 workerlz4_decompress(const char* source, size_t inputSize, | |
| 49 char* dest, size_t maxOutputSize, | |
| 50 size_t *bytesOutput) { | |
| 51 return LZ4::decompress(source, inputSize, | |
| 52 dest, maxOutputSize, | |
| 53 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 workerlz4_maxCompressedSize(size_t inputSize) | |
| 68 { | |
| 69 return LZ4::maxCompressedSize(inputSize); | |
| 70 } | |
| 71 | |
| 72 | |
| 73 |
