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author | 2023-12-11 10:48:02 +1100 | |
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committer | 2023-12-11 10:48:02 +1100 | |
commit | 05e69b43e9770e16c4bf1c6ca3e585e64c3f6ff9 (patch) | |
tree | 00ff2118ddc01455ee55785283a2fcfb9bfaf77e /3rdparty/zstd/examples/dictionary_compression.c | |
parent | 1a4287925e3982e2f782dee6f62b198984b839de (diff) |
Added Zstandard support for zip archives and CHDs. (#11827)
* 3rdparty/zstd: Added Zstandard compression library version 1.5.5.
* util/unzip.cpp: Added support for Zstandard compression (method 93).
* util/chdcodec.cpp: Added support for Zstandard compression.
* 3rdparty/flac: Always define NDEBUG to avoid log spam.
Diffstat (limited to '3rdparty/zstd/examples/dictionary_compression.c')
-rw-r--r-- | 3rdparty/zstd/examples/dictionary_compression.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/3rdparty/zstd/examples/dictionary_compression.c b/3rdparty/zstd/examples/dictionary_compression.c new file mode 100644 index 00000000000..83edc1cad9b --- /dev/null +++ b/3rdparty/zstd/examples/dictionary_compression.c @@ -0,0 +1,107 @@ +/* + * Copyright (c) Meta Platforms, Inc. and affiliates. + * All rights reserved. + * + * This source code is licensed under both the BSD-style license (found in the + * LICENSE file in the root directory of this source tree) and the GPLv2 (found + * in the COPYING file in the root directory of this source tree). + * You may select, at your option, one of the above-listed licenses. +**/ + +/* This example deals with Dictionary compression, + * its counterpart is `examples/dictionary_decompression.c` . + * These examples presume that a dictionary already exists. + * The main method to create a dictionary is `zstd --train`, + * look at the CLI documentation for details. + * Another possible method is to employ dictionary training API, + * published in `lib/zdict.h` . +**/ + +#include <stdio.h> // printf +#include <stdlib.h> // free +#include <string.h> // memset, strcat +#include <zstd.h> // presumes zstd library is installed +#include "common.h" // Helper functions, CHECK(), and CHECK_ZSTD() + +/* createDict() : +** `dictFileName` is supposed already created using `zstd --train` */ +static ZSTD_CDict* createCDict_orDie(const char* dictFileName, int cLevel) +{ + size_t dictSize; + printf("loading dictionary %s \n", dictFileName); + void* const dictBuffer = mallocAndLoadFile_orDie(dictFileName, &dictSize); + ZSTD_CDict* const cdict = ZSTD_createCDict(dictBuffer, dictSize, cLevel); + CHECK(cdict != NULL, "ZSTD_createCDict() failed!"); + free(dictBuffer); + return cdict; +} + + +static void compress(const char* fname, const char* oname, const ZSTD_CDict* cdict) +{ + size_t fSize; + void* const fBuff = mallocAndLoadFile_orDie(fname, &fSize); + size_t const cBuffSize = ZSTD_compressBound(fSize); + void* const cBuff = malloc_orDie(cBuffSize); + + /* Compress using the dictionary. + * This function writes the dictionary id, and content size into the header. + * But, it doesn't use a checksum. You can control these options using the + * advanced API: ZSTD_CCtx_setParameter(), ZSTD_CCtx_refCDict(), + * and ZSTD_compress2(). + */ + ZSTD_CCtx* const cctx = ZSTD_createCCtx(); + CHECK(cctx != NULL, "ZSTD_createCCtx() failed!"); + size_t const cSize = ZSTD_compress_usingCDict(cctx, cBuff, cBuffSize, fBuff, fSize, cdict); + CHECK_ZSTD(cSize); + + saveFile_orDie(oname, cBuff, cSize); + + /* success */ + printf("%25s : %6u -> %7u - %s \n", fname, (unsigned)fSize, (unsigned)cSize, oname); + + ZSTD_freeCCtx(cctx); /* never fails */ + free(fBuff); + free(cBuff); +} + + +static char* createOutFilename_orDie(const char* filename) +{ + size_t const inL = strlen(filename); + size_t const outL = inL + 5; + void* outSpace = malloc_orDie(outL); + memset(outSpace, 0, outL); + strcat(outSpace, filename); + strcat(outSpace, ".zst"); + return (char*)outSpace; +} + +int main(int argc, const char** argv) +{ + const char* const exeName = argv[0]; + int const cLevel = 3; + + if (argc<3) { + fprintf(stderr, "wrong arguments\n"); + fprintf(stderr, "usage:\n"); + fprintf(stderr, "%s [FILES] dictionary\n", exeName); + return 1; + } + + /* load dictionary only once */ + const char* const dictName = argv[argc-1]; + ZSTD_CDict* const dictPtr = createCDict_orDie(dictName, cLevel); + + int u; + for (u=1; u<argc-1; u++) { + const char* inFilename = argv[u]; + char* const outFilename = createOutFilename_orDie(inFilename); + compress(inFilename, outFilename, dictPtr); + free(outFilename); + } + + ZSTD_freeCDict(dictPtr); + printf("All %u files compressed. \n", argc-2); + return 0; +} |