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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
commit | 19fcec84d8d7d21e796c7624e521b60d28ee21ed (patch) | |
tree | 42d26aa27d1e3f7c0b8bd3fd14e7d7082f5008dc /src/zstd/examples/streaming_compression.c | |
parent | Initial commit. (diff) | |
download | ceph-upstream.tar.xz ceph-upstream.zip |
Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/zstd/examples/streaming_compression.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/src/zstd/examples/streaming_compression.c b/src/zstd/examples/streaming_compression.c new file mode 100644 index 000000000..f0f1065b1 --- /dev/null +++ b/src/zstd/examples/streaming_compression.c @@ -0,0 +1,123 @@ +/* + * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc. + * 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. + */ + + +#include <stdio.h> // printf +#include <stdlib.h> // free +#include <string.h> // memset, strcat, strlen +#include <zstd.h> // presumes zstd library is installed +#include "common.h" // Helper functions, CHECK(), and CHECK_ZSTD() + + +static void compressFile_orDie(const char* fname, const char* outName, int cLevel) +{ + /* Open the input and output files. */ + FILE* const fin = fopen_orDie(fname, "rb"); + FILE* const fout = fopen_orDie(outName, "wb"); + /* Create the input and output buffers. + * They may be any size, but we recommend using these functions to size them. + * Performance will only suffer significantly for very tiny buffers. + */ + size_t const buffInSize = ZSTD_CStreamInSize(); + void* const buffIn = malloc_orDie(buffInSize); + size_t const buffOutSize = ZSTD_CStreamOutSize(); + void* const buffOut = malloc_orDie(buffOutSize); + + /* Create the context. */ + ZSTD_CCtx* const cctx = ZSTD_createCCtx(); + CHECK(cctx != NULL, "ZSTD_createCCtx() failed!"); + + /* Set any parameters you want. + * Here we set the compression level, and enable the checksum. + */ + CHECK_ZSTD( ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, cLevel) ); + CHECK_ZSTD( ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, 1) ); + + /* This loop read from the input file, compresses that entire chunk, + * and writes all output produced to the output file. + */ + size_t const toRead = buffInSize; + for (;;) { + size_t read = fread_orDie(buffIn, toRead, fin); + /* Select the flush mode. + * If the read may not be finished (read == toRead) we use + * ZSTD_e_continue. If this is the last chunk, we use ZSTD_e_end. + * Zstd optimizes the case where the first flush mode is ZSTD_e_end, + * since it knows it is compressing the entire source in one pass. + */ + int const lastChunk = (read < toRead); + ZSTD_EndDirective const mode = lastChunk ? ZSTD_e_end : ZSTD_e_continue; + /* Set the input buffer to what we just read. + * We compress until the input buffer is empty, each time flushing the + * output. + */ + ZSTD_inBuffer input = { buffIn, read, 0 }; + int finished; + do { + /* Compress into the output buffer and write all of the output to + * the file so we can reuse the buffer next iteration. + */ + ZSTD_outBuffer output = { buffOut, buffOutSize, 0 }; + size_t const remaining = ZSTD_compressStream2(cctx, &output , &input, mode); + CHECK_ZSTD(remaining); + fwrite_orDie(buffOut, output.pos, fout); + /* If we're on the last chunk we're finished when zstd returns 0, + * which means its consumed all the input AND finished the frame. + * Otherwise, we're finished when we've consumed all the input. + */ + finished = lastChunk ? (remaining == 0) : (input.pos == input.size); + } while (!finished); + CHECK(input.pos == input.size, + "Impossible: zstd only returns 0 when the input is completely consumed!"); + + if (lastChunk) { + break; + } + } + + ZSTD_freeCCtx(cctx); + fclose_orDie(fout); + fclose_orDie(fin); + free(buffIn); + free(buffOut); +} + + +static char* createOutFilename_orDie(const char* filename) +{ + size_t const inL = strlen(filename); + size_t const outL = inL + 5; + void* const 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]; + + if (argc!=2) { + printf("wrong arguments\n"); + printf("usage:\n"); + printf("%s FILE\n", exeName); + return 1; + } + + const char* const inFilename = argv[1]; + + char* const outFilename = createOutFilename_orDie(inFilename); + compressFile_orDie(inFilename, outFilename, 1); + + free(outFilename); /* not strictly required, since program execution stops there, + * but some static analyzer main complain otherwise */ + return 0; +} |