120 lines
4.4 KiB
C
120 lines
4.4 KiB
C
/*
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* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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*/
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#include <stdio.h> // printf
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#include <stdlib.h> // free
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#include <string.h> // memset, strcat, strlen
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#include <zstd.h> // presumes zstd library is installed
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#include "common.h" // Helper functions, CHECK(), and CHECK_ZSTD()
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static void compressFile_orDie(const char* fname, const char* outName, int cLevel)
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{
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/* Open the input and output files. */
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FILE* const fin = fopen_orDie(fname, "rb");
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FILE* const fout = fopen_orDie(outName, "wb");
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/* Create the input and output buffers.
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* They may be any size, but we recommend using these functions to size them.
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* Performance will only suffer significantly for very tiny buffers.
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*/
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size_t const buffInSize = ZSTD_CStreamInSize();
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void* const buffIn = malloc_orDie(buffInSize);
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size_t const buffOutSize = ZSTD_CStreamOutSize();
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void* const buffOut = malloc_orDie(buffOutSize);
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/* Create the context. */
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ZSTD_CCtx* const cctx = ZSTD_createCCtx();
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CHECK(cctx != NULL, "ZSTD_createCCtx() failed!");
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/* Set any parameters you want.
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* Here we set the compression level, and enable the checksum.
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*/
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CHECK_ZSTD( ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, cLevel) );
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CHECK_ZSTD( ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, 1) );
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/* This loop read from the input file, compresses that entire chunk,
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* and writes all output produced to the output file.
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*/
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size_t const toRead = buffInSize;
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size_t read;
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while ((read = fread_orDie(buffIn, toRead, fin))) {
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/* Select the flush mode.
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* If the read may not be finished (read == toRead) we use
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* ZSTD_e_continue. If this is the last chunk, we use ZSTD_e_end.
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* Zstd optimizes the case where the first flush mode is ZSTD_e_end,
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* since it knows it is compressing the entire source in one pass.
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*/
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int const lastChunk = (read < toRead);
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ZSTD_EndDirective const mode = lastChunk ? ZSTD_e_end : ZSTD_e_continue;
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/* Set the input buffer to what we just read.
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* We compress until the input buffer is empty, each time flushing the
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* output.
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*/
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ZSTD_inBuffer input = { buffIn, read, 0 };
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int finished;
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do {
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/* Compress into the output buffer and write all of the output to
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* the file so we can reuse the buffer next iteration.
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*/
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ZSTD_outBuffer output = { buffOut, buffOutSize, 0 };
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size_t const remaining = ZSTD_compressStream2(cctx, &output , &input, mode);
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CHECK_ZSTD(remaining);
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fwrite_orDie(buffOut, output.pos, fout);
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/* If we're on the last chunk we're finished when zstd returns 0,
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* which means its consumed all the input AND finished the frame.
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* Otherwise, we're finished when we've consumed all the input.
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*/
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finished = lastChunk ? (remaining == 0) : (input.pos == input.size);
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} while (!finished);
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CHECK(input.pos == input.size,
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"Impossible: zstd only returns 0 when the input is completely consumed!");
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}
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ZSTD_freeCCtx(cctx);
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fclose_orDie(fout);
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fclose_orDie(fin);
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free(buffIn);
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free(buffOut);
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}
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static char* createOutFilename_orDie(const char* filename)
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{
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size_t const inL = strlen(filename);
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size_t const outL = inL + 5;
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void* const outSpace = malloc_orDie(outL);
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memset(outSpace, 0, outL);
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strcat(outSpace, filename);
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strcat(outSpace, ".zst");
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return (char*)outSpace;
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}
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int main(int argc, const char** argv)
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{
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const char* const exeName = argv[0];
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if (argc!=2) {
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printf("wrong arguments\n");
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printf("usage:\n");
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printf("%s FILE\n", exeName);
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return 1;
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}
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const char* const inFilename = argv[1];
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char* const outFilename = createOutFilename_orDie(inFilename);
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compressFile_orDie(inFilename, outFilename, 1);
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free(outFilename); /* not strictly required, since program execution stops there,
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* but some static analyzer main complain otherwise */
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return 0;
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}
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