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134 lines
4.4 KiB
134 lines
4.4 KiB
/*
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* Copyright (c) 2016-2020, 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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/* The objective of this example is to show of to compress multiple successive files
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* while preserving memory management.
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* All structures and buffers will be created only once,
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* and shared across all compression operations */
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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
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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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typedef struct {
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void* buffIn;
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void* buffOut;
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size_t buffInSize;
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size_t buffOutSize;
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ZSTD_CCtx* cctx;
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} resources;
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static resources createResources_orDie(int cLevel)
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{
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resources ress;
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ress.buffInSize = ZSTD_CStreamInSize(); /* can always read one full block */
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ress.buffOutSize= ZSTD_CStreamOutSize(); /* can always flush a full block */
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ress.buffIn = malloc_orDie(ress.buffInSize);
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ress.buffOut= malloc_orDie(ress.buffOutSize);
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ress.cctx = ZSTD_createCCtx();
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CHECK(ress.cctx != NULL, "ZSTD_createCCtx() failed!");
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/* Set any compression parameters you want here.
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* They will persist for every compression operation.
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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(ress.cctx, ZSTD_c_compressionLevel, cLevel) );
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CHECK_ZSTD( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_checksumFlag, 1) );
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return ress;
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}
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static void freeResources(resources ress)
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{
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ZSTD_freeCCtx(ress.cctx);
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free(ress.buffIn);
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free(ress.buffOut);
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}
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static void compressFile_orDie(resources ress, const char* fname, const char* outName)
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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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/* Reset the context to a clean state to start a new compression operation.
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* The parameters are sticky, so we keep the compression level and extra
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* parameters that we set in createResources_orDie().
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*/
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CHECK_ZSTD( ZSTD_CCtx_reset(ress.cctx, ZSTD_reset_session_only) );
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size_t const toRead = ress.buffInSize;
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size_t read;
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while ( (read = fread_orDie(ress.buffIn, toRead, fin)) ) {
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/* This loop is the same as streaming_compression.c.
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* See that file for detailed comments.
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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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ZSTD_inBuffer input = { ress.buffIn, read, 0 };
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int finished;
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do {
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ZSTD_outBuffer output = { ress.buffOut, ress.buffOutSize, 0 };
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size_t const remaining = ZSTD_compressStream2(ress.cctx, &output, &input, mode);
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CHECK_ZSTD(remaining);
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fwrite_orDie(ress.buffOut, output.pos, fout);
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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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fclose_orDie(fout);
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fclose_orDie(fin);
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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(s)\n", exeName);
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return 1;
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}
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int const cLevel = 7;
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resources const ress = createResources_orDie(cLevel);
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void* ofnBuffer = NULL;
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size_t ofnbSize = 0;
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int argNb;
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for (argNb = 1; argNb < argc; argNb++) {
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const char* const ifn = argv[argNb];
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size_t const ifnSize = strlen(ifn);
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size_t const ofnSize = ifnSize + 5;
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if (ofnbSize <= ofnSize) {
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ofnbSize = ofnSize + 16;
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free(ofnBuffer);
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ofnBuffer = malloc_orDie(ofnbSize);
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}
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memset(ofnBuffer, 0, ofnSize);
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strcat(ofnBuffer, ifn);
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strcat(ofnBuffer, ".zst");
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compressFile_orDie(ress, ifn, ofnBuffer);
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}
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freeResources(ress);
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free(ofnBuffer);
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printf("compressed %i files \n", argc-1);
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return 0;
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}
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