139 lines
3.8 KiB
C
139 lines
3.8 KiB
C
/*
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* Copyright (c) 2017-present, 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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*/
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#include <stdlib.h> // malloc, exit
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#include <stdio.h> // fprintf, perror, feof
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#include <string.h> // strerror
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#include <errno.h> // errno
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#define ZSTD_STATIC_LINKING_ONLY
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#include <zstd.h> // presumes zstd library is installed
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#include <zstd_errors.h>
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#include "zstd_seekable.h"
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#define MIN(a, b) ((a) < (b) ? (a) : (b))
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static void* malloc_orDie(size_t size)
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{
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void* const buff = malloc(size);
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if (buff) return buff;
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/* error */
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perror("malloc");
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exit(1);
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}
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static void* realloc_orDie(void* ptr, size_t size)
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{
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ptr = realloc(ptr, size);
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if (ptr) return ptr;
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/* error */
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perror("realloc");
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exit(1);
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}
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static FILE* fopen_orDie(const char *filename, const char *instruction)
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{
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FILE* const inFile = fopen(filename, instruction);
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if (inFile) return inFile;
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/* error */
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perror(filename);
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exit(3);
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}
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static size_t fread_orDie(void* buffer, size_t sizeToRead, FILE* file)
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{
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size_t const readSize = fread(buffer, 1, sizeToRead, file);
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if (readSize == sizeToRead) return readSize; /* good */
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if (feof(file)) return readSize; /* good, reached end of file */
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/* error */
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perror("fread");
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exit(4);
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}
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static size_t fwrite_orDie(const void* buffer, size_t sizeToWrite, FILE* file)
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{
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size_t const writtenSize = fwrite(buffer, 1, sizeToWrite, file);
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if (writtenSize == sizeToWrite) return sizeToWrite; /* good */
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/* error */
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perror("fwrite");
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exit(5);
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}
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static size_t fclose_orDie(FILE* file)
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{
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if (!fclose(file)) return 0;
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/* error */
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perror("fclose");
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exit(6);
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}
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static void fseek_orDie(FILE* file, long int offset, int origin) {
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if (!fseek(file, offset, origin)) {
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if (!fflush(file)) return;
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}
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/* error */
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perror("fseek");
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exit(7);
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}
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static void decompressFile_orDie(const char* fname, unsigned startOffset, unsigned endOffset)
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{
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FILE* const fin = fopen_orDie(fname, "rb");
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FILE* const fout = stdout;
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size_t const buffOutSize = ZSTD_DStreamOutSize(); /* Guarantee to successfully flush at least one complete compressed block in all circumstances. */
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void* const buffOut = malloc_orDie(buffOutSize);
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ZSTD_seekable* const seekable = ZSTD_seekable_create();
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if (seekable==NULL) { fprintf(stderr, "ZSTD_seekable_create() error \n"); exit(10); }
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size_t const initResult = ZSTD_seekable_initFile(seekable, fin);
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if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_seekable_init() error : %s \n", ZSTD_getErrorName(initResult)); exit(11); }
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while (startOffset < endOffset) {
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size_t const result = ZSTD_seekable_decompress(seekable, buffOut, MIN(endOffset - startOffset, buffOutSize), startOffset);
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if (ZSTD_isError(result)) {
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fprintf(stderr, "ZSTD_seekable_decompress() error : %s \n",
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ZSTD_getErrorName(result));
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exit(12);
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}
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fwrite_orDie(buffOut, result, fout);
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startOffset += result;
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}
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ZSTD_seekable_free(seekable);
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fclose_orDie(fin);
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fclose_orDie(fout);
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free(buffOut);
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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!=4) {
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fprintf(stderr, "wrong arguments\n");
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fprintf(stderr, "usage:\n");
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fprintf(stderr, "%s FILE START END\n", exeName);
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return 1;
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}
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{
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const char* const inFilename = argv[1];
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unsigned const startOffset = (unsigned) atoi(argv[2]);
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unsigned const endOffset = (unsigned) atoi(argv[3]);
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decompressFile_orDie(inFilename, startOffset, endOffset);
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}
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return 0;
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}
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