| 1 | /* |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * This source code is licensed under both the BSD-style license (found in the |
| 6 | * LICENSE file in the root directory of this source tree) and the GPLv2 (found |
| 7 | * in the COPYING file in the root directory of this source tree). |
| 8 | */ |
| 9 | |
| 10 | |
| 11 | #include <stdlib.h> // malloc, exit |
| 12 | #include <stdio.h> // fprintf, perror, feof |
| 13 | #include <string.h> // strerror |
| 14 | #include <errno.h> // errno |
| 15 | #define ZSTD_STATIC_LINKING_ONLY |
| 16 | #include <zstd.h> // presumes zstd library is installed |
| 17 | #include <zstd_errors.h> |
| 18 | |
| 19 | #include "../zstd_seekable.h" |
| 20 | |
| 21 | #define MIN(a, b) ((a) < (b) ? (a) : (b)) |
| 22 | |
| 23 | static void* malloc_orDie(size_t size) |
| 24 | { |
| 25 | void* const buff = malloc(size); |
| 26 | if (buff) return buff; |
| 27 | /* error */ |
| 28 | perror("malloc"); |
| 29 | exit(1); |
| 30 | } |
| 31 | |
| 32 | static void* realloc_orDie(void* ptr, size_t size) |
| 33 | { |
| 34 | ptr = realloc(ptr, size); |
| 35 | if (ptr) return ptr; |
| 36 | /* error */ |
| 37 | perror("realloc"); |
| 38 | exit(1); |
| 39 | } |
| 40 | |
| 41 | static FILE* fopen_orDie(const char *filename, const char *instruction) |
| 42 | { |
| 43 | FILE* const inFile = fopen(filename, instruction); |
| 44 | if (inFile) return inFile; |
| 45 | /* error */ |
| 46 | perror(filename); |
| 47 | exit(3); |
| 48 | } |
| 49 | |
| 50 | static size_t fread_orDie(void* buffer, size_t sizeToRead, FILE* file) |
| 51 | { |
| 52 | size_t const readSize = fread(buffer, 1, sizeToRead, file); |
| 53 | if (readSize == sizeToRead) return readSize; /* good */ |
| 54 | if (feof(file)) return readSize; /* good, reached end of file */ |
| 55 | /* error */ |
| 56 | perror("fread"); |
| 57 | exit(4); |
| 58 | } |
| 59 | |
| 60 | static size_t fwrite_orDie(const void* buffer, size_t sizeToWrite, FILE* file) |
| 61 | { |
| 62 | size_t const writtenSize = fwrite(buffer, 1, sizeToWrite, file); |
| 63 | if (writtenSize == sizeToWrite) return sizeToWrite; /* good */ |
| 64 | /* error */ |
| 65 | perror("fwrite"); |
| 66 | exit(5); |
| 67 | } |
| 68 | |
| 69 | static size_t fclose_orDie(FILE* file) |
| 70 | { |
| 71 | if (!fclose(file)) return 0; |
| 72 | /* error */ |
| 73 | perror("fclose"); |
| 74 | exit(6); |
| 75 | } |
| 76 | |
| 77 | static void fseek_orDie(FILE* file, long int offset, int origin) { |
| 78 | if (!fseek(file, offset, origin)) { |
| 79 | if (!fflush(file)) return; |
| 80 | } |
| 81 | /* error */ |
| 82 | perror("fseek"); |
| 83 | exit(7); |
| 84 | } |
| 85 | |
| 86 | |
| 87 | static void decompressFile_orDie(const char* fname, off_t startOffset, off_t endOffset) |
| 88 | { |
| 89 | FILE* const fin = fopen_orDie(fname, "rb"); |
| 90 | FILE* const fout = stdout; |
| 91 | size_t const buffOutSize = ZSTD_DStreamOutSize(); /* Guarantee to successfully flush at least one complete compressed block in all circumstances. */ |
| 92 | void* const buffOut = malloc_orDie(buffOutSize); |
| 93 | |
| 94 | ZSTD_seekable* const seekable = ZSTD_seekable_create(); |
| 95 | if (seekable==NULL) { fprintf(stderr, "ZSTD_seekable_create() error \n"); exit(10); } |
| 96 | |
| 97 | size_t const initResult = ZSTD_seekable_initFile(seekable, fin); |
| 98 | if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_seekable_init() error : %s \n", ZSTD_getErrorName(initResult)); exit(11); } |
| 99 | |
| 100 | while (startOffset < endOffset) { |
| 101 | size_t const result = ZSTD_seekable_decompress(seekable, buffOut, MIN(endOffset - startOffset, buffOutSize), startOffset); |
| 102 | if (!result) { |
| 103 | break; |
| 104 | } |
| 105 | |
| 106 | if (ZSTD_isError(result)) { |
| 107 | fprintf(stderr, "ZSTD_seekable_decompress() error : %s \n", |
| 108 | ZSTD_getErrorName(result)); |
| 109 | exit(12); |
| 110 | } |
| 111 | fwrite_orDie(buffOut, result, fout); |
| 112 | startOffset += result; |
| 113 | } |
| 114 | |
| 115 | ZSTD_seekable_free(seekable); |
| 116 | fclose_orDie(fin); |
| 117 | fclose_orDie(fout); |
| 118 | free(buffOut); |
| 119 | } |
| 120 | |
| 121 | |
| 122 | int main(int argc, const char** argv) |
| 123 | { |
| 124 | const char* const exeName = argv[0]; |
| 125 | |
| 126 | if (argc!=4) { |
| 127 | fprintf(stderr, "wrong arguments\n"); |
| 128 | fprintf(stderr, "usage:\n"); |
| 129 | fprintf(stderr, "%s FILE START END\n", exeName); |
| 130 | return 1; |
| 131 | } |
| 132 | |
| 133 | { |
| 134 | const char* const inFilename = argv[1]; |
| 135 | off_t const startOffset = atoll(argv[2]); |
| 136 | off_t const endOffset = atoll(argv[3]); |
| 137 | decompressFile_orDie(inFilename, startOffset, endOffset); |
| 138 | } |
| 139 | |
| 140 | return 0; |
| 141 | } |