| 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 | * You may select, at your option, one of the above-listed licenses. |
| 9 | */ |
| 10 | |
| 11 | #include <string.h> |
| 12 | #include <stdio.h> |
| 13 | #include <stdlib.h> |
| 14 | |
| 15 | #define ZSTD_STATIC_LINKING_ONLY |
| 16 | #include "util.h" |
| 17 | #include "zstd.h" |
| 18 | |
| 19 | #define CHECK(cond, ...) \ |
| 20 | do { \ |
| 21 | if (!(cond)) { \ |
| 22 | fprintf(stderr, "%s:%d CHECK(%s) failed: ", __FILE__, __LINE__, #cond); \ |
| 23 | fprintf(stderr, "" __VA_ARGS__); \ |
| 24 | fprintf(stderr, "\n"); \ |
| 25 | exit(1); \ |
| 26 | } \ |
| 27 | } while (0) |
| 28 | |
| 29 | static void usage(char const *program) { |
| 30 | fprintf(stderr, "USAGE: %s FILE.zst PREFIX\n", program); |
| 31 | fprintf(stderr, "FILE.zst: A zstd compressed file with multiple frames\n"); |
| 32 | fprintf(stderr, "PREFIX: The output prefix. Uncompressed files will be " |
| 33 | "created named ${PREFIX}0 ${PREFIX}1...\n\n"); |
| 34 | fprintf(stderr, "This program takes concatenated zstd frames and " |
| 35 | "decompresses them into individual files.\n"); |
| 36 | fprintf(stderr, "E.g. files created with a command like: zstd -r directory " |
| 37 | "-o file.zst\n"); |
| 38 | } |
| 39 | |
| 40 | typedef struct { |
| 41 | char *data; |
| 42 | size_t size; |
| 43 | size_t frames; |
| 44 | size_t maxFrameSize; |
| 45 | } ZstdFrames; |
| 46 | |
| 47 | static ZstdFrames readFile(char const *fileName) { |
| 48 | U64 const fileSize = UTIL_getFileSize(fileName); |
| 49 | CHECK(fileSize != UTIL_FILESIZE_UNKNOWN, "Unknown file size!"); |
| 50 | |
| 51 | char *const data = (char *)malloc(fileSize); |
| 52 | CHECK(data != NULL, "Allocation failed"); |
| 53 | |
| 54 | FILE *file = fopen(fileName, "rb"); |
| 55 | CHECK(file != NULL, "fopen failed"); |
| 56 | |
| 57 | size_t const readSize = fread(data, 1, fileSize, file); |
| 58 | CHECK(readSize == fileSize, "fread failed"); |
| 59 | |
| 60 | fclose(file); |
| 61 | ZstdFrames frames; |
| 62 | frames.data = (char *)data; |
| 63 | frames.size = fileSize; |
| 64 | frames.frames = 0; |
| 65 | |
| 66 | size_t index; |
| 67 | size_t maxFrameSize = 0; |
| 68 | for (index = 0; index < fileSize;) { |
| 69 | size_t const frameSize = |
| 70 | ZSTD_findFrameCompressedSize(data + index, fileSize - index); |
| 71 | CHECK(!ZSTD_isError(frameSize), "Bad zstd frame: %s", |
| 72 | ZSTD_getErrorName(frameSize)); |
| 73 | if (frameSize > maxFrameSize) |
| 74 | maxFrameSize = frameSize; |
| 75 | frames.frames += 1; |
| 76 | index += frameSize; |
| 77 | } |
| 78 | CHECK(index == fileSize, "Zstd file corrupt!"); |
| 79 | frames.maxFrameSize = maxFrameSize; |
| 80 | |
| 81 | return frames; |
| 82 | } |
| 83 | |
| 84 | static int computePadding(size_t numFrames) { |
| 85 | return snprintf(NULL, 0, "%u", (unsigned)numFrames); |
| 86 | } |
| 87 | |
| 88 | int main(int argc, char **argv) { |
| 89 | if (argc != 3) { |
| 90 | usage(argv[0]); |
| 91 | exit(1); |
| 92 | } |
| 93 | char const *const zstdFile = argv[1]; |
| 94 | char const *const prefix = argv[2]; |
| 95 | |
| 96 | ZstdFrames frames = readFile(zstdFile); |
| 97 | |
| 98 | if (frames.frames <= 1) { |
| 99 | fprintf( |
| 100 | stderr, |
| 101 | "%s only has %u zstd frame. Simply use `zstd -d` to decompress it.\n", |
| 102 | zstdFile, (unsigned)frames.frames); |
| 103 | exit(1); |
| 104 | } |
| 105 | |
| 106 | int const padding = computePadding(frames.frames - 1); |
| 107 | |
| 108 | size_t const outFileNameSize = strlen(prefix) + padding + 1; |
| 109 | char* outFileName = malloc(outFileNameSize); |
| 110 | CHECK(outFileName != NULL, "Allocation failure"); |
| 111 | |
| 112 | size_t const bufferSize = 128 * 1024; |
| 113 | void *buffer = malloc(bufferSize); |
| 114 | CHECK(buffer != NULL, "Allocation failure"); |
| 115 | |
| 116 | ZSTD_DCtx* dctx = ZSTD_createDCtx(); |
| 117 | CHECK(dctx != NULL, "Allocation failure"); |
| 118 | |
| 119 | fprintf(stderr, "Recovering %u files...\n", (unsigned)frames.frames); |
| 120 | |
| 121 | size_t index; |
| 122 | size_t frame = 0; |
| 123 | for (index = 0; index < frames.size; ++frame) { |
| 124 | size_t const frameSize = |
| 125 | ZSTD_findFrameCompressedSize(frames.data + index, frames.size - index); |
| 126 | |
| 127 | int const ret = snprintf(outFileName, outFileNameSize, "%s%0*u", prefix, padding, (unsigned)frame); |
| 128 | CHECK(ret >= 0 && (size_t)ret <= outFileNameSize, "snprintf failed!"); |
| 129 | |
| 130 | FILE* outFile = fopen(outFileName, "wb"); |
| 131 | CHECK(outFile != NULL, "fopen failed"); |
| 132 | |
| 133 | ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only); |
| 134 | ZSTD_inBuffer in = {frames.data + index, frameSize, 0}; |
| 135 | while (in.pos < in.size) { |
| 136 | ZSTD_outBuffer out = {buffer, bufferSize, 0}; |
| 137 | CHECK(!ZSTD_isError(ZSTD_decompressStream(dctx, &out, &in)), "decompression failed"); |
| 138 | size_t const writeSize = fwrite(out.dst, 1, out.pos, outFile); |
| 139 | CHECK(writeSize == out.pos, "fwrite failed"); |
| 140 | } |
| 141 | fclose(outFile); |
| 142 | fprintf(stderr, "Recovered %s\n", outFileName); |
| 143 | index += frameSize; |
| 144 | } |
| 145 | fprintf(stderr, "Complete\n"); |
| 146 | |
| 147 | free(outFileName); |
| 148 | ZSTD_freeDCtx(dctx); |
| 149 | free(buffer); |
| 150 | free(frames.data); |
| 151 | return 0; |
| 152 | } |