diff options
Diffstat (limited to 'tools/applypatch/xdelta3.c')
-rw-r--r-- | tools/applypatch/xdelta3.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/tools/applypatch/xdelta3.c b/tools/applypatch/xdelta3.c new file mode 100644 index 0000000..c9a0f73 --- /dev/null +++ b/tools/applypatch/xdelta3.c @@ -0,0 +1,121 @@ +/* + * Copyright (C) 2008 The Android Open Source Project + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#include <stdio.h> +#include <errno.h> +#include <unistd.h> + +#include "xdelta3.h" +#include "mincrypt/sha.h" + +int ApplyXDelta3Patch(const unsigned char* old_data, ssize_t old_size, + const char* patch_filename, + FILE* output, SHA_CTX* ctx) { +#define WINDOW_SIZE 32768 + + int ret; + xd3_stream stream; + xd3_config config; + + xd3_init_config(&config, 0); + config.winsize = WINDOW_SIZE; + ret = xd3_config_stream(&stream, &config); + if (ret != 0) { + fprintf(stderr, "xd3_config_stream error: %s\n", xd3_strerror(ret)); + return 1; + } + + // In xdelta3 terms, the "input" is the patch file: it contains a + // sequence of instruction codes and data that will be executed to + // produce the output file. The "source" is the original data file; + // it is a blob of data to which instructions in the input may refer + // (eg, an instruction may say "copy such-and-such range of bytes + // from the source to the output"). + + // For simplicity, we provide the entire source to xdelta as a + // single block. This means it should never have to ask us to load + // blocks of the source file. + xd3_source source; + source.name = "old name"; + source.size = old_size; + source.ioh = NULL; + source.blksize = old_size; + source.curblkno = 0; + source.curblk = old_data; + source.onblk = old_size; + + ret = xd3_set_source(&stream, &source); + if (ret != 0) { + fprintf(stderr, "xd3_set_source error: %s\n", xd3_strerror(ret)); + return 1; + } + + unsigned char buffer[WINDOW_SIZE]; + FILE* input = fopen(patch_filename, "rb"); + if (input == NULL) { + fprintf(stderr, "failed to open patch file %s: %d (%s)\n", + patch_filename, errno, strerror(errno)); + return 1; + } + + size_t bytes_read; + + do { + bytes_read = fread(buffer, 1, WINDOW_SIZE, input); + if (feof(input)) { + xd3_set_flags(&stream, XD3_FLUSH); + } + xd3_avail_input(&stream, buffer, bytes_read); + process: + ret = xd3_decode_input(&stream); + switch (ret) { + case XD3_INPUT: + continue; + case XD3_OUTPUT: + SHA_update(ctx, stream.next_out, stream.avail_out); + if (fwrite(stream.next_out, 1, stream.avail_out, output) != + stream.avail_out) { + fprintf(stderr, "short write of output file: %d (%s)\n", + errno, strerror(errno)); + return 1; + } + xd3_consume_output(&stream); + goto process; + case XD3_GETSRCBLK: + // We provided the entire source file already; it should never + // have to ask us for a block. + fprintf(stderr, "xd3_decode_input: unexpected GETSRCBLK\n"); + return 1; + case XD3_GOTHEADER: + case XD3_WINSTART: + case XD3_WINFINISH: + // These are informational events we don't care about. + goto process; + default: + fprintf(stderr, "xd3_decode_input: unknown error %s (%s)\n", + xd3_strerror(ret), stream.msg); + return 1; + } + } while (!feof(input)); + + fclose(input); + return 0; + +#undef WINDOW_SIZE +} |