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/* This file is part of Nekopack.
Copyright (C) 2017 Jakob Tsar-Fox, All Rights Reserved.
Nekopack 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 3 of the License, or (at
your option) any later version.
Nekopack 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 Nekopack. If not, see <http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "cli.h"
#include "extract.h"
#define XP3_MAGIC "XP3\x0d\x0a\x20\x0a\x1a\x8b\x67\x01"
#define XP3_TABLE_OFFSET 11
#define XP3_VERSION_OFFSET 19
int is_xp3_archive(FILE *archive);
int get_archive_version(FILE *archive);
uint64_t get_table_offset(FILE *archive, uint8_t archive_version);
/* Global instance of the command-line configuration structure. */
struct configuration arguments;
int main(int argc, char *argv[]) {
arguments = parse_args(argc, argv);
FILE *archive = fopen(arguments.archive_path, "rb");
if (archive == NULL) {
perror(arguments.archive_path);
exit(EXIT_FAILURE);
} else if (!is_xp3_archive(archive)) {
fprintf(stderr, "File is not an XP3 archive.\n");
fclose(archive);
exit(EXIT_FAILURE);
}
int archive_version = get_archive_version(archive);
uint64_t table_offset = get_table_offset(archive, archive_version);
extract(archive, table_offset);
fclose(archive);
return 0;
}
/* Simple check of the archive's magic number to decide
whether or not it represents a valid XP3 archive. */
int is_xp3_archive(FILE *archive) {
char* magic_buffer = malloc(11);
rewind(archive);
fread(magic_buffer, 11, 1, archive);
if (memcmp(magic_buffer, XP3_MAGIC, 11)) {
free(magic_buffer);
return 0;
}
free(magic_buffer);
return 1;
}
/* Returns the version of XP3 used to pack the archive. */
int get_archive_version(FILE *archive) {
uint32_t version_word;
fseek(archive, XP3_VERSION_OFFSET, SEEK_SET);
fread(&version_word, sizeof(uint32_t), 1, archive);
/* 0x00 indicates version 1, and 0x01 indicates version 2. */
return version_word == 1 ? 2 : 1;
}
/* Subroutine for finding the archive's table offset. If the
minor_version is invalid, the program will exit. */
uint64_t get_table_offset(FILE *archive, uint8_t archive_version) {
uint64_t table_offset;
fseek(archive, XP3_TABLE_OFFSET, SEEK_SET);
fread(&table_offset, sizeof(uint64_t), 1, archive);
if (archive_version == 1)
return table_offset;
/* The minor version is only present in XP3 version 2. */
uint32_t minor_version;
fread(&minor_version, sizeof(uint32_t), 1, archive);
if (minor_version != 1) {
fprintf(stderr, "Minor version not implemented.\n");
fclose(archive);
}
/* The read table_offset is an offset to the real table offset. */
fseek(archive, table_offset, SEEK_SET);
/* Table flags and size are ignored in the parsing process. */
fseek(archive, sizeof(uint8_t) + sizeof(uint64_t), SEEK_CUR);
fread(&table_offset, sizeof(uint64_t), 1, archive);
return table_offset;
}
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