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/* header.c -- Code for handling the archive's header section.
Copyright (C) 2017 Jakob Tsar-Fox, All Rights Reserved.
This file is part of Nekopack.
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 <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "header.h"
#include "io.h"
static bool is_xp3(struct xp3_header *h);
static bool is_supported(struct xp3_header *h);
/* Reads from the given stream into a newly allocated xp3_header
structure. NULL is returned if the header contains an invalid magic
number, or if the archive's version is not supported. */
struct xp3_header *read_header(struct stream *s) {
struct xp3_header *h = malloc(sizeof(struct xp3_header));
if (h == NULL) return NULL;
/* The header structure can't be read into directly because of
potential alignment issues. */
stream_read(h->magic, s, 11);
stream_read(&h->info_offset, s, sizeof(uint64_t));
stream_read(&h->version, s, sizeof(uint32_t));
stream_read(&h->table_size, s, sizeof(uint64_t));
stream_read(&h->flags, s, sizeof(uint8_t));
stream_read(&h->table_offset, s, sizeof(uint64_t));
if (!is_xp3(h) || !is_supported(h)) {
free(h);
return NULL;
}
return h;
}
/* Checks that the header contains the correct magic number. */
static bool is_xp3(struct xp3_header *h) {
return !memcmp(h->magic, XP3_MAGIC, 11);
}
/* Checks that the archive's version is supported. */
static bool is_supported(struct xp3_header *h) {
return h->version == 1;
}
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