Implemented a basic parser for the XP3 header.

1 files changed, 53 insertions, 0 deletions

diff --git a/src/header.c b/src/header.c
new file mode 100644
index 0000000..e039447
--- /dev/null
+++ b/src/header.c
@@ -0,0 +1,53 @@
+/* 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 data from the given stream into a newly allocated xp3_header
+   structure. The stream is assumed to be at the header's beginning.
+   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;
+    stream_read(h, s, sizeof(struct xp3_header));
+    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 is of XP3 version 2. */
+static bool is_supported(struct xp3_header *h) {
+    return h->version == 1;
+}