Initial commit.

1 files changed, 116 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..b81d58b
--- /dev/null
+++ b/src/main.c
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+/* main.c
+
+   The entry point to Nekopack.
+
+   Copyright (C) 2013 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 <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define XP3_MAGIC "XP3\x0d\x0a\x20\x0a\x1a\x8b\x67\x01"
+#define XP3_VERSION_1_TABLE_OFFSET 11
+#define XP3_VERSION_OFFSET 19
+
+int is_xp3_archive(FILE *archive);
+int get_archive_version(FILE *archive);
+int get_table_offset(FILE *archive, uint8_t archive_version);
+int table_is_compressed(FILE *archive, uint8_t table_offset);
+
+
+int main(int argc, char *argv[]) {
+    if (argc != 2) {
+        fprintf(stderr, "Usage: %s (PATH TO ARCHIVE)\n", argv[0]);
+        exit(1);
+    }
+    uint8_t archive_version;
+    FILE *archive = fopen(argv[1], "rb");
+    if (!is_xp3_archive(archive)) {
+        fprintf(stderr, "File is not an XP3 archive.\n");
+        fclose(archive);
+        exit(1);
+    }
+    archive_version = get_archive_version(archive);
+    /* After the table_is_compressed byte is 8 bytes containing the
+       compressed size followed by 8 bytes containing the original size
+       (if the archive is compressed). Use zlib's inflate function to
+       decompress the compressed size worth of chunks if it's compressed.
+
+       The decompressed data will contain a four-byte magic number, 
+       followed by 8 bytes containing the file size, followed by the
+       file size worth of data.
+
+       See the following link for magic numbers and entry handling
+       procedures.
+
+       https://github.com/vn-tools/arc_unpacker/blob/master/src/dec
+       /kirikiri/xp3_archive_decoder.cc */
+    fclose(archive);
+    return 0;
+}
+
+
+/* Returns whether or not the stream represents an XP3 archive. */
+int is_xp3_archive(FILE *archive) {
+    char *magic_buffer = malloc(12);
+    if (magic_buffer == NULL) {
+        perror("calloc");
+        fclose(archive);
+        exit(1);
+    }
+    rewind(archive);
+    fread(magic_buffer, 11, 1, archive);
+    if (strcmp(magic_buffer, XP3_MAGIC)) {
+        printf("Not an XP3 archive\n");
+        return 0;
+    }
+    return 1;
+}
+
+
+/* Returns the version of (???) used to pack the archive. */
+int get_archive_version(FILE *archive) {
+    uint8_t archive_version;
+    fseek(archive, XP3_VERSION_OFFSET, SEEK_SET);
+    fread(&archive_version, 1, 1, archive);
+    return archive_version;
+}
+
+
+/* Returns the table offset for the archive. */
+int get_table_offset(FILE *archive, uint8_t archive_version) {
+    if (archive_version == 1) {
+        uint8_t table_offset;
+        fseek(archive, XP3_VERSION_1_TABLE_OFFSET, SEEK_SET);
+        fread(&table_offset, 1, 1, archive);
+        return table_offset;
+    }
+    fprintf(stderr, "Not implemented.\n");
+    exit(1);
+}
+
+
+/* Returns whether or not the archive is compressed. */
+int table_is_compressed(FILE *archive, uint8_t table_offset) {
+    uint8_t is_compressed;
+    fseek(archive, table_offset, SEEK_SET);
+    fread(&is_compressed, 1, 1, archive);
+    return is_compressed;
+}