Monster Hunter Generations Ultimate ARC extractor

arc.c

#define _CRT_SECURE_NO_WARNINGS
#define ZLIB_WINAPI

#include <direct.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>

#include <zlib.h>

#define BUFFERSIZE 0x10000000

typedef struct {
	char magic[4];
	short unk1;
	short count;
	int unk2;
} header;

typedef struct {
	char name[0x40];
	int unk1;
	int size;
	int unk2;
	int offset;
} fileEntry;

// Source: https://stackoverflow.com/questions/4901842/in-memory-decompression-with-zlib
int decompress(const void *src, int srcLen, void *dst, int dstLen) {
	z_stream strm  = { 0 };
	strm.total_in  = strm.avail_in = srcLen;
	strm.total_out = strm.avail_out = dstLen;
	strm.next_in   = (Bytef *)src;
	strm.next_out  = (Bytef *)dst;

	strm.zalloc = Z_NULL;
	strm.zfree  = Z_NULL;
	strm.opaque = Z_NULL;

	int err = -1;
	int ret = -1;

	err = inflateInit2(&strm, (15 + 32));
	if (err == Z_OK) {
		err = inflate(&strm, Z_FINISH);
		if (err == Z_STREAM_END) {
			ret = strm.total_out;
		}
		else {
			inflateEnd(&strm);
			return err;
		}
	}
	else {
		inflateEnd(&strm);
		return err;
	}

	inflateEnd(&strm);
	return ret;
}

int rmakedir(const char *dir) {
	char tmp[256];
	char *p = NULL;
	struct stat sb;

	size_t len = strnlen(dir, 256);
	memcpy(tmp, dir, len);
	tmp[len] = '\0';

	if (tmp[len - 1] == '\\')
		tmp[len - 1] = '\0';

	for (p = tmp + 1; *p; p++) {
		if (*p == '\\') {
			*p = 0;
			if (stat(tmp, &sb))
				if (_mkdir(tmp) < 0)
					return -1;
			*p = '\\';
		}
	}

	if (stat(tmp, &sb))
		if (_mkdir(tmp) < 0)
			return -1;

	return 0;
}

int main(int argc, char **argv) {
	if (argc != 2) {
		fprintf(stderr, "Usage: %s file.arc", argv[0]);
		return 1;
	}

	FILE *in = fopen(argv[1], "rb");

	header hdr;
	fread(&hdr, sizeof(hdr), 1, in);

	fileEntry *entries = malloc(sizeof(fileEntry) * hdr.count);
	fread(entries, sizeof(fileEntry), hdr.count, in);

	for (int i = 0; i < hdr.count; i++) {
		char *name    = calloc(0x40, 1),
			 *dirname = calloc(0x40, 1);

		strcpy(name, entries[i].name);

		char *fnm = strrchr(name, '\\');

		if (fnm) {
			strncpy(dirname, name, (int)(fnm - name));
			rmakedir(dirname);
		}

		printf("Saving %s...\n", name);

		FILE *out = fopen(name, "wb");

		char *buf = malloc(entries[i].size),
			*comp = malloc(BUFFERSIZE);

		fseek(in, entries[i].offset, 0);
		fread(buf, 1, entries[i].size, in);

		int sz = decompress(buf, entries[i].size, comp, BUFFERSIZE);

		fwrite(comp, 1, sz, out);
		fclose(out);
		free(buf);
		free(comp);
	}

	puts("\nDone!");

	fclose(in);
}