unpack embedded .rmf objects from .ol WorldCraft prefab library to current directory

unpack_prefab.c

// unpack embedded .rmf objects from .ol WorldCraft prefab library to current directory.
// list of names and descriptions would be dump into info.txt.
// reference: https://github.com/LogicAndTrick/sledge-formats/blob/master/Sledge.Formats.Map/Formats/WorldcraftPrefabLibrary.cs

#include <stdio.h>
#include <string.h>

typedef unsigned char uint8_t;
typedef unsigned short uint16_t;
typedef unsigned int uint32_t;

struct object {
	uint32_t offset, length;
	char name[31];
	char desc[205];
};

int main(int argc, char** argv)
{
	if (argc < 2) {
		fprintf(stderr, "usage: unpack FILE\n");
		return 1;
	}

	FILE *p;
	p = fopen(argv[1], "rb");
	if (!p) {
		fprintf(stderr, "failed to open file\n");
		return 1;
	}

	const char *EXPECTED_HEADER = "Worldcraft Prefab Library\r\n\x1A";
	char header[28];
	fread(header, 28, 1, p);
	if (strncmp(header, EXPECTED_HEADER, 28) != 0) {
		fprintf(stderr, "error: header unmatch\n");
		fclose(p);
		return 1;
	}

	float version;
	fread(&version, 4, 1, p);
	printf("version: %.1f", version);

	uint32_t offset;
	fread(&offset, 4, 1, p);

	uint16_t nobjects; 
	fread(&nobjects, 2, 1, p);

	struct object objects[nobjects];

	FILE *info_p = fopen("info.txt", "w");
	if (!p) {
		fprintf(stderr, "failed to write info.txt\n");
		fclose(p);
		return 1;
	}

	fseek(p, offset, SEEK_SET);
	for (int i = 0; i < nobjects; i++) {
		fread(&objects[i], sizeof(struct object), 1, p);
		fprintf(info_p, "%s : %s\n", objects[i].name, objects[i].desc);
		fseek(p, 300, SEEK_CUR);
	}

	for (int i = 0; i < nobjects; i++) {
		char fname[256];
		sprintf(fname, "%s.rmf", objects[i].name);
		FILE *rmfp = fopen(fname, "wb");
		fseek(p, objects[i].offset, SEEK_SET);
		for (int j = 0; j < objects[i].length; j++)
			fputc(fgetc(p), rmfp);
		fclose(rmfp);
	}

	fclose(info_p);
	fclose(p);
	return 0;
}