Converts SmileBASIC .DAT files to real little-endian binary files

b2bin.c

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

typedef unsigned long long u64;
typedef unsigned int u32;
typedef unsigned short u16;
typedef unsigned char u8;

int main(int argc, char** argv)
{
	if(argc < 2)
	{
		printf("Usage: %s <filename> [output]\n", argv[0]);
		return 1;
	}
	
	FILE* f = fopen(argv[1], "rb");
	if(f<=0)
	{
		printf("Error: can't open file \"%s\"\n", argv[1]);
		return 1;
	}
	
	char* of;
	if(argc > 2)
	{
		of = argv[2];
	}
	else
	{
		of = malloc((strlen(argv[1]) + 4) * sizeof(char));
		memset(of, 0, sizeof(of));
		strcpy(of, argv[1]);
		strcat(of, ".bin");
	}
	
	FILE* o = fopen(of, "wb");
	if(o<=0)
	{
		fclose(f);
		printf("Error: can't open output \"%s\"\n", of);
		if(argc < 2) free(of);
		return 1;
	}
	
	u8* buf = malloc(8);
	u32 cnt;
	
	fseek(f, 0x5C, SEEK_SET);
	fread(buf, 4, 1, f);
	cnt = (buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24));
	
	printf("Output filesize: %d bytes\n", cnt);
	
	fseek(f, 0x6C, SEEK_SET);
	
	int testflag = 1;
	int bigflag = !*(u8*)&testflag;
	
	printf("Your system is %s-endian\n", bigflag ? "big" : "little");
	
	u32 read = 0;
	while(read != cnt)
	{
		fread(buf, 8, 1, f);
		
		if(bigflag)
		{
			do
			{
				u8 tmp;
				int i;
				for(i = 0; i != 4; i++)
				{
					tmp = buf[i];
					buf[i] = buf[7 - i];
					buf[7 - i] = tmp;
				}
			}
			while(0);
		}
		
		double dbl = *(double*)buf;
		u16 on = (u16)dbl;
		
		buf[0] = on & 0xFF;
		buf[1] = (on >> 8) & 0xFF;
		
		fwrite(buf,2,1,o);
		read++;
	}
	fflush(o);
	fclose(o);
	fclose(f);
	free(of);
	free(buf);
	
	puts("Successful conversion");
	return 0;
}