general.h


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/*
 *  general.h
 *  
 *
 *  Created by Alex Marshall on 09/01/30.
 *  Copyright 2009 __MyCompanyName__. All rights reserved.
 *
 */

#define fatal(x)	printf(x); exit(1)

void LZ77Decompress(void *indata, size_t dlen, u8* ret)
{
	int inp = 0;
	u8* data = (u8*)calloc(dlen + 16, 1);
	memcpy(data, indata, dlen);
	int i;
	u8 bitmask;
	ret = (u8*)calloc(dlen, 256);		// HORRIBLY INEFFICIENT.
						// FIGURE SOMETHING ELSE OUT
	int retoff = 0;
	
	while(inp < dlen) {
		bitmask = data[inp];
		inp++;
		
		for(i = 0; i < 8; i++) {
			if(bitmask & 0x80) {
				u8 rep = data[inp];
				u8 repLength = (rep >> 4) + 3;
				inp++;
				u16 repOff = data[inp] | ((rep & 0x0F) << 8);
				inp++;
				
				if(repOff <= retoff) {
					fatal("Offset too high!\nQuitting\n");
				}
				
				while(repLength > 0) {
					ret[retoff] = ret[(retoff - repOff) - 1];
					repLength--;
					retoff++;
				}
			}else{
				ret[retoff] = data[inp];
				retoff++;
				inp++;
			}
			bitmask = bitmask << 1;
		}
	}
}