code:

char *replaceEntities(char *to, const char *from, size_t n) {
	const char *end = from + n;
	const char *r = from;
	char *w = to;
		
	while (r < end) {
		char x = *r++;
		if (x == '&') {
			if (r < end) {
				const char *tmp = r;
				char y = *tmp;
				if (y == '#') {
					// decimal code or hex code?  Meh, we're assuming decimal code.
					
					tmp++;
					const char *tmptmp = tmp;
					int num = readNonNegativeNumber(&tmptmp, end);
					if (tmp < tmptmp && tmptmp < end && *tmptmp == ';' && num < 256) {
						r = tmptmp + 1;
						*w++ = num;
					} else {
						*w++ = x;
					}					
				} else {
					// Only do the common entities...
					if (eatThroughString(&tmp, end, "lt;")) {
						r = tmp;
						*w++ = '<';
					} else if (eatThroughString(&tmp, end, "gt;")) {
						r = tmp;
						*w++ = '>';
					} else if (eatThroughString(&tmp, end, "quot;")) {
						r = tmp;
						*w++ = '"';
					} else if (eatThroughString(&tmp, end, "apos;")) {
						r = tmp;
						*w++ = '\'';
					} else if (eatThroughString(&tmp, end, "amp;")) {
						r = tmp;
						*w++ = '&';
					} else {
						*w++ = x;
					}
				}
			} else {
				*w++ = x;	
			}
		} else {
			*w++ = x;
		}
	}
	return w;
}


// hilarious
NSString *initEntityString(NSString *allocedString, const char *beg, const char *end) {
	size_t n = end - beg;
	char *buf = malloc(n);
	char *bufEnd = replaceEntities(buf, beg, n);
	return [allocedString initWithBytesNoCopy:buf length:bufEnd-buf encoding:NSUTF8StringEncoding freeWhenDone:YES];
}