/* oldrand.c : random number generators used in old compilers/libraries */
/* Jon Mayo - PUBLIC DOMAIN - October 24, 2006 */

/* NOTICE: these pseudo-random number generators are not meant to be used in
 * new software, they are only for maintaining compatability with legacy
 * software. */

/* information from:
 * http://www.std.com/~franl/crypto/random-numbers.html
 * http://everything2.com/index.pl?node=rand() 
 */

/* Microsoft C v4.0 implementation:
 *   ms_srand(), ms_rand()
 * ANSI C 1989 rand() implementation:
 *   ans_srand(), ans_rand()
 * Borland Turbo Pascal v6.0 implementation:
 *   btp_srand(), btp_rand()
 */

/* current seed values */
static unsigned long ms_seed;
static unsigned long ans_seed; 
static unsigned long btp_seed; 

void ms_srand(unsigned long seed) {
	ms_seed=seed;
}

unsigned short ms_rand(void) {
	ms_seed=(ms_seed*214013+2531011)&0x7fffffff;
	return (ms_seed>>16)&0x7fff;
}

void ans_srand(unsigned long seed) {
	ans_seed=seed;
}

unsigned ans_rand(void) {
	ans_seed=(1103515245*ans_seed+12345)&0x7fffffff;
	return ans_seed;
}

void btp_srand(unsigned long seed) {
	btp_seed=seed;
}

unsigned btp_rand(void) {
	btp_seed=(134775813*btp_seed+1);
	return (btp_seed>>16);
}