lib/posixcompat/random.c

31 static char sccsid[] = "@(#)random.c	8.2 (Berkeley) 5/19/95";
47  * random.c:
49  * An improved random number generation package.  In addition to the standard
53  * then initialized to contain information for random number generation with
58  * information and generates far better random numbers than a linear
70  * The random number generation technique is a linear feedback shift register
77  * influenced by pseudo-random carries out of the lower bits.  The total
98  * state information and generates far better random numbers than a linear
106  * For each of the currently supported random number generators, we have a
108  * many bytes of state info to support this random number generator), a degree
170 /* The random sequences do not vary much with the seed */
191  * could get away with just one pointer, but the code for random() is more
208  * of random(), we remember the first location of the state information, not
227  * The random sequences do not vary much with the seed,
257  * Initialize the random number generator based on the given seed.  If the
281 		(void)random();
290  * secure random(4) interface.  Note that this particular seeding
307 	fd = _open("/dev/random", O_RDONLY, 0);
334  * random number generation.  Based on the number of bytes we are given, and
367 		    "random: not enough state (%ld bytes); ignored.\n", n);
444 		    "random: state info corrupted; not changed.\n");
456  * random:
464  * generated, reduced to 31 bits by throwing away the "least random" low bit.
470  * Returns a 31-bit random number.
472 long random(void)
486 		i = (*f >> 1) & 0x7fffffff;	/* chucking least random bit */