RAND31 random number generator in D. Suitable for generating white noise for audio applications.

rand31.d

/*
 * rand31.d
 * Copyright (C) 2013 Adrian Perez <[email protected]>
 *
 * Implements the rand31 random number generation algorithm, which is
 * particularly suitable for use as white noise for sound applications.
 *
 * For more information on the algorithm, please refer to:
 * http://www.firstpr.com.au/dsp/rand31/
 *
 * Distributed under terms of the MIT license.
 */

module rand31;

private const constapmc = 16807;
long seed = 1;

ulong next() {
	ulong lo = constapmc * (seed & 0xFFFF);
	ulong hi = constapmc * (seed >> 16);
	lo += (hi & 0x7FFF) << 16;
	lo += hi >> 15;
	if (lo > 0x7FFFFFFF) lo -= 0x7FFFFFFF;
	return (seed = cast(long) lo);
}

double nextf() {
  return next() / 2147483647.0;
}