libpostal-sys 0.1.1

Low-level wrappers for libpostal address normalization (with locks to support thread-safe initialization)
Documentation 
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/*
 * Copyright (c) 1993 Martin Birgmeier
 * All rights reserved.

 * You may redistribute unmodified or modified versions of this source
 * code provided that the above copyright notice and this and the
 * following conditions are retained.

 * This software is provided ``as is'', and comes with no warranties
 * of any kind. I shall in no event be liable for anything that happens
 * to anyone/anything when using this software.
*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifndef HAVE_DRAND48

#include <math.h>
#include "drand48.h"

#define	RAND48_SEED_0	(0x330e)
#define	RAND48_SEED_1	(0xabcd)
#define	RAND48_SEED_2	(0x1234)
#define	RAND48_MULT_0	(0xe66d)
#define	RAND48_MULT_1	(0xdeec)
#define	RAND48_MULT_2	(0x0005)
#define	RAND48_ADD	    (0x000b)

unsigned short _rand48_seed[3] = {
	RAND48_SEED_0,
	RAND48_SEED_1,
	RAND48_SEED_2
};

unsigned short _rand48_mult[3] = {
	RAND48_MULT_0,
	RAND48_MULT_1,
	RAND48_MULT_2
};

unsigned short _rand48_add = RAND48_ADD;

void _dorand48(unsigned short xseed[3])
{
	unsigned long accu;
	unsigned short temp[2];

	accu = (unsigned long) _rand48_mult[0] * (unsigned long) xseed[0] + (unsigned long) _rand48_add;
	temp[0] = (unsigned short) accu;	/* lower 16 bits */
	accu >>= sizeof(unsigned short) * 8;
	accu += (unsigned long) _rand48_mult[0] * (unsigned long) xseed[1] + (unsigned long) _rand48_mult[1] * (unsigned long) xseed[0];
	temp[1] = (unsigned short) accu;	/* middle 16 bits */
	accu >>= sizeof(unsigned short) * 8;
	accu += _rand48_mult[0] * xseed[2] + _rand48_mult[1] * xseed[1] + _rand48_mult[2] * xseed[0];
	xseed[0] = temp[0];
	xseed[1] = temp[1];
	xseed[2] = (unsigned short) accu;
}

double erand48(unsigned short xseed[3])
{
	_dorand48(xseed);
	return ldexp((double) xseed[0], -48) +
	       ldexp((double) xseed[1], -32) +
	       ldexp((double) xseed[2], -16);
}

double drand48(void)
{
	return erand48(_rand48_seed);
}

#endif // HAVE_DRAND48