/usr/share/htslib-test/os/rand.c is in htslib-test 1.7-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 | /* rand.c -- drand48 implementation from the FreeBSD source tree. */
// This file is an amalgamation of the many small files in FreeBSD to do with
// drand48 and friends implementations.
// It comprises _rand48.c, rand48.h, srand48.c, drand48.c, erand48.c, lrand48.c
/*
* 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.
*/
//#include <sys/cdefs.h>
//__FBSDID("$FreeBSD: src/lib/libc/gen/_rand48.c,v 1.2 2002/03/22 21:52:05 obrien Exp $");
#include <math.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)
static unsigned short _rand48_seed[3] = {
RAND48_SEED_0,
RAND48_SEED_1,
RAND48_SEED_2
};
static unsigned short _rand48_mult[3] = {
RAND48_MULT_0,
RAND48_MULT_1,
RAND48_MULT_2
};
static unsigned short _rand48_add = RAND48_ADD;
static 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;
}
void
hts_srand48(long seed)
{
_rand48_seed[0] = RAND48_SEED_0;
_rand48_seed[1] = (unsigned short) seed;
_rand48_seed[2] = (unsigned short) (seed >> 16);
_rand48_mult[0] = RAND48_MULT_0;
_rand48_mult[1] = RAND48_MULT_1;
_rand48_mult[2] = RAND48_MULT_2;
_rand48_add = RAND48_ADD;
}
double
hts_erand48(unsigned short xseed[3])
{
_dorand48(xseed);
return ldexp((double) xseed[0], -48) +
ldexp((double) xseed[1], -32) +
ldexp((double) xseed[2], -16);
}
double
hts_drand48(void)
{
return hts_erand48(_rand48_seed);
}
long
hts_lrand48(void)
{
_dorand48(_rand48_seed);
return ((long) _rand48_seed[2] << 15) + ((long) _rand48_seed[1] >> 1);
}
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