stk/Mp/gmp-1.3.2/mpz_random.c

69 lines
1.6 KiB
C

/* mpz_random -- Generate a random MP_INT of specified size.
Copyright (C) 1991, 1993 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
The GNU MP Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with the GNU MP Library; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "gmp.h"
#include "gmp-impl.h"
#if defined (hpux) || defined (__alpha__)
/* HPUX lacks random(). DEC Alpha's random() returns a double. */
static inline long
urandom ()
{
return mrand48 ();
}
#else
long random ();
static inline long
urandom ()
{
/* random() returns 31 bits, we want 32. */
return random() ^ (random() << 1);
}
#endif
void
#ifdef __STDC__
mpz_random (MP_INT *x, mp_size size)
#else
mpz_random (x, size)
MP_INT *x;
mp_size size;
#endif
{
mp_size i;
mp_limb ran;
if (x->alloc < size)
_mpz_realloc (x, size);
for (i = 0; i < size; i++)
{
ran = urandom ();
x->d[i] = ran;
}
for (i = size - 1; i >= 0; i--)
if (x->d[i] != 0)
break;
x->size = i + 1;
}