89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
/* mpz_random2 -- Generate a positive random MP_INT of specified size, with
|
|
long runs of consecutive ones and zeros in the binary representation.
|
|
Meant for testing of other MP routines.
|
|
|
|
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
|
|
random ()
|
|
{
|
|
return mrand48 ();
|
|
}
|
|
#else
|
|
long random ();
|
|
#endif
|
|
|
|
void
|
|
#ifdef __STDC__
|
|
mpz_random2 (MP_INT *x, mp_size size)
|
|
#else
|
|
mpz_random2 (x, size)
|
|
MP_INT *x;
|
|
mp_size size;
|
|
#endif
|
|
{
|
|
mp_limb ran, cy_limb;
|
|
mp_ptr xp;
|
|
mp_size xsize, abs_size;
|
|
int n_bits;
|
|
|
|
abs_size = ABS (size);
|
|
|
|
if (abs_size != 0)
|
|
{
|
|
if (x->alloc < abs_size)
|
|
_mpz_realloc (x, abs_size);
|
|
xp = x->d;
|
|
|
|
xp[0] = 1;
|
|
for (xsize = 1;; )
|
|
{
|
|
ran = random ();
|
|
n_bits = (ran >> 1) % BITS_PER_MP_LIMB;
|
|
|
|
if (n_bits == 0)
|
|
{
|
|
if (xsize == abs_size)
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
/* Would we get a too large result in mpn_lshift? */
|
|
if (xsize == abs_size
|
|
&& (xp[xsize - 1] >> (BITS_PER_MP_LIMB - n_bits)) != 0)
|
|
break;
|
|
|
|
cy_limb = mpn_lshift (xp, xp, xsize, n_bits);
|
|
if (cy_limb != 0)
|
|
xp[xsize++] = cy_limb;
|
|
|
|
if (ran & 1)
|
|
xp[0] |= ((mp_limb) 1 << n_bits) - 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
x->size = size;
|
|
}
|