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Diff for /OpenXM_contrib/gmp/mpn/generic/Attic/random2.c between version 1.1.1.1 and 1.1.1.3

version 1.1.1.1, 2000/01/10 15:35:23 version 1.1.1.3, 2003/08/25 16:06:20
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 /* mpn_random2 -- Generate random numbers with relatively long strings  /* mpn_random2 -- Generate random numbers with relatively long strings
    of ones and zeroes.  Suitable for border testing.     of ones and zeroes.  Suitable for border testing.
   
 Copyright (C) 1992, 1993, 1994, 1996 Free Software Foundation, Inc.  Copyright 1992, 1993, 1994, 1996, 2000, 2001, 2002 Free Software Foundation, Inc.
   
 This file is part of the GNU MP Library.  This file is part of the GNU MP Library.
   
 The GNU MP Library is free software; you can redistribute it and/or modify  The GNU MP Library is free software; you can redistribute it and/or modify
 it under the terms of the GNU Library General Public License as published by  it under the terms of the GNU Lesser General Public License as published by
 the Free Software Foundation; either version 2 of the License, or (at your  the Free Software Foundation; either version 2.1 of the License, or (at your
 option) any later version.  option) any later version.
   
 The GNU MP Library is distributed in the hope that it will be useful, but  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  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 License for more details.  License for more details.
   
 You should have received a copy of the GNU Library General Public License  You should have received a copy of the GNU Lesser General Public License
 along with the GNU MP Library; see the file COPYING.LIB.  If not, write to  along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,  the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 MA 02111-1307, USA. */  MA 02111-1307, USA. */
Line 23  MA 02111-1307, USA. */
Line 23  MA 02111-1307, USA. */
 #include "gmp.h"  #include "gmp.h"
 #include "gmp-impl.h"  #include "gmp-impl.h"
   
 #if defined (__hpux) || defined (alpha__)  || defined (__svr4__) || defined (__SVR4)  
 /* HPUX lacks random().  DEC OSF/1 1.2 random() returns a double.  */  /* It's a bit tricky to get this right, so please test the code well if you
 long mrand48 ();     hack with it.  Some early versions of the function produced random numbers
 static inline long     with the leading limb == 0, and some versions never made the most
 random ()     significant bit set.
 {  
   return mrand48 ();     This code and mpz_rrandomb are almost identical, though the latter makes bit
 }     runs of 1 to 16, and doesn't force the first block to contain 1-bits.
   
      The RANDS random state currently produces 32 random bits per underlying lc
      invocation (BITS_PER_RANDCALL).  We therefore ask for that, presuming that
      limbs are at least 32 bits.  FIXME: Handle smaller limbs, such as 4-bit
      limbs useful for testing purposes, or limbs truncated by nailing.
   
      For efficiency, we make sure to use most bits returned from _gmp_rand, since
      the underlying random number generator is slow.  Keep returned bits in
      ranm/ran, and a count of how many bits remaining in ran_nbits.  */
   
   #define LOGBITS_PER_BLOCK 4
   
   /* Ask _gmp_rand for 32 bits per call unless that's more than a limb can hold.
      Thus, we get the same random number sequence in the common cases.
      FIXME: We should always generate the same random number sequence!  */
   #if GMP_NUMB_BITS < 32
   #define BITS_PER_RANDCALL GMP_NUMB_BITS
 #else  #else
 long random ();  #define BITS_PER_RANDCALL 32
 #endif  #endif
   
 /* It's a bit tricky to get this right, so please test the code well  
    if you hack with it.  Some early versions of the function produced  
    random numbers with the leading limb == 0, and some versions never  
    made the most significant bit set.  */  
   
 void  void
 mpn_random2 (res_ptr, size)  mpn_random2 (mp_ptr rp, mp_size_t n)
      mp_ptr res_ptr;  
      mp_size_t size;  
 {  {
   int n_bits;    gmp_randstate_ptr rstate = RANDS;
   int bit_pos;    int nb;
   mp_size_t limb_pos;    int bit_pos;                  /* bit number of least significant bit where
   unsigned int ran;                                     next bit field to be inserted */
   mp_limb_t limb;    mp_size_t ri;                 /* index in rp */
     mp_limb_t ran, ranm;          /* buffer for random bits */
     mp_limb_t acc;                /* accumulate output random data here */
     int ran_nbits;                /* number of valid bits in ran */
   
   limb = 0;    /* FIXME: Is n==0 supposed to be allowed? */
     ASSERT (n >= 0);
     ASSERT_ALWAYS (BITS_PER_MP_LIMB > LOGBITS_PER_BLOCK);
   
   /* Start off in a random bit position in the most significant limb.  */    _gmp_rand (&ranm, rstate, BITS_PER_RANDCALL);
   bit_pos = random () & (BITS_PER_MP_LIMB - 1);    ran = ranm;
   
   /* Least significant bit of RAN chooses string of ones/string of zeroes.    /* Start off at a random bit position in the most significant limb.  */
     bit_pos = ran % GMP_NUMB_BITS;
     ran >>= 6;                            /* Ideally   log2(GMP_NUMB_BITS) */
     ran_nbits = BITS_PER_RANDCALL - 6;    /* Ideally - log2(GMP_NUMB_BITS) */
   
     /* Bit 0 of ran chooses string of ones/string of zeroes.
      Make most significant limb be non-zero by setting bit 0 of RAN.  */       Make most significant limb be non-zero by setting bit 0 of RAN.  */
   ran = random () | 1;    ran |= 1;
   
   for (limb_pos = size - 1; limb_pos >= 0; )    ri = n - 1;
   
     acc = 0;
     while (ri >= 0)
     {      {
       n_bits = (ran >> 1) % BITS_PER_MP_LIMB + 1;        if (ran_nbits < LOGBITS_PER_BLOCK + 1)
           {
             _gmp_rand (&ranm, rstate, BITS_PER_RANDCALL);
             ran = ranm;
             ran_nbits = BITS_PER_RANDCALL;
           }
   
         nb = (ran >> 1) % (1 << LOGBITS_PER_BLOCK) + 1;
       if ((ran & 1) != 0)        if ((ran & 1) != 0)
         {          {
           /* Generate a string of ones.  */            /* Generate a string of nb ones.  */
           if (n_bits >= bit_pos)            if (nb > bit_pos)
             {              {
               res_ptr[limb_pos--] = limb | ((((mp_limb_t) 2) << bit_pos) - 1);                rp[ri--] = acc | (((mp_limb_t) 2 << bit_pos) - 1);
               bit_pos += BITS_PER_MP_LIMB;                bit_pos += GMP_NUMB_BITS;
               limb = (~(mp_limb_t) 0) << (bit_pos - n_bits);                bit_pos -= nb;
                 acc = ((~(mp_limb_t) 1) << bit_pos) & GMP_NUMB_MASK;
             }              }
           else            else
             {              {
               limb |= ((((mp_limb_t) 1) << n_bits) - 1) << (bit_pos - n_bits + 1);                bit_pos -= nb;
                 acc |= (((mp_limb_t) 2 << nb) - 2) << bit_pos;
             }              }
         }          }
       else        else
         {          {
           /* Generate a string of zeroes.  */            /* Generate a string of nb zeroes.  */
           if (n_bits >= bit_pos)            if (nb > bit_pos)
             {              {
               res_ptr[limb_pos--] = limb;                rp[ri--] = acc;
               limb = 0;                acc = 0;
               bit_pos += BITS_PER_MP_LIMB;                bit_pos += GMP_NUMB_BITS;
             }              }
             bit_pos -= nb;
         }          }
       bit_pos -= n_bits;        ran_nbits -= LOGBITS_PER_BLOCK + 1;
       ran = random ();        ran >>= LOGBITS_PER_BLOCK + 1;
     }      }
 }  }
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