=================================================================== RCS file: /home/cvs/OpenXM_contrib/gmp/mpn/generic/Attic/random2.c,v retrieving revision 1.1.1.1 retrieving revision 1.1.1.3 diff -u -p -r1.1.1.1 -r1.1.1.3 --- OpenXM_contrib/gmp/mpn/generic/Attic/random2.c 2000/01/10 15:35:23 1.1.1.1 +++ OpenXM_contrib/gmp/mpn/generic/Attic/random2.c 2003/08/25 16:06:20 1.1.1.3 @@ -1,21 +1,21 @@ /* mpn_random2 -- Generate random numbers with relatively long strings 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. 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 -the Free Software Foundation; either version 2 of the License, or (at your +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 2.1 of the License, 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 Library General Public +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 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 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ @@ -23,71 +23,104 @@ MA 02111-1307, USA. */ #include "gmp.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. */ -long mrand48 (); -static inline long -random () -{ - return mrand48 (); -} + +/* 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. + + 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 -long random (); +#define BITS_PER_RANDCALL 32 #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 -mpn_random2 (res_ptr, size) - mp_ptr res_ptr; - mp_size_t size; +mpn_random2 (mp_ptr rp, mp_size_t n) { - int n_bits; - int bit_pos; - mp_size_t limb_pos; - unsigned int ran; - mp_limb_t limb; + gmp_randstate_ptr rstate = RANDS; + int nb; + int bit_pos; /* bit number of least significant bit where + next bit field to be inserted */ + 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. */ - bit_pos = random () & (BITS_PER_MP_LIMB - 1); + _gmp_rand (&ranm, rstate, BITS_PER_RANDCALL); + 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. */ - 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) { - /* Generate a string of ones. */ - if (n_bits >= bit_pos) + /* Generate a string of nb ones. */ + if (nb > bit_pos) { - res_ptr[limb_pos--] = limb | ((((mp_limb_t) 2) << bit_pos) - 1); - bit_pos += BITS_PER_MP_LIMB; - limb = (~(mp_limb_t) 0) << (bit_pos - n_bits); + rp[ri--] = acc | (((mp_limb_t) 2 << bit_pos) - 1); + bit_pos += GMP_NUMB_BITS; + bit_pos -= nb; + acc = ((~(mp_limb_t) 1) << bit_pos) & GMP_NUMB_MASK; } 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 { - /* Generate a string of zeroes. */ - if (n_bits >= bit_pos) + /* Generate a string of nb zeroes. */ + if (nb > bit_pos) { - res_ptr[limb_pos--] = limb; - limb = 0; - bit_pos += BITS_PER_MP_LIMB; + rp[ri--] = acc; + acc = 0; + bit_pos += GMP_NUMB_BITS; } + bit_pos -= nb; } - bit_pos -= n_bits; - ran = random (); + ran_nbits -= LOGBITS_PER_BLOCK + 1; + ran >>= LOGBITS_PER_BLOCK + 1; } }