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-rw-r--r--vendor/gmp-6.3.0/mpz/rrandomb.c102
1 files changed, 102 insertions, 0 deletions
diff --git a/vendor/gmp-6.3.0/mpz/rrandomb.c b/vendor/gmp-6.3.0/mpz/rrandomb.c
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+/* mpz_rrandomb -- Generate a positive random mpz_t of specified bit size, with
+ long runs of consecutive ones and zeros in the binary representation.
+ Meant for testing of other MP routines.
+
+Copyright 2000-2002, 2004, 2012 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 either:
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at your
+ option) any later version.
+
+or
+
+ * the GNU General Public License as published by the Free Software
+ Foundation; either version 2 of the License, or (at your option) any
+ later version.
+
+or both in parallel, as here.
+
+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 copies of the GNU General Public License and the
+GNU Lesser General Public License along with the GNU MP Library. If not,
+see https://www.gnu.org/licenses/. */
+
+#include "gmp-impl.h"
+
+static void gmp_rrandomb (mp_ptr, gmp_randstate_ptr, mp_bitcnt_t);
+
+void
+mpz_rrandomb (mpz_ptr x, gmp_randstate_ptr rstate, mp_bitcnt_t nbits)
+{
+ mp_size_t nl;
+ mp_ptr xp;
+
+ nl = BITS_TO_LIMBS (nbits);
+ if (nbits != 0)
+ {
+ xp = MPZ_NEWALLOC (x, nl);
+ gmp_rrandomb (xp, rstate, nbits);
+ }
+
+ SIZ(x) = nl;
+}
+
+/* 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
+#define BITS_PER_RANDCALL 32
+#endif
+
+static void
+gmp_rrandomb (mp_ptr rp, gmp_randstate_ptr rstate, mp_bitcnt_t nbits)
+{
+ mp_bitcnt_t bi;
+ mp_limb_t ranm; /* buffer for random bits */
+ unsigned cap_chunksize, chunksize;
+ mp_size_t i;
+
+ /* Set entire result to 111..1 */
+ i = BITS_TO_LIMBS (nbits) - 1;
+ rp[i] = GMP_NUMB_MAX >> (GMP_NUMB_BITS - (nbits % GMP_NUMB_BITS)) % GMP_NUMB_BITS;
+ for (i = i - 1; i >= 0; i--)
+ rp[i] = GMP_NUMB_MAX;
+
+ _gmp_rand (&ranm, rstate, BITS_PER_RANDCALL);
+ cap_chunksize = nbits / (ranm % 4 + 1);
+ cap_chunksize += cap_chunksize == 0; /* make it at least 1 */
+
+ bi = nbits;
+
+ for (;;)
+ {
+ _gmp_rand (&ranm, rstate, BITS_PER_RANDCALL);
+ chunksize = 1 + ranm % cap_chunksize;
+ bi = (bi < chunksize) ? 0 : bi - chunksize;
+
+ if (bi == 0)
+ break; /* low chunk is ...1 */
+
+ rp[bi / GMP_NUMB_BITS] ^= CNST_LIMB (1) << bi % GMP_NUMB_BITS;
+
+ _gmp_rand (&ranm, rstate, BITS_PER_RANDCALL);
+ chunksize = 1 + ranm % cap_chunksize;
+ bi = (bi < chunksize) ? 0 : bi - chunksize;
+
+ mpn_incr_u (rp + bi / GMP_NUMB_BITS, CNST_LIMB (1) << bi % GMP_NUMB_BITS);
+
+ if (bi == 0)
+ break; /* low chunk is ...0 */
+ }
+}