Imported gcc-4.4.3

[msp430-gcc.git] / gmp / mpz / rrandomb.c

diff --git a/gmp/mpz/rrandomb.c b/gmp/mpz/rrandomb.c
new file mode 100644 (file)
index 0000000..f34aaec
--- /dev/null
+++ b/gmp/mpz/rrandomb.c
@@ -0,0 +1,91 @@
+/* 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, 2001, 2002, 2004 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 Lesser General Public License as published by
+the Free Software Foundation; either version 3 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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+
+static void gmp_rrandomb __GMP_PROTO ((mp_ptr, gmp_randstate_t, unsigned long int));
+
+void
+mpz_rrandomb (mpz_ptr x, gmp_randstate_t rstate, unsigned long int nbits)
+{
+  mp_size_t nl;
+
+  nl = (nbits + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS;
+  if (nbits != 0)
+    {
+      MPZ_REALLOC (x, nl);
+      gmp_rrandomb (PTR(x), 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_t rstate, unsigned long int nbits)
+{
+  unsigned long int bi;
+  mp_limb_t ranm;              /* buffer for random bits */
+  unsigned cap_chunksize, chunksize;
+  mp_size_t i;
+
+  /* Set entire result to 111..1  */
+  i = (nbits + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS - 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 */
+    }
+}