49 lines
1.6 KiB
C
49 lines
1.6 KiB
C
/* gmp_urandomb_ui -- random bits returned in a ulong.
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Copyright 2003, 2004 Free Software Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include "gmp.h"
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#include "gmp-impl.h"
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/* Currently bits>=BITS_PER_ULONG is quietly truncated to BITS_PER_ULONG,
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maybe this should raise an exception or something. */
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unsigned long
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gmp_urandomb_ui (gmp_randstate_ptr rstate, unsigned long bits)
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{
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mp_limb_t a[LIMBS_PER_ULONG];
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/* start with zeros, since if bits==0 then _gmp_rand will store nothing at
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all, or if bits <= GMP_NUMB_BITS then it will store only a[0] */
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a[0] = 0;
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#if LIMBS_PER_ULONG > 1
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a[1] = 0;
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#endif
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_gmp_rand (a, rstate, MIN (bits, BITS_PER_ULONG));
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#if LIMBS_PER_ULONG == 1
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return a[0];
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#else
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return a[0] | (a[1] << GMP_NUMB_BITS);
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#endif
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}
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