1/* gmp_urandomb_ui -- random bits returned in a ulong. 2 3Copyright 2003, 2004 Free Software Foundation, Inc. 4 5This file is part of the GNU MP Library. 6 7The GNU MP Library is free software; you can redistribute it and/or modify 8it under the terms of the GNU Lesser General Public License as published by 9the Free Software Foundation; either version 3 of the License, or (at your 10option) any later version. 11 12The GNU MP Library is distributed in the hope that it will be useful, but 13WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 14or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 15License for more details. 16 17You should have received a copy of the GNU Lesser General Public License 18along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */ 19 20#include "gmp.h" 21#include "gmp-impl.h" 22 23 24/* Currently bits>=BITS_PER_ULONG is quietly truncated to BITS_PER_ULONG, 25 maybe this should raise an exception or something. */ 26 27unsigned long 28gmp_urandomb_ui (gmp_randstate_ptr rstate, unsigned long bits) 29{ 30 mp_limb_t a[LIMBS_PER_ULONG]; 31 32 /* start with zeros, since if bits==0 then _gmp_rand will store nothing at 33 all, or if bits <= GMP_NUMB_BITS then it will store only a[0] */ 34 a[0] = 0; 35#if LIMBS_PER_ULONG > 1 36 a[1] = 0; 37#endif 38 39 _gmp_rand (a, rstate, MIN (bits, BITS_PER_ULONG)); 40 41#if LIMBS_PER_ULONG == 1 42 return a[0]; 43#else 44 return a[0] | (a[1] << GMP_NUMB_BITS); 45#endif 46} 47