| Austin Schuh | dace2a6 | 2020-08-18 10:56:48 -0700 | [diff] [blame] | 1 | /* gmp_urandomb_ui -- random bits returned in a ulong. |
| 2 | |
| 3 | Copyright 2003, 2004 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of the GNU MP Library. |
| 6 | |
| 7 | The GNU MP Library is free software; you can redistribute it and/or modify |
| 8 | it under the terms of either: |
| 9 | |
| 10 | * the GNU Lesser General Public License as published by the Free |
| 11 | Software Foundation; either version 3 of the License, or (at your |
| 12 | option) any later version. |
| 13 | |
| 14 | or |
| 15 | |
| 16 | * the GNU General Public License as published by the Free Software |
| 17 | Foundation; either version 2 of the License, or (at your option) any |
| 18 | later version. |
| 19 | |
| 20 | or both in parallel, as here. |
| 21 | |
| 22 | The GNU MP Library is distributed in the hope that it will be useful, but |
| 23 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| 24 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 25 | for more details. |
| 26 | |
| 27 | You should have received copies of the GNU General Public License and the |
| 28 | GNU Lesser General Public License along with the GNU MP Library. If not, |
| 29 | see https://www.gnu.org/licenses/. */ |
| 30 | |
| 31 | #include "gmp-impl.h" |
| 32 | |
| 33 | |
| 34 | /* Currently bits>=BITS_PER_ULONG is quietly truncated to BITS_PER_ULONG, |
| 35 | maybe this should raise an exception or something. */ |
| 36 | |
| 37 | unsigned long |
| 38 | gmp_urandomb_ui (gmp_randstate_ptr rstate, unsigned long bits) |
| 39 | { |
| 40 | mp_limb_t a[LIMBS_PER_ULONG]; |
| 41 | |
| 42 | /* start with zeros, since if bits==0 then _gmp_rand will store nothing at |
| 43 | all, or if bits <= GMP_NUMB_BITS then it will store only a[0] */ |
| 44 | a[0] = 0; |
| 45 | #if LIMBS_PER_ULONG > 1 |
| 46 | a[1] = 0; |
| 47 | #endif |
| 48 | |
| 49 | _gmp_rand (a, rstate, MIN (bits, BITS_PER_ULONG)); |
| 50 | |
| 51 | #if LIMBS_PER_ULONG == 1 |
| 52 | return a[0]; |
| 53 | #else |
| 54 | return a[0] | (a[1] << GMP_NUMB_BITS); |
| 55 | #endif |
| 56 | } |