| Austin Schuh | bb1338c | 2024-06-15 19:31:16 -0700 | [diff] [blame^] | 1 | /* mpf_fits_u*_p -- test whether an mpf fits a C unsigned type. |
| 2 | |
| 3 | Copyright 2001, 2002, 2013, 2014 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 | /* Notice this is equivalent to mpz_set_f + mpz_fits_u*_p. */ |
| 35 | |
| 36 | int |
| 37 | FUNCTION (mpf_srcptr f) __GMP_NOTHROW |
| 38 | { |
| 39 | mp_size_t fn; |
| 40 | mp_srcptr fp; |
| 41 | mp_exp_t exp; |
| 42 | mp_limb_t fl; |
| 43 | |
| 44 | exp = EXP(f); |
| 45 | if (exp < 1) |
| 46 | return 1; /* -1 < f < 1 truncates to zero, so fits */ |
| 47 | |
| 48 | fn = SIZ(f); |
| 49 | if (fn < 0) /* zero catched by exp == 0 */ |
| 50 | return 0; /* negatives don't fit */ |
| 51 | |
| 52 | fp = PTR(f); |
| 53 | |
| 54 | if (exp == 1) |
| 55 | { |
| 56 | fl = fp[fn-1]; |
| 57 | } |
| 58 | #if GMP_NAIL_BITS != 0 |
| 59 | else if (exp == 2 && MAXIMUM > GMP_NUMB_MAX) |
| 60 | { |
| 61 | fl = fp[fn-1]; |
| 62 | if ((fl >> GMP_NAIL_BITS) != 0) |
| 63 | return 0; |
| 64 | fl = (fl << GMP_NUMB_BITS); |
| 65 | if (fn >= 2) |
| 66 | fl |= fp[fn-2]; |
| 67 | } |
| 68 | #endif |
| 69 | else |
| 70 | return 0; |
| 71 | |
| 72 | return fl <= MAXIMUM; |
| 73 | } |