1 /* mpfr_fits_uintmax_p -- test whether an mpfr fits an uintmax_t. 2 3 Copyright 2004, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc. 4 Contributed by the AriC and Caramel projects, INRIA. 5 6 This file is part of the GNU MPFR Library. 7 8 The GNU MPFR Library is free software; you can redistribute it and/or modify 9 it under the terms of the GNU Lesser General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or (at your 11 option) any later version. 12 13 The GNU MPFR Library is distributed in the hope that it will be useful, but 14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 16 License for more details. 17 18 You should have received a copy of the GNU Lesser General Public License 19 along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see 20 http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., 21 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */ 22 23 #ifdef HAVE_CONFIG_H 24 # include "config.h" /* for a build within gmp */ 25 #endif 26 27 #include "mpfr-intmax.h" 28 #include "mpfr-impl.h" 29 30 #ifdef _MPFR_H_HAVE_INTMAX_T 31 32 /* We can't use fits_u.h <= mpfr_cmp_ui */ 33 int 34 mpfr_fits_uintmax_p (mpfr_srcptr f, mpfr_rnd_t rnd) 35 { 36 mpfr_exp_t e; 37 int prec; 38 uintmax_t s; 39 mpfr_t x; 40 int res; 41 42 if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (f))) 43 /* Zero always fit */ 44 return MPFR_IS_ZERO (f) ? 1 : 0; 45 else if (MPFR_IS_NEG (f)) 46 /* Negative numbers don't fit */ 47 return 0; 48 /* now it fits if 49 (a) f <= MAXIMUM 50 (b) round(f, prec(slong), rnd) <= MAXIMUM */ 51 52 e = MPFR_GET_EXP (f); 53 54 /* first compute prec(MAXIMUM); fits in an int */ 55 for (s = MPFR_UINTMAX_MAX, prec = 0; s != 0; s /= 2, prec ++); 56 57 /* MAXIMUM needs prec bits, i.e. MAXIMUM = 2^prec - 1 */ 58 59 /* if e <= prec - 1, then f < 2^(prec-1) < MAXIMUM */ 60 if (e <= prec - 1) 61 return 1; 62 63 /* if e >= prec + 1, then f >= 2^prec > MAXIMUM */ 64 if (e >= prec + 1) 65 return 0; 66 67 MPFR_ASSERTD (e == prec); 68 69 /* hard case: first round to prec bits, then check */ 70 mpfr_init2 (x, prec); 71 mpfr_set (x, f, rnd); 72 res = MPFR_GET_EXP (x) == e; 73 mpfr_clear (x); 74 return res; 75 } 76 77 #endif 78