| /* mpfr_fits_intmax_p -- test whether an mpfr fits an intmax_t. |
| |
| Copyright 2004, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc. |
| Contributed by the AriC and Caramel projects, INRIA. |
| |
| This file is part of the GNU MPFR Library. |
| |
| The GNU MPFR Library is free software; you can redistribute it and/or modify |
| it under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or (at your |
| option) any later version. |
| |
| The GNU MPFR Library is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
| License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see |
| http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., |
| 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */ |
| |
| #ifdef HAVE_CONFIG_H |
| # include "config.h" /* for a build within gmp */ |
| #endif |
| |
| #include "mpfr-intmax.h" |
| #include "mpfr-impl.h" |
| |
| #ifdef _MPFR_H_HAVE_INTMAX_T |
| |
| /* We can't use fits_s.h <= mpfr_cmp_ui */ |
| int |
| mpfr_fits_intmax_p (mpfr_srcptr f, mpfr_rnd_t rnd) |
| { |
| mpfr_exp_t e; |
| int prec; |
| mpfr_t x, y; |
| int neg; |
| int res; |
| |
| if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (f))) |
| /* Zero always fit */ |
| return MPFR_IS_ZERO (f) ? 1 : 0; |
| |
| /* now it fits if either |
| (a) MINIMUM <= f <= MAXIMUM |
| (b) or MINIMUM <= round(f, prec(slong), rnd) <= MAXIMUM */ |
| |
| e = MPFR_EXP (f); |
| if (e < 1) |
| return 1; /* |f| < 1: always fits */ |
| |
| neg = MPFR_IS_NEG (f); |
| |
| /* let EXTREMUM be MAXIMUM if f > 0, and MINIMUM if f < 0 */ |
| |
| /* first compute prec(EXTREMUM), this could be done at configure time, |
| but the result can depend on neg (the loop is moved inside the "if" |
| to give the compiler a better chance to compute prec statically) */ |
| if (neg) |
| { |
| uintmax_t s; |
| /* In C89, the division on negative integers isn't well-defined. */ |
| s = SAFE_ABS (uintmax_t, MPFR_INTMAX_MIN); |
| for (prec = 0; s != 0; s /= 2, prec ++); |
| } |
| else |
| { |
| intmax_t s; |
| s = MPFR_INTMAX_MAX; |
| for (prec = 0; s != 0; s /= 2, prec ++); |
| } |
| |
| /* EXTREMUM needs prec bits, i.e. 2^(prec-1) <= |EXTREMUM| < 2^prec */ |
| |
| /* if e <= prec - 1, then f < 2^(prec-1) <= |EXTREMUM| */ |
| if (e <= prec - 1) |
| return 1; |
| |
| /* if e >= prec + 1, then f >= 2^prec > |EXTREMUM| */ |
| if (e >= prec + 1) |
| return 0; |
| |
| MPFR_ASSERTD (e == prec); |
| |
| /* hard case: first round to prec bits, then check */ |
| mpfr_init2 (x, prec); |
| mpfr_set (x, f, rnd); |
| |
| if (neg) |
| { |
| mpfr_init2 (y, prec); |
| mpfr_set_sj (y, MPFR_INTMAX_MIN, MPFR_RNDN); |
| res = mpfr_cmp (x, y) >= 0; |
| mpfr_clear (y); |
| } |
| else |
| { |
| res = MPFR_GET_EXP (x) == e; |
| } |
| |
| mpfr_clear (x); |
| return res; |
| } |
| |
| #endif |