1/* mpf_ceil, mpf_floor -- round an mpf to an integer. 2 3Copyright 2001, 2004, 2012 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 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 14or 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 20or both in parallel, as here. 21 22The GNU MP Library is distributed in the hope that it will be useful, but 23WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 24or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 25for more details. 26 27You should have received copies of the GNU General Public License and the 28GNU Lesser General Public License along with the GNU MP Library. If not, 29see https://www.gnu.org/licenses/. */ 30 31#include "gmp-impl.h" 32 33 34/* dir==1 for ceil, dir==-1 for floor 35 36 Notice the use of prec+1 ensures mpf_ceil and mpf_floor are equivalent to 37 mpf_set if u is already an integer. */ 38 39static void __gmpf_ceil_or_floor (REGPARM_2_1 (mpf_ptr, mpf_srcptr, int)) REGPARM_ATTR (1); 40#define mpf_ceil_or_floor(r,u,dir) __gmpf_ceil_or_floor (REGPARM_2_1 (r, u, dir)) 41 42REGPARM_ATTR (1) static void 43mpf_ceil_or_floor (mpf_ptr r, mpf_srcptr u, int dir) 44{ 45 mp_ptr rp, up, p; 46 mp_size_t size, asize, prec; 47 mp_exp_t exp; 48 49 size = SIZ(u); 50 if (size == 0) 51 { 52 zero: 53 SIZ(r) = 0; 54 EXP(r) = 0; 55 return; 56 } 57 58 rp = PTR(r); 59 exp = EXP(u); 60 if (exp <= 0) 61 { 62 /* u is only a fraction */ 63 if ((size ^ dir) < 0) 64 goto zero; 65 rp[0] = 1; 66 EXP(r) = 1; 67 SIZ(r) = dir; 68 return; 69 } 70 EXP(r) = exp; 71 72 up = PTR(u); 73 asize = ABS (size); 74 up += asize; 75 76 /* skip fraction part of u */ 77 asize = MIN (asize, exp); 78 79 /* don't lose precision in the copy */ 80 prec = PREC (r) + 1; 81 82 /* skip excess over target precision */ 83 asize = MIN (asize, prec); 84 85 up -= asize; 86 87 if ((size ^ dir) >= 0) 88 { 89 /* rounding direction matches sign, must increment if ignored part is 90 non-zero */ 91 for (p = PTR(u); p != up; p++) 92 { 93 if (*p != 0) 94 { 95 if (mpn_add_1 (rp, up, asize, CNST_LIMB(1))) 96 { 97 /* was all 0xFF..FFs, which have become zeros, giving just 98 a carry */ 99 rp[0] = 1; 100 asize = 1; 101 EXP(r)++; 102 } 103 SIZ(r) = (size >= 0 ? asize : -asize); 104 return; 105 } 106 } 107 } 108 109 SIZ(r) = (size >= 0 ? asize : -asize); 110 if (rp != up) 111 MPN_COPY_INCR (rp, up, asize); 112} 113 114 115void 116mpf_ceil (mpf_ptr r, mpf_srcptr u) 117{ 118 mpf_ceil_or_floor (r, u, 1); 119} 120 121void 122mpf_floor (mpf_ptr r, mpf_srcptr u) 123{ 124 mpf_ceil_or_floor (r, u, -1); 125} 126