186d7f5d3SJohn Marino /* mpf_trunc -- truncate an mpf to an integer.
286d7f5d3SJohn Marino
386d7f5d3SJohn Marino Copyright 2001 Free Software Foundation, Inc.
486d7f5d3SJohn Marino
586d7f5d3SJohn Marino This file is part of the GNU MP Library.
686d7f5d3SJohn Marino
786d7f5d3SJohn Marino The GNU MP Library is free software; you can redistribute it and/or modify
886d7f5d3SJohn Marino it under the terms of the GNU Lesser General Public License as published by
986d7f5d3SJohn Marino the Free Software Foundation; either version 3 of the License, or (at your
1086d7f5d3SJohn Marino option) any later version.
1186d7f5d3SJohn Marino
1286d7f5d3SJohn Marino The GNU MP Library is distributed in the hope that it will be useful, but
1386d7f5d3SJohn Marino WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
1486d7f5d3SJohn Marino or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
1586d7f5d3SJohn Marino License for more details.
1686d7f5d3SJohn Marino
1786d7f5d3SJohn Marino You should have received a copy of the GNU Lesser General Public License
1886d7f5d3SJohn Marino along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
1986d7f5d3SJohn Marino
2086d7f5d3SJohn Marino #include "gmp.h"
2186d7f5d3SJohn Marino #include "gmp-impl.h"
2286d7f5d3SJohn Marino
2386d7f5d3SJohn Marino
2486d7f5d3SJohn Marino /* Notice the use of prec+1 ensures mpf_trunc is equivalent to mpf_set if u
2586d7f5d3SJohn Marino is already an integer. */
2686d7f5d3SJohn Marino
2786d7f5d3SJohn Marino void
mpf_trunc(mpf_ptr r,mpf_srcptr u)2886d7f5d3SJohn Marino mpf_trunc (mpf_ptr r, mpf_srcptr u)
2986d7f5d3SJohn Marino {
3086d7f5d3SJohn Marino mp_ptr rp;
3186d7f5d3SJohn Marino mp_srcptr up;
3286d7f5d3SJohn Marino mp_size_t size, asize, prec;
3386d7f5d3SJohn Marino mp_exp_t exp;
3486d7f5d3SJohn Marino
3586d7f5d3SJohn Marino exp = EXP(u);
3686d7f5d3SJohn Marino size = SIZ(u);
3786d7f5d3SJohn Marino if (size == 0 || exp <= 0)
3886d7f5d3SJohn Marino {
3986d7f5d3SJohn Marino /* u is only a fraction */
4086d7f5d3SJohn Marino SIZ(r) = 0;
4186d7f5d3SJohn Marino EXP(r) = 0;
4286d7f5d3SJohn Marino return;
4386d7f5d3SJohn Marino }
4486d7f5d3SJohn Marino
4586d7f5d3SJohn Marino up = PTR(u);
4686d7f5d3SJohn Marino EXP(r) = exp;
4786d7f5d3SJohn Marino asize = ABS (size);
4886d7f5d3SJohn Marino up += asize;
4986d7f5d3SJohn Marino
5086d7f5d3SJohn Marino /* skip fraction part of u */
5186d7f5d3SJohn Marino asize = MIN (asize, exp);
5286d7f5d3SJohn Marino
5386d7f5d3SJohn Marino /* don't lose precision in the copy */
5486d7f5d3SJohn Marino prec = PREC(r) + 1;
5586d7f5d3SJohn Marino
5686d7f5d3SJohn Marino /* skip excess over target precision */
5786d7f5d3SJohn Marino asize = MIN (asize, prec);
5886d7f5d3SJohn Marino
5986d7f5d3SJohn Marino up -= asize;
6086d7f5d3SJohn Marino rp = PTR(r);
6186d7f5d3SJohn Marino SIZ(r) = (size >= 0 ? asize : -asize);
6286d7f5d3SJohn Marino if (rp != up)
6386d7f5d3SJohn Marino MPN_COPY_INCR (rp, up, asize);
6486d7f5d3SJohn Marino }
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