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Annotation of OpenXM_contrib/gmp/mpf/trunc.c, Revision 1.1

1.1     ! ohara       1: /* mpf_trunc -- truncate an mpf to an integer.
        !             2:
        !             3: Copyright 2001 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 the GNU Lesser General Public License as published by
        !             9: the Free Software Foundation; either version 2.1 of the License, or (at your
        !            10: option) any later version.
        !            11:
        !            12: The GNU MP Library is distributed in the hope that it will be useful, but
        !            13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
        !            14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
        !            15: License for more details.
        !            16:
        !            17: You should have received a copy of the GNU Lesser General Public License
        !            18: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
        !            19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
        !            20: MA 02111-1307, USA. */
        !            21:
        !            22: #include "gmp.h"
        !            23: #include "gmp-impl.h"
        !            24:
        !            25:
        !            26: /* Notice the use of prec+1 ensures mpf_trunc is equivalent to mpf_set if u
        !            27:    is already an integer.  */
        !            28:
        !            29: void
        !            30: mpf_trunc (mpf_ptr r, mpf_srcptr u)
        !            31: {
        !            32:   mp_ptr     rp;
        !            33:   mp_srcptr  up;
        !            34:   mp_size_t  size, asize, prec;
        !            35:   mp_exp_t   exp;
        !            36:
        !            37:   exp = EXP(u);
        !            38:   size = SIZ(u);
        !            39:   if (size == 0 || exp <= 0)
        !            40:     {
        !            41:       /* u is only a fraction */
        !            42:       SIZ(r) = 0;
        !            43:       EXP(r) = 0;
        !            44:       return;
        !            45:     }
        !            46:
        !            47:   up = PTR(u);
        !            48:   EXP(r) = exp;
        !            49:   asize = ABS (size);
        !            50:   up += asize;
        !            51:
        !            52:   /* skip fraction part of u */
        !            53:   asize = MIN (asize, exp);
        !            54:
        !            55:   /* don't lose precision in the copy */
        !            56:   prec = PREC(r) + 1;
        !            57:
        !            58:   /* skip excess over target precision */
        !            59:   asize = MIN (asize, prec);
        !            60:
        !            61:   up -= asize;
        !            62:   rp = PTR(r);
        !            63:   SIZ(r) = (size >= 0 ? asize : -asize);
        !            64:   if (rp != up)
        !            65:     MPN_COPY_INCR (rp, up, asize);
        !            66: }