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Annotation of OpenXM_contrib/gmp/mpf/trunc.c, Revision 1.1.1.1

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: }