contrib/gmp/mpz/tdiv_q.c

   1 /* mpz_tdiv_q -- divide two integers and produce a quotient.
   2
   3 Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2005, 2010 Free Software Foundation,
   4 Inc.
   5
   6 This file is part of the GNU MP Library.
   7
   8 The GNU MP Library is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU Lesser General Public License as published by
  10 the Free Software Foundation; either version 3 of the License, or (at your
  11 option) any later version.
  12
  13 The GNU MP Library is distributed in the hope that it will be useful, but
  14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  16 License for more details.
  17
  18 You should have received a copy of the GNU Lesser General Public License
  19 along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
  20
  21 #include "gmp.h"
  22 #include "gmp-impl.h"
  23 #include "longlong.h"
  24
  25 void
  26 mpz_tdiv_q (mpz_ptr quot, mpz_srcptr num, mpz_srcptr den)
  27 {
  28   mp_size_t ql;
  29   mp_size_t ns, ds, nl, dl;
  30   mp_ptr np, dp, qp;
  31   TMP_DECL;
  32
  33   ns = SIZ (num);
  34   ds = SIZ (den);
  35   nl = ABS (ns);
  36   dl = ABS (ds);
  37   ql = nl - dl + 1;
  38
  39   if (dl == 0)
  40     DIVIDE_BY_ZERO;
  41
  42   if (ql <= 0)
  43     {
  44       SIZ (quot) = 0;
  45       return;
  46     }
  47
  48   MPZ_REALLOC (quot, ql);
  49
  50   TMP_MARK;
  51   qp = PTR (quot);
  52   np = PTR (num);
  53   dp = PTR (den);
  54
  55   /* Copy denominator to temporary space if it overlaps with the quotient.  */
  56   if (dp == qp)
  57     {
  58       mp_ptr tp;
  59       tp = TMP_ALLOC_LIMBS (dl);
  60       MPN_COPY (tp, dp, dl);
  61       dp = tp;
  62     }
  63   /* Copy numerator to temporary space if it overlaps with the quotient.  */
  64   if (np == qp)
  65     {
  66       mp_ptr tp;
  67       tp = TMP_ALLOC_LIMBS (nl + 1);
  68       MPN_COPY (tp, np, nl);
  69       /* Overlap dividend and scratch.  */
  70       mpn_div_q (qp, tp, nl, dp, dl, tp);
  71     }
  72   else
  73     {
  74       mp_ptr tp;
  75       tp = TMP_ALLOC_LIMBS (nl + 1);
  76       mpn_div_q (qp, np, nl, dp, dl, tp);
  77     }
  78
  79   ql -=  qp[ql - 1] == 0;
  80
  81   SIZ (quot) = (ns ^ ds) >= 0 ? ql : -ql;
  82   TMP_FREE;
  83 }