source/libs/gmp/gmp-src/mpz/tdiv_qr.c

   1 /* mpz_tdiv_qr(quot,rem,dividend,divisor) -- Set QUOT to DIVIDEND/DIVISOR,
   2    and REM to DIVIDEND mod DIVISOR.
   3
   4 Copyright 1991, 1993, 1994, 2000, 2001, 2005, 2011, 2012 Free Software
   5 Foundation, Inc.
   6
   7 This file is part of the GNU MP Library.
   8
   9 The GNU MP Library is free software; you can redistribute it and/or modify
  10 it under the terms of either:
  11
  12   * the GNU Lesser General Public License as published by the Free
  13     Software Foundation; either version 3 of the License, or (at your
  14     option) any later version.
  15
  16 or
  17
  18   * the GNU General Public License as published by the Free Software
  19     Foundation; either version 2 of the License, or (at your option) any
  20     later version.
  21
  22 or both in parallel, as here.
  23
  24 The GNU MP Library is distributed in the hope that it will be useful, but
  25 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  26 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  27 for more details.
  28
  29 You should have received copies of the GNU General Public License and the
  30 GNU Lesser General Public License along with the GNU MP Library.  If not,
  31 see https://www.gnu.org/licenses/.  */
  32
  33 #include "gmp.h"
  34 #include "gmp-impl.h"
  35 #include "longlong.h"
  36
  37 void
  38 mpz_tdiv_qr (mpz_ptr quot, mpz_ptr rem, mpz_srcptr num, mpz_srcptr den)
  39 {
  40   mp_size_t ql;
  41   mp_size_t ns, ds, nl, dl;
  42   mp_ptr np, dp, qp, rp;
  43   TMP_DECL;
  44
  45   ns = SIZ (num);
  46   ds = SIZ (den);
  47   nl = ABS (ns);
  48   dl = ABS (ds);
  49   ql = nl - dl + 1;
  50
  51   if (UNLIKELY (dl == 0))
  52     DIVIDE_BY_ZERO;
  53
  54   rp = MPZ_REALLOC (rem, dl);
  55
  56   if (ql <= 0)
  57     {
  58       if (num != rem)
  59         {
  60           np = PTR (num);
  61           MPN_COPY (rp, np, nl);
  62           SIZ (rem) = SIZ (num);
  63         }
  64       /* This needs to follow the assignment to rem, in case the
  65          numerator and quotient are the same.  */
  66       SIZ (quot) = 0;
  67       return;
  68     }
  69
  70   qp = MPZ_REALLOC (quot, ql);
  71
  72   TMP_MARK;
  73   np = PTR (num);
  74   dp = PTR (den);
  75
  76   /* FIXME: We should think about how to handle the temporary allocation.
  77      Perhaps mpn_tdiv_qr should handle it, since it anyway often needs to
  78      allocate temp space.  */
  79
  80   /* Copy denominator to temporary space if it overlaps with the quotient
  81      or remainder.  */
  82   if (dp == rp || dp == qp)
  83     {
  84       mp_ptr tp;
  85       tp = TMP_ALLOC_LIMBS (dl);
  86       MPN_COPY (tp, dp, dl);
  87       dp = tp;
  88     }
  89   /* Copy numerator to temporary space if it overlaps with the quotient or
  90      remainder.  */
  91   if (np == rp || np == qp)
  92     {
  93       mp_ptr tp;
  94       tp = TMP_ALLOC_LIMBS (nl);
  95       MPN_COPY (tp, np, nl);
  96       np = tp;
  97     }
  98
  99   mpn_tdiv_qr (qp, rp, 0L, np, nl, dp, dl);
 100
 101   ql -=  qp[ql - 1] == 0;
 102   MPN_NORMALIZE (rp, dl);
 103
 104   SIZ (quot) = (ns ^ ds) >= 0 ? ql : -ql;
 105   SIZ (rem) = ns >= 0 ? dl : -dl;
 106   TMP_FREE;
 107 }