1  /* mpz_tdiv_r(rem, dividend, divisor) -- Set REM to DIVIDEND mod DIVISOR.
       2  
       3  Copyright 1991, 1993, 1994, 2000, 2001, 2005, 2012, 2021 Free Software
       4  Foundation, 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 either:
      10  
      11    * the GNU Lesser General Public License as published by the Free
      12      Software Foundation; either version 3 of the License, or (at your
      13      option) any later version.
      14  
      15  or
      16  
      17    * the GNU General Public License as published by the Free Software
      18      Foundation; either version 2 of the License, or (at your option) any
      19      later version.
      20  
      21  or both in parallel, as here.
      22  
      23  The GNU MP Library is distributed in the hope that it will be useful, but
      24  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      25  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      26  for more details.
      27  
      28  You should have received copies of the GNU General Public License and the
      29  GNU Lesser General Public License along with the GNU MP Library.  If not,
      30  see https://www.gnu.org/licenses/.  */
      31  
      32  #include "gmp-impl.h"
      33  #include "longlong.h"
      34  
      35  void
      36  mpz_tdiv_r (mpz_ptr rem, mpz_srcptr num, mpz_srcptr den)
      37  {
      38    mp_size_t ql, n0;
      39    mp_size_t ns, nl, dl;
      40    mp_ptr np, dp, qp, rp;
      41    TMP_DECL;
      42  
      43    ns = SIZ (num);
      44    nl = ABS (ns);
      45    dl = ABSIZ (den);
      46    ql = nl - dl + 1;
      47  
      48    if (UNLIKELY (dl == 0))
      49      DIVIDE_BY_ZERO;
      50  
      51    if (ql <= 0)
      52      {
      53        if (num != rem)
      54  	{
      55  	  SIZ (rem) = ns;
      56  	  rp = MPZ_NEWALLOC (rem, nl);
      57  	  np = PTR (num);
      58  	  MPN_COPY (rp, np, nl);
      59  	}
      60        return;
      61      }
      62  
      63    rp = MPZ_REALLOC (rem, dl);
      64  
      65    TMP_MARK;
      66    qp = TMP_ALLOC_LIMBS (ql);
      67    np = PTR (num);
      68    dp = PTR (den);
      69  
      70    /* FIXME: We should think about how to handle the temporary allocation.
      71       Perhaps mpn_tdiv_qr should handle it, since it anyway often needs to
      72       allocate temp space.  */
      73  
      74    /* Copy denominator to temporary space if it overlaps with the remainder.  */
      75    if (dp == rp)
      76      {
      77        mp_ptr tp;
      78        tp = TMP_ALLOC_LIMBS (dl);
      79        MPN_COPY (tp, dp, dl);
      80        dp = tp;
      81      }
      82    /* Copy numerator to temporary space if it overlaps with the remainder.  */
      83    if (np == rp)
      84      {
      85        mp_ptr tp;
      86        tp = TMP_ALLOC_LIMBS (nl);
      87        MPN_COPY (tp, np, nl);
      88        np = tp;
      89      }
      90  
      91    for (n0 = 0; *dp == 0; ++dp)
      92      {
      93        rp [n0++] = *np++;
      94        --nl;
      95      }
      96    mpn_tdiv_qr (qp, rp + n0, 0L, np, nl, dp, dl - n0);
      97  
      98    MPN_NORMALIZE (rp, dl);
      99  
     100    SIZ (rem) = ns >= 0 ? dl : -dl;
     101    TMP_FREE;
     102  }