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, 2021 Free
       5  Software 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-impl.h"
      34  #include "longlong.h"
      35  
      36  void
      37  mpz_tdiv_qr (mpz_ptr quot, mpz_ptr rem, mpz_srcptr num, mpz_srcptr den)
      38  {
      39    mp_size_t ql, n0;
      40    mp_size_t ns, ds, nl, dl;
      41    mp_ptr np, dp, qp, rp;
      42    TMP_DECL;
      43  
      44    ns = SIZ (num);
      45    ds = SIZ (den);
      46    nl = ABS (ns);
      47    dl = ABS (ds);
      48    ql = nl - dl + 1;
      49  
      50    if (UNLIKELY (dl == 0))
      51      DIVIDE_BY_ZERO;
      52  
      53    rp = MPZ_REALLOC (rem, dl);
      54  
      55    if (ql <= 0)
      56      {
      57        if (num != rem)
      58  	{
      59  	  np = PTR (num);
      60  	  MPN_COPY (rp, np, nl);
      61  	  SIZ (rem) = SIZ (num);
      62  	}
      63        /* This needs to follow the assignment to rem, in case the
      64  	 numerator and quotient are the same.  */
      65        SIZ (quot) = 0;
      66        return;
      67      }
      68  
      69    qp = MPZ_REALLOC (quot, ql);
      70  
      71    TMP_MARK;
      72    np = PTR (num);
      73    dp = PTR (den);
      74  
      75    /* FIXME: We should think about how to handle the temporary allocation.
      76       Perhaps mpn_tdiv_qr should handle it, since it anyway often needs to
      77       allocate temp space.  */
      78  
      79    /* Copy denominator to temporary space if it overlaps with the quotient
      80       or remainder.  */
      81    if (dp == rp || dp == qp)
      82      {
      83        mp_ptr tp;
      84        tp = TMP_ALLOC_LIMBS (dl);
      85        MPN_COPY (tp, dp, dl);
      86        dp = tp;
      87      }
      88    /* Copy numerator to temporary space if it overlaps with the quotient or
      89       remainder.  */
      90    if (np == rp || np == qp)
      91      {
      92        mp_ptr tp;
      93        tp = TMP_ALLOC_LIMBS (nl);
      94        MPN_COPY (tp, np, nl);
      95        np = tp;
      96      }
      97  
      98    for (n0 = 0; *dp == 0; ++dp)
      99      {
     100        rp [n0++] = *np++;
     101        --nl;
     102      }
     103    mpn_tdiv_qr (qp, rp + n0, 0L, np, nl, dp, dl - n0);
     104  
     105    ql -=  qp[ql - 1] == 0;
     106    MPN_NORMALIZE (rp, dl);
     107  
     108    SIZ (quot) = (ns ^ ds) >= 0 ? ql : -ql;
     109    SIZ (rem) = ns >= 0 ? dl : -dl;
     110    TMP_FREE;
     111  }