mpir/mpz/tdiv_q.c
2014-02-26 18:31:48 +00:00

87 lines
2.1 KiB
C

/* mpz_tdiv_q -- divide two integers and produce a quotient.
Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2005 Free Software Foundation,
Inc.
Copyright 2009, William Hart
This file is part of the MPIR Library.
The MPIR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.
The MPIR Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the MPIR Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA. */
#include "mpir.h"
#include "gmp-impl.h"
#include "longlong.h"
void
mpz_tdiv_q (mpz_ptr quot, mpz_srcptr num, mpz_srcptr den)
{
mp_size_t ql;
mp_size_t ns, ds, nl, dl;
mp_ptr np, dp, qp;
TMP_DECL;
ns = SIZ (num);
ds = SIZ (den);
nl = ABS (ns);
dl = ABS (ds);
ql = nl - dl + 1;
if (dl == 0)
DIVIDE_BY_ZERO;
if (ql <= 0)
{
SIZ (quot) = 0;
return;
}
MPZ_REALLOC (quot, ql);
TMP_MARK;
qp = PTR (quot);
np = PTR (num);
dp = PTR (den);
/* FIXME: We should think about how to handle the temporary allocation.
Perhaps mpn_tdiv_qr should handle it, since it anyway often needs to
allocate temp space. */
/* Copy denominator to temporary space if it overlaps with the quotient. */
if (dp == qp)
{
mp_ptr tp;
tp = (mp_ptr) TMP_ALLOC (dl * BYTES_PER_MP_LIMB);
MPN_COPY (tp, dp, dl);
dp = tp;
}
/* Copy numerator to temporary space if it overlaps with the quotient. */
if (np == qp)
{
mp_ptr tp;
tp = (mp_ptr) TMP_ALLOC (nl * BYTES_PER_MP_LIMB);
MPN_COPY (tp, np, nl);
np = tp;
}
mpn_tdiv_q (qp, np, nl, dp, dl);
ql -= qp[ql - 1] == 0;
SIZ (quot) = (ns ^ ds) >= 0 ? ql : -ql;
TMP_FREE;
}