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/* mpq_cmp(u,v) -- Compare U, V. Return postive, zero, or negative
based on if U > V, U == V, or U < V.
Copyright (C) 1991, 1994, 1996 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Library General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
The GNU MP 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 Library General Public
License for more details.
You should have received a copy of the GNU Library General Public License
along with the GNU MP Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
int
#if __STDC__
mpq_cmp (const MP_RAT *op1, const MP_RAT *op2)
#else
mpq_cmp (op1, op2)
const MP_RAT *op1;
const MP_RAT *op2;
#endif
{
mp_size_t num1_size = op1->_mp_num._mp_size;
mp_size_t den1_size = op1->_mp_den._mp_size;
mp_size_t num2_size = op2->_mp_num._mp_size;
mp_size_t den2_size = op2->_mp_den._mp_size;
mp_size_t tmp1_size, tmp2_size;
mp_ptr tmp1_ptr, tmp2_ptr;
mp_size_t num1_sign;
int cc;
TMP_DECL (marker);
if (num1_size == 0)
return -num2_size;
if (num2_size == 0)
return num1_size;
if ((num1_size ^ num2_size) < 0) /* I.e. are the signs different? */
return num1_size;
num1_sign = num1_size;
num1_size = ABS (num1_size);
num2_size = ABS (num2_size);
tmp1_size = num1_size + den2_size;
tmp2_size = num2_size + den1_size;
/* 1. Check to see if we can tell which operand is larger by just looking at
the number of limbs. */
/* NUM1 x DEN2 is either TMP1_SIZE limbs or TMP1_SIZE-1 limbs.
Same for NUM1 x DEN1 with respect to TMP2_SIZE. */
if (tmp1_size > tmp2_size + 1)
/* NUM1 x DEN2 is surely larger in magnitude than NUM2 x DEN1. */
return num1_sign;
if (tmp2_size > tmp1_size + 1)
/* NUM1 x DEN2 is surely smaller in magnitude than NUM2 x DEN1. */
return -num1_sign;
/* 2. Same, but compare the number of significant bits. */
{
int cnt1, cnt2;
unsigned long int bits1, bits2;
count_leading_zeros (cnt1, op1->_mp_num._mp_d[num1_size - 1]);
count_leading_zeros (cnt2, op2->_mp_den._mp_d[den2_size - 1]);
bits1 = tmp1_size * BITS_PER_MP_LIMB - cnt1 - cnt2;
count_leading_zeros (cnt1, op2->_mp_num._mp_d[num2_size - 1]);
count_leading_zeros (cnt2, op1->_mp_den._mp_d[den1_size - 1]);
bits2 = tmp2_size * BITS_PER_MP_LIMB - cnt1 - cnt2;
if (bits1 > bits2 + 1)
return num1_sign;
if (bits2 > bits1 + 1)
return -num1_sign;
}
/* 3. Finally, cross multiply and compare. */
TMP_MARK (marker);
tmp1_ptr = (mp_ptr) TMP_ALLOC (tmp1_size * BYTES_PER_MP_LIMB);
tmp2_ptr = (mp_ptr) TMP_ALLOC (tmp2_size * BYTES_PER_MP_LIMB);
if (num1_size >= den2_size)
tmp1_size -= 0 == mpn_mul (tmp1_ptr,
op1->_mp_num._mp_d, num1_size,
op2->_mp_den._mp_d, den2_size);
else
tmp1_size -= 0 == mpn_mul (tmp1_ptr,
op2->_mp_den._mp_d, den2_size,
op1->_mp_num._mp_d, num1_size);
if (num2_size >= den1_size)
tmp2_size -= 0 == mpn_mul (tmp2_ptr,
op2->_mp_num._mp_d, num2_size,
op1->_mp_den._mp_d, den1_size);
else
tmp2_size -= 0 == mpn_mul (tmp2_ptr,
op1->_mp_den._mp_d, den1_size,
op2->_mp_num._mp_d, num2_size);
cc = tmp1_size - tmp2_size != 0
? tmp1_size - tmp2_size : mpn_cmp (tmp1_ptr, tmp2_ptr, tmp1_size);
TMP_FREE (marker);
return num1_sign < 0 ? -cc : cc;
}
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