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/* mpq_cmp(u,v) -- Compare U, V. Return positive, zero, or negative
based on if U > V, U == V, or U < V.
Copyright 1991, 1994, 1996, 2001, 2002, 2005 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 Lesser General Public License as published
by the Free Software Foundation; either version 3 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 Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library. If not, see https://www.gnu.org/licenses/. */
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
int
mpq_cmp (const mpq_t op1, const mpq_t op2)
{
mp_size_t num1_size = SIZ(NUM(op1));
mp_size_t den1_size = SIZ(DEN(op1));
mp_size_t num2_size = SIZ(NUM(op2));
mp_size_t den2_size = SIZ(DEN(op2));
mp_size_t tmp1_size, tmp2_size;
mp_ptr tmp1_ptr, tmp2_ptr;
mp_size_t num1_sign;
int cc;
TMP_DECL;
/* need canonical signs to get right result */
ASSERT (den1_size > 0);
ASSERT (den2_size > 0);
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;
mp_bitcnt_t bits1, bits2;
count_leading_zeros (cnt1, PTR(NUM(op1))[num1_size - 1]);
count_leading_zeros (cnt2, PTR(DEN(op2))[den2_size - 1]);
bits1 = tmp1_size * GMP_NUMB_BITS - cnt1 - cnt2 + 2 * GMP_NAIL_BITS;
count_leading_zeros (cnt1, PTR(NUM(op2))[num2_size - 1]);
count_leading_zeros (cnt2, PTR(DEN(op1))[den1_size - 1]);
bits2 = tmp2_size * GMP_NUMB_BITS - cnt1 - cnt2 + 2 * GMP_NAIL_BITS;
if (bits1 > bits2 + 1)
return num1_sign;
if (bits2 > bits1 + 1)
return -num1_sign;
}
/* 3. Finally, cross multiply and compare. */
TMP_MARK;
TMP_ALLOC_LIMBS_2 (tmp1_ptr,tmp1_size, tmp2_ptr,tmp2_size);
if (num1_size >= den2_size)
tmp1_size -= 0 == mpn_mul (tmp1_ptr,
PTR(NUM(op1)), num1_size,
PTR(DEN(op2)), den2_size);
else
tmp1_size -= 0 == mpn_mul (tmp1_ptr,
PTR(DEN(op2)), den2_size,
PTR(NUM(op1)), num1_size);
if (num2_size >= den1_size)
tmp2_size -= 0 == mpn_mul (tmp2_ptr,
PTR(NUM(op2)), num2_size,
PTR(DEN(op1)), den1_size);
else
tmp2_size -= 0 == mpn_mul (tmp2_ptr,
PTR(DEN(op1)), den1_size,
PTR(NUM(op2)), num2_size);
cc = tmp1_size - tmp2_size != 0
? tmp1_size - tmp2_size : mpn_cmp (tmp1_ptr, tmp2_ptr, tmp1_size);
TMP_FREE;
return num1_sign < 0 ? -cc : cc;
}
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