cmp_ui.c
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上传日期:2022-08-06
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- /* mpq_cmp_ui(u,vn,vd) -- Compare U with Vn/Vd. Return positive, zero, or
- negative based on if U > V, U == V, or U < V. Vn and Vd may have
- common factors.
- Copyright 1993, 1994, 1996, 2000, 2001, 2002, 2003, 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 http://www.gnu.org/licenses/. */
- #include "gmp.h"
- #include "gmp-impl.h"
- int
- _mpq_cmp_ui (const MP_RAT *op1, unsigned long int num2, unsigned long int den2)
- {
- mp_size_t num1_size = op1->_mp_num._mp_size;
- mp_size_t den1_size = op1->_mp_den._mp_size;
- mp_size_t tmp1_size, tmp2_size;
- mp_ptr tmp1_ptr, tmp2_ptr;
- mp_limb_t cy_limb;
- int cc;
- TMP_DECL;
- #if GMP_NAIL_BITS != 0
- if ((num2 | den2) > GMP_NUMB_MAX)
- {
- mpq_t op2;
- mpq_init (op2);
- mpz_set_ui (mpq_numref (op2), num2);
- mpz_set_ui (mpq_denref (op2), den2);
- cc = mpq_cmp (op1, op2);
- mpq_clear (op2);
- return cc;
- }
- #endif
- /* need canonical sign to get right result */
- ASSERT (den1_size > 0);
- if (den2 == 0)
- DIVIDE_BY_ZERO;
- if (num1_size == 0)
- return -(num2 != 0);
- if (num1_size < 0)
- return num1_size;
- if (num2 == 0)
- return num1_size;
- /* NUM1 x DEN2 is either TMP1_SIZE limbs or TMP1_SIZE-1 limbs.
- Same for NUM1 x DEN1 with respect to TMP2_SIZE. */
- if (num1_size > den1_size + 1)
- /* NUM1 x DEN2 is surely larger in magnitude than NUM2 x DEN1. */
- return num1_size;
- if (den1_size > num1_size + 1)
- /* NUM1 x DEN2 is surely smaller in magnitude than NUM2 x DEN1. */
- return -num1_size;
- TMP_MARK;
- tmp1_ptr = TMP_ALLOC_LIMBS (num1_size + 1);
- tmp2_ptr = TMP_ALLOC_LIMBS (den1_size + 1);
- cy_limb = mpn_mul_1 (tmp1_ptr, op1->_mp_num._mp_d, num1_size,
- (mp_limb_t) den2);
- tmp1_ptr[num1_size] = cy_limb;
- tmp1_size = num1_size + (cy_limb != 0);
- cy_limb = mpn_mul_1 (tmp2_ptr, op1->_mp_den._mp_d, den1_size,
- (mp_limb_t) num2);
- tmp2_ptr[den1_size] = cy_limb;
- tmp2_size = den1_size + (cy_limb != 0);
- cc = tmp1_size - tmp2_size != 0
- ? tmp1_size - tmp2_size : mpn_cmp (tmp1_ptr, tmp2_ptr, tmp1_size);
- TMP_FREE;
- return cc;
- }