77 lines
2.4 KiB
C
77 lines
2.4 KiB
C
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/* mpq_div -- divide two rational numbers.
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Copyright 1991, 1994, 1995, 1996, 2000, 2001 Free Software Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include "gmp.h"
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#include "gmp-impl.h"
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void
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mpq_div (mpq_ptr quot, mpq_srcptr op1, mpq_srcptr op2)
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{
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mpz_t gcd1, gcd2;
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mpz_t tmp1, tmp2;
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mpz_t numtmp;
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if (op2->_mp_num._mp_size == 0)
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DIVIDE_BY_ZERO;
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mpz_init (gcd1);
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mpz_init (gcd2);
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mpz_init (tmp1);
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mpz_init (tmp2);
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mpz_init (numtmp);
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/* QUOT might be identical to either operand, so don't store the
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result there until we are finished with the input operands. We
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dare to overwrite the numerator of QUOT when we are finished
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with the numerators of OP1 and OP2. */
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mpz_gcd (gcd1, &(op1->_mp_num), &(op2->_mp_num));
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mpz_gcd (gcd2, &(op2->_mp_den), &(op1->_mp_den));
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mpz_divexact_gcd (tmp1, &(op1->_mp_num), gcd1);
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mpz_divexact_gcd (tmp2, &(op2->_mp_den), gcd2);
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mpz_mul (numtmp, tmp1, tmp2);
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mpz_divexact_gcd (tmp1, &(op2->_mp_num), gcd1);
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mpz_divexact_gcd (tmp2, &(op1->_mp_den), gcd2);
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mpz_mul (&(quot->_mp_den), tmp1, tmp2);
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/* We needed to go via NUMTMP to take care of QUOT being the same
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as either input operands. Now move NUMTMP to QUOT->_mp_num. */
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mpz_set (&(quot->_mp_num), numtmp);
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/* Keep the denominator positive. */
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if (quot->_mp_den._mp_size < 0)
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{
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quot->_mp_den._mp_size = -quot->_mp_den._mp_size;
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quot->_mp_num._mp_size = -quot->_mp_num._mp_size;
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}
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mpz_clear (numtmp);
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mpz_clear (tmp2);
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mpz_clear (tmp1);
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mpz_clear (gcd2);
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mpz_clear (gcd1);
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}
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