93 lines
2.6 KiB
C
93 lines
2.6 KiB
C
/* mpq_div -- divide two rational numbers.
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Copyright (C) 1991 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 General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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The GNU MP Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with the GNU MP Library; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, 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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#ifdef __STDC__
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mpq_div (MP_RAT *quot, const MP_RAT *dividend, const MP_RAT *divisor)
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#else
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mpq_div (quot, dividend, divisor)
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MP_RAT *quot;
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const MP_RAT *dividend;
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const MP_RAT *divisor;
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#endif
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{
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MP_INT gcd1, gcd2;
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MP_INT tmp1, tmp2;
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MP_INT numtmp;
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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 DIVIDEND and DIVISOR. */
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mpz_gcd (&gcd1, &(dividend->num), &(divisor->num));
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mpz_gcd (&gcd2, &(divisor->den), &(dividend->den));
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if (gcd1.size > 1 || gcd1.d[0] != 1)
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mpz_div (&tmp1, &(dividend->num), &gcd1);
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else
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mpz_set (&tmp1, &(dividend->num));
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if (gcd2.size > 1 || gcd2.d[0] != 1)
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mpz_div (&tmp2, &(divisor->den), &gcd2);
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else
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mpz_set (&tmp2, &(divisor->den));
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mpz_mul (&numtmp, &tmp1, &tmp2);
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if (gcd1.size > 1 || gcd1.d[0] != 1)
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mpz_div (&tmp1, &(divisor->num), &gcd1);
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else
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mpz_set (&tmp1, &(divisor->num));
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if (gcd2.size > 1 || gcd2.d[0] != 1)
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mpz_div (&tmp2, &(dividend->den), &gcd2);
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else
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mpz_set (&tmp2, &(dividend->den));
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mpz_mul (&(quot->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->NUM. */
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mpz_set (&(quot->num), &numtmp);
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/* Keep the denominator positive. */
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if (quot->den.size < 0)
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{
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quot->den.size = -quot->den.size;
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quot->num.size = -quot->num.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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