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4c74403188
Change-Id: Iae65e95cfa0d92091b8b0a424ae36d88efa76aa9 Reviewed-on: https://review.haiku-os.org/c/buildtools/+/3020 Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>
134 lines
3.2 KiB
C
134 lines
3.2 KiB
C
/* mpq_div -- divide two rational numbers.
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Copyright 1991, 1994-1996, 2000, 2001, 2015, 2018 Free Software
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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 either:
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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or
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* the GNU General Public License as published by the Free Software
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Foundation; either version 2 of the License, or (at your option) any
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later version.
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or both in parallel, as here.
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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 General Public License
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for more details.
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You should have received copies of the GNU General Public License and the
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GNU Lesser General Public License along with the GNU MP Library. If not,
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see https://www.gnu.org/licenses/. */
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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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mp_size_t op1_size;
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mp_size_t op2_size;
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mp_size_t alloc;
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TMP_DECL;
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op2_size = SIZ(NUM(op2));
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if (UNLIKELY (op2_size == 0))
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DIVIDE_BY_ZERO;
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if (UNLIKELY (quot == op2))
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{
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if (UNLIKELY (op1 == op2))
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{
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mpq_set_ui (quot, 1, 1);
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return;
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}
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/* We checked for op1 == op2: we are not in the x=x/x case.
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We compute x=y/x by computing x=inv(x)*y */
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MPN_PTR_SWAP (PTR(NUM(quot)), ALLOC(NUM(quot)),
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PTR(DEN(quot)), ALLOC(DEN(quot)));
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if (op2_size > 0)
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{
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SIZ(NUM(quot)) = SIZ(DEN(quot));
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SIZ(DEN(quot)) = op2_size;
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}
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else
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{
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SIZ(NUM(quot)) = - SIZ(DEN(quot));
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SIZ(DEN(quot)) = - op2_size;
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}
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mpq_mul (quot, quot, op1);
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return;
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}
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op1_size = ABSIZ(NUM(op1));
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if (op1_size == 0)
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{
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/* We special case this to simplify allocation logic; gcd(0,x) = x
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is a singular case for the allocations. */
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SIZ(NUM(quot)) = 0;
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MPZ_NEWALLOC (DEN(quot), 1)[0] = 1;
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SIZ(DEN(quot)) = 1;
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return;
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}
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op2_size = ABS(op2_size);
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TMP_MARK;
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alloc = MIN (op1_size, op2_size);
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MPZ_TMP_INIT (gcd1, alloc);
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alloc = MAX (op1_size, op2_size);
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MPZ_TMP_INIT (tmp1, alloc);
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op2_size = SIZ(DEN(op2));
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op1_size = SIZ(DEN(op1));
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alloc = MIN (op1_size, op2_size);
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MPZ_TMP_INIT (gcd2, alloc);
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alloc = MAX (op1_size, op2_size);
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MPZ_TMP_INIT (tmp2, alloc);
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/* QUOT might be identical to OP1, so don't store the result there
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until we are finished with the input operand. We can overwrite
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the numerator of QUOT when we are finished with the numerator of
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OP1. */
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mpz_gcd (gcd1, NUM(op1), NUM(op2));
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mpz_gcd (gcd2, DEN(op2), DEN(op1));
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mpz_divexact_gcd (tmp1, NUM(op1), gcd1);
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mpz_divexact_gcd (tmp2, DEN(op2), gcd2);
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mpz_mul (NUM(quot), tmp1, tmp2);
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mpz_divexact_gcd (tmp1, NUM(op2), gcd1);
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mpz_divexact_gcd (tmp2, DEN(op1), gcd2);
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mpz_mul (DEN(quot), tmp1, tmp2);
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/* Keep the denominator positive. */
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if (SIZ(DEN(quot)) < 0)
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{
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SIZ(DEN(quot)) = -SIZ(DEN(quot));
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SIZ(NUM(quot)) = -SIZ(NUM(quot));
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}
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TMP_FREE;
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}
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