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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>
103 lines
2.8 KiB
C
103 lines
2.8 KiB
C
/* mpq_mul -- multiply two rational numbers.
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Copyright 1991, 1994-1996, 2000-2002 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 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_mul (mpq_ptr prod, 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_num_size;
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mp_size_t op1_den_size;
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mp_size_t op2_num_size;
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mp_size_t op2_den_size;
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mp_size_t alloc;
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TMP_DECL;
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if (op1 == op2)
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{
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/* No need for any GCDs when squaring. */
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mpz_mul (mpq_numref (prod), mpq_numref (op1), mpq_numref (op1));
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mpz_mul (mpq_denref (prod), mpq_denref (op1), mpq_denref (op1));
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return;
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}
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op1_num_size = ABSIZ(NUM(op1));
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op1_den_size = SIZ(DEN(op1));
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op2_num_size = ABSIZ(NUM(op2));
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op2_den_size = SIZ(DEN(op2));
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if (op1_num_size == 0 || op2_num_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(prod)) = 0;
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MPZ_NEWALLOC (DEN(prod), 1)[0] = 1;
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SIZ(DEN(prod)) = 1;
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return;
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}
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TMP_MARK;
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alloc = MIN (op1_num_size, op2_den_size);
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MPZ_TMP_INIT (gcd1, alloc);
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alloc = MIN (op2_num_size, op1_den_size);
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MPZ_TMP_INIT (gcd2, alloc);
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alloc = MAX (op1_num_size, op2_den_size);
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MPZ_TMP_INIT (tmp1, alloc);
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alloc = MAX (op2_num_size, op1_den_size);
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MPZ_TMP_INIT (tmp2, alloc);
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/* PROD might be identical to either operand, so don't store the result there
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until we are finished with the input operands. We can overwrite the
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numerator of PROD when we are finished with the numerators of OP1 and
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OP2. */
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mpz_gcd (gcd1, NUM(op1), DEN(op2));
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mpz_gcd (gcd2, NUM(op2), DEN(op1));
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mpz_divexact_gcd (tmp1, NUM(op1), gcd1);
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mpz_divexact_gcd (tmp2, NUM(op2), gcd2);
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mpz_mul (NUM(prod), tmp1, tmp2);
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mpz_divexact_gcd (tmp1, DEN(op2), gcd1);
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mpz_divexact_gcd (tmp2, DEN(op1), gcd2);
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mpz_mul (DEN(prod), tmp1, tmp2);
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TMP_FREE;
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}
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