1*86d7f5d3SJohn Marino /* mpq_div -- divide two rational numbers.
2*86d7f5d3SJohn Marino
3*86d7f5d3SJohn Marino Copyright 1991, 1994, 1995, 1996, 2000, 2001 Free Software Foundation, Inc.
4*86d7f5d3SJohn Marino
5*86d7f5d3SJohn Marino This file is part of the GNU MP Library.
6*86d7f5d3SJohn Marino
7*86d7f5d3SJohn Marino The GNU MP Library is free software; you can redistribute it and/or modify
8*86d7f5d3SJohn Marino it under the terms of the GNU Lesser General Public License as published by
9*86d7f5d3SJohn Marino the Free Software Foundation; either version 3 of the License, or (at your
10*86d7f5d3SJohn Marino option) any later version.
11*86d7f5d3SJohn Marino
12*86d7f5d3SJohn Marino The GNU MP Library is distributed in the hope that it will be useful, but
13*86d7f5d3SJohn Marino WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14*86d7f5d3SJohn Marino or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
15*86d7f5d3SJohn Marino License for more details.
16*86d7f5d3SJohn Marino
17*86d7f5d3SJohn Marino You should have received a copy of the GNU Lesser General Public License
18*86d7f5d3SJohn Marino along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
19*86d7f5d3SJohn Marino
20*86d7f5d3SJohn Marino #include "gmp.h"
21*86d7f5d3SJohn Marino #include "gmp-impl.h"
22*86d7f5d3SJohn Marino
23*86d7f5d3SJohn Marino
24*86d7f5d3SJohn Marino void
mpq_div(mpq_ptr quot,mpq_srcptr op1,mpq_srcptr op2)25*86d7f5d3SJohn Marino mpq_div (mpq_ptr quot, mpq_srcptr op1, mpq_srcptr op2)
26*86d7f5d3SJohn Marino {
27*86d7f5d3SJohn Marino mpz_t gcd1, gcd2;
28*86d7f5d3SJohn Marino mpz_t tmp1, tmp2;
29*86d7f5d3SJohn Marino mpz_t numtmp;
30*86d7f5d3SJohn Marino mp_size_t op1_num_size;
31*86d7f5d3SJohn Marino mp_size_t op1_den_size;
32*86d7f5d3SJohn Marino mp_size_t op2_num_size;
33*86d7f5d3SJohn Marino mp_size_t op2_den_size;
34*86d7f5d3SJohn Marino mp_size_t alloc;
35*86d7f5d3SJohn Marino TMP_DECL;
36*86d7f5d3SJohn Marino
37*86d7f5d3SJohn Marino op1_num_size = ABS (op1->_mp_num._mp_size);
38*86d7f5d3SJohn Marino op1_den_size = op1->_mp_den._mp_size;
39*86d7f5d3SJohn Marino op2_num_size = ABS (op2->_mp_num._mp_size);
40*86d7f5d3SJohn Marino op2_den_size = op2->_mp_den._mp_size;
41*86d7f5d3SJohn Marino
42*86d7f5d3SJohn Marino if (op2_num_size == 0)
43*86d7f5d3SJohn Marino DIVIDE_BY_ZERO;
44*86d7f5d3SJohn Marino
45*86d7f5d3SJohn Marino if (op1_num_size == 0)
46*86d7f5d3SJohn Marino {
47*86d7f5d3SJohn Marino /* We special case this to simplify allocation logic; gcd(0,x) = x
48*86d7f5d3SJohn Marino is a singular case for the allocations. */
49*86d7f5d3SJohn Marino quot->_mp_num._mp_size = 0;
50*86d7f5d3SJohn Marino quot->_mp_den._mp_d[0] = 1;
51*86d7f5d3SJohn Marino quot->_mp_den._mp_size = 1;
52*86d7f5d3SJohn Marino return;
53*86d7f5d3SJohn Marino }
54*86d7f5d3SJohn Marino
55*86d7f5d3SJohn Marino TMP_MARK;
56*86d7f5d3SJohn Marino
57*86d7f5d3SJohn Marino alloc = MIN (op1_num_size, op2_num_size);
58*86d7f5d3SJohn Marino MPZ_TMP_INIT (gcd1, alloc);
59*86d7f5d3SJohn Marino
60*86d7f5d3SJohn Marino alloc = MIN (op1_den_size, op2_den_size);
61*86d7f5d3SJohn Marino MPZ_TMP_INIT (gcd2, alloc);
62*86d7f5d3SJohn Marino
63*86d7f5d3SJohn Marino alloc = MAX (op1_num_size, op2_num_size);
64*86d7f5d3SJohn Marino MPZ_TMP_INIT (tmp1, alloc);
65*86d7f5d3SJohn Marino
66*86d7f5d3SJohn Marino alloc = MAX (op1_den_size, op2_den_size);
67*86d7f5d3SJohn Marino MPZ_TMP_INIT (tmp2, alloc);
68*86d7f5d3SJohn Marino
69*86d7f5d3SJohn Marino alloc = op1_num_size + op2_den_size;
70*86d7f5d3SJohn Marino MPZ_TMP_INIT (numtmp, alloc);
71*86d7f5d3SJohn Marino
72*86d7f5d3SJohn Marino /* QUOT might be identical to either operand, so don't store the result there
73*86d7f5d3SJohn Marino until we are finished with the input operands. We can overwrite the
74*86d7f5d3SJohn Marino numerator of QUOT when we are finished with the numerators of OP1 and
75*86d7f5d3SJohn Marino OP2. */
76*86d7f5d3SJohn Marino
77*86d7f5d3SJohn Marino mpz_gcd (gcd1, &(op1->_mp_num), &(op2->_mp_num));
78*86d7f5d3SJohn Marino mpz_gcd (gcd2, &(op2->_mp_den), &(op1->_mp_den));
79*86d7f5d3SJohn Marino
80*86d7f5d3SJohn Marino mpz_divexact_gcd (tmp1, &(op1->_mp_num), gcd1);
81*86d7f5d3SJohn Marino mpz_divexact_gcd (tmp2, &(op2->_mp_den), gcd2);
82*86d7f5d3SJohn Marino
83*86d7f5d3SJohn Marino mpz_mul (numtmp, tmp1, tmp2);
84*86d7f5d3SJohn Marino
85*86d7f5d3SJohn Marino mpz_divexact_gcd (tmp1, &(op2->_mp_num), gcd1);
86*86d7f5d3SJohn Marino mpz_divexact_gcd (tmp2, &(op1->_mp_den), gcd2);
87*86d7f5d3SJohn Marino
88*86d7f5d3SJohn Marino mpz_mul (&(quot->_mp_den), tmp1, tmp2);
89*86d7f5d3SJohn Marino
90*86d7f5d3SJohn Marino /* We needed to go via NUMTMP to take care of QUOT being the same as OP2.
91*86d7f5d3SJohn Marino Now move NUMTMP to QUOT->_mp_num. */
92*86d7f5d3SJohn Marino mpz_set (&(quot->_mp_num), numtmp);
93*86d7f5d3SJohn Marino
94*86d7f5d3SJohn Marino /* Keep the denominator positive. */
95*86d7f5d3SJohn Marino if (quot->_mp_den._mp_size < 0)
96*86d7f5d3SJohn Marino {
97*86d7f5d3SJohn Marino quot->_mp_den._mp_size = -quot->_mp_den._mp_size;
98*86d7f5d3SJohn Marino quot->_mp_num._mp_size = -quot->_mp_num._mp_size;
99*86d7f5d3SJohn Marino }
100*86d7f5d3SJohn Marino
101*86d7f5d3SJohn Marino TMP_FREE;
102*86d7f5d3SJohn Marino }
103