1/* mpq_get_str -- mpq to string conversion.
2
3Copyright 2001, 2002, 2006 Free Software Foundation, Inc.
4
5This file is part of the GNU MP Library.
6
7The GNU MP Library is free software; you can redistribute it and/or modify
8it under the terms of the GNU Lesser General Public License as published by
9the Free Software Foundation; either version 3 of the License, or (at your
10option) any later version.
11
12The GNU MP Library is distributed in the hope that it will be useful, but
13WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
15License for more details.
16
17You should have received a copy of the GNU Lesser General Public License
18along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
19
20#include <stdio.h>
21#include <string.h>
22#include "gmp.h"
23#include "gmp-impl.h"
24
25char *
26mpq_get_str (char *str, int base, mpq_srcptr q)
27{
28  size_t  str_alloc, len;
29
30  ASSERT (ABS(base) >= 2);
31  ASSERT (ABS(base) <= 62);
32
33  str_alloc = 0;
34  if (str == NULL)
35    {
36      /* This is an overestimate since we don't bother checking how much of
37         the high limbs of num and den are used.  +2 for rounding up the
38         chars per bit of num and den.  +3 for sign, slash and '\0'.  */
39      str_alloc = ((size_t) ((ABS (q->_mp_num._mp_size) + q->_mp_den._mp_size)
40                             * GMP_LIMB_BITS
41                             * mp_bases[ABS(base)].chars_per_bit_exactly))
42                   + 5;
43      str = (char *) (*__gmp_allocate_func) (str_alloc);
44    }
45
46  mpz_get_str (str, base, mpq_numref(q));
47  len = strlen (str);
48  if (! MPZ_EQUAL_1_P (mpq_denref (q)))
49    {
50      str[len++] = '/';
51      mpz_get_str (str+len, base, mpq_denref(q));
52      len += strlen (str+len);
53    }
54
55  ASSERT (len == strlen(str));
56  ASSERT (str_alloc == 0 || len+1 <= str_alloc);
57  ASSERT (len+1 <=  /* size recommended to applications */
58          mpz_sizeinbase (mpq_numref(q), ABS(base)) +
59          mpz_sizeinbase (mpq_denref(q), ABS(base)) + 3);
60
61  if (str_alloc != 0)
62    __GMP_REALLOCATE_FUNC_MAYBE_TYPE (str, str_alloc, len+1, char);
63
64  return str;
65}
66