get_str.c
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上传日期:2022-08-06
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- /* mpq_get_str -- mpq to string conversion.
- Copyright 2001, 2002, 2006 Free Software Foundation, Inc.
- This file is part of the GNU MP Library.
- The GNU MP Library is free software; you can redistribute it and/or modify
- it under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 3 of the License, or (at your
- option) any later version.
- The GNU MP Library is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
- License for more details.
- You should have received a copy of the GNU Lesser General Public License
- along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
- #include <stdio.h>
- #include <string.h>
- #include "gmp.h"
- #include "gmp-impl.h"
- char *
- mpq_get_str (char *str, int base, mpq_srcptr q)
- {
- size_t str_alloc, len;
- ASSERT (ABS(base) >= 2);
- ASSERT (ABS(base) <= 62);
- str_alloc = 0;
- if (str == NULL)
- {
- /* This is an overestimate since we don't bother checking how much of
- the high limbs of num and den are used. +2 for rounding up the
- chars per bit of num and den. +3 for sign, slash and ' '. */
- str_alloc = ((size_t) ((ABS (q->_mp_num._mp_size) + q->_mp_den._mp_size)
- * GMP_LIMB_BITS
- * mp_bases[ABS(base)].chars_per_bit_exactly))
- + 5;
- str = (char *) (*__gmp_allocate_func) (str_alloc);
- }
- mpz_get_str (str, base, mpq_numref(q));
- len = strlen (str);
- if (! MPZ_EQUAL_1_P (mpq_denref (q)))
- {
- str[len++] = '/';
- mpz_get_str (str+len, base, mpq_denref(q));
- len += strlen (str+len);
- }
- ASSERT (len == strlen(str));
- ASSERT (str_alloc == 0 || len+1 <= str_alloc);
- ASSERT (len+1 <= /* size recommended to applications */
- mpz_sizeinbase (mpq_numref(q), ABS(base)) +
- mpz_sizeinbase (mpq_denref(q), ABS(base)) + 3);
- if (str_alloc != 0)
- __GMP_REALLOCATE_FUNC_MAYBE_TYPE (str, str_alloc, len+1, char);
- return str;
- }