get_str.c
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上传日期:2022-08-06
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- /* mpz_get_str (string, base, mp_src) -- Convert the multiple precision
- number MP_SRC to a string STRING of base BASE. If STRING is NULL
- allocate space for the result. In any case, return a pointer to the
- result. If STRING is not NULL, the caller must ensure enough space is
- available to store the result.
- Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2002, 2005 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 <string.h> /* for strlen */
- #include "gmp.h"
- #include "gmp-impl.h"
- #include "longlong.h"
- char *
- mpz_get_str (char *res_str, int base, mpz_srcptr x)
- {
- mp_ptr xp;
- mp_size_t x_size = x->_mp_size;
- char *str;
- char *return_str;
- size_t str_size;
- size_t alloc_size = 0;
- char *num_to_text;
- int i;
- TMP_DECL;
- if (base >= 0)
- {
- num_to_text = "0123456789abcdefghijklmnopqrstuvwxyz";
- if (base == 0)
- base = 10;
- else if (base > 36)
- {
- num_to_text = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
- if (base > 62)
- return NULL;
- }
- }
- else
- {
- base = -base;
- num_to_text = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
- }
- /* allocate string for the user if necessary */
- if (res_str == NULL)
- {
- /* digits, null terminator, possible minus sign */
- MPN_SIZEINBASE (alloc_size, PTR(x), ABS(x_size), base);
- alloc_size += 1 + (x_size<0);
- res_str = (char *) (*__gmp_allocate_func) (alloc_size);
- }
- return_str = res_str;
- if (x_size < 0)
- {
- *res_str++ = '-';
- x_size = -x_size;
- }
- /* mpn_get_str clobbers its input on non power-of-2 bases */
- TMP_MARK;
- xp = x->_mp_d;
- if (! POW2_P (base))
- {
- xp = TMP_ALLOC_LIMBS (x_size + 1); /* +1 in case x_size==0 */
- MPN_COPY (xp, x->_mp_d, x_size);
- }
- str_size = mpn_get_str ((unsigned char *) res_str, base, xp, x_size);
- ASSERT (alloc_size == 0 || str_size <= alloc_size - (SIZ(x) < 0));
- /* might have a leading zero, skip it */
- str = res_str;
- if (*res_str == 0 && str_size != 1)
- {
- str_size--;
- str++;
- ASSERT (*str != 0); /* at most one leading zero */
- }
- /* Convert result to printable chars, and move down if there was a leading
- zero. */
- for (i = 0; i < str_size; i++)
- res_str[i] = num_to_text[(int) str[i]];
- res_str[str_size] = 0;
- TMP_FREE;
- /* if allocated then resize down to the actual space required */
- if (alloc_size != 0)
- {
- size_t actual_size = str_size + 1 + (res_str - return_str);
- ASSERT (actual_size == strlen (return_str) + 1);
- __GMP_REALLOCATE_FUNC_MAYBE_TYPE (return_str, alloc_size, actual_size,
- char);
- }
- return return_str;
- }