inp_str.c
上传用户:qaz666999
上传日期:2022-08-06
资源大小:2570k
文件大小:4k
- /* mpz_inp_str(dest_integer, stream, base) -- Input a number in base
- BASE from stdio stream STREAM and store the result in DEST_INTEGER.
- OF THE FUNCTIONS IN THIS FILE, ONLY mpz_inp_str IS FOR EXTERNAL USE, THE
- REST ARE INTERNALS AND ARE ALMOST CERTAIN TO BE SUBJECT TO INCOMPATIBLE
- CHANGES OR DISAPPEAR COMPLETELY IN FUTURE GNU MP RELEASES.
- Copyright 1991, 1993, 1994, 1996, 1998, 2000, 2001, 2002, 2003 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 <ctype.h>
- #include "gmp.h"
- #include "gmp-impl.h"
- extern const unsigned char __gmp_digit_value_tab[];
- #define digit_value_tab __gmp_digit_value_tab
- size_t
- mpz_inp_str (mpz_ptr x, FILE *stream, int base)
- {
- int c;
- size_t nread;
- if (stream == 0)
- stream = stdin;
- nread = 0;
- /* Skip whitespace. */
- do
- {
- c = getc (stream);
- nread++;
- }
- while (isspace (c));
- return mpz_inp_str_nowhite (x, stream, base, c, nread);
- }
- /* shared by mpq_inp_str */
- size_t
- mpz_inp_str_nowhite (mpz_ptr x, FILE *stream, int base, int c, size_t nread)
- {
- char *str;
- size_t alloc_size, str_size;
- int negative;
- mp_size_t xsize;
- const unsigned char *digit_value;
- ASSERT_ALWAYS (EOF == -1); /* FIXME: handle this by adding explicit */
- /* comparisons of c and EOF before each */
- /* read of digit_value[]. */
- digit_value = digit_value_tab;
- if (base > 36)
- {
- /* For bases > 36, use the collating sequence
- 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz. */
- digit_value += 224;
- if (base > 62)
- return 0; /* too large base */
- }
- negative = 0;
- if (c == '-')
- {
- negative = 1;
- c = getc (stream);
- nread++;
- }
- if (c == EOF || digit_value[c] >= (base == 0 ? 10 : base))
- return 0; /* error if no digits */
- /* If BASE is 0, try to find out the base by looking at the initial
- characters. */
- if (base == 0)
- {
- base = 10;
- if (c == '0')
- {
- base = 8;
- c = getc (stream);
- nread++;
- if (c == 'x' || c == 'X')
- {
- base = 16;
- c = getc (stream);
- nread++;
- }
- else if (c == 'b' || c == 'B')
- {
- base = 2;
- c = getc (stream);
- nread++;
- }
- }
- }
- /* Skip leading zeros. */
- while (c == '0')
- {
- c = getc (stream);
- nread++;
- }
- alloc_size = 100;
- str = (char *) (*__gmp_allocate_func) (alloc_size);
- str_size = 0;
- while (c != EOF)
- {
- int dig;
- dig = digit_value[c];
- if (dig >= base)
- break;
- if (str_size >= alloc_size)
- {
- size_t old_alloc_size = alloc_size;
- alloc_size = alloc_size * 3 / 2;
- str = (char *) (*__gmp_reallocate_func) (str, old_alloc_size, alloc_size);
- }
- str[str_size++] = dig;
- c = getc (stream);
- }
- nread += str_size;
- ungetc (c, stream);
- nread--;
- /* Make sure the string is not empty, mpn_set_str would fail. */
- if (str_size == 0)
- {
- x->_mp_size = 0;
- }
- else
- {
- xsize = 2 + (mp_size_t)
- (str_size / (GMP_NUMB_BITS * mp_bases[base].chars_per_bit_exactly));
- MPZ_REALLOC (x, xsize);
- /* Convert the byte array in base BASE to our bignum format. */
- xsize = mpn_set_str (x->_mp_d, (unsigned char *) str, str_size, base);
- x->_mp_size = negative ? -xsize : xsize;
- }
- (*__gmp_free_func) (str, alloc_size);
- return nread;
- }