source/libs/gmp/gmp-src/mpz/inp_str.c

   1 /* mpz_inp_str(dest_integer, stream, base) -- Input a number in base
   2    BASE from stdio stream STREAM and store the result in DEST_INTEGER.
   3
   4    OF THE FUNCTIONS IN THIS FILE, ONLY mpz_inp_str IS FOR EXTERNAL USE, THE
   5    REST ARE INTERNALS AND ARE ALMOST CERTAIN TO BE SUBJECT TO INCOMPATIBLE
   6    CHANGES OR DISAPPEAR COMPLETELY IN FUTURE GNU MP RELEASES.
   7
   8 Copyright 1991, 1993, 1994, 1996, 1998, 2000-2003, 2011-2013 Free Software
   9 Foundation, Inc.
  10
  11 This file is part of the GNU MP Library.
  12
  13 The GNU MP Library is free software; you can redistribute it and/or modify
  14 it under the terms of either:
  15
  16   * the GNU Lesser General Public License as published by the Free
  17     Software Foundation; either version 3 of the License, or (at your
  18     option) any later version.
  19
  20 or
  21
  22   * the GNU General Public License as published by the Free Software
  23     Foundation; either version 2 of the License, or (at your option) any
  24     later version.
  25
  26 or both in parallel, as here.
  27
  28 The GNU MP Library is distributed in the hope that it will be useful, but
  29 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  30 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  31 for more details.
  32
  33 You should have received copies of the GNU General Public License and the
  34 GNU Lesser General Public License along with the GNU MP Library.  If not,
  35 see https://www.gnu.org/licenses/.  */
  36
  37 #include <stdio.h>
  38 #include <ctype.h>
  39 #include "gmp.h"
  40 #include "gmp-impl.h"
  41 #include "longlong.h"
  42
  43 #define digit_value_tab __gmp_digit_value_tab
  44
  45 size_t
  46 mpz_inp_str (mpz_ptr x, FILE *stream, int base)
  47 {
  48   int c;
  49   size_t nread;
  50
  51   if (stream == 0)
  52     stream = stdin;
  53
  54   nread = 0;
  55
  56   /* Skip whitespace.  */
  57   do
  58     {
  59       c = getc (stream);
  60       nread++;
  61     }
  62   while (isspace (c));
  63
  64   return mpz_inp_str_nowhite (x, stream, base, c, nread);
  65 }
  66
  67 /* shared by mpq_inp_str */
  68 size_t
  69 mpz_inp_str_nowhite (mpz_ptr x, FILE *stream, int base, int c, size_t nread)
  70 {
  71   char *str;
  72   size_t alloc_size, str_size;
  73   int negative;
  74   mp_size_t xsize;
  75   const unsigned char *digit_value;
  76
  77   ASSERT_ALWAYS (EOF == -1);    /* FIXME: handle this by adding explicit */
  78                                 /* comparisons of c and EOF before each  */
  79                                 /* read of digit_value[].  */
  80
  81   digit_value = digit_value_tab;
  82   if (base > 36)
  83     {
  84       /* For bases > 36, use the collating sequence
  85          0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz.  */
  86       digit_value += 208;
  87       if (base > 62)
  88         return 0;               /* too large base */
  89     }
  90
  91   negative = 0;
  92   if (c == '-')
  93     {
  94       negative = 1;
  95       c = getc (stream);
  96       nread++;
  97     }
  98
  99   if (c == EOF || digit_value[c] >= (base == 0 ? 10 : base))
 100     return 0;                   /* error if no digits */
 101
 102   /* If BASE is 0, try to find out the base by looking at the initial
 103      characters.  */
 104   if (base == 0)
 105     {
 106       base = 10;
 107       if (c == '0')
 108         {
 109           base = 8;
 110           c = getc (stream);
 111           nread++;
 112           if (c == 'x' || c == 'X')
 113             {
 114               base = 16;
 115               c = getc (stream);
 116               nread++;
 117             }
 118           else if (c == 'b' || c == 'B')
 119             {
 120               base = 2;
 121               c = getc (stream);
 122               nread++;
 123             }
 124         }
 125     }
 126
 127   /* Skip leading zeros.  */
 128   while (c == '0')
 129     {
 130       c = getc (stream);
 131       nread++;
 132     }
 133
 134   alloc_size = 100;
 135   str = (char *) (*__gmp_allocate_func) (alloc_size);
 136   str_size = 0;
 137
 138   while (c != EOF)
 139     {
 140       int dig;
 141       dig = digit_value[c];
 142       if (dig >= base)
 143         break;
 144       if (str_size >= alloc_size)
 145         {
 146           size_t old_alloc_size = alloc_size;
 147           alloc_size = alloc_size * 3 / 2;
 148           str = (char *) (*__gmp_reallocate_func) (str, old_alloc_size, alloc_size);
 149         }
 150       str[str_size++] = dig;
 151       c = getc (stream);
 152     }
 153   nread += str_size;
 154
 155   ungetc (c, stream);
 156   nread--;
 157
 158   /* Make sure the string is not empty, mpn_set_str would fail.  */
 159   if (str_size == 0)
 160     {
 161       SIZ (x) = 0;
 162     }
 163   else
 164     {
 165       LIMBS_PER_DIGIT_IN_BASE (xsize, str_size, base);
 166       MPZ_REALLOC (x, xsize);
 167
 168       /* Convert the byte array in base BASE to our bignum format.  */
 169       xsize = mpn_set_str (PTR (x), (unsigned char *) str, str_size, base);
 170       SIZ (x) = negative ? -xsize : xsize;
 171     }
 172   (*__gmp_free_func) (str, alloc_size);
 173   return nread;
 174 }