contrib/gmp/mpz/set_str.c

   1 /* mpz_set_str(mp_dest, string, base) -- Convert the \0-terminated
   2    string STRING in base BASE to multiple precision integer in
   3    MP_DEST.  Allow white space in the string.  If BASE == 0 determine
   4    the base in the C standard way, i.e.  0xhh...h means base 16,
   5    0oo...o means base 8, otherwise assume base 10.
   6
   7 Copyright 1991, 1993, 1994, 1996, 1997, 1998, 2000, 2001, 2002, 2003, 2005
   8 Free Software Foundation, Inc.
   9
  10 This file is part of the GNU MP Library.
  11
  12 The GNU MP Library is free software; you can redistribute it and/or modify
  13 it under the terms of the GNU Lesser General Public License as published by
  14 the Free Software Foundation; either version 3 of the License, or (at your
  15 option) any later version.
  16
  17 The GNU MP Library is distributed in the hope that it will be useful, but
  18 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  20 License for more details.
  21
  22 You should have received a copy of the GNU Lesser General Public License
  23 along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
  24
  25 #include <string.h>
  26 #include <ctype.h>
  27 #include "gmp.h"
  28 #include "gmp-impl.h"
  29
  30 extern const unsigned char __gmp_digit_value_tab[];
  31 #define digit_value_tab __gmp_digit_value_tab
  32
  33 int
  34 mpz_set_str (mpz_ptr x, const char *str, int base)
  35 {
  36   size_t str_size;
  37   char *s, *begs;
  38   size_t i;
  39   mp_size_t xsize;
  40   int c;
  41   int negative;
  42   const unsigned char *digit_value;
  43   TMP_DECL;
  44
  45   digit_value = digit_value_tab;
  46   if (base > 36)
  47     {
  48       /* For bases > 36, use the collating sequence
  49          0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz.  */
  50       digit_value += 224;
  51       if (base > 62)
  52         return -1;              /* too large base */
  53     }
  54
  55   /* Skip whitespace.  */
  56   do
  57     c = (unsigned char) *str++;
  58   while (isspace (c));
  59
  60   negative = 0;
  61   if (c == '-')
  62     {
  63       negative = 1;
  64       c = (unsigned char) *str++;
  65     }
  66
  67   if (digit_value[c] >= (base == 0 ? 10 : base))
  68     return -1;                  /* error if no valid digits */
  69
  70   /* If BASE is 0, try to find out the base by looking at the initial
  71      characters.  */
  72   if (base == 0)
  73     {
  74       base = 10;
  75       if (c == '0')
  76         {
  77           base = 8;
  78           c = (unsigned char) *str++;
  79           if (c == 'x' || c == 'X')
  80             {
  81               base = 16;
  82               c = (unsigned char) *str++;
  83             }
  84           else if (c == 'b' || c == 'B')
  85             {
  86               base = 2;
  87               c = (unsigned char) *str++;
  88             }
  89         }
  90     }
  91
  92   /* Skip leading zeros and white space.  */
  93   while (c == '0' || isspace (c))
  94     c = (unsigned char) *str++;
  95   /* Make sure the string does not become empty, mpn_set_str would fail.  */
  96   if (c == 0)
  97     {
  98       x->_mp_size = 0;
  99       return 0;
 100     }
 101
 102   TMP_MARK;
 103   str_size = strlen (str - 1);
 104   s = begs = (char *) TMP_ALLOC (str_size + 1);
 105
 106   /* Remove spaces from the string and convert the result from ASCII to a
 107      byte array.  */
 108   for (i = 0; i < str_size; i++)
 109     {
 110       if (!isspace (c))
 111         {
 112           int dig = digit_value[c];
 113           if (dig >= base)
 114             {
 115               TMP_FREE;
 116               return -1;
 117             }
 118           *s++ = dig;
 119         }
 120       c = (unsigned char) *str++;
 121     }
 122
 123   str_size = s - begs;
 124
 125   xsize = 2 + (mp_size_t)
 126     (str_size / (GMP_NUMB_BITS * mp_bases[base].chars_per_bit_exactly));
 127   MPZ_REALLOC (x, xsize);
 128
 129   /* Convert the byte array in base BASE to our bignum format.  */
 130   xsize = mpn_set_str (x->_mp_d, (unsigned char *) begs, str_size, base);
 131   x->_mp_size = negative ? -xsize : xsize;
 132
 133   TMP_FREE;
 134   return 0;
 135 }