source/libs/gmp/gmp-src/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, 1996-1998, 2000-2003, 2005, 2011-2013 Free Software
   8 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 either:
  14
  15   * the GNU Lesser General Public License as published by the Free
  16     Software Foundation; either version 3 of the License, or (at your
  17     option) any later version.
  18
  19 or
  20
  21   * the GNU General Public License as published by the Free Software
  22     Foundation; either version 2 of the License, or (at your option) any
  23     later version.
  24
  25 or both in parallel, as here.
  26
  27 The GNU MP Library is distributed in the hope that it will be useful, but
  28 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  29 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  30 for more details.
  31
  32 You should have received copies of the GNU General Public License and the
  33 GNU Lesser General Public License along with the GNU MP Library.  If not,
  34 see https://www.gnu.org/licenses/.  */
  35
  36 #include <string.h>
  37 #include <ctype.h>
  38 #include "gmp.h"
  39 #include "gmp-impl.h"
  40 #include "longlong.h"
  41
  42 #define digit_value_tab __gmp_digit_value_tab
  43
  44 int
  45 mpz_set_str (mpz_ptr x, const char *str, int base)
  46 {
  47   size_t str_size;
  48   char *s, *begs;
  49   size_t i;
  50   mp_size_t xsize;
  51   int c;
  52   int negative;
  53   const unsigned char *digit_value;
  54   TMP_DECL;
  55
  56   digit_value = digit_value_tab;
  57   if (base > 36)
  58     {
  59       /* For bases > 36, use the collating sequence
  60          0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz.  */
  61       digit_value += 208;
  62       if (base > 62)
  63         return -1;              /* too large base */
  64     }
  65
  66   /* Skip whitespace.  */
  67   do
  68     c = (unsigned char) *str++;
  69   while (isspace (c));
  70
  71   negative = 0;
  72   if (c == '-')
  73     {
  74       negative = 1;
  75       c = (unsigned char) *str++;
  76     }
  77
  78   if (digit_value[c] >= (base == 0 ? 10 : base))
  79     return -1;                  /* error if no valid digits */
  80
  81   /* If BASE is 0, try to find out the base by looking at the initial
  82      characters.  */
  83   if (base == 0)
  84     {
  85       base = 10;
  86       if (c == '0')
  87         {
  88           base = 8;
  89           c = (unsigned char) *str++;
  90           if (c == 'x' || c == 'X')
  91             {
  92               base = 16;
  93               c = (unsigned char) *str++;
  94             }
  95           else if (c == 'b' || c == 'B')
  96             {
  97               base = 2;
  98               c = (unsigned char) *str++;
  99             }
 100         }
 101     }
 102
 103   /* Skip leading zeros and white space.  */
 104   while (c == '0' || isspace (c))
 105     c = (unsigned char) *str++;
 106   /* Make sure the string does not become empty, mpn_set_str would fail.  */
 107   if (c == 0)
 108     {
 109       SIZ (x) = 0;
 110       return 0;
 111     }
 112
 113   TMP_MARK;
 114   str_size = strlen (str - 1);
 115   s = begs = (char *) TMP_ALLOC (str_size + 1);
 116
 117   /* Remove spaces from the string and convert the result from ASCII to a
 118      byte array.  */
 119   for (i = 0; i < str_size; i++)
 120     {
 121       if (!isspace (c))
 122         {
 123           int dig = digit_value[c];
 124           if (dig >= base)
 125             {
 126               TMP_FREE;
 127               return -1;
 128             }
 129           *s++ = dig;
 130         }
 131       c = (unsigned char) *str++;
 132     }
 133
 134   str_size = s - begs;
 135
 136   LIMBS_PER_DIGIT_IN_BASE (xsize, str_size, base);
 137   MPZ_REALLOC (x, xsize);
 138
 139   /* Convert the byte array in base BASE to our bignum format.  */
 140   xsize = mpn_set_str (PTR (x), (unsigned char *) begs, str_size, base);
 141   SIZ (x) = negative ? -xsize : xsize;
 142
 143   TMP_FREE;
 144   return 0;
 145 }