github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpz/set_str.c (about)

     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  }