1  /* Copyright (C) 1995-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <stdlib.h>
      19  
      20  #define TABLE_BASE 0x2e
      21  #define TABLE_SIZE 0x4d
      22  
      23  #define XX ((char)0x40)
      24  
      25  
      26  static const char a64l_table[TABLE_SIZE] =
      27  {
      28    /* 0x2e */                                                           0,  1,
      29    /* 0x30 */   2,  3,  4,  5,  6,  7,  8,  9, 10, 11, XX, XX, XX, XX, XX, XX,
      30    /* 0x40 */  XX, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
      31    /* 0x50 */  27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, XX, XX, XX, XX, XX,
      32    /* 0x60 */  XX, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,
      33    /* 0x70 */  53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63
      34  };
      35  
      36  
      37  long int
      38  a64l (const char *string)
      39  {
      40    const char *ptr = string;
      41    unsigned long int result = 0ul;
      42    const char *end = ptr + 6;
      43    int shift = 0;
      44  
      45    do
      46      {
      47        unsigned index;
      48        unsigned value;
      49  
      50        index = *ptr - TABLE_BASE;
      51        if ((unsigned int) index >= TABLE_SIZE)
      52  	break;
      53        value = (int) a64l_table[index];
      54        if (value == (int) XX)
      55  	break;
      56        ++ptr;
      57        result |= value << shift;
      58        shift += 6;
      59      }
      60    while (ptr != end);
      61  
      62    return (long int) result;
      63  }