stdlib/a64l.c

   1 /* Copyright (C) 1995, 1997, 1998 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <stdlib.h>
  21
  22 #define TABLE_BASE 0x20
  23 #define TABLE_SIZE 0x60
  24
  25 #define XX ((char)0x40)
  26
  27
  28 static const char a64l_table[TABLE_SIZE] =
  29 {
  30   /* 0x20 */  XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,  0,  1,
  31   /* 0x30 */   2,  3,  4,  5,  6,  7,  8,  9, 10, 11, XX, XX, XX, XX, XX, XX,
  32   /* 0x40 */  XX, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
  33   /* 0x50 */  27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, XX, XX, XX, XX, XX,
  34   /* 0x60 */  XX, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,
  35   /* 0x70 */  53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, XX, XX, XX, XX, XX
  36 };
  37
  38
  39 long int
  40 a64l (string)
  41      const char *string;
  42 {
  43   const char *ptr = string;
  44   unsigned long int result = 0ul;
  45   const char *end = ptr + 6;
  46
  47   do
  48     {
  49       unsigned index;
  50       unsigned value;
  51
  52       index = *ptr - TABLE_BASE;
  53       if ((unsigned int) index >= TABLE_SIZE)
  54         break;
  55       value = (int) a64l_table[index];
  56       if (value == (int) XX)
  57         break;
  58       result <<= 6;
  59       ++ptr;
  60       result |= value;
  61     }
  62   while (ptr != end);
  63
  64   return (long int) result;
  65 }