stdlib/a64l.c

   1 /* Copyright (C) 1995-2016 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.org>, 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <stdlib.h>
  20
  21 #define TABLE_BASE 0x2e
  22 #define TABLE_SIZE 0x4d
  23
  24 #define XX ((char)0x40)
  25
  26
  27 static const char a64l_table[TABLE_SIZE] =
  28 {
  29   /* 0x2e */                                                           0,  1,
  30   /* 0x30 */   2,  3,  4,  5,  6,  7,  8,  9, 10, 11, XX, XX, XX, XX, XX, XX,
  31   /* 0x40 */  XX, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
  32   /* 0x50 */  27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, XX, XX, XX, XX, XX,
  33   /* 0x60 */  XX, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,
  34   /* 0x70 */  53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63
  35 };
  36
  37
  38 long int
  39 a64l (const char *string)
  40 {
  41   const char *ptr = string;
  42   unsigned long int result = 0ul;
  43   const char *end = ptr + 6;
  44   int shift = 0;
  45
  46   do
  47     {
  48       unsigned index;
  49       unsigned value;
  50
  51       index = *ptr - TABLE_BASE;
  52       if ((unsigned int) index >= TABLE_SIZE)
  53         break;
  54       value = (int) a64l_table[index];
  55       if (value == (int) XX)
  56         break;
  57       ++ptr;
  58       result |= value << shift;
  59       shift += 6;
  60     }
  61   while (ptr != end);
  62
  63   return (long int) result;
  64 }