stdlib/l64a.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.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 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 /* Conversion table.  */
  22 static const char conv_table[64] =
  23 {
  24   '.', '/', '0', '1', '2', '3', '4', '5',
  25   '6', '7', '8', '9', 'A', 'B', 'C', 'D',
  26   'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L',
  27   'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
  28   'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b',
  29   'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
  30   'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r',
  31   's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
  32 };
  33
  34 char *
  35 l64a (long int n)
  36 {
  37   unsigned long int m = (unsigned long int) n;
  38   static char result[7];
  39   int cnt;
  40
  41   /* The standard says that only 32 bits are used.  */
  42   m &= 0xffffffff;
  43
  44   if (m == 0ul)
  45     /* The value for N == 0 is defined to be the empty string. */
  46     return (char *) "";
  47
  48   for (cnt = 0; m > 0ul; ++cnt)
  49     {
  50       result[cnt] = conv_table[m & 0x3f];
  51       m >>= 6;
  52     }
  53   result[cnt] = '\0';
  54
  55   return result;
  56 }