src/util/base32.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 #include <afsconfig.h>
  11 #include <afs/param.h>
  12
  13
  14 #include "afsutil.h"
  15
  16 static char *c_xlate = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  17
  18
  19 /* int_to_base32
  20  * Create a base 32 string representation of a number.
  21  * The supplied string 's' must be at least 8 bytes long.
  22  * Use the b32_string_t tyepdef.
  23  */
  24 char *
  25 int_to_base32(b32_string_t s, int a)
  26 {
  27     int i, j;
  28     unsigned int n;
  29
  30     i = 0;
  31     if (a == 0)
  32         s[i++] = c_xlate[0];
  33     else {
  34         j = 25;
  35         n = a & 0xc0000000;
  36         if (n) {
  37             n >>= 30;
  38             s[i++] = c_xlate[n];
  39             a &= ~0xc0000000;
  40         } else {
  41             for (; j >= 0; j -= 5) {
  42                 n = a & (0x1f << j);
  43                 if (n)
  44                     break;      /* found highest bits set. */
  45             }
  46             s[i++] = c_xlate[n >> j];
  47             a &= ~(0x1f << j);
  48             j -= 5;
  49         }
  50         /* more to do. */
  51         for (; j >= 0; j -= 5) {
  52             n = a & (0x1f << j);
  53             s[i++] = c_xlate[n >> j];
  54             a &= ~(0x1f << j);
  55         }
  56     }
  57     s[i] = '\0';
  58     return s;
  59 }
  60
  61 int
  62 base32_to_int(char *s)
  63 {
  64     int n = 0;
  65     int result = 0;
  66
  67     for (; *s; s++) {
  68         if (*s <= '9') {
  69             n = (int)(*s - '0');
  70         } else {
  71             n = 10 + (int)(*s - 'A');
  72         }
  73         result = (result << 5) + n;
  74     }
  75     return result;
  76 }