src/util/flipbase64.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  * Portions Copyright (c) 2003 Apple Computer, Inc.
  10  */
  11
  12 #include <afsconfig.h>
  13 #include <afs/param.h>
  14
  15 #include <roken.h>
  16
  17 #include "afsutil.h"
  18
  19 /* This version of base64 gets it right and starts converting from the low
  20  * bits to the high bits.
  21  */
  22 /* This table needs to be in lexical order to efficiently map back from
  23  * characters to the numerical value.
  24  *
  25  * In c_reverse, we use 99 to represent an illegal value, rather than -1
  26  * which would assume "char" is signed.
  27  */
  28 #ifdef AFS_DARWIN_ENV
  29 static char c_xlate[80] =
  30         "!\"#$%&()*+,-0123456789:;<=>?@[]^_`abcdefghijklmnopqrstuvwxyz{|}~";
  31 static char c_reverse[] = {
  32     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  33     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  34     99,  0,  1,  2,  3,  4,  5, 99,  6,  7,  8,  9, 10, 11, 99, 99,
  35     12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
  36     28, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  37     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 29, 99, 30, 31, 32,
  38     33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
  39     49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 99,
  40     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  41     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  42     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  43     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  44     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  45     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  46     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  47     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99
  48 };
  49 #else /* AFS_DARWIN_ENV */
  50 static char c_xlate[80] =
  51     "+=0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  52 static char c_reverse[] = {
  53     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  54     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  55     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,  0, 99, 99, 99, 99,
  56      2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 99, 99, 99,  1, 99, 99,
  57     99, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
  58     27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 99, 99, 99, 99, 99,
  59     99, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,
  60     53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 99, 99, 99, 99, 99,
  61     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  62     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  63     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  64     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  65     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  66     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  67     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
  68     99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99
  69 };
  70 #endif /* AFS_DARWIN_ENV */
  71
  72 /* int_to_base64
  73  * Create a base 64 string representation of a number.
  74  * The supplied string 's' must be at least 12 bytes long.
  75  * lb64_string in stds.h provides a typedef to get the length.
  76  */
  77 char *
  78 int64_to_flipbase64(lb64_string_t s, afs_uint64 a)
  79 {
  80     int i;
  81     afs_uint64 n;
  82
  83     i = 0;
  84     if (a == 0)
  85         s[i++] = c_xlate[0];
  86     else {
  87         for (n = a & 0x3f; a; n = ((a >>= 6) & 0x3f)) {
  88             s[i++] = c_xlate[n];
  89         }
  90     }
  91     s[i] = '\0';
  92     return s;
  93 }
  94
  95
  96 afs_int64
  97 flipbase64_to_int64(char *s)
  98 {
  99     afs_int64 n = 0;
 100     afs_int64 result = 0;
 101     int shift;
 102
 103     for (shift = 0; *s; s++) {
 104         n = c_reverse[*(unsigned char *)s];
 105         if (n >= 64)    /* should never happen */
 106             continue;
 107         n <<= shift;
 108         result |= n ;
 109         shift += 6;
 110     }
 111     return result;
 112 }