src/servers/app/drawing/interface/html5/base64.cpp

   1 /*
   2  * Copyright 2011, Haiku, Inc. All rights reserved.
   3  * Copyright 2001-2003 Dr. Zoidberg Enterprises. All rights reserved.
   4  */
   5
   6
   7 #include <ctype.h>
   8 #include <string.h>
   9
  10 #include <mail_encoding.h>
  11 #include <SupportDefs.h>
  12
  13 static const char kBase64Alphabet[64] = {
  14   'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
  15   'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
  16   'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
  17   'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
  18   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
  19   '+',
  20   '/'
  21  };
  22
  23 static const char kHexAlphabet[16] = {'0', '1', '2', '3', '4', '5', '6', '7',
  24         '8','9','A','B','C','D','E','F'};
  25
  26
  27 ssize_t
  28 encode_base64(char *out, const char *in, off_t length, bool packed)
  29 {
  30         uint32 concat;
  31         int i = 0;
  32         int k = 0;
  33
  34         while (i < length) {
  35                 concat = ((in[i] & 0xff) << 16);
  36
  37                 if ((i+1) < length)
  38                         concat |= ((in[i+1] & 0xff) << 8);
  39                 if ((i+2) < length)
  40                         concat |= (in[i+2] & 0xff);
  41
  42                 i += 3;
  43
  44                 out[k++] = kBase64Alphabet[(concat >> 18) & 63];
  45                 out[k++] = kBase64Alphabet[(concat >> 12) & 63];
  46                 if ((i+1) < length)
  47                         out[k++] = kBase64Alphabet[(concat >> 6) & 63];
  48                 else if (!packed)
  49                         out[k++] = '=';
  50                 if ((i+2) < length)
  51                         out[k++] = kBase64Alphabet[concat & 63];
  52                 else if (!packed)
  53                         out[k++] = '=';
  54         }
  55
  56         return k;
  57 }
  58
  59
  60 ssize_t
  61 decode_base64(char *out, const char *in, off_t length)
  62 {
  63         uint32 concat, value;
  64         int lastOutLine = 0;
  65         int i, j;
  66         int outIndex = 0;
  67
  68         for (i = 0; i < length; i += 4) {
  69                 concat = 0;
  70
  71                 for (j = 0; j < 4 && (i + j) < length; j++) {
  72                         value = in[i + j];
  73
  74                         if (value == '\n' || value == '\r') {
  75                                 // jump over line breaks
  76                                 lastOutLine = outIndex;
  77                                 i++;
  78                                 j--;
  79                                 continue;
  80                         }
  81
  82                         if ((value >= 'A') && (value <= 'Z'))
  83                                 value -= 'A';
  84                         else if ((value >= 'a') && (value <= 'z'))
  85                                 value = value - 'a' + 26;
  86                         else if ((value >= '0') && (value <= '9'))
  87                                 value = value - '0' + 52;
  88                         else if (value == '+')
  89                                 value = 62;
  90                         else if (value == '/')
  91                                 value = 63;
  92                         else if (value == '=')
  93                                 break;
  94                         else {
  95                                 // there is an invalid character in this line - we will
  96                                 // ignore the whole line and go to the next
  97                                 outIndex = lastOutLine;
  98                                 while (i < length && in[i] != '\n' && in[i] != '\r')
  99                                         i++;
 100                                 concat = 0;
 101                         }
 102
 103                         value = value << ((3-j)*6);
 104
 105                         concat |= value;
 106                 }
 107
 108                 if (j > 1)
 109                         out[outIndex++] = (concat & 0x00ff0000) >> 16;
 110                 if (j > 2)
 111                         out[outIndex++] = (concat & 0x0000ff00) >> 8;
 112                 if (j > 3)
 113                         out[outIndex++] = (concat & 0x000000ff);
 114         }
 115
 116         return outIndex;
 117 }
 118
 119