includes/clientside/static/base64.js
changeset 1 fe660c52c48f
equal deleted inserted replaced
0:902822492a68 1:fe660c52c48f
       
     1 // Base64 encoder/decoder - pulled from http://ostermiller.org/calc/encode.html. Licensed under the GPL.
       
     2 
       
     3 var END_OF_INPUT = -1;
       
     4 
       
     5 var base64Chars = new Array(
       
     6     'A','B','C','D','E','F','G','H',
       
     7     'I','J','K','L','M','N','O','P',
       
     8     'Q','R','S','T','U','V','W','X',
       
     9     'Y','Z','a','b','c','d','e','f',
       
    10     'g','h','i','j','k','l','m','n',
       
    11     'o','p','q','r','s','t','u','v',
       
    12     'w','x','y','z','0','1','2','3',
       
    13     '4','5','6','7','8','9','+','/'
       
    14 );
       
    15 
       
    16 var reverseBase64Chars = new Array();
       
    17 for (var i=0; i < base64Chars.length; i++){
       
    18     reverseBase64Chars[base64Chars[i]] = i;
       
    19 }
       
    20 
       
    21 var base64Str;
       
    22 var base64Count;
       
    23 
       
    24 function setBase64Str(str){
       
    25     base64Str = str;
       
    26     base64Count = 0;
       
    27 }
       
    28 function readBase64(){    
       
    29     if (!base64Str) return END_OF_INPUT;
       
    30     if (base64Count >= base64Str.length) return END_OF_INPUT;
       
    31     var c = base64Str.charCodeAt(base64Count) & 0xff;
       
    32     base64Count++;
       
    33     return c;
       
    34 }
       
    35 function encodeBase64(str){
       
    36     setBase64Str(str);
       
    37     var result = '';
       
    38     var inBuffer = new Array(3);
       
    39     var lineCount = 0;
       
    40     var done = false;
       
    41     while (!done && (inBuffer[0] = readBase64()) != END_OF_INPUT){
       
    42         inBuffer[1] = readBase64();
       
    43         inBuffer[2] = readBase64();
       
    44         result += (base64Chars[ inBuffer[0] >> 2 ]);
       
    45         if (inBuffer[1] != END_OF_INPUT){
       
    46             result += (base64Chars [(( inBuffer[0] << 4 ) & 0x30) | (inBuffer[1] >> 4) ]);
       
    47             if (inBuffer[2] != END_OF_INPUT){
       
    48                 result += (base64Chars [((inBuffer[1] << 2) & 0x3c) | (inBuffer[2] >> 6) ]);
       
    49                 result += (base64Chars [inBuffer[2] & 0x3F]);
       
    50             } else {
       
    51                 result += (base64Chars [((inBuffer[1] << 2) & 0x3c)]);
       
    52                 result += ('=');
       
    53                 done = true;
       
    54             }
       
    55         } else {
       
    56             result += (base64Chars [(( inBuffer[0] << 4 ) & 0x30)]);
       
    57             result += ('=');
       
    58             result += ('=');
       
    59             done = true;
       
    60         }
       
    61         lineCount += 4;
       
    62         if (lineCount >= 76){
       
    63             result += ('\n');
       
    64             lineCount = 0;
       
    65         }
       
    66     }
       
    67     return result;
       
    68 }
       
    69 function readReverseBase64(){   
       
    70     if (!base64Str) return END_OF_INPUT;
       
    71     while (true){      
       
    72         if (base64Count >= base64Str.length) return END_OF_INPUT;
       
    73         var nextCharacter = base64Str.charAt(base64Count);
       
    74         base64Count++;
       
    75         if (reverseBase64Chars[nextCharacter]){
       
    76             return reverseBase64Chars[nextCharacter];
       
    77         }
       
    78         if (nextCharacter == 'A') return 0;
       
    79     }
       
    80     return END_OF_INPUT;
       
    81 }
       
    82 
       
    83 function ntos(n){
       
    84     n=n.toString(16);
       
    85     if (n.length == 1) n="0"+n;
       
    86     n="%"+n;
       
    87     return unescape(n);
       
    88 }
       
    89 
       
    90 function decodeBase64(str){
       
    91     setBase64Str(str);
       
    92     var result = "";
       
    93     var inBuffer = new Array(4);
       
    94     var done = false;
       
    95     while (!done && (inBuffer[0] = readReverseBase64()) != END_OF_INPUT
       
    96         && (inBuffer[1] = readReverseBase64()) != END_OF_INPUT){
       
    97         inBuffer[2] = readReverseBase64();
       
    98         inBuffer[3] = readReverseBase64();
       
    99         result += ntos((((inBuffer[0] << 2) & 0xff)| inBuffer[1] >> 4));
       
   100         if (inBuffer[2] != END_OF_INPUT){
       
   101             result +=  ntos((((inBuffer[1] << 4) & 0xff)| inBuffer[2] >> 2));
       
   102             if (inBuffer[3] != END_OF_INPUT){
       
   103                 result +=  ntos((((inBuffer[2] << 6)  & 0xff) | inBuffer[3]));
       
   104             } else {
       
   105                 done = true;
       
   106             }
       
   107         } else {
       
   108             done = true;
       
   109         }
       
   110     }
       
   111     return result;
       
   112 }
       
   113