131 lines
3.0 KiB
JavaScript
131 lines
3.0 KiB
JavaScript
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/**
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* Uses the new array typed in javascript to binary base64 encode/decode
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* at the moment just decodes a binary base64 encoded
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* into either an ArrayBuffer (decodeArrayBuffer)
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* or into an Uint8Array (decode)
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*
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* References:
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* https://developer.mozilla.org/en/JavaScript_typed_arrays/ArrayBuffer
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* https://developer.mozilla.org/en/JavaScript_typed_arrays/Uint8Array
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*/
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var Base64 = {
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_key : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
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_encode : null,
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_decode : null,
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initialize: function()
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{
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if (this._decode != null)
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return;
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this._decode = new Uint8Array(0xFF);
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for (var i=0; i<this._key.length; ++i)
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this._decode[this._key.charCodeAt(i)] = i;
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this._encode = new Uint8Array(this._key.length);
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for (var i=0; i<this._key.length; ++i)
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this._encode[i] = this._key.charCodeAt(i) & 0xFF;
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},
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decode: function(input)
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{
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var bytes = new Uint8Array(input.length);
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var i;
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for (i=0; i<input.length; ++i)
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bytes[i] = input.charCodeAt(i) & 0xFF;
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return Base64.decodeBytes(bytes);
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},
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decodeBytes: function(input)
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{
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this.initialize();
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//get last chars to see if are valid
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var lkey1 = this._decode[input[input.length-1]];
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var lkey2 = this._decode[input[input.length-2]];
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var bytes = (input.length/4) * 3;
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if (lkey1 == 64) bytes--; //padding chars, so skip
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if (lkey2 == 64) bytes--; //padding chars, so skip
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var out = [];
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var chr1, chr2, chr3;
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var enc1, enc2, enc3, enc4;
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var i = 0;
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var j = 0;
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while (j < input.length)
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{
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enc1 = this._decode[input[j++]];
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enc2 = this._decode[input[j++]];
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enc3 = this._decode[input[j++]];
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enc4 = this._decode[input[j++]];
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chr1 = (enc1 << 2) | (enc2 >> 4);
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chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
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chr3 = ((enc3 & 3) << 6) | enc4;
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out[i++] = chr1 & 0xFF;
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if (enc3 != 64) out[i++] = chr2 & 0xFF;
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if (enc4 != 64) out[i++] = chr3 & 0xFF;
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}
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return out;
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},
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encodeBytes : function(input)
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{
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this.initialize();
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var length = input.length;
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var bytes = ((length+2)/3)*4;
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var output = [];
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var i = 0;
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var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
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var j=0;
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while (i < length)
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{
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var count = length - i;
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chr1 = input[i++] & 0xFF;
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chr2 = (i<length) ? (input[i++]&0xFF) : 0;
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chr3 = (i<length) ? (input[i++]&0xFF) : 0;
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enc1 = chr1 >> 2;
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enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
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enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
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enc4 = chr3 & 63;
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if (count == 1)
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enc3 = enc4 = 64;
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else
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if (count == 2)
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enc4 = 64;
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output[j++] = this._encode[enc1];
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output[j++] = this._encode[enc2];
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output[j++] = this._encode[enc3];
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output[j++] = this._encode[enc4];
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}
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return output;
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},
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encode: function(input)
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{
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var bytes = this.encodeBytes(input);
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var s = "";
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for (var i=0; i<bytes.length; ++i)
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s += String.fromCharCode(bytes[i]);
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return s;
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}
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} ;
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/** end **/ |