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60 lines
1.6 KiB
JavaScript
60 lines
1.6 KiB
JavaScript
dojo.provide("dojox.encoding.ascii85");
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(function(){
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var c = function(input, length, result){
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var i, j, n, b = [0, 0, 0, 0, 0];
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for(i = 0; i < length; i += 4){
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n = ((input[i] * 256 + input[i+1]) * 256 + input[i+2]) * 256 + input[i+3];
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if(!n){
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result.push("z");
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}else{
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for(j = 0; j < 5; b[j++] = n % 85 + 33, n = Math.floor(n / 85));
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}
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result.push(String.fromCharCode(b[4], b[3], b[2], b[1], b[0]));
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}
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};
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dojox.encoding.ascii85.encode = function(input){
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// summary: encodes input data in ascii85 string
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// input: Array: an array of numbers (0-255) to encode
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var result = [], reminder = input.length % 4, length = input.length - reminder;
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c(input, length, result);
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if(reminder){
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var t = input.slice(length);
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while(t.length < 4){ t.push(0); }
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c(t, 4, result);
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var x = result.pop();
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if(x == "z"){ x = "!!!!!"; }
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result.push(x.substr(0, reminder + 1));
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}
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return result.join(""); // String
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};
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dojox.encoding.ascii85.decode = function(input){
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// summary: decodes the input string back to array of numbers
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// input: String: the input string to decode
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var n = input.length, r = [], b = [0, 0, 0, 0, 0], i, j, t, x, y, d;
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for(i = 0; i < n; ++i){
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if(input.charAt(i) == "z"){
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r.push(0, 0, 0, 0);
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continue;
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}
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for(j = 0; j < 5; ++j){ b[j] = input.charCodeAt(i + j) - 33; }
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d = n - i;
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if(d < 5){
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for(j = d; j < 4; b[++j] = 0);
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b[d] = 85;
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}
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t = (((b[0] * 85 + b[1]) * 85 + b[2]) * 85 + b[3]) * 85 + b[4];
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x = t & 255;
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t >>>= 8;
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y = t & 255;
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t >>>= 8;
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r.push(t >>> 8, t & 255, y, x);
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for(j = d; j < 5; ++j, r.pop());
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i += 4;
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}
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return r;
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};
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})();
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