root / trunk / web / dojo / dojox / encoding / compression / splay.js
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/*
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Copyright (c) 2004-2010, The Dojo Foundation All Rights Reserved.
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Available via Academic Free License >= 2.1 OR the modified BSD license.
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see: http://dojotoolkit.org/license for details
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*/
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if(!dojo._hasResource["dojox.encoding.compression.splay"]){ |
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dojo._hasResource["dojox.encoding.compression.splay"]=true; |
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dojo.provide("dojox.encoding.compression.splay");
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dojo.require("dojox.encoding.bits");
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dojox.encoding.compression.Splay=function(n){ |
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this.up=new Array(2*n+1); |
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this.left=new Array(n); |
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this.right=new Array(n); |
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this.reset();
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}; |
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dojo.extend(dojox.encoding.compression.Splay,{reset:function(){ |
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for(var i=1;i<this.up.length;this.up[i]=Math.floor((i-1)/2),++i){ |
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} |
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for(var i=0;i<this.left.length;this.left[i]=2*i+1,this.right[i]=2*i+2,++i){ |
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} |
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},splay:function(i){ |
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var a=i+this.left.length; |
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do{
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var c=this.up[a]; |
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if(c){
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var d=this.up[c]; |
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var b=this.left[d]; |
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if(c==b){
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b=this.right[d];
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this.right[d]=a;
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}else{
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this.left[d]=a;
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} |
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this[a==this.left[c]?"left":"right"][c]=b; |
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this.up[a]=d;
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this.up[b]=c;
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a=d; |
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}else{
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a=c; |
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} |
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}while(a);
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},encode:function(_1,_2){ |
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var s=[],a=_1+this.left.length; |
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do{
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s.push(this.right[this.up[a]]==a); |
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a=this.up[a];
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}while(a);
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this.splay(_1);
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var l=s.length;
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while(s.length){
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_2.putBits(s.pop()?1:0,1); |
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} |
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return l;
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},decode:function(_3){ |
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var a=0; |
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do{
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a=this[_3.getBits(1)?"right":"left"][a]; |
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}while(a<this.left.length); |
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a-=this.left.length;
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this.splay(a);
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return a;
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}}); |
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} |