offline-editor-js/lib/tiles/base64utils.js

O.esri.Tiles.Base64Utils={};
O.esri.Tiles.Base64Utils.outputTypes={
    //	summary:
    //		Enumeration for input and output encodings.
    Base64:0, Hex:1, String:2, Raw:3
};

	//	word-based addition
O.esri.Tiles.Base64Utils.addWords=function(/* word */a, /* word */b){
    //	summary:
    //		add a pair of words together with rollover
    var l=(a&0xFFFF)+(b&0xFFFF);
    var m=(a>>16)+(b>>16)+(l>>16);
    return (m<<16)|(l&0xFFFF);	//	word
};

O.esri.Tiles.Base64Utils.stringToWord=function(/* string */s){
    //	summary:
    //		convert a string to a word array


    //	word-based conversion method, for efficiency sake;
    //	most digests operate on words, and this should be faster
    //	than the encoding version (which works on bytes).
    var chrsz=8;	//	16 for Unicode
    var mask=(1<<chrsz)-1;

    var wa=[];
    for(var i=0, l=s.length*chrsz; i<l; i+=chrsz){
        wa[i>>5]|=(s.charCodeAt(i/chrsz)&mask)<<(i%32);
    }
    return wa;	//	word[]
};

O.esri.Tiles.Base64Utils.wordToString=function(/* word[] */wa){
    //	summary:
    //		convert an array of words to a string

    //	word-based conversion method, for efficiency sake;
    //	most digests operate on words, and this should be faster
    //	than the encoding version (which works on bytes).
    var chrsz=8;	//	16 for Unicode
    var mask=(1<<chrsz)-1;

    var s=[];
    for(var i=0, l=wa.length*32; i<l; i+=chrsz){
        s.push(String.fromCharCode((wa[i>>5]>>>(i%32))&mask));
    }
    return s.join("");	//	string
};

O.esri.Tiles.Base64Utils.wordToHex=function(/* word[] */wa){
    //	summary:
    //		convert an array of words to a hex tab
    var h="0123456789abcdef", s=[];
    for(var i=0, l=wa.length*4; i<l; i++){
        s.push(h.charAt((wa[i>>2]>>((i%4)*8+4))&0xF)+h.charAt((wa[i>>2]>>((i%4)*8))&0xF));
    }
    return s.join("");	//	string
};

O.esri.Tiles.Base64Utils.wordToBase64=function(/* word[] */wa){
    //	summary:
    //		convert an array of words to base64 encoding, should be more efficient
    //		than using dojox.encoding.base64
    var p="=", tab="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/", s=[];
    for(var i=0, l=wa.length*4; i<l; i+=3){
        var t=(((wa[i>>2]>>8*(i%4))&0xFF)<<16)|(((wa[i+1>>2]>>8*((i+1)%4))&0xFF)<<8)|((wa[i+2>>2]>>8*((i+2)%4))&0xFF);
        for(var j=0; j<4; j++){
            if(i*8+j*6>wa.length*32){
                s.push(p);
            } else {
                s.push(tab.charAt((t>>6*(3-j))&0x3F));
            }
        }
    }
    return s.join("");	//	string
};