Module("codecs","$Revision: 44 $",function(mod){
mod.listEncoders=function(){
var c=[];
for(var attr in String.prototype){
if(attr.slice(0,7)=="encode_"){
c.push(attr.slice(7));
}
}
return c;
};
mod.listDecoders=function(){
var c=[];
for(var attr in String.prototype){
if(attr.slice(0,7)=="decode_"){
c.push(attr.slice(7));
}
}
return c;
};
String.prototype.decode=function(codec){
var n="decode_"+codec;
if(String.prototype[n]){
var args=[];
for(var i=1;i<arguments.length;i++){
args[i-1]=arguments[i];
}
return String.prototype[n].apply(this,args);
}else{
throw new mod.Exception("Decoder '%s' not found.".format(codec));
}
};
String.prototype.encode=function(codec){
var n="encode_"+codec;
if(String.prototype[n]){
var args=[];
for(var i=1;i<arguments.length;i++){
args[i-1]=arguments[i];
}
return String.prototype[n].apply(this,args);
}else{
throw new mod.Exception("Ecnoder '%s' not found.".format(codec));
}
};
String.prototype.decode_base64=function(){
if((this.length%4)==0){
if(typeof(atob)!="undefined"){
return atob(this);
}else{
var nBits;
var sDecoded=new Array(this.length/4);
var base64='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
for(var i=0;i<this.length;i+=4){
nBits=(base64.indexOf(this.charAt(i))&0xff)<<18|
(base64.indexOf(this.charAt(i+1))&0xff)<<12|
(base64.indexOf(this.charAt(i+2))&0xff)<<6|
base64.indexOf(this.charAt(i+3))&0xff;
sDecoded[i]=String.fromCharCode((nBits&0xff0000)>>16,(nBits&0xff00)>>8,nBits&0xff);
}
sDecoded[sDecoded.length-1]=sDecoded[sDecoded.length-1].substring(0,3-((this.charCodeAt(i-2)==61)?2:(this.charCodeAt(i-1)==61?1:0)));
return sDecoded.join("");
}
}else{
throw new mod.Exception("String length must be divisible by 4.");
}
};
String.prototype.encode_base64=function(){
if(typeof(btoa)!="undefined"){
return btoa(this);
}else{
var base64=['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
'0','1','2','3','4','5','6','7','8','9','+','/'];
var sbin;
var pad=0;
var s=""+this;
if((s.length%3)==1){
s+=String.fromCharCode(0);
s+=String.fromCharCode(0);
pad=2;
}else if((s.length%3)==2){
s+=String.fromCharCode(0);
pad=1;
}
var rslt=new Array(s.length/3);
var ri=0;
for(var i=0;i<s.length;i+=3){
sbin=((s.charCodeAt(i)&0xff)<<16)|((s.charCodeAt(i+1)&0xff)<<8)|(s.charCodeAt(i+2)&0xff);
rslt[ri]=(base64[(sbin>>18)&0x3f]+base64[(sbin>>12)&0x3f]+base64[(sbin>>6)&0x3f]+base64[sbin&0x3f]);
ri++;
}
if(pad>0){
rslt[rslt.length-1]=rslt[rslt.length-1].substr(0,4-pad)+((pad==2)?"==":(pad==1)?"=":"");
}
return rslt.join("");
}
};
String.prototype.decode_uri=function(){
return decodeURIComponent(this);
};
String.prototype.encode_uri=function(){
return encodeURIComponent(this);
};
String.prototype.encode_lzw=function(){
var dict={};
var data=(this+"").split("");
var out=[];
var currChar;
var phrase=data[0];
var code=256;
for(var i=1;i<data.length;i++){
currChar=data[i];
if(dict[phrase+currChar]!=null){
phrase+=currChar;
}else{
out.push(phrase.length>1?dict[phrase]:phrase.charCodeAt(0));
dict[phrase+currChar]=code;
code++;
phrase=currChar;
}
}
out.push(phrase.length>1?dict[phrase]:phrase.charCodeAt(0));
for(var i=0;i<out.length;i++){
out[i]=String.fromCharCode(out[i]);
}
return out.join("");
};
String.prototype.decode_lzw=function(){
var dict={};
var data=(this+"").split("");
var currChar=data[0];
var oldPhrase=currChar;
var out=[currChar];
var code=256;
var phrase;
for(var i=1;i<data.length;i++){
var currCode=data[i].charCodeAt(0);
if(currCode<256){
phrase=data[i];
}else{
phrase=dict[currCode]?dict[currCode]:(oldPhrase+currChar);
}
out.push(phrase);
currChar=phrase.charAt(0);
dict[code]=oldPhrase+currChar;
code++;
oldPhrase=phrase;
}
return out.join("");
};
});