class com.miian.toolbox.PrtEncoder{
	private static var default_alphabet=
		"abcdefghijklmnopqrstuvwxyz-"+//<([{,:+*!'@$|^/"+
		"ABCDEFGHIJKLMNOPQRSTUVWXYZ+"+//>)]}.;-%?`#&_~\\"+
		"0123456789";
	private static var base64_alphabet=
		"ABCDEFGHIJKLMNOPQRSTUVWXYZ"+
		"abcdefghijklmnopqrstuvwxyz"+
		"123456789+/=";
	private static var system_alphabet=
		"0123456789"+
		"abcdefghijklmnopqrstuvwxyz";
	private static var _default_encoder;
	private static var powerTable;

	private var ascii_table;
	private var sys2ab_table;
	private var ab2sys_table;
	private var _alphabet;
	private var _scaleRadix;
	private var _maxScale;
	private var defaultRadix;

	private function PrtEncoder(){
		initEncoder(default_alphabet,10,2);
	}
	public static function getInstance(){
		if(_default_encoder==undefined){
			_default_encoder=new PrtEncoder();
		}
		return _default_encoder;
	}
	public static function encode(source){
		if(typeof(source)=="string"){
			return getInstance().num2str(Number(source));
		}else if(typeof(source)=="number"){
			return getInstance().num2str(source);
		}else{
			return getInstance().encodeArray(source);
		}
	}
	public static function decode(str){
		var r=getInstance().decodeArray(str);
		if(r.length==0){
			return r[0];
		}else{
			return r;
		}
	}
	public static function encode2DAry(ary){
		var t=[ary[0][0],ary[0][1]];
		for(var i=1;i<ary.length;i++){
			t[i*2]=ary[i][0]-t[(i-1)*2];
			t[i*2+1]=ary[i][1]-t[(i-1)*2+1];
		}
		return encode(t);
	}
	public static function decode2DAry(str){
		var r=decode(str);
		var t=[[r[0],r[1]]];
		for(var i=1;i<r.length/2;i++){
			t[i]=[r[i*2]+r[(i-1)*2],r[i*2+1]+r[(i-1)*2+1]];
		}
		return t;
	}
	public function initEncoder(alphabet,scaleRadix,maxScale){
		if(scaleRadix!=undefined){
			_scaleRadix=scaleRadix;
		}
		if((alphabet.length-_scaleRadix)%2!=0){
			alphabet=alphabet.substr(0,alphabet.length-1);
		}
		if(maxScale==undefined){
			maxScale=2;
		}
		_maxScale=maxScale;
		_alphabet=[];
		ascii_table=[];
		ab2sys_table=[];
		var lowercase=alphabet.toLowerCase();
		for(var i=0;i<alphabet.length;i++){
			_alphabet.push(alphabet.charAt(i));
			ascii_table[alphabet.charCodeAt(i)]=i;
			ab2sys_table[alphabet.charCodeAt(i)]=system_alphabet.charAt(alphabet.indexOf(lowercase.charAt(i)));
		}
		sys2ab_table=[];
		for(var i=0;i<system_alphabet.length;i++){
			sys2ab_table[system_alphabet.charCodeAt(i)]=_alphabet[i];
		}
		//trace("!!"+sys2ab_table);
		//trace("??"+ab2sys_table);
		//trace(_alphabet);
		//trace(ascii_table);
		defaultRadix=(_alphabet.length-_scaleRadix)/2;
	}
	public function rectifyRadix(radix){
		/*if(_alphabet==undefined || ascii_table==undefined){
			initEncoder(default_alphabet);
		}*/
		if(radix == undefined || 
			radix>defaultRadix) {
			return defaultRadix;
		}else{
			return radix;
		}
	}
	public function getScaleIndex(n){
		if(n==Math.floor(n)){
			return 0;
		}else{
			var s=n.toString().length-n.toString().lastIndexOf(".")-1;
			if(s>_maxScale){
				s=_maxScale;
			}
			return s;
		}
	}
	private function power(radix,i){
		if(powerTable==undefined){
			powerTable=[];
		}
		if(powerTable[radix]==undefined){
			powerTable[radix]=[1];
		}
		if(i>powerTable[radix].length-1){
			var l=powerTable[radix].length;
			for(var j=l;j<l+i+1;j++){
				//trace(j);
				powerTable[radix].push(Math.pow(radix,j));
			}
		}
		return powerTable[radix][i];
	}
	public function num2str(n, radix, maxScale){
		radix=rectifyRadix(radix);
		if(maxScale==undefined){
			maxScale=_scaleRadix;
		}
		if(n!=Math.floor(n)){
			//float
			var scale=getScaleIndex(n);
			if(scale>maxScale){
				scale=maxScale;
			}
			//trace("encode "+scale+" "+radix);
			return int2str(scale, _scaleRadix, radix*2)+
				int2str(Math.round(n * power(10, scale)), radix);
		}else{
			return int2str(n, radix);
			//return tostr(n, radix, 0);
		}
	}
	public function tostr(n, radix, offset){
		//radix=rectifyRadix(radix);
		var s=signed2int(n).toString(radix);
		var r="";
		var i;
		for(i=0;i<s.length;i++){
			if(i==s.length-1){
				r=r.toUpperCase();
			}
			r+=sys2ab_table[s.charCodeAt(i)+offset];
		}
		//trace(s+" "+r);
		return r;
	}
	public function toint(str, radix, offset){
		//radix=rectifyRadix(radix);
		var s="";
		for(var i=0;i<str.length;i++){
			//trace(i+" "+str.charCodeAt(i)+" "+ab2sys_table[str.charCodeAt(i)]);
			s+=ab2sys_table[str.charCodeAt(i)-offset];
		}
		//trace(str+" "+s);
		return int2signed(parseInt(s, radix));
	}
	public function int2str(n, radix, offset) {
		//trace(n);
		radix=rectifyRadix(radix);
		if(offset==undefined){
			offset=0;
		}
		n=signed2int(n);
		//trace(n+" "+radix);
		var s = "";
		do {
			//trace(n%radix);
			var mod=Math.round(n%radix);
			if(mod==radix){
				mod=0;
			}
			if (n<radix || (radix+mod+offset)>=_alphabet.length) {
				s += index2char(mod, offset);
				//trace("end "+s);
			} else {
				s += index2char(radix+mod, offset);
				//trace("digi "+s);
			}
			//trace(": "+n+" "+mod+" "+s);
			n = Math.floor(n/radix);
		}while (n>0)
		//trace("- "+s);
		return s;
	}
	public function extractNumber(str, i, radix) {
		radix=rectifyRadix(radix);
		var s = "";
		do {
			var c = str.charAt(i);
			//if(c<radix*2){
				s += c;
			//}
			i++;
			//trace(i+" "+char2index(c));
		} while (char2index(c)>=radix);
		return s;
	}
	public function extractScale(str, i, radix){
		var s="";
		var radix2=radix*2;
		var c;
		while((c=char2index(str.charAt(i)))>=radix2){
			s+=str.charAt(i);
			i++;
		}
		if(s==""){
			return;
		}else{
			return str2int(s, _scaleRadix, radix2);
		}
	}
	public function str2num(s, radix){
		//radix=rectifyRadix(radix);
		var scale=extractScale(s,0,radix);
		if(scale==undefined){
			scale=0;
		}
		//trace("decode "+scale);
		return str2int(s, radix)/power(10, scale);
		//return toint(s, radix, 0);
	}
	public function str2int(s, radix, offset) {
		//trace(s);
		//radix=rectifyRadix(radix);
		if(offset==undefined){
			offset=0;
		}
		var x = 0;
		//trace(s.length);
		var c=0;
		for (var j = 1; j<=s.length; j++) {
			var d = char2index(s.charAt(j-1),offset);
			if (d>=radix && d<radix*2) {
				d = d-radix;
			}else if(d>=radix*2){
				continue;
			}
			//trace("j "+j+" "+s.charAt(j-1)+" "+d); 
			if (d <0) {
				return x;
			}
			x += power(radix, c)*d;
			c++;
		}
		x=int2signed(x);
		//trace("decode "+x);
		return x;
	}
	public function encodeArray(ary, radix) {
		var s = "";
		var t=[];
		var lastScale=0;
		radix=rectifyRadix(radix);
		var radix2=radix*2;
		for (var i = 0; i<ary.length; i++) {
			var scale=getScaleIndex(ary[i]);
			//trace("encode "+ary[i]+" "+scale);
			if(scale!=lastScale){
				//trace(" ="+int2str(scale,_scaleRadix,radix2));
				s+=int2str(scale,_scaleRadix,radix2);
				lastScale=scale;
			}
			//trace(" +="+ary[i]*power(10,scale)+" "+int2str(ary[i]*power(10,scale),radix));
			s+=int2str(Math.round(ary[i]*power(10,scale)),radix);
		}
		return s;
	}
	public function decodeArray(str, radix) {
		radix=rectifyRadix(radix);
		var a = [];
		var i = 0;
		//var c=0;
		var t=[];
		var currentScale=0;
		while(i<str.length){
			var scale=extractScale(str,i,radix);
			//trace("decode "+scale);
			if(scale!=undefined && scale!=currentScale){
				currentScale=scale;
			}
			var s=extractNumber(str,i,radix);
			//trace("n="+s);
			//trace(" ="+str2int(s, radix)+"/"+power(10, currentScale));
			//trace(" ="+str2int(s, radix)/power(10, currentScale));
			//t.push(s);
			a.push(str2int(s, radix)/power(10, currentScale));
			i+=s.length;
			//trace(s+" "+i)
		}
		//trace(t);
		return a;
	}
	public function char2index(char, offset) {
		if(offset==undefined){
			offset=0;
		}
		return ascii_table[char.charCodeAt(0)]-offset;//_alphabet.indexOf(char)-offset;
	}
	public function index2char(index, offset){
		//trace(index);
		if(offset==undefined){
			offset=0;
		}
		//trace(index+" "+_alphabet.charAt(index+offset));
		index=Math.round(index);
		//trace(index+" "+_alphabet[index+offset]);
		return _alphabet[index+offset];
	}
	public function signed2int(num){
		//num=Math.round(num);
		if (num<0) {
			return -(num+num)-1;
		} else{
			return num+num;
		}
	}
	public function int2signed(num){
		num=Math.round(num);
		if(num%2!=0){
			return -(num+1)/2;
		}else{
			return num/2;
		}
	}
}