as2解析json
as2写的json解析，带容错，如果要做格式检查，得自己修改了，直接贴代码
//--------------------------------------------------json解析----------------------------------------------------------
class Json extends Object{
public static var pos:Number=0;
private static function isDigit( ch:String ):Boolean
{
return ( ch >= '0' && ch <= '9' )||( ch == "+" )||( ch == "-" )||( ch == "." );
}
private static function isHexDigit( ch:String ):Boolean
{
return ( isDigit( ch ) || ( ch >= 'A' && ch <= 'F' ) || ( ch >= 'a' && ch <= 'f' ) );
}
private static function toTrue(str:String, from:Number,to:Number)
{
pos=from+3;
return true;
}
private static function toFalse(str:String, from:Number, to:Number)
{
pos=from+4;
return false;
}
private static function toNull(str:String, from:Number, to:Number)
{
pos=from+3;
return null;
}
private static function toNAN(str:String, from:Number, to:Number)
{
pos=from+2;
return Number.NaN;
}
private static function toNumber(str:String, from:Number, to:Number)
{
var i:Number = from+1;
while(i<=to)
{
var c = str.charAt(i);
if(!isDigit(c))
break
i++;
}
var num:Number = Number(str.substring(from, i))
if(!isFinite(num))
throw{msg:"json格式错误，不正确的数字, 错误位置:"+from};
pos=i-1;
return num;
}
public static function unescapeString( str:String ):String
{
var pos:Number = 0;
var result="";
while(pos<str.length)
{
var c:String=str.charAt(pos);
if(c=="\\"){
if((pos+5<str.length) && str.charAt(pos+1)=="u")
{
var hexValue:String = "";
for ( var i:Number = pos+2; i < pos + 6; i++ )
{
var c:String = str.charAt( i );
if ( !isHexDigit( c ) )
{
throw{msg:"json格式错误，字符串unicode编码转换错误，错误位置:"+i};
}
hexValue += c;
}
result += String.fromCharCode( parseInt( hexValue, 16 ) );
pos=pos+5;
}else{
result=result+c;
}
}else{
result=result+c;
}
pos=pos+1;
}
return result;
}
private static function toStr(str:String, from:Number, to:Number)
{
var ignor:Boolean = false
for(var i:Number = from+1; i<=to; i++)
{
var c:String=str.charAt(i);
if(!ignor)
{
if(c=="\"")
{
pos=i;
return unescapeString(str.substring(from+1, i));
//return str.substring(from+1, i);
}else if(c=="\\")
ignor=true;
}else{
ignor=false;
}
}
throw{msg:'json格式错误，字符串没有找到结尾, 错误位置:'+from};
}
private static function toArray(str:String, from:Number, to:Number)
{
var arr:Array = [];
pos=from+1;
while(pos<=to)
{
var c:String = str.charAt(pos);
switch(c)
{
case "\"":
arr.push(toStr(str, pos, to));
break;
case "[":
arr.push(toArray(str, pos, to));
break;
case "{":
arr.push(toObject(str, pos, to));
break;
case "]":
return arr;
case "f":
arr.push(toFalse(str, pos, to));
break;
case "F":
arr.push(toFalse(str, pos, to));
break;
case "t":
arr.push(toTrue(str, pos, to));
break;
case "T":
arr.push(toTrue(str, pos, to));
break;
case "n":
arr.push(toNull(str, pos, to));
break;
case "N":
arr.push(toNAN(str, pos, to));
break;
default:
if(isDigit(c))
arr.push(toNumber(str, pos, to));
}
pos=pos+1;
}
throw{msg: 'json格式错误，表没有找到结尾, 错误位置:'+from};
}
private static function toObject(str:String, from:Number, to:Number)
{
var obj:Object = {};
var key;
pos=from+1;
while(pos<=to)
{
var c:String = str.charAt(pos);
switch(c)
{
case "\"":
if(!key)
{
key=toStr(str, pos, to);
}else{
obj[key] = toStr(str,pos,to);
key = null;
}
break;
case "[":
if(!key){
key=toArray(str, pos, to);
}else{
obj[key]=toArray(str, pos, to);
key=null;
}
break;
case "{":
if(!key){
key=toObject(str, pos, to);
}else{
obj[key]=toObject(str, pos, to);
key=null;
}
break;
case "}":
return obj;
case "]":
return obj;
case "f":
if(!key)
throw{msg:"json格式错误，boolean不能做key, 错误位置:"+from};
obj[key]=toFalse(str, pos, to);
break;
case "F":
if(!key)
throw{msg:"json格式错误，boolean不能做key, 错误位置:"+from};
obj[key]=toFalse(str, pos, to);
break;
case "t":
if(!key)
throw{msg:"json格式错误，boolean不能做key, 错误位置:"+from};
obj[key]=toTrue(str, pos, to);
case "T":
if(!key)
throw{msg:"json格式错误，boolean不能做key, 错误位置:"+from};
obj[key]=toTrue(str, pos, to);
break;
case "n":
if(!key)
throw{msg:"json格式错误，null不能做key, 错误位置:"+from};
obj[key]=toNull(str, pos, to);
break;
case "N":
if(!key)
throw{msg:"json格式错误，nan不能做key, 错误位置:"+from};
obj[key]=toNAN(str, pos, to);
break;
default:
if(isDigit(c)){
if(!key){
key=toNumber(str, pos, to);
}else{
obj[key]=toNumber(str, pos, to);
key=null;
}
}
}
pos = pos + 1
}
throw{msg:'json格式错误，表没有找到结尾, 错误位置:}'+from};
}
public static function decode(str:String)
{
pos=0;
if(str=="")
return null;
var c=str.charAt(pos);
switch(c)
{
case "\"":
return toStr(str, pos, str.length-1);
case "[":
return toArray(str, pos, str.length-1);
case "{":
return toObject(str, pos, str.length-1);
case "f":
return false;
case "F":
return false;
case "t":
return true;
case "n":
return null;
case "N":
return Number.NaN;
case "T":
return true;
default:
if(isDigit(c))
return toNumber(str, pos, str.length-1);
}
}
}
