ActionScript3中的Int64与ByteArray转换

ActionScript3中没有int64(long)类型，因此在与其它语言写的应用程序进行数据通信及交互时，存在数据转换的问题。如网络传输中Int64的网络字符序列要能够成功接收和发送，而ByteArray中又没有相应的读写方法，只提供了对short,int,uint,double,float,String,Object等数据的类型的read和write方法。内容可参见AS3帮助文档中的ByteArray类。

如果要实现Int64与ByteArray的相互转换，可实现的方法有很多：

Int64与ByteArray的相互转换 方法一

//Int64转换成ByteArray
public function writeInt64(bigInt:Number):ByteArray {
    const zeros:String = "00000000";
    var bytes:ByteArray = new ByteArray();
    var str = bigInt.toString(16);
    str = zeros.substr(0,16-str.length)+str;
    bytes.writeUnsignedInt(parseInt(str.substr(0,8),16));
    bytes.writeUnsignedInt(parseInt(str.substr(8,8),16));
    bytes.position = 0;
    return bytes;
}

//ByteArray转换成Int64
public function readInt64(bytes:ByteArray):Number {
    const zeros:String = "00000000";
    var s:String = bytes.readUnsignedInt().toString(16);
    var str:String = zeros.substr(0,8-s.length) + s;
    s = bytes.readUnsignedInt().toString(16);
    str += zeros.substr(0,8-s.length) + s ;
    return Number(parseInt(str, 16).toString());
}

Int64与ByteArray的相互转换 方法二

//http://stackoverflow.com/questions/9504487/number-type-and-bitwise-operations

//Int64 to ByteArray
public function writeInt64(n:Number):ByteArray                   
{                                                                         
    // Write your IEEE 754 64-bit double-precision number to a byte array.
    var b:ByteArray = new ByteArray();                                    
    b.writeDouble(n);   
    
    trace("--"+n);
    for(var i:int = 0 ;i<b.length;i++)
    {
        trace(b[i].toString(2));
    }
    trace("--"+n);
                                                      
    var e:int = ((b[0] & 0x7F) << 4) | (b[1] >> 4); // 取得指数 
    var s:int = e - 1023;  // Significant bits. 
    var x:int = (52 - s) % 8; // Number of bits to shift towards the right. 
    var r:int = 8 - int((52 - s) / 8);  // Read and write positions in the byte array.                                    
    var w:int = 8;
    
    // Clear the first two bytes of the sign bit and the exponent.        
    b[0] &= 0x80;                                                         
    b[1] &= 0xF;                                                           
    // Add the "hidden" fraction bit.                                     
    b[1] |= 0x10;                                                      
    // Shift everything.                                                  
    while (w > 1) {                                                       
        if (--r > 0) {                                                    
            if (w < 8)                                                    
                b[w] |= b[r] << (8 - x);                                  
                                                                          
            b[--w] = b[r] >> x;                                           
                                                                          
        } else {                                                          
            b[--w] = 0;                                                   
        }                                                                 
    }                                                                                  
    // Now you've got your 64-bit signed two's complement integer.        
    return b;                                                             
}

//ByteArray to Int64
public function readInt64(bytes:ByteArray):Number {
    //待实现
    return 0;
}

对于ActionScript加入对Int64数据的支持，Google Code中有开源的类。

开源类一

开源类二