/*
* This program is free software; you can redistribute it and/or modify it under the terms of
* the GNU AFFERO GENERAL PUBLIC LICENSE as published by the Free Software Foundation; either version 3 of the License,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU AFFERO GENERAL PUBLIC LICENSE for more details.
* You should have received a copy of the GNU AFFERO GENERAL PUBLIC LICENSE along with this program;
* if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
package com.meidusa.amoeba.mongodb.io;
import com.meidusa.amoeba.net.io.PacketInputStream;
/**
* <pre>
* struct MsgHeader {
* int32 messageLength; // total message size, including this
* int32 requestID; // identifier for this message
* int32 responseTo; // requestID from the original request
* // (used in reponses from db)
* int32 opCode; // request type - see table below
* }
* </pre>
* @see <a href="http://www.mongodb.org/display/DOCS/Mongo+Wire+Protocol#MongoWireProtocol-TableOfContents">mongodb wire protocol</a>
*
* @author <a href=mailto:piratebase@sina.com>Struct chen</a>
*
*/
public class MongodbFramedInputStream extends PacketInputStream implements MongodbPacketConstant{
private boolean readPackedWithHead;
public MongodbFramedInputStream(boolean readPackedWithHead){
this.readPackedWithHead = readPackedWithHead;
}
protected int decodeLength() {
/**
* �ж�һ�����ǵ�ǰ�Ѿ���ȡ�����ݰ��������Ƿ�Ȱ�ͷ��,�����:����Լ����������ij���,����-1
*/
if (_have < getHeaderSize()) {
return -1;
}
//_buffer.rewind();
/**
* mysql ���ݲ��֣���ͷ=�������ݰ�����
*/
int length = (_buffer.get(0) & 0xff)
| ((_buffer.get(1) & 0xff) << 8)
| ((_buffer.get(2) & 0xff) << 16)
| ((_buffer.get(3) & 0xff) << 24);
return length;
}
public int getHeaderSize() {
return HEADER_SIZE;
}
/*protected boolean checkForCompletePacket ()
{
if (_length == -1 || _have < _length) {
return false;
}
//��buffer �����������ݰ���������ͷ����
if(readPackedWithHead){
_buffer.position(0);
}else{
_buffer.position(this.getHeaderSize());
}
_buffer.limit(_length);
return true;
}*/
protected byte[] readPacket(){
byte[] msg = new byte[_length];
int position = _buffer.position();
if(readPackedWithHead){
_buffer.position(0);
}else{
_buffer.position(this.getHeaderSize());
}
_buffer.get(msg, 0, _length);
try{
_buffer.limit(_have);
_buffer.compact();
_buffer.position(position - _length);
_have -= _length;
_length = this.decodeLength();
}catch(IllegalArgumentException e){
throw new IllegalArgumentException("old position="+_buffer.position()+", new position="+_length+",old limit="+_buffer.limit() +", have(new limit)="+_have,e);
}
return msg;
}
}