package com.AUG21.ProtocolEncapsulation;

import java.io.*;
import java.net.UnknownHostException;
import java.nio.*;

public class BussinessOuthelp {//包文構(gòu)建方法
    private ByteBuffer bb = null;
    private int length = 0;
    private int pos = 0;

    public BussinessOuthelp(int allocatesize) throws UnknownHostException {//在構(gòu)造方法中構(gòu)造包文大小
        bb = ByteBuffer.allocate(allocatesize);//定義字節(jié)緩沖區(qū)大小
        bb.order(ByteOrder.LITTLE_ENDIAN);//獲取此緩沖區(qū)的字節(jié)順序
        bb.position();//返回此緩沖區(qū)的位置。

        initHead();//自定義包頭結(jié)構(gòu)
    }

    private void initHead() throws UnknownHostException {
    	bb.put(Config.getIP().getBytes());
        bb.putInt(Config.port);
        pos = bb.position();
        bb.putInt(length);
        bb.putLong(Config.getSerialNo());
    }

    public void writeInt(int i){
    	bb.putInt(i);
    }
    
    public void writeString(String input, int length) throws IOException {
        int i = 0;
        int setPos = 0;
        byte buf[] = null;
        try {
            buf = input.getBytes("GBK");
        } catch (UnsupportedEncodingException ex) {
            ex.printStackTrace();
        }
        int strLen = buf.length;
        while (i < length) {
            byte ch = (setPos < strLen ? buf[setPos++] : 0);
            bb.put(ch);
            i++;
        }
    }

    public byte[] getBytes() throws IOException {
        if (bb.hasArray()) {
            length = bb.position();
            bb.position(pos);
            bb.putInt(length);
            bb.position(length);
            return bb.array();
        } else {
            return null;
        }
    }

    public String getString(int length) throws IOException {
        byte[] buffer = new byte[length];
        for (int i = 0; i < length; i++) {
            buffer[i] = bb.get();
        }
        return new String(buffer, "GBK").trim();
    }
}