符号化及び復号化方法へのTCP / IPプロトコルではビッグエンディアン

2019ユニコーン企業重く募集エンジニアのPythonの標準>>>

package com.tcpip;

/**
 * 在tcp/ip协议中以BigEndian方式的编码与解码
 * @author 
 *
 */
public class BruteForceCoding {
	private static byte byteVal = 101;
	private static short shortVal = 10001;
	private static int intVal = 100000001;
	private static long longVal = 1000000000001L;
	
	private final static int BSIZE = Byte.SIZE;
	private final static int SSIZE = Short.SIZE;
	private final static int ISIZE = Integer.SIZE;
	private final static int LSIZE = Long.SIZE;
	
	private final static int BYTEMASK = 0xFF;
	
	public static String byteArrayToDecimalString(byte[] bArray){
		StringBuilder rtn = new StringBuilder();
		for(byte b:bArray){
			rtn.append(b&BYTEMASK).append(" ");
		}
		return rtn.toString();
	}
	
	/**
	 * 对val进行编码
	 * @param dst 源字节数组
	 * @param val 需要编码的long值
	 * @param offset 编码起始的偏移量
	 * @param size	编码的位数
	 * @return
	 */
	public static int encodeIntBigEndian(byte[] dst,long val,int offset,int size){
		for(int i=0;i<size;i++){
			dst[offset++] = (byte)(val >> ((size-i-1)*Byte.SIZE));
		}
		return offset;
	}
	
	/**
	 * 对字节数组val进行解码
	 * @param val 源字节数组
	 * @param offset 解码起始的偏移量
	 * @param size 解码的位数
	 * @return
	 */
	public static long decodeIntBigEndian(byte[] val,int offset,int size){
		long rtn = 0;
		for(int i=0;i<size;i++){
			rtn = (rtn<<Byte.SIZE) | ((long)val[offset+i] & BYTEMASK);
		}
		return rtn;
	}
	
	public static void main(String args[]){
		byte[] message= new byte[BSIZE];
		int r = encodeIntBigEndian(message,1999999999,0,BSIZE);
		System.out.println(r);
		long rl = decodeIntBigEndian(message,0,BSIZE);
		System.out.println(rl);
	}
	
}

ます。https：//my.oschina.net/u/2552902/blog/543962で再現