package com.ioufev;

import java.nio.ByteOrder;

public class ByteArrayConveter {
 
	// char转换为byte[2]数组
	public static byte[] getByteArray(char c) {
		byte[] b = new byte[2];
		b[0] = (byte) ((c & 0xff00) >> 8);
		b[1] = (byte) (c & 0x00ff);
		return b;
	}
 
	// 从byte数组的index处的连续两个字节获得一个char
	public static char getChar(byte[] arr, int index) {
		return (char) (0xff00 & arr[index] << 8 | (0xff & arr[index + 1]));
	}
	// short转换为byte[2]数组
	public static byte[] getByteArray(short s) {
		byte[] b = new byte[2];
		b[0] = (byte) ((s & 0xff00) >> 8);
		b[1] = (byte) (s & 0x00ff);
		return b;
	}
	// 从byte数组的index处的连续两个字节获得一个short
	public static short getShort(byte[] arr, int index) {
		return (short) (0xff00 & arr[index] << 8 | (0xff & arr[index + 1]));
	}
	// int转换为byte[4]数组
	public static byte[] getByteArray(int i) {
		byte[] b = new byte[4];
		b[0] = (byte) ((i & 0xff000000) >> 24);
		b[1] = (byte) ((i & 0x00ff0000) >> 16);
		b[2] = (byte) ((i & 0x0000ff00) >> 8);
		b[3] = (byte)  (i & 0x000000ff);
		return b;
	}
	// 从byte数组的index处的连续4个字节获得一个int
	public static int getInt(byte[] arr, int index) {
		return 	(0xff000000 	& (arr[index+0] << 24))  | 
				(0x00ff0000 	& (arr[index+1] << 16))  | 
				(0x0000ff00 	& (arr[index+2] << 8))   | 
				(0x000000ff 	&  arr[index+3]);
	}
	// float转换为byte[4]数组
	public static byte[] getByteArray(float f) {
		int intbits = Float.floatToIntBits(f);//将float里面的二进制串解释为int整数
		return getByteArray(intbits);
	}
	// 从byte数组的index处的连续4个字节获得一个float
	public static float getFloat(byte[] arr, int index) {
		return Float.intBitsToFloat(getInt(arr, index));
	}
	// long转换为byte[8]数组
	public static byte[] getByteArray(long l) {
		byte b[] = new byte[8];
		b[0] = (byte)  (0xff & (l >> 56));
		b[1] = (byte)  (0xff & (l >> 48));
		b[2] = (byte)  (0xff & (l >> 40));
		b[3] = (byte)  (0xff & (l >> 32));
		b[4] = (byte)  (0xff & (l >> 24));
		b[5] = (byte)  (0xff & (l >> 16));
		b[6] = (byte)  (0xff & (l >> 8));
		b[7] = (byte)  (0xff & l);
		return b;
	}
	// 从byte数组的index处的连续8个字节获得一个long
	public static long getLong(byte[] arr, int index) {
		return 	(0xff00000000000000L 	& ((long)arr[index+0] << 56))  | 
				(0x00ff000000000000L 	& ((long)arr[index+1] << 48))  | 
				(0x0000ff0000000000L 	& ((long)arr[index+2] << 40))  | 
				(0x000000ff00000000L 	& ((long)arr[index+3] << 32))  |
				(0x00000000ff000000L 	& ((long)arr[index+4] << 24))  | 
				(0x0000000000ff0000L 	& ((long)arr[index+5] << 16))  | 
				(0x000000000000ff00L 	& ((long)arr[index+6] << 8))   | 
				(0x00000000000000ffL 	&  (long)arr[index+7]);
	}
	// double转换为byte[8]数组
	public static byte[] getByteArray(double d) {
		long longbits = Double.doubleToLongBits(d);
		return getByteArray(longbits);
	}
	// 从byte数组的index处的连续8个字节获得一个double
	public static double getDouble(byte[] arr, int index) {
		return Double.longBitsToDouble(getLong(arr, index));
	}
 
	public static void main(String[] args) {
		System.out.println(ByteOrder.nativeOrder());
		if(args.length < 1){
			System.out.println("enter 'char' test method about char");
			System.out.println("enter 'short' test method about short");
			System.out.println("enter 'int' test method about int");
			System.out.println("enter 'float' test method about float");
			System.out.println("enter 'long' test method about long");
			System.out.println("enter 'double' test method about double");
			return;
		}
		if(args[0].equals("char")){
			char c = '\u0000';
			while( c < '\uffff'){
				System.out.println(getChar(getByteArray(c),0));
				c++;
			}
		}else if(args[0].equals("short")){
			short s = Short.MIN_VALUE;
			while( s < Short.MAX_VALUE){
				System.out.println(getShort(getByteArray(s), 0));
				s++;
			}
		}else if(args[0].equals("int")){
			int i = Integer.MIN_VALUE;
			while( i < Integer.MAX_VALUE){
				System.out.println(getInt(getByteArray(i), 0));
				i++;
			}
		}else if(args[0].equals("float")){
			float f = Float.MIN_VALUE;
			while(f < Float.MAX_VALUE){
				System.out.println(getFloat(getByteArray(f), 0));
				f+=1.1111f;
			}
		}else if(args[0].equals("long")){
			long l = Long.MIN_VALUE;
			while(l < Long.MAX_VALUE){
				System.out.println(getLong(getByteArray(l), 0));
				l++;
			}
		}else if(args[0].equals("double")){
			double d = Double.MIN_VALUE;
			while(d < Double.MAX_VALUE){
				System.out.println(getDouble(getByteArray(d), 0));
				d+=1.111D;
			}
		}
	}
}