ByteUtil.java

/*
 *  Copyright 2009-2016 Weibo, Inc.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

package com.weibo.api.motan.util;

import java.util.ArrayList;
import java.util.List;

/**
 * @author maijunsheng
 * @version 创建时间：2013-5-22
 */
public class ByteUtil {

    public static List<Byte> toList(byte[] array) {
        if (array == null) {
            return null;
        }

        List<Byte> list = new ArrayList<Byte>(array.length);

        for (byte value : array) {
            list.add(value);
        }

        return list;
    }

    public static byte[] toArray(List<Byte> list) {
        if (list == null) {
            return null;
        }

        byte[] array = new byte[list.size()];

        int index = 0;
        for (byte value : list) {
            array[index++] = value;
        }

        return array;
    }


    /**
     * 把long类型的value转为8个byte字节，放到byte数组的off开始的位置，高位在前
     *
     * @param value
     * @param bytes
     * @param off
     */
    public static void long2bytes(long value, byte[] bytes, int off) {
        bytes[off + 7] = (byte) value;
        bytes[off + 6] = (byte) (value >>> 8);
        bytes[off + 5] = (byte) (value >>> 16);
        bytes[off + 4] = (byte) (value >>> 24);
        bytes[off + 3] = (byte) (value >>> 32);
        bytes[off + 2] = (byte) (value >>> 40);
        bytes[off + 1] = (byte) (value >>> 48);
        bytes[off] = (byte) (value >>> 56);
    }

    /**
     * 把byte数组中off开始的8个字节，转为long类型，高位在前
     *
     * @param bytes
     * @param off
     */
    public static long bytes2long(byte[] bytes, int off) {
        return ((bytes[off + 7] & 0xFFL)) + ((bytes[off + 6] & 0xFFL) << 8) + ((bytes[off + 5] & 0xFFL) << 16)
                + ((bytes[off + 4] & 0xFFL) << 24) + ((bytes[off + 3] & 0xFFL) << 32) + ((bytes[off + 2] & 0xFFL) << 40)
                + ((bytes[off + 1] & 0xFFL) << 48) + (((long) bytes[off]) << 56);
    }

    /**
     * 把int类型的value转为4个byte字节，放到byte数组的off开始的位置，高位在前
     *
     * @param value
     * @param bytes
     * @param off
     */
    public static void int2bytes(int value, byte[] bytes, int off) {
        bytes[off + 3] = (byte) value;
        bytes[off + 2] = (byte) (value >>> 8);
        bytes[off + 1] = (byte) (value >>> 16);
        bytes[off] = (byte) (value >>> 24);
    }

    /**
     * 把byte数组中off开始的4个字节，转为int类型，高位在前
     *
     * @param bytes
     * @param off
     */
    public static int bytes2int(byte[] bytes, int off) {
        return ((bytes[off + 3] & 0xFF)) + ((bytes[off + 2] & 0xFF) << 8) + ((bytes[off + 1] & 0xFF) << 16) + ((bytes[off]) << 24);
    }

    /**
     * 把short类型的value转为2个byte字节，放到byte数组的off开始的位置，高位在前
     *
     * @param value
     * @param bytes
     * @param off
     */
    public static void short2bytes(short value, byte[] bytes, int off) {
        bytes[off + 1] = (byte) value;
        bytes[off] = (byte) (value >>> 8);
    }

    /**
     * 把byte数组中off开始的2个字节，转为short类型，高位在前
     *
     * @param b
     * @param off
     */
    public static short bytes2short(byte[] b, int off) {
        return (short) (((b[off + 1] & 0xFF)) + ((b[off] & 0xFF) << 8));
    }
}