/*
 * Copyright (c) 2002-2012 Alibaba Group Holding Limited.
 * All rights reserved.
 *
 * 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.alibaba.citrus.util.io;

import static com.alibaba.citrus.util.Assert.*;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * 代表一个byte数组。
 *
 * @author Michael Zhou
 */
public class ByteArray {
    private final byte[] bytes;
    private final int    offset;
    private final int    length;

    public ByteArray(byte[] bytes) {
        this(bytes, 0, Integer.MIN_VALUE);
    }

    public ByteArray(byte[] bytes, int offset, int length) {
        assertNotNull(bytes, "bytes");
        assertTrue(offset >= 0, "offset", offset);

        if (length == Integer.MIN_VALUE) {
            length = bytes.length - offset;
        }

        assertTrue(length >= 0 && length <= bytes.length - offset, "length");

        this.bytes = bytes;
        this.offset = offset;
        this.length = length;
    }

    public byte[] getRawBytes() {
        return bytes;
    }

    public int getOffset() {
        return offset;
    }

    public int getLength() {
        return length;
    }

    public byte[] toByteArray() {
        byte[] copy = new byte[length];

        System.arraycopy(bytes, offset, copy, 0, length);

        return copy;
    }

    public InputStream toInputStream() {
        return new ByteArrayInputStream(bytes, offset, length);
    }

    public void writeTo(OutputStream out) throws IOException {
        out.write(bytes, offset, length);
    }

    @Override
    public String toString() {
        return "byte[" + length + "]";
    }
}