/*
 * Licensed to Elastic Search and Shay Banon under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Elastic Search licenses this
 * file to you 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 org.elasticsearch.common.bytes;

import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;

import java.io.IOException;
import java.io.OutputStream;

/**
 * A reference to bytes.
 */
public interface BytesReference {

    /**
     * Returns the byte at the specified index. Need to be between 0 and length.
     */
    byte get(int index);

    /**
     * The length.
     */
    int length();

    /**
     * Slice the bytes from the <tt>from</tt> index up to <tt>length</tt>.
     */
    BytesReference slice(int from, int length);

    /**
     * A stream input of the bytes.
     */
    StreamInput streamInput();

    /**
     * Writes the bytes into the output, with an optional length header (variable encoded).
     */
    void writeTo(StreamOutput out, boolean withLength) throws IOException;

    void writeTo(OutputStream os) throws IOException;

    /**
     * Returns the bytes as a single byte array.
     */
    byte[] toBytes();

    /**
     * Returns the bytes as a byte array, possibly sharing the underlying byte buffer.
     */
    BytesArray toBytesArray();

    /**
     * Returns the bytes copied over as a byte array.
     */
    BytesArray copyBytesArray();

    /**
     * Is there an underlying byte array for this bytes reference.
     */
    boolean hasArray();

    /**
     * The underlying byte array (if exists).
     */
    byte[] array();

    /**
     * The offset into the underlying byte array.
     */
    int arrayOffset();
}