com.google.code.proto.streamio.IPBWireByteMarkerHelper Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of gpb-stream-reader-writer Show documentation
A package to read and write Google Protocol Buffer messages to and from Input and Output Streams
There is a newer version: 1.5.5
Show newest version
/*
 * The MIT License
 *
 * Copyright 2011 Climb With Your Feet.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.google.code.proto.streamio;

import com.google.protobuf.GeneratedMessage;
import java.util.List;

/**
 * Interface for class to help write delimiting byte markers for Google protocol buffer 
 * generated messages used with PBStreamReader.  The delimeter is a byte array holding
 * the size of the generated message that will follow.
 * 
 * @author nichole
 */
public interface IPBWireByteMarkerHelper {

    /**
     * Convert the marker byte array to an integer where each item is part of byte shifted integer
     *
     * @param marker big endian byte marker
     * @return value held in marker
     */
    int bytesToInteger(byte[] marker);

    /**
     * Create a delimiter for the given GeneratedMessage.
     *
     * @param message instance of GeneratedMessage
     * @return byte array of size delimiterSize, to be used preceding serialized GeneratedMessages
     * in a stream.  The delimiter to separate serialized objects is
     * a start byte of followed by a byteMarkerSize big-endian bytes holding the length
     */
    byte[] createMessageDelimiter(GeneratedMessage message);

    /**
     * Estimate the total number of bytes that will be used in a stream for a list
     * of messages - this includes delimeters.  
     * This is useful to set the content-length in an HTTP response.
     *
     * @param messages instances of GeneratedMessage
     * @return total number of bytes needed for a list of generated messages.
     * The total includes the delimiters too.
     */
    int estimateTotalContentLength(List messages);

    /**
     * Get the number of bytes holding a message size, where these bytes are within
     * the delimiter byte array and follow the byte marker.
     *
     * @return number of bytes holding a message size.
     */
    int getByteMarkerSize();

    /**
     * Get the total number of bytes of a delimeter for a generated message.
     *
     * @return the number of bytes in a delimiter
     */
    int getDelimiterSize();

    /**
     * Get the byte marker used to identify the start of the delimiter.
     *
     * @return byte marker used to identify the start of the delimiter
     */
    byte getMarkerForStart();

    /**
     * Convert the integer into a byte array composed of byte shifted parts of the integer.
     *
     * @param value the integer to be represented by the returned byte array
     * @return big endian byte array holding value
     */
    byte[] integerToBytesBigEndian(int value);
    
}