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Berkeley DB Java Edition is a open source, transactional storage solution for Java applications. The Direct Persistence Layer (DPL) API is faster and easier to develop, deploy, and manage than serialized object files or ORM-based Java persistence solutions. The Collections API enhances the standard java.util.collections classes allowing them to be persisted to a local file system and accessed concurrently while protected by ACID transactions. Data is stored by serializing objects and managing class and instance data separately so as not to waste space. Berkeley DB Java Edition is the reliable drop-in solution for complex, fast, and scalable storage. Source for this release is in 'je-4.0.92-sources.jar', the Javadoc is located at 'http://download.oracle.com/berkeley-db/docs/je/4.0.92/'.

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/*-
 * Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
 *
 * This file was distributed by Oracle as part of a version of Oracle Berkeley
 * DB Java Edition made available at:
 *
 * http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
 *
 * Please see the LICENSE file included in the top-level directory of the
 * appropriate version of Oracle Berkeley DB Java Edition for a copy of the
 * license and additional information.
 */

package com.sleepycat.bind.tuple;

import com.sleepycat.je.DatabaseEntry;
import com.sleepycat.util.PackedInteger;

/**
 * A concrete TupleBinding for an unsorted Integer
 * primitive wrapper or an unsorted int primitive, that stores the
 * value in the smallest number of bytes possible.
 *
 * There are two ways to use this class:
 * 
 * When using the {@link com.sleepycat.je} package directly, the static
 * methods in this class can be used to convert between primitive values and
 * {@link DatabaseEntry} objects.
 * When using the {@link com.sleepycat.collections} package, an instance of
 * this class can be used with any stored collection.
 * 
 *
 * @see Integer Formats
 */
public class PackedIntegerBinding extends TupleBinding {
    
    // javadoc is inherited
    public Integer entryToObject(TupleInput input) {

        return input.readPackedInt();
    }
    
    // javadoc is inherited
    public void objectToEntry(Integer object, TupleOutput output) {

        output.writePackedInt(object);
    }
    
    // javadoc is inherited
    protected TupleOutput getTupleOutput(Integer object) {

        return sizedOutput();
    }
    
    /**
     * Converts an entry buffer into a simple int value.
     *
     * @param entry is the source entry buffer.
     *
     * @return the resulting value.
     */
    public static int entryToInt(DatabaseEntry entry) {

        return entryToInput(entry).readPackedInt();
    }
    
    /**
     * Converts a simple int value into an entry buffer, using 
     * PackedInteger format.
     *
     * @param val is the source value.
     *
     * @param entry is the destination entry buffer.
     */
    public static void intToEntry(int val, DatabaseEntry entry) {

        outputToEntry(sizedOutput().writePackedInt(val), entry);
    }
    
    /**
     * Returns a tuple output object of the maximum size needed, to avoid
     * wasting space when a single primitive is output.
     */
    private static TupleOutput sizedOutput() {

        return new TupleOutput(new byte[PackedInteger.MAX_LENGTH]);
    }
}