Buffer.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF 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.apache.tomcat.jni;

import java.nio.ByteBuffer;

/** Buffer
 *
 * @author Mladen Turk
 */
public class Buffer {

    /**
     * Allocate a new ByteBuffer from memory
     * @param size The amount of memory to allocate
     * @return The ByteBuffer with allocated memory
     */
    public static native ByteBuffer malloc(int size);

    /**
     * Allocate a new ByteBuffer from memory and set all of the memory to 0
     * @param num Number of elements.
     * @param size Length in bytes of each element.
     * @return The ByteBuffer with allocated memory
     */
    public static native ByteBuffer calloc(int num, int size);

    /**
     * Allocate a new ByteBuffer from a pool
     * @param p The pool to allocate from
     * @param size The amount of memory to allocate
     * @return The ByteBuffer with allocated memory
     */
    public static native ByteBuffer palloc(long p, int size);

    /**
     * Allocate a new ByteBuffer from a pool and set all of the memory to 0
     * @param p The pool to allocate from
     * @param size The amount of memory to allocate
     * @return The ByteBuffer with allocated memory
     */
    public static native ByteBuffer pcalloc(long p, int size);

    /**
     * Allocate a new ByteBuffer from already allocated memory.
     * <br>Allocated memory must be provided from call to the
     * Stdlib.alloc or Stdlib.calloc methods.
     * @param mem The memory to use
     * @param size The amount of memory to use
     * @return The ByteBuffer with attached memory
     */
    public static native ByteBuffer create(long mem, int size);

    /**
     * Deallocates or frees a memory block used by ByteBuffer
     * <br><b>Warning :</b> Call this method only on ByteBuffers
     * that were created by calling Buffer.alloc or Buffer.calloc.
     * @param buf Previously allocated ByteBuffer to be freed.
     */
    public static native void free(ByteBuffer buf);

    /**
     * Returns the memory address of the ByteBuffer.
     * @param buf Previously allocated ByteBuffer.
     * @return the memory address
     */
    public static native long address(ByteBuffer buf);

    /**
     * Returns the allocated memory size of the ByteBuffer.
     * @param buf Previously allocated ByteBuffer.
     * @return the size
     */
    public static native long size(ByteBuffer buf);

}