/*
 * Copyright (c) 2009 JogAmp Community. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of
 *       conditions and the following disclaimer.
 *
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list
 *       of conditions and the following disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are those of the
 * authors and should not be interpreted as representing official policies, either expressed
 * or implied, of JogAmp Community.
 */

package com.jogamp.opencl;

import com.jogamp.common.nio.Buffers;

import java.util.List;

import com.jogamp.common.nio.PointerBuffer;
import com.jogamp.opencl.llb.CL;

import java.nio.Buffer;
import java.util.ArrayList;
import java.util.Collections;

/**
 * OpenCL buffer object wrapping an optional NIO buffer.
 * @author Michael Bien, et al.
 */
public class CLBuffer<B extends Buffer> extends CLMemory<B> {

    private List<CLSubBuffer<B>> childs;

    protected CLBuffer(final CLContext context, final long size, final long id, final int flags) {
        this(context, null, size, id, flags);
    }

    protected CLBuffer(final CLContext context, final B directBuffer, final long size, final long id, final int flags) {
        super(context, directBuffer, size, id, flags);
    }

    @SuppressWarnings("rawtypes")
    static CLBuffer<?> create(final CLContext context, final int size, final int flags) {

        if(isHostPointerFlag(flags)) {
            throw new IllegalArgumentException("no host pointer defined");
        }

        final CL binding = context.getPlatform().getCLBinding();
        final int[] result = new int[1];
        final long id = binding.clCreateBuffer(context.ID, flags, size, null, result, 0);
        CLException.checkForError(result[0], "can not create cl buffer");

        return new CLBuffer(context, size, id, flags);
    }

    static <B extends Buffer> CLBuffer<B> create(final CLContext context, final B directBuffer, final int flags) {

        if(!directBuffer.isDirect())
            throw new IllegalArgumentException("buffer is not direct");

        B host_ptr = null;
        if(isHostPointerFlag(flags)) {
            host_ptr = directBuffer;
        }

        final CL binding = context.getPlatform().getCLBinding();
        final int[] result = new int[1];
        final int size = Buffers.sizeOfBufferElem(directBuffer) * directBuffer.limit();
        final long id = binding.clCreateBuffer(context.ID, flags, size, host_ptr, result, 0);
        CLException.checkForError(result[0], "can not create cl buffer");

        return new CLBuffer<B>(context, directBuffer, size, id, flags);
    }

    /**
     * Creates a sub buffer with the specified region from this buffer.
     * If this buffer contains a NIO buffer, the sub buffer will also contain a slice
     * matching the specified region of the parent buffer. The region is specified
     * by the offset and size in buffer elements or bytes if this buffer does not
     * contain any NIO buffer.
     * @param offset The offset in buffer elements.
     * @param size The size in buffer elements.
     */
    public CLSubBuffer<B> createSubBuffer(int offset, int size, final Mem... flags) {

        final B slice;
        if(buffer != null) {
            slice = Buffers.slice(buffer, offset, size);
            final int elemSize = Buffers.sizeOfBufferElem(buffer);
            offset *= elemSize;
            size *= elemSize;
        } else {
            slice = null;
        }

        final PointerBuffer info = PointerBuffer.allocateDirect(2);
        info.put(0, offset);
        info.put(1, size);
        final int bitset = Mem.flagsToInt(flags);

        final CL binding = getPlatform().getCLBinding();
        final int[] err = new int[1];
        final long subID = binding.clCreateSubBuffer(ID, bitset, CL.CL_BUFFER_CREATE_TYPE_REGION, info.getBuffer(), err, 0);
        CLException.checkForError(err[0], "can not create sub buffer");

        final CLSubBuffer<B> clSubBuffer = new CLSubBuffer<B>(this, offset, size, slice, subID, bitset);
        if(childs == null) {
            childs = new ArrayList<CLSubBuffer<B>>();
        }
        childs.add(clSubBuffer);
        return clSubBuffer;
    }

    @Override
    public void release() {
        if(childs != null) {
            while(!childs.isEmpty()) {
                childs.get(0).release();
            }
        }
        super.release();
    }

    void onReleaseSubBuffer(final CLSubBuffer<?> sub) {
        childs.remove(sub);
    }

    /**
     * Returns the list of subbuffers.
     */
    @SuppressWarnings("unchecked")
    public List<CLSubBuffer<B>> getSubBuffers() {
        if(childs == null) {
            return Collections.EMPTY_LIST;
        }else{
            return Collections.unmodifiableList(childs);
        }
    }

    /**
     * Returns true if this is a sub buffer.
     */
    public boolean isSubBuffer() {
        return false;
    }

    @Override
    public <T extends Buffer> CLBuffer<T> cloneWith(final T directBuffer) {
        return new CLBuffer<T>(context, directBuffer, size, ID, FLAGS);
    }

}