/*

 * Copyright (C) 2009 Apple Inc. 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 APPLE COMPUTER, INC. ``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 APPLE COMPUTER, INC. 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. 

 */

#include "config.h"

#if ENABLE(3D_CANVAS)

#include "WebGLBuffer.h"

#include "WebGLRenderingContext.h"

namespace WebCore {

PassRefPtr<WebGLBuffer> WebGLBuffer::create(WebGLRenderingContext* ctx)

{

    return adoptRef(new WebGLBuffer(ctx));

}

WebGLBuffer::WebGLBuffer(WebGLRenderingContext* ctx)

    : CanvasObject(ctx)

    , m_target(0)

    , m_byteLength(0)

    , m_nextAvailableCacheEntry(0)

{

    setObject(context()->graphicsContext3D()->createBuffer());

    clearCachedMaxIndices();

}

void WebGLBuffer::_deleteObject(Platform3DObject object)

{

    context()->graphicsContext3D()->deleteBuffer(object);

}

bool WebGLBuffer::associateBufferData(int size)

{

    if (!m_target)

        return false;

    if (m_target == GraphicsContext3D::ELEMENT_ARRAY_BUFFER) {

        m_byteLength = size;

        clearCachedMaxIndices();

        m_elementArrayBuffer = ArrayBuffer::create(size, 1);

        if (!m_elementArrayBuffer) {

            m_byteLength = 0;

            return false;

        }

        return true;

    } else if (m_target == GraphicsContext3D::ARRAY_BUFFER) {

        m_byteLength = size;

        return true;

    }

    return false;

}

bool WebGLBuffer::associateBufferData(ArrayBuffer* array)

{

    if (!m_target)

        return false;

    if (!array)

        return false;

    if (m_target == GraphicsContext3D::ELEMENT_ARRAY_BUFFER) {

        clearCachedMaxIndices();

        m_byteLength = array->byteLength();

        // We must always clone the incoming data because client-side

        // modifications without calling bufferData or bufferSubData

        // must never be able to change the validation results.

        m_elementArrayBuffer = ArrayBuffer::create(array);

        if (!m_elementArrayBuffer) {

            m_byteLength = 0;

            return false;

        }

        return true;

    }

    if (m_target == GraphicsContext3D::ARRAY_BUFFER) {

        m_byteLength = array->byteLength();

        return true;

    }

    return false;

}

bool WebGLBuffer::associateBufferData(ArrayBufferView* array)

{

    if (!m_target)

        return false;

    if (!array)

        return false;

    if (m_target == GraphicsContext3D::ELEMENT_ARRAY_BUFFER) {

        clearCachedMaxIndices();

        m_byteLength = array->byteLength();

        // We must always clone the incoming data because client-side

        // modifications without calling bufferData or bufferSubData

        // must never be able to change the validation results.

        m_elementArrayBuffer = ArrayBuffer::create(array->buffer().get());

        if (!m_elementArrayBuffer) {

            m_byteLength = 0;

            return false;

        }

        return true;

    }

    if (m_target == GraphicsContext3D::ARRAY_BUFFER) {

        m_byteLength = array->byteLength();

        return true;

    }

    return false;

}

bool WebGLBuffer::associateBufferSubData(long offset, ArrayBuffer* array)

{

    if (!m_target)

        return false;

    if (!array)

        return false;

    if (m_target == GraphicsContext3D::ELEMENT_ARRAY_BUFFER) {

        clearCachedMaxIndices();

        // We need to protect against integer overflow with these tests

        if (offset < 0)

            return false;

        unsigned long uoffset = static_cast<unsigned long>(offset);

        if (uoffset > m_byteLength || array->byteLength() > m_byteLength - uoffset)

            return false;

        if (!m_elementArrayBuffer)

            return false;

        memcpy(static_cast<unsigned char*>(m_elementArrayBuffer->data()) + offset,

               static_cast<unsigned char*>(array->data()),

               array->byteLength());

        return true;

    }

    if (m_target == GraphicsContext3D::ARRAY_BUFFER)

        return array->byteLength() + offset <= m_byteLength;

    return false;

}

bool WebGLBuffer::associateBufferSubData(long offset, ArrayBufferView* array)

{

    if (!m_target)

        return false;

    if (!array)

        return false;

    if (m_target == GraphicsContext3D::ELEMENT_ARRAY_BUFFER) {

        clearCachedMaxIndices();

        // We need to protect against integer overflow with these tests

        if (offset < 0)

            return false;

        unsigned long uoffset = static_cast<unsigned long>(offset);

        if (uoffset > m_byteLength || array->byteLength() > m_byteLength - uoffset)

            return false;

        if (!m_elementArrayBuffer)

            return false;

        memcpy(static_cast<unsigned char*>(m_elementArrayBuffer->data()) + offset, array->baseAddress(), array->byteLength());

        return true;

    }

    if (m_target == GraphicsContext3D::ARRAY_BUFFER)

        return array->byteLength() + offset <= m_byteLength;

    return false;

}

unsigned WebGLBuffer::byteLength() const

{

    return m_byteLength;

}

long WebGLBuffer::getCachedMaxIndex(unsigned long type)

{

    size_t numEntries = sizeof(m_maxIndexCache) / sizeof(MaxIndexCacheEntry);

    for (size_t i = 0; i < numEntries; i++)

        if (m_maxIndexCache[i].type == type)

            return m_maxIndexCache[i].maxIndex;

    return -1;

}

void WebGLBuffer::setCachedMaxIndex(unsigned long type, long value)

{

    int numEntries = sizeof(m_maxIndexCache) / sizeof(MaxIndexCacheEntry);

    for (int i = 0; i < numEntries; i++)

        if (m_maxIndexCache[i].type == type) {

            m_maxIndexCache[i].maxIndex = value;

            return;

        }

    m_maxIndexCache[m_nextAvailableCacheEntry].type = type;

    m_maxIndexCache[m_nextAvailableCacheEntry].maxIndex = value;

    m_nextAvailableCacheEntry = (m_nextAvailableCacheEntry + 1) % numEntries;

}

void WebGLBuffer::setTarget(unsigned long target)

{

    // In WebGL, a buffer is bound to one target in its lifetime

    if (m_target)

        return;

    if (target == GraphicsContext3D::ARRAY_BUFFER || target == GraphicsContext3D::ELEMENT_ARRAY_BUFFER)

        m_target = target;

}

void WebGLBuffer::clearCachedMaxIndices()

{

    memset(m_maxIndexCache, 0, sizeof(m_maxIndexCache));

}

}

#endif // ENABLE(3D_CANVAS)