/*
 * Copyright (C) 2010 Apple Inc. All rights reserved.
 * Copyright (C) 2010 Google Inc. All rights reserved.
 * Copyright (C) 2010 Mozilla Corporation. 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 USE(3D_GRAPHICS)

#include "GraphicsContext3D.h"
#include "GraphicsContext3DNEON.h"

#include "CheckedInt.h"
#include "DrawingBuffer.h"
#include "Extensions3D.h"
#include "Image.h"
#include "ImageData.h"
#include "ImageObserver.h"

#include <wtf/ArrayBufferView.h>
#include <wtf/OwnArrayPtr.h>
#include <wtf/PassOwnArrayPtr.h>

namespace WebCore {

namespace {

GraphicsContext3D::DataFormat getDataFormat(GC3Denum destinationFormat, GC3Denum destinationType)
{
    GraphicsContext3D::DataFormat dstFormat = GraphicsContext3D::DataFormatRGBA8;
    switch (destinationType) {
    case GraphicsContext3D::UNSIGNED_BYTE:
        switch (destinationFormat) {
        case GraphicsContext3D::RGB:
            dstFormat = GraphicsContext3D::DataFormatRGB8;
            break;
        case GraphicsContext3D::RGBA:
            dstFormat = GraphicsContext3D::DataFormatRGBA8;
            break;
        case GraphicsContext3D::ALPHA:
            dstFormat = GraphicsContext3D::DataFormatA8;
            break;
        case GraphicsContext3D::LUMINANCE:
            dstFormat = GraphicsContext3D::DataFormatR8;
            break;
        case GraphicsContext3D::LUMINANCE_ALPHA:
            dstFormat = GraphicsContext3D::DataFormatRA8;
            break;
        default:
            ASSERT_NOT_REACHED();
        }
        break;
    case GraphicsContext3D::UNSIGNED_SHORT_4_4_4_4:
        dstFormat = GraphicsContext3D::DataFormatRGBA4444;
        break;
    case GraphicsContext3D::UNSIGNED_SHORT_5_5_5_1:
        dstFormat = GraphicsContext3D::DataFormatRGBA5551;
        break;
    case GraphicsContext3D::UNSIGNED_SHORT_5_6_5:
        dstFormat = GraphicsContext3D::DataFormatRGB565;
        break;
    case GraphicsContext3D::FLOAT: // OES_texture_float
        switch (destinationFormat) {
        case GraphicsContext3D::RGB:
            dstFormat = GraphicsContext3D::DataFormatRGB32F;
            break;
        case GraphicsContext3D::RGBA:
            dstFormat = GraphicsContext3D::DataFormatRGBA32F;
            break;
        case GraphicsContext3D::ALPHA:
            dstFormat = GraphicsContext3D::DataFormatA32F;
            break;
        case GraphicsContext3D::LUMINANCE:
            dstFormat = GraphicsContext3D::DataFormatR32F;
            break;
        case GraphicsContext3D::LUMINANCE_ALPHA:
            dstFormat = GraphicsContext3D::DataFormatRA32F;
            break;
        default:
            ASSERT_NOT_REACHED();
        }
        break;
    default:
        ASSERT_NOT_REACHED();
    }
    return dstFormat;
}

} // anonymous namespace

bool GraphicsContext3D::texImage2DResourceSafe(GC3Denum target, GC3Dint level, GC3Denum internalformat, GC3Dsizei width, GC3Dsizei height, GC3Dint border, GC3Denum format, GC3Denum type, GC3Dint unpackAlignment)
{
    ASSERT(unpackAlignment == 1 || unpackAlignment == 2 || unpackAlignment == 4 || unpackAlignment == 8);
    OwnArrayPtr<unsigned char> zero;
    if (!isResourceSafe() && width > 0 && height > 0) {
        unsigned int size;
        GC3Denum error = computeImageSizeInBytes(format, type, width, height, unpackAlignment, &size, 0);
        if (error != GraphicsContext3D::NO_ERROR) {
            synthesizeGLError(error);
            return false;
        }
        zero = adoptArrayPtr(new unsigned char[size]);
        if (!zero) {
            synthesizeGLError(GraphicsContext3D::INVALID_VALUE);
            return false;
        }
        memset(zero.get(), 0, size);
    }
    return texImage2D(target, level, internalformat, width, height, border, format, type, zero.get());
}

bool GraphicsContext3D::computeFormatAndTypeParameters(GC3Denum format,
                                                       GC3Denum type,
                                                       unsigned int* componentsPerPixel,
                                                       unsigned int* bytesPerComponent)
{
    switch (format) {
    case GraphicsContext3D::ALPHA:
    case GraphicsContext3D::LUMINANCE:
    case GraphicsContext3D::DEPTH_COMPONENT:
    case GraphicsContext3D::DEPTH_STENCIL:
        *componentsPerPixel = 1;
        break;
    case GraphicsContext3D::LUMINANCE_ALPHA:
        *componentsPerPixel = 2;
        break;
    case GraphicsContext3D::RGB:
        *componentsPerPixel = 3;
        break;
    case GraphicsContext3D::RGBA:
    case Extensions3D::BGRA_EXT: // GL_EXT_texture_format_BGRA8888
        *componentsPerPixel = 4;
        break;
    default:
        return false;
    }
    switch (type) {
    case GraphicsContext3D::UNSIGNED_BYTE:
        *bytesPerComponent = sizeof(GC3Dubyte);
        break;
    case GraphicsContext3D::UNSIGNED_SHORT:
        *bytesPerComponent = sizeof(GC3Dushort);
        break;
    case GraphicsContext3D::UNSIGNED_SHORT_5_6_5:
    case GraphicsContext3D::UNSIGNED_SHORT_4_4_4_4:
    case GraphicsContext3D::UNSIGNED_SHORT_5_5_5_1:
        *componentsPerPixel = 1;
        *bytesPerComponent = sizeof(GC3Dushort);
        break;
    case GraphicsContext3D::UNSIGNED_INT_24_8:
    case GraphicsContext3D::UNSIGNED_INT:
        *bytesPerComponent = sizeof(GC3Duint);
        break;
    case GraphicsContext3D::FLOAT: // OES_texture_float
        *bytesPerComponent = sizeof(GC3Dfloat);
        break;
    default:
        return false;
    }
    return true;
}

GC3Denum GraphicsContext3D::computeImageSizeInBytes(GC3Denum format, GC3Denum type, GC3Dsizei width, GC3Dsizei height, GC3Dint alignment,
                                                    unsigned int* imageSizeInBytes, unsigned int* paddingInBytes)
{
    ASSERT(imageSizeInBytes);
    ASSERT(alignment == 1 || alignment == 2 || alignment == 4 || alignment == 8);
    if (width < 0 || height < 0)
        return GraphicsContext3D::INVALID_VALUE;
    unsigned int bytesPerComponent, componentsPerPixel;
    if (!computeFormatAndTypeParameters(format, type, &bytesPerComponent, &componentsPerPixel))
        return GraphicsContext3D::INVALID_ENUM;
    if (!width || !height) {
        *imageSizeInBytes = 0;
        if (paddingInBytes)
            *paddingInBytes = 0;
        return GraphicsContext3D::NO_ERROR;
    }
    CheckedInt<uint32_t> checkedValue(bytesPerComponent * componentsPerPixel);
    checkedValue *=  width;
    if (!checkedValue.isValid())
        return GraphicsContext3D::INVALID_VALUE;
    unsigned int validRowSize = checkedValue.value();
    unsigned int padding = 0;
    unsigned int residual = validRowSize % alignment;
    if (residual) {
        padding = alignment - residual;
        checkedValue += padding;
    }
    // Last row needs no padding.
    checkedValue *= (height - 1);
    checkedValue += validRowSize;
    if (!checkedValue.isValid())
        return GraphicsContext3D::INVALID_VALUE;
    *imageSizeInBytes = checkedValue.value();
    if (paddingInBytes)
        *paddingInBytes = padding;
    return GraphicsContext3D::NO_ERROR;
}

GraphicsContext3D::ImageExtractor::ImageExtractor(Image* image, ImageHtmlDomSource imageHtmlDomSource, bool premultiplyAlpha, bool ignoreGammaAndColorProfile)
{
    m_image = image;
    m_imageHtmlDomSource = imageHtmlDomSource;
    m_extractSucceeded = extractImage(premultiplyAlpha, ignoreGammaAndColorProfile);
}

bool GraphicsContext3D::packImageData(
    Image* image,
    const void* pixels,
    GC3Denum format,
    GC3Denum type,
    bool flipY,
    AlphaOp alphaOp,
    DataFormat sourceFormat,
    unsigned width,
    unsigned height,
    unsigned sourceUnpackAlignment,
    Vector<uint8_t>& data)
{
    if (!pixels)
        return false;

    unsigned packedSize;
    // Output data is tightly packed (alignment == 1).
    if (computeImageSizeInBytes(format, type, width, height, 1, &packedSize, 0) != GraphicsContext3D::NO_ERROR)
        return false;
    data.resize(packedSize);

    if (!packPixels(reinterpret_cast<const uint8_t*>(pixels), sourceFormat, width, height, sourceUnpackAlignment, format, type, alphaOp, data.data(), flipY))
        return false;
    if (ImageObserver *observer = image->imageObserver())
        observer->didDraw(image);
    return true;
}

bool GraphicsContext3D::extractImageData(ImageData* imageData,
                                         GC3Denum format,
                                         GC3Denum type,
                                         bool flipY,
                                         bool premultiplyAlpha,
                                         Vector<uint8_t>& data)
{
    if (!imageData)
        return false;
    int width = imageData->width();
    int height = imageData->height();

    unsigned int packedSize;
    // Output data is tightly packed (alignment == 1).
    if (computeImageSizeInBytes(format, type, width, height, 1, &packedSize, 0) != GraphicsContext3D::NO_ERROR)
        return false;
    data.resize(packedSize);

    if (!packPixels(imageData->data()->data(), DataFormatRGBA8, width, height, 0, format, type, premultiplyAlpha ? AlphaDoPremultiply : AlphaDoNothing, data.data(), flipY))
        return false;

    return true;
}

bool GraphicsContext3D::extractTextureData(unsigned int width, unsigned int height,
                                           GC3Denum format, GC3Denum type,
                                           unsigned int unpackAlignment,
                                           bool flipY, bool premultiplyAlpha,
                                           const void* pixels,
                                           Vector<uint8_t>& data)
{
    // Assumes format, type, etc. have already been validated.
    DataFormat sourceDataFormat = getDataFormat(format, type);

    // Resize the output buffer.
    unsigned int componentsPerPixel, bytesPerComponent;
    if (!computeFormatAndTypeParameters(format, type,
                                        &componentsPerPixel,
                                        &bytesPerComponent))
        return false;
    unsigned int bytesPerPixel = componentsPerPixel * bytesPerComponent;
    data.resize(width * height * bytesPerPixel);

    if (!packPixels(static_cast<const uint8_t*>(pixels), sourceDataFormat, width, height, unpackAlignment, format, type, (premultiplyAlpha ? AlphaDoPremultiply : AlphaDoNothing), data.data(), flipY))
        return false;

    return true;
}

namespace {

/* BEGIN CODE SHARED WITH MOZILLA FIREFOX */

// The following packing and unpacking routines are expressed in terms of function templates and inline functions to achieve generality and speedup.
// Explicit template specializations correspond to the cases that would occur.
// Some code are merged back from Mozilla code in http://mxr.mozilla.org/mozilla-central/source/content/canvas/src/WebGLTexelConversions.h

//----------------------------------------------------------------------
// Pixel unpacking routines.
template<int format, typename SourceType, typename DstType>
ALWAYS_INLINE void unpack(const SourceType*, DstType*, unsigned)
{
    ASSERT_NOT_REACHED();
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatRGB8, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        destination[1] = source[1];
        destination[2] = source[2];
        destination[3] = 0xFF;
        source += 3;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatBGR8, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[2];
        destination[1] = source[1];
        destination[2] = source[0];
        destination[3] = 0xFF;
        source += 3;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatARGB8, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[1];
        destination[1] = source[2];
        destination[2] = source[3];
        destination[3] = source[0];
        source += 4;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatABGR8, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[3];
        destination[1] = source[2];
        destination[2] = source[1];
        destination[3] = source[0];
        source += 4;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatBGRA8, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    const uint32_t* source32 = reinterpret_cast_ptr<const uint32_t*>(source);
    uint32_t* destination32 = reinterpret_cast_ptr<uint32_t*>(destination);
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        uint32_t bgra = source32[i];
#if CPU(BIG_ENDIAN)
        uint32_t brMask = 0xff00ff00;
        uint32_t gaMask = 0x00ff00ff;
#else
        uint32_t brMask = 0x00ff00ff;
        uint32_t gaMask = 0xff00ff00;
#endif
        uint32_t rgba = (((bgra >> 16) | (bgra << 16)) & brMask) | (bgra & gaMask);
        destination32[i] = rgba;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatRGBA5551, uint16_t, uint8_t>(const uint16_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
#if HAVE(ARM_NEON_INTRINSICS)
    SIMD::unpackOneRowOfRGBA5551ToRGBA8(source, destination, pixelsPerRow);
#endif
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        uint16_t packedValue = source[0];
        uint8_t r = packedValue >> 11;
        uint8_t g = (packedValue >> 6) & 0x1F;
        uint8_t b = (packedValue >> 1) & 0x1F;
        destination[0] = (r << 3) | (r & 0x7);
        destination[1] = (g << 3) | (g & 0x7);
        destination[2] = (b << 3) | (b & 0x7);
        destination[3] = (packedValue & 0x1) ? 0xFF : 0x0;
        source += 1;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatRGBA4444, uint16_t, uint8_t>(const uint16_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
#if HAVE(ARM_NEON_INTRINSICS)
    SIMD::unpackOneRowOfRGBA4444ToRGBA8(source, destination, pixelsPerRow);
#endif
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        uint16_t packedValue = source[0];
        uint8_t r = packedValue >> 12;
        uint8_t g = (packedValue >> 8) & 0x0F;
        uint8_t b = (packedValue >> 4) & 0x0F;
        uint8_t a = packedValue & 0x0F;
        destination[0] = r << 4 | r;
        destination[1] = g << 4 | g;
        destination[2] = b << 4 | b;
        destination[3] = a << 4 | a;
        source += 1;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatRGB565, uint16_t, uint8_t>(const uint16_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
#if HAVE(ARM_NEON_INTRINSICS)
    SIMD::unpackOneRowOfRGB565ToRGBA8(source, destination, pixelsPerRow);
#endif
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        uint16_t packedValue = source[0];
        uint8_t r = packedValue >> 11;
        uint8_t g = (packedValue >> 5) & 0x3F;
        uint8_t b = packedValue & 0x1F;
        destination[0] = (r << 3) | (r & 0x7);
        destination[1] = (g << 2) | (g & 0x3);
        destination[2] = (b << 3) | (b & 0x7);
        destination[3] = 0xFF;
        source += 1;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatR8, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        destination[1] = source[0];
        destination[2] = source[0];
        destination[3] = 0xFF;
        source += 1;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatRA8, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        destination[1] = source[0];
        destination[2] = source[0];
        destination[3] = source[1];
        source += 2;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatAR8, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[1];
        destination[1] = source[1];
        destination[2] = source[1];
        destination[3] = source[0];
        source += 2;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatA8, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = 0x0;
        destination[1] = 0x0;
        destination[2] = 0x0;
        destination[3] = source[0];
        source += 1;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatRGBA8, uint8_t, float>(const uint8_t* source, float* destination, unsigned pixelsPerRow)
{
    const float scaleFactor = 1.0f / 255.0f;
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0] * scaleFactor;
        destination[1] = source[1] * scaleFactor;
        destination[2] = source[2] * scaleFactor;
        destination[3] = source[3] * scaleFactor;
        source += 4;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatBGRA8, uint8_t, float>(const uint8_t* source, float* destination, unsigned pixelsPerRow)
{
    const float scaleFactor = 1.0f / 255.0f;
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[2] * scaleFactor;
        destination[1] = source[1] * scaleFactor;
        destination[2] = source[0] * scaleFactor;
        destination[3] = source[3] * scaleFactor;
        source += 4;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatABGR8, uint8_t, float>(const uint8_t* source, float* destination, unsigned pixelsPerRow)
{
    const float scaleFactor = 1.0f / 255.0f;
    for (unsigned i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[3] * scaleFactor;
        destination[1] = source[2] * scaleFactor;
        destination[2] = source[1] * scaleFactor;
        destination[3] = source[0] * scaleFactor;
        source += 4;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatARGB8, uint8_t, float>(const uint8_t* source, float* destination, unsigned pixelsPerRow)
{
    const float scaleFactor = 1.0f / 255.0f;
    for (unsigned i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[1] * scaleFactor;
        destination[1] = source[2] * scaleFactor;
        destination[2] = source[3] * scaleFactor;
        destination[3] = source[0] * scaleFactor;
        source += 4;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatRGB8, uint8_t, float>(const uint8_t* source, float* destination, unsigned pixelsPerRow)
{
    const float scaleFactor = 1.0f / 255.0f;
    for (unsigned i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0] * scaleFactor;
        destination[1] = source[1] * scaleFactor;
        destination[2] = source[2] * scaleFactor;
        destination[3] = 1;
        source += 3;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatBGR8, uint8_t, float>(const uint8_t* source, float* destination, unsigned pixelsPerRow)
{
    const float scaleFactor = 1.0f / 255.0f;
    for (unsigned i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[2] * scaleFactor;
        destination[1] = source[1] * scaleFactor;
        destination[2] = source[0] * scaleFactor;
        destination[3] = 1;
        source += 3;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatRGB32F, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        destination[1] = source[1];
        destination[2] = source[2];
        destination[3] = 1;
        source += 3;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatR32F, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        destination[1] = source[0];
        destination[2] = source[0];
        destination[3] = 1;
        source += 1;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatRA32F, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        destination[1] = source[0];
        destination[2] = source[0];
        destination[3] = source[1];
        source += 2;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void unpack<GraphicsContext3D::DataFormatA32F, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = 0;
        destination[1] = 0;
        destination[2] = 0;
        destination[3] = source[0];
        source += 1;
        destination += 4;
    }
}

//----------------------------------------------------------------------
// Pixel packing routines.
//

template<int format, int alphaOp, typename SourceType, typename DstType>
ALWAYS_INLINE void pack(const SourceType*, DstType*, unsigned)
{
    ASSERT_NOT_REACHED();
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatA8, GraphicsContext3D::AlphaDoNothing, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[3];
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatR8, GraphicsContext3D::AlphaDoNothing, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatR8, GraphicsContext3D::AlphaDoPremultiply, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] / 255.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        destination[0] = sourceR;
        source += 4;
        destination += 1;
    }
}

// FIXME: this routine is lossy and must be removed.
template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatR8, GraphicsContext3D::AlphaDoUnmultiply, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 255.0f / source[3] : 1.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        destination[0] = sourceR;
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRA8, GraphicsContext3D::AlphaDoNothing, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        destination[1] = source[3];
        source += 4;
        destination += 2;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRA8, GraphicsContext3D::AlphaDoPremultiply, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] / 255.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        destination[0] = sourceR;
        destination[1] = source[3];
        source += 4;
        destination += 2;
    }
}

// FIXME: this routine is lossy and must be removed.
template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRA8, GraphicsContext3D::AlphaDoUnmultiply, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 255.0f / source[3] : 1.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        destination[0] = sourceR;
        destination[1] = source[3];
        source += 4;
        destination += 2;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGB8, GraphicsContext3D::AlphaDoNothing, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        destination[1] = source[1];
        destination[2] = source[2];
        source += 4;
        destination += 3;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGB8, GraphicsContext3D::AlphaDoPremultiply, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] / 255.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        uint8_t sourceG = static_cast<uint8_t>(static_cast<float>(source[1]) * scaleFactor);
        uint8_t sourceB = static_cast<uint8_t>(static_cast<float>(source[2]) * scaleFactor);
        destination[0] = sourceR;
        destination[1] = sourceG;
        destination[2] = sourceB;
        source += 4;
        destination += 3;
    }
}

// FIXME: this routine is lossy and must be removed.
template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGB8, GraphicsContext3D::AlphaDoUnmultiply, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 255.0f / source[3] : 1.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        uint8_t sourceG = static_cast<uint8_t>(static_cast<float>(source[1]) * scaleFactor);
        uint8_t sourceB = static_cast<uint8_t>(static_cast<float>(source[2]) * scaleFactor);
        destination[0] = sourceR;
        destination[1] = sourceG;
        destination[2] = sourceB;
        source += 4;
        destination += 3;
    }
}


template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA8, GraphicsContext3D::AlphaDoNothing, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    memcpy(destination, source, pixelsPerRow * 4);
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA8, GraphicsContext3D::AlphaDoPremultiply, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] / 255.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        uint8_t sourceG = static_cast<uint8_t>(static_cast<float>(source[1]) * scaleFactor);
        uint8_t sourceB = static_cast<uint8_t>(static_cast<float>(source[2]) * scaleFactor);
        destination[0] = sourceR;
        destination[1] = sourceG;
        destination[2] = sourceB;
        destination[3] = source[3];
        source += 4;
        destination += 4;
    }
}

// FIXME: this routine is lossy and must be removed.
template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA8, GraphicsContext3D::AlphaDoUnmultiply, uint8_t, uint8_t>(const uint8_t* source, uint8_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 255.0f / source[3] : 1.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        uint8_t sourceG = static_cast<uint8_t>(static_cast<float>(source[1]) * scaleFactor);
        uint8_t sourceB = static_cast<uint8_t>(static_cast<float>(source[2]) * scaleFactor);
        destination[0] = sourceR;
        destination[1] = sourceG;
        destination[2] = sourceB;
        destination[3] = source[3];
        source += 4;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA4444, GraphicsContext3D::AlphaDoNothing, uint8_t, uint16_t>(const uint8_t* source, uint16_t* destination, unsigned pixelsPerRow)
{
#if HAVE(ARM_NEON_INTRINSICS)
    SIMD::packOneRowOfRGBA8ToUnsignedShort4444(source, destination, pixelsPerRow);
#endif
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        *destination = (((source[0] & 0xF0) << 8)
                        | ((source[1] & 0xF0) << 4)
                        | (source[2] & 0xF0)
                        | (source[3] >> 4));
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA4444, GraphicsContext3D::AlphaDoPremultiply, uint8_t, uint16_t>(const uint8_t* source, uint16_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] / 255.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        uint8_t sourceG = static_cast<uint8_t>(static_cast<float>(source[1]) * scaleFactor);
        uint8_t sourceB = static_cast<uint8_t>(static_cast<float>(source[2]) * scaleFactor);
        *destination = (((sourceR & 0xF0) << 8)
                        | ((sourceG & 0xF0) << 4)
                        | (sourceB & 0xF0)
                        | (source[3] >> 4));
        source += 4;
        destination += 1;
    }
}

// FIXME: this routine is lossy and must be removed.
template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA4444, GraphicsContext3D::AlphaDoUnmultiply, uint8_t, uint16_t>(const uint8_t* source, uint16_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 255.0f / source[3] : 1.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        uint8_t sourceG = static_cast<uint8_t>(static_cast<float>(source[1]) * scaleFactor);
        uint8_t sourceB = static_cast<uint8_t>(static_cast<float>(source[2]) * scaleFactor);
        *destination = (((sourceR & 0xF0) << 8)
                        | ((sourceG & 0xF0) << 4)
                        | (sourceB & 0xF0)
                        | (source[3] >> 4));
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA5551, GraphicsContext3D::AlphaDoNothing, uint8_t, uint16_t>(const uint8_t* source, uint16_t* destination, unsigned pixelsPerRow)
{
#if HAVE(ARM_NEON_INTRINSICS)
    SIMD::packOneRowOfRGBA8ToUnsignedShort5551(source, destination, pixelsPerRow);
#endif
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        *destination = (((source[0] & 0xF8) << 8)
                        | ((source[1] & 0xF8) << 3)
                        | ((source[2] & 0xF8) >> 2)
                        | (source[3] >> 7));
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA5551, GraphicsContext3D::AlphaDoPremultiply, uint8_t, uint16_t>(const uint8_t* source, uint16_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] / 255.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        uint8_t sourceG = static_cast<uint8_t>(static_cast<float>(source[1]) * scaleFactor);
        uint8_t sourceB = static_cast<uint8_t>(static_cast<float>(source[2]) * scaleFactor);
        *destination = (((sourceR & 0xF8) << 8)
                        | ((sourceG & 0xF8) << 3)
                        | ((sourceB & 0xF8) >> 2)
                        | (source[3] >> 7));
        source += 4;
        destination += 1;
    }
}

// FIXME: this routine is lossy and must be removed.
template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA5551, GraphicsContext3D::AlphaDoUnmultiply, uint8_t, uint16_t>(const uint8_t* source, uint16_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 255.0f / source[3] : 1.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        uint8_t sourceG = static_cast<uint8_t>(static_cast<float>(source[1]) * scaleFactor);
        uint8_t sourceB = static_cast<uint8_t>(static_cast<float>(source[2]) * scaleFactor);
        *destination = (((sourceR & 0xF8) << 8)
                        | ((sourceG & 0xF8) << 3)
                        | ((sourceB & 0xF8) >> 2)
                        | (source[3] >> 7));
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGB565, GraphicsContext3D::AlphaDoNothing, uint8_t, uint16_t>(const uint8_t* source, uint16_t* destination, unsigned pixelsPerRow)
{
#if HAVE(ARM_NEON_INTRINSICS)
    SIMD::packOneRowOfRGBA8ToUnsignedShort565(source, destination, pixelsPerRow);
#endif
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        *destination = (((source[0] & 0xF8) << 8)
                        | ((source[1] & 0xFC) << 3)
                        | ((source[2] & 0xF8) >> 3));
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGB565, GraphicsContext3D::AlphaDoPremultiply, uint8_t, uint16_t>(const uint8_t* source, uint16_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] / 255.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        uint8_t sourceG = static_cast<uint8_t>(static_cast<float>(source[1]) * scaleFactor);
        uint8_t sourceB = static_cast<uint8_t>(static_cast<float>(source[2]) * scaleFactor);
        *destination = (((sourceR & 0xF8) << 8)
                        | ((sourceG & 0xFC) << 3)
                        | ((sourceB & 0xF8) >> 3));
        source += 4;
        destination += 1;
    }
}

// FIXME: this routine is lossy and must be removed.
template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGB565, GraphicsContext3D::AlphaDoUnmultiply, uint8_t, uint16_t>(const uint8_t* source, uint16_t* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 255.0f / source[3] : 1.0f;
        uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
        uint8_t sourceG = static_cast<uint8_t>(static_cast<float>(source[1]) * scaleFactor);
        uint8_t sourceB = static_cast<uint8_t>(static_cast<float>(source[2]) * scaleFactor);
        *destination = (((sourceR & 0xF8) << 8)
                        | ((sourceG & 0xFC) << 3)
                        | ((sourceB & 0xF8) >> 3));
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGB32F, GraphicsContext3D::AlphaDoNothing, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        destination[1] = source[1];
        destination[2] = source[2];
        source += 4;
        destination += 3;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGB32F, GraphicsContext3D::AlphaDoPremultiply, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3];
        destination[0] = source[0] * scaleFactor;
        destination[1] = source[1] * scaleFactor;
        destination[2] = source[2] * scaleFactor;
        source += 4;
        destination += 3;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGB32F, GraphicsContext3D::AlphaDoUnmultiply, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 1.0f / source[3] : 1.0f;
        destination[0] = source[0] * scaleFactor;
        destination[1] = source[1] * scaleFactor;
        destination[2] = source[2] * scaleFactor;
        source += 4;
        destination += 3;
    }
}

// Used only during RGBA8 or BGRA8 -> floating-point uploads.
template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA32F, GraphicsContext3D::AlphaDoNothing, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    memcpy(destination, source, pixelsPerRow * 4 * sizeof(float));
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA32F, GraphicsContext3D::AlphaDoPremultiply, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3];
        destination[0] = source[0] * scaleFactor;
        destination[1] = source[1] * scaleFactor;
        destination[2] = source[2] * scaleFactor;
        destination[3] = source[3];
        source += 4;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRGBA32F, GraphicsContext3D::AlphaDoUnmultiply, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 1.0f / source[3] : 1.0f;
        destination[0] = source[0] * scaleFactor;
        destination[1] = source[1] * scaleFactor;
        destination[2] = source[2] * scaleFactor;
        destination[3] = source[3];
        source += 4;
        destination += 4;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatA32F, GraphicsContext3D::AlphaDoNothing, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[3];
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatR32F, GraphicsContext3D::AlphaDoNothing, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatR32F, GraphicsContext3D::AlphaDoPremultiply, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3];
        destination[0] = source[0] * scaleFactor;
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatR32F, GraphicsContext3D::AlphaDoUnmultiply, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 1.0f / source[3] : 1.0f;
        destination[0] = source[0] * scaleFactor;
        source += 4;
        destination += 1;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRA32F, GraphicsContext3D::AlphaDoNothing, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        destination[0] = source[0];
        destination[1] = source[3];
        source += 4;
        destination += 2;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRA32F, GraphicsContext3D::AlphaDoPremultiply, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3];
        destination[0] = source[0] * scaleFactor;
        destination[1] = source[3];
        source += 4;
        destination += 2;
    }
}

template<> ALWAYS_INLINE void pack<GraphicsContext3D::DataFormatRA32F, GraphicsContext3D::AlphaDoUnmultiply, float, float>(const float* source, float* destination, unsigned pixelsPerRow)
{
    for (unsigned int i = 0; i < pixelsPerRow; ++i) {
        float scaleFactor = source[3] ? 1.0f / source[3] : 1.0f;
        destination[0] = source[0] * scaleFactor;
        destination[1] = source[3];
        source += 4;
        destination += 2;
    }
}

ALWAYS_INLINE bool HasAlpha(int format)
{
    return format == GraphicsContext3D::DataFormatA8
        || format == GraphicsContext3D::DataFormatA32F
        || format == GraphicsContext3D::DataFormatRA8
        || format == GraphicsContext3D::DataFormatAR8
        || format == GraphicsContext3D::DataFormatRA32F
        || format == GraphicsContext3D::DataFormatRGBA8
        || format == GraphicsContext3D::DataFormatBGRA8
        || format == GraphicsContext3D::DataFormatARGB8
        || format == GraphicsContext3D::DataFormatABGR8
        || format == GraphicsContext3D::DataFormatRGBA32F
        || format == GraphicsContext3D::DataFormatRGBA4444
        || format == GraphicsContext3D::DataFormatRGBA5551;
}

ALWAYS_INLINE bool HasColor(int format)
{
    return format == GraphicsContext3D::DataFormatRGBA8
        || format == GraphicsContext3D::DataFormatRGBA32F
        || format == GraphicsContext3D::DataFormatRGB8
        || format == GraphicsContext3D::DataFormatRGB32F
        || format == GraphicsContext3D::DataFormatBGR8
        || format == GraphicsContext3D::DataFormatBGRA8
        || format == GraphicsContext3D::DataFormatARGB8
        || format == GraphicsContext3D::DataFormatABGR8
        || format == GraphicsContext3D::DataFormatRGBA5551
        || format == GraphicsContext3D::DataFormatRGBA4444
        || format == GraphicsContext3D::DataFormatRGB565
        || format == GraphicsContext3D::DataFormatR8
        || format == GraphicsContext3D::DataFormatR32F
        || format == GraphicsContext3D::DataFormatRA8
        || format == GraphicsContext3D::DataFormatRA32F
        || format == GraphicsContext3D::DataFormatAR8;
}

template<int Format>
struct IsFloatFormat {
    static const bool Value =
        Format == GraphicsContext3D::DataFormatRGBA32F
        || Format == GraphicsContext3D::DataFormatRGB32F
        || Format == GraphicsContext3D::DataFormatRA32F
        || Format == GraphicsContext3D::DataFormatR32F
        || Format == GraphicsContext3D::DataFormatA32F;
};

template<int Format>
struct Is16bppFormat {
    static const bool Value =
        Format == GraphicsContext3D::DataFormatRGBA5551
        || Format == GraphicsContext3D::DataFormatRGBA4444
        || Format == GraphicsContext3D::DataFormatRGB565;
};

template<int Format, bool IsFloat = IsFloatFormat<Format>::Value, bool Is16bpp = Is16bppFormat<Format>::Value>
struct DataTypeForFormat {
    typedef uint8_t Type;
};

template<int Format>
struct DataTypeForFormat<Format, true, false> {
    typedef float Type;
};

template<int Format>
struct DataTypeForFormat<Format, false, true> {
    typedef uint16_t Type;
};

template<int Format>
struct IntermediateFormat {
    static const int Value = IsFloatFormat<Format>::Value ? GraphicsContext3D::DataFormatRGBA32F : GraphicsContext3D::DataFormatRGBA8;
};

ALWAYS_INLINE unsigned TexelBytesForFormat(GraphicsContext3D::DataFormat format)
{
    switch (format) {
    case GraphicsContext3D::DataFormatR8:
    case GraphicsContext3D::DataFormatA8:
        return 1;
    case GraphicsContext3D::DataFormatRA8:
    case GraphicsContext3D::DataFormatAR8:
    case GraphicsContext3D::DataFormatRGBA5551:
    case GraphicsContext3D::DataFormatRGBA4444:
    case GraphicsContext3D::DataFormatRGB565:
        return 2;
    case GraphicsContext3D::DataFormatRGB8:
    case GraphicsContext3D::DataFormatBGR8:
        return 3;
    case GraphicsContext3D::DataFormatRGBA8:
    case GraphicsContext3D::DataFormatARGB8:
    case GraphicsContext3D::DataFormatABGR8:
    case GraphicsContext3D::DataFormatBGRA8:
    case GraphicsContext3D::DataFormatR32F:
    case GraphicsContext3D::DataFormatA32F:
        return 4;
    case GraphicsContext3D::DataFormatRA32F:
        return 8;
    case GraphicsContext3D::DataFormatRGB32F:
        return 12;
    case GraphicsContext3D::DataFormatRGBA32F:
        return 16;
    default:
        return 0;
    }
}

/* END CODE SHARED WITH MOZILLA FIREFOX */

class FormatConverter {
public:
    FormatConverter(unsigned width, unsigned height,
        const void* srcStart, void* dstStart, int srcStride, int dstStride)
        : m_width(width), m_height(height), m_srcStart(srcStart), m_dstStart(dstStart), m_srcStride(srcStride), m_dstStride(dstStride), m_success(false)
    {
        const unsigned MaxNumberOfComponents = 4;
        const unsigned MaxBytesPerComponent  = 4;
        m_unpackedIntermediateSrcData = adoptArrayPtr(new uint8_t[m_width * MaxNumberOfComponents *MaxBytesPerComponent]);
        ASSERT(m_unpackedIntermediateSrcData.get());
    }

    void convert(GraphicsContext3D::DataFormat srcFormat, GraphicsContext3D::DataFormat dstFormat, GraphicsContext3D::AlphaOp);
    bool Success() const { return m_success; }

private:
    template<GraphicsContext3D::DataFormat SrcFormat>
    ALWAYS_INLINE void convert(GraphicsContext3D::DataFormat dstFormat, GraphicsContext3D::AlphaOp);

    template<GraphicsContext3D::DataFormat SrcFormat, GraphicsContext3D::DataFormat DstFormat>
    ALWAYS_INLINE void convert(GraphicsContext3D::AlphaOp);

    template<GraphicsContext3D::DataFormat SrcFormat, GraphicsContext3D::DataFormat DstFormat, GraphicsContext3D::AlphaOp alphaOp>
    ALWAYS_INLINE void convert();

    const unsigned m_width, m_height;
    const void* const m_srcStart;
    void* const m_dstStart;
    const int m_srcStride, m_dstStride;
    bool m_success;
    OwnArrayPtr<uint8_t> m_unpackedIntermediateSrcData;
};

void FormatConverter::convert(GraphicsContext3D::DataFormat srcFormat, GraphicsContext3D::DataFormat dstFormat, GraphicsContext3D::AlphaOp alphaOp)
{
#define FORMATCONVERTER_CASE_SRCFORMAT(SrcFormat) \
    case SrcFormat: \
        return convert<SrcFormat>(dstFormat, alphaOp);

        switch (srcFormat) {
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatR8)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatA8)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatR32F)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatA32F)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatRA8)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatRA32F)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatRGB8)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatBGR8)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatRGB565)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatRGB32F)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatRGBA8)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatARGB8)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatABGR8)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatAR8)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatBGRA8)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatRGBA5551)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatRGBA4444)
            FORMATCONVERTER_CASE_SRCFORMAT(GraphicsContext3D::DataFormatRGBA32F)
        default:
            ASSERT_NOT_REACHED();
        }
#undef FORMATCONVERTER_CASE_SRCFORMAT
}

template<GraphicsContext3D::DataFormat SrcFormat>
ALWAYS_INLINE void FormatConverter::convert(GraphicsContext3D::DataFormat dstFormat, GraphicsContext3D::AlphaOp alphaOp)
{
#define FORMATCONVERTER_CASE_DSTFORMAT(DstFormat) \
    case DstFormat: \
        return convert<SrcFormat, DstFormat>(alphaOp);

        switch (dstFormat) {
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatR8)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatA8)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatR32F)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatA32F)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatRA8)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatRA32F)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatRGB8)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatRGB565)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatRGB32F)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatRGBA8)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatRGBA5551)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatRGBA4444)
            FORMATCONVERTER_CASE_DSTFORMAT(GraphicsContext3D::DataFormatRGBA32F)
        default:
            ASSERT_NOT_REACHED();
        }

#undef FORMATCONVERTER_CASE_DSTFORMAT
}

template<GraphicsContext3D::DataFormat SrcFormat, GraphicsContext3D::DataFormat DstFormat>
ALWAYS_INLINE void FormatConverter::convert(GraphicsContext3D::AlphaOp alphaOp)
{
#define FORMATCONVERTER_CASE_ALPHAOP(alphaOp) \
    case alphaOp: \
        return convert<SrcFormat, DstFormat, alphaOp>();

        switch (alphaOp) {
            FORMATCONVERTER_CASE_ALPHAOP(GraphicsContext3D::AlphaDoNothing)
            FORMATCONVERTER_CASE_ALPHAOP(GraphicsContext3D::AlphaDoPremultiply)
            FORMATCONVERTER_CASE_ALPHAOP(GraphicsContext3D::AlphaDoUnmultiply)
        default:
            ASSERT_NOT_REACHED();
        }
#undef FORMATCONVERTER_CASE_ALPHAOP
}

template<GraphicsContext3D::DataFormat SrcFormat, GraphicsContext3D::DataFormat DstFormat, GraphicsContext3D::AlphaOp alphaOp>
ALWAYS_INLINE void FormatConverter::convert()
{
    // Many instantiations of this template function will never be entered, so we try
    // to return immediately in these cases to avoid the compiler to generate useless code.
    if (SrcFormat == DstFormat && alphaOp == GraphicsContext3D::AlphaDoNothing) {
        ASSERT_NOT_REACHED();
        return;
    }
    if (!IsFloatFormat<DstFormat>::Value && IsFloatFormat<SrcFormat>::Value) {
        ASSERT_NOT_REACHED();
        return;
    }

    // Only textures uploaded from DOM elements or ImageData can allow DstFormat != SrcFormat.
    const bool srcFormatComesFromDOMElementOrImageData = GraphicsContext3D::srcFormatComeFromDOMElementOrImageData(SrcFormat);
    if (!srcFormatComesFromDOMElementOrImageData && SrcFormat != DstFormat) {
        ASSERT_NOT_REACHED();
        return;
    }
    // Likewise, only textures uploaded from DOM elements or ImageData can possibly have to be unpremultiplied.
    if (!srcFormatComesFromDOMElementOrImageData && alphaOp == GraphicsContext3D::AlphaDoUnmultiply) {
        ASSERT_NOT_REACHED();
        return;
    }
    if ((!HasAlpha(SrcFormat) || !HasColor(SrcFormat) || !HasColor(DstFormat)) && alphaOp != GraphicsContext3D::AlphaDoNothing) {
        ASSERT_NOT_REACHED();
        return;
    }

    typedef typename DataTypeForFormat<SrcFormat>::Type SrcType;
    typedef typename DataTypeForFormat<DstFormat>::Type DstType;
    const int IntermediateSrcFormat = IntermediateFormat<DstFormat>::Value;
    typedef typename DataTypeForFormat<IntermediateSrcFormat>::Type IntermediateSrcType;
    const ptrdiff_t srcStrideInElements = m_srcStride / sizeof(SrcType);
    const ptrdiff_t dstStrideInElements = m_dstStride / sizeof(DstType);
    const bool trivialUnpack = (SrcFormat == GraphicsContext3D::DataFormatRGBA8 && !IsFloatFormat<DstFormat>::Value) || SrcFormat == GraphicsContext3D::DataFormatRGBA32F;
    const bool trivialPack = (DstFormat == GraphicsContext3D::DataFormatRGBA8 || DstFormat == GraphicsContext3D::DataFormatRGBA32F) && alphaOp == GraphicsContext3D::AlphaDoNothing && m_dstStride > 0;
    ASSERT(!trivialUnpack || !trivialPack);

    const SrcType *srcRowStart = static_cast<const SrcType*>(m_srcStart);
    DstType* dstRowStart = static_cast<DstType*>(m_dstStart);
    if (!trivialUnpack && trivialPack) {
        for (size_t i = 0; i < m_height; ++i) {
            unpack<SrcFormat>(srcRowStart, dstRowStart, m_width);
            srcRowStart += srcStrideInElements;
            dstRowStart += dstStrideInElements;
        }
    } else if (!trivialUnpack && !trivialPack) {
        for (size_t i = 0; i < m_height; ++i) {
            unpack<SrcFormat>(srcRowStart, reinterpret_cast<IntermediateSrcType*>(m_unpackedIntermediateSrcData.get()), m_width);
            pack<DstFormat, alphaOp>(reinterpret_cast<IntermediateSrcType*>(m_unpackedIntermediateSrcData.get()), dstRowStart, m_width);
            srcRowStart += srcStrideInElements;
            dstRowStart += dstStrideInElements;
        }
    } else {
        for (size_t i = 0; i < m_height; ++i) {
            pack<DstFormat, alphaOp>(srcRowStart, dstRowStart, m_width);
            srcRowStart += srcStrideInElements;
            dstRowStart += dstStrideInElements;
        }
    }
    m_success = true;
    return;
}

} // anonymous namespace

bool GraphicsContext3D::packPixels(const uint8_t* sourceData, DataFormat sourceDataFormat, unsigned width, unsigned height, unsigned sourceUnpackAlignment, unsigned destinationFormat, unsigned destinationType, AlphaOp alphaOp, void* destinationData, bool flipY)
{
    int validSrc = width * TexelBytesForFormat(sourceDataFormat);
    int remainder = sourceUnpackAlignment ? (validSrc % sourceUnpackAlignment) : 0;
    int srcStride = remainder ? (validSrc + sourceUnpackAlignment - remainder) : validSrc;

    DataFormat dstDataFormat = getDataFormat(destinationFormat, destinationType);
    int dstStride = width * TexelBytesForFormat(dstDataFormat);
    if (flipY) {
        destinationData = static_cast<uint8_t*>(destinationData) + dstStride*(height - 1);
        dstStride = -dstStride;
    }
    if (!HasAlpha(sourceDataFormat) || !HasColor(sourceDataFormat) || !HasColor(dstDataFormat))
        alphaOp = AlphaDoNothing;

    if (sourceDataFormat == dstDataFormat && alphaOp == AlphaDoNothing) {
        const uint8_t* ptr = sourceData;
        const uint8_t* ptrEnd = sourceData + srcStride * height;
        unsigned rowSize = (dstStride > 0) ? dstStride: -dstStride;
        uint8_t* dst = static_cast<uint8_t*>(destinationData);
        while (ptr < ptrEnd) {
            memcpy(dst, ptr, rowSize);
            ptr += srcStride;
            dst += dstStride;
        }
        return true;
    }

    FormatConverter converter(width, height, sourceData, destinationData, srcStride, dstStride);
    converter.convert(sourceDataFormat, dstDataFormat, alphaOp);
    if (!converter.Success())
        return false;
    return true;
}

unsigned GraphicsContext3D::getClearBitsByAttachmentType(GC3Denum attachment)
{
    switch (attachment) {
    case GraphicsContext3D::COLOR_ATTACHMENT0:
        return GraphicsContext3D::COLOR_BUFFER_BIT;
    case GraphicsContext3D::DEPTH_ATTACHMENT:
        return GraphicsContext3D::DEPTH_BUFFER_BIT;
    case GraphicsContext3D::STENCIL_ATTACHMENT:
        return GraphicsContext3D::STENCIL_BUFFER_BIT;
    case GraphicsContext3D::DEPTH_STENCIL_ATTACHMENT:
        return GraphicsContext3D::DEPTH_BUFFER_BIT | GraphicsContext3D::STENCIL_BUFFER_BIT;
    default:
        return 0;
    }
}

unsigned GraphicsContext3D::getClearBitsByFormat(GC3Denum format)
{
    switch (format) {
    case GraphicsContext3D::ALPHA:
    case GraphicsContext3D::LUMINANCE:
    case GraphicsContext3D::LUMINANCE_ALPHA:
    case GraphicsContext3D::RGB:
    case GraphicsContext3D::RGB565:
    case GraphicsContext3D::RGBA:
    case GraphicsContext3D::RGBA4:
    case GraphicsContext3D::RGB5_A1:
        return GraphicsContext3D::COLOR_BUFFER_BIT;
    case GraphicsContext3D::DEPTH_COMPONENT16:
    case GraphicsContext3D::DEPTH_COMPONENT:
        return GraphicsContext3D::DEPTH_BUFFER_BIT;
    case GraphicsContext3D::STENCIL_INDEX8:
        return GraphicsContext3D::STENCIL_BUFFER_BIT;
    case GraphicsContext3D::DEPTH_STENCIL:
        return GraphicsContext3D::DEPTH_BUFFER_BIT | GraphicsContext3D::STENCIL_BUFFER_BIT;
    default:
        return 0;
    }
}

unsigned GraphicsContext3D::getChannelBitsByFormat(GC3Denum format)
{
    switch (format) {
    case GraphicsContext3D::ALPHA:
        return ChannelAlpha;
    case GraphicsContext3D::LUMINANCE:
        return ChannelRGB;
    case GraphicsContext3D::LUMINANCE_ALPHA:
        return ChannelRGBA;
    case GraphicsContext3D::RGB:
    case GraphicsContext3D::RGB565:
        return ChannelRGB;
    case GraphicsContext3D::RGBA:
    case GraphicsContext3D::RGBA4:
    case GraphicsContext3D::RGB5_A1:
        return ChannelRGBA;
    case GraphicsContext3D::DEPTH_COMPONENT16:
    case GraphicsContext3D::DEPTH_COMPONENT:
        return ChannelDepth;
    case GraphicsContext3D::STENCIL_INDEX8:
        return ChannelStencil;
    case GraphicsContext3D::DEPTH_STENCIL:
        return ChannelDepth | ChannelStencil;
    default:
        return 0;
    }
}

} // namespace WebCore

#endif // USE(3D_GRAPHICS)
