/*
 * Copyright (C) 2010 Apple Inc. All rights reserved.
 * Copyright (C) 2010 Google 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 "GraphicsContext3D.h"

#include "Image.h"
#include "ImageData.h"

namespace WebCore {

bool GraphicsContext3D::computeFormatAndTypeParameters(unsigned int format,
                                                       unsigned int type,
                                                       unsigned long* componentsPerPixel,
                                                       unsigned long* bytesPerComponent)
{
    switch (format) {
    case GraphicsContext3D::ALPHA:
        *componentsPerPixel = 1;
        break;
    case GraphicsContext3D::LUMINANCE:
        *componentsPerPixel = 1;
        break;
    case GraphicsContext3D::LUMINANCE_ALPHA:
        *componentsPerPixel = 2;
        break;
    case GraphicsContext3D::RGB:
        *componentsPerPixel = 3;
        break;
    case GraphicsContext3D::RGBA:
        *componentsPerPixel = 4;
        break;
    default:
        return false;
    }
    switch (type) {
    case GraphicsContext3D::UNSIGNED_BYTE:
        *bytesPerComponent = sizeof(unsigned char);
        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(unsigned short);
        break;
    default:
        return false;
    }
    return true;
}

bool GraphicsContext3D::extractImageData(Image* image,
                                         unsigned int format,
                                         unsigned int type,
                                         bool flipY,
                                         bool premultiplyAlpha,
                                         Vector<uint8_t>& data)
{
    if (!image)
        return false;
    if (!getImageData(image, format, type, premultiplyAlpha, data))
        return false;
    if (flipY) {
        unsigned long componentsPerPixel, bytesPerComponent;
        if (!computeFormatAndTypeParameters(format, type,
                                            &componentsPerPixel,
                                            &bytesPerComponent))
            return false;
        // The image data is tightly packed, and we upload it as such.
        unsigned int unpackAlignment = 1;
        flipVertically(data.data(), image->width(), image->height(),
                       componentsPerPixel * bytesPerComponent,
                       unpackAlignment);
    }
    return true;
}

bool GraphicsContext3D::extractImageData(ImageData* imageData,
                                         unsigned int format,
                                         unsigned int type,
                                         bool flipY,
                                         bool premultiplyAlpha,
                                         Vector<uint8_t>& data)
{
    if (!imageData)
        return false;
    int width = imageData->width();
    int height = imageData->height();
    int dataBytes = width * height * 4;
    data.resize(dataBytes);
    if (!packPixels(imageData->data()->data()->data(),
                    kSourceFormatRGBA8,
                    width,
                    height,
                    format,
                    type,
                    premultiplyAlpha ? kAlphaDoPremultiply : kAlphaDoNothing,
                    data.data()))
        return false;
    if (flipY) {
        unsigned long componentsPerPixel, bytesPerComponent;
        if (!computeFormatAndTypeParameters(format, type,
                                            &componentsPerPixel,
                                            &bytesPerComponent))
            return false;
        // The image data is tightly packed, and we upload it as such.
        unsigned int unpackAlignment = 1;
        flipVertically(data.data(), width, height,
                       componentsPerPixel * bytesPerComponent,
                       unpackAlignment);
    }
    return true;
}

void GraphicsContext3D::flipVertically(void* imageData,
                                       unsigned int width,
                                       unsigned int height,
                                       unsigned int bytesPerPixel,
                                       unsigned int unpackAlignment)
{
    if (!width || !height)
        return;
    unsigned int validRowBytes = width * bytesPerPixel;
    unsigned int totalRowBytes = validRowBytes;
    unsigned int remainder = validRowBytes % unpackAlignment;
    if (remainder)
        totalRowBytes += remainder;
    uint8_t* tempRow = new uint8_t[validRowBytes];
    uint8_t* data = static_cast<uint8_t*>(imageData);
    for (unsigned i = 0; i < height / 2; i++) {
        uint8_t* lowRow = data + (totalRowBytes * i);
        uint8_t* highRow = data + (totalRowBytes * (height - i - 1));
        memcpy(tempRow, lowRow, validRowBytes);
        memcpy(lowRow, highRow, validRowBytes);
        memcpy(highRow, tempRow, validRowBytes);
    }
    delete[] tempRow;
}

// These functions can not be static, or gcc will not allow them to be
// used as template parameters. Use an anonymous namespace to prevent
// the need to declare prototypes for them.
namespace {

//----------------------------------------------------------------------
// Pixel unpacking routines.

void unpackRGB8ToRGBA8(const uint8_t* source, uint8_t* destination)
{
    destination[0] = source[0];
    destination[1] = source[1];
    destination[2] = source[2];
    destination[3] = 0xFF;
}

void unpackBGRA8ToRGBA8(const uint8_t* source, uint8_t* destination)
{
    destination[0] = source[2];
    destination[1] = source[1];
    destination[2] = source[0];
    destination[3] = source[3];
}

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

void packRGBA8ToA8(const uint8_t* source, uint8_t* destination)
{
    destination[0] = source[3];
}

void packRGBA8ToR8(const uint8_t* source, uint8_t* destination)
{
    destination[0] = source[0];
}

void packRGBA8ToR8Premultiply(const uint8_t* source, uint8_t* destination)
{
    float scaleFactor = source[3] / 255.0f;
    uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
    destination[0] = sourceR;
}

// FIXME: this routine is lossy and must be removed.
void packRGBA8ToR8Unmultiply(const uint8_t* source, uint8_t* destination)
{
    float scaleFactor = 1.0f / (source[3] ? source[3] / 255.0f : 1.0f);
    uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
    destination[0] = sourceR;
}

void packRGBA8ToRA8(const uint8_t* source, uint8_t* destination)
{
    destination[0] = source[0];
    destination[1] = source[3];
}

void packRGBA8ToRA8Premultiply(const uint8_t* source, uint8_t* destination)
{
    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];
}

// FIXME: this routine is lossy and must be removed.
void packRGBA8ToRA8Unmultiply(const uint8_t* source, uint8_t* destination)
{
    float scaleFactor = 1.0f / (source[3] ? source[3] / 255.0f : 1.0f);
    uint8_t sourceR = static_cast<uint8_t>(static_cast<float>(source[0]) * scaleFactor);
    destination[0] = sourceR;
    destination[1] = source[3];
}

void packRGBA8ToRGB8(const uint8_t* source, uint8_t* destination)
{
    destination[0] = source[0];
    destination[1] = source[1];
    destination[2] = source[2];
}

void packRGBA8ToRGB8Premultiply(const uint8_t* source, uint8_t* destination)
{
    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;
}

// FIXME: this routine is lossy and must be removed.
void packRGBA8ToRGB8Unmultiply(const uint8_t* source, uint8_t* destination)
{
    float scaleFactor = 1.0f / (source[3] ? source[3] / 255.0f : 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;
}

// This is only used when the source format is different than kSourceFormatRGBA8.
void packRGBA8ToRGBA8(const uint8_t* source, uint8_t* destination)
{
    destination[0] = source[0];
    destination[1] = source[1];
    destination[2] = source[2];
    destination[3] = source[3];
}

void packRGBA8ToRGBA8Premultiply(const uint8_t* source, uint8_t* destination)
{
    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;
}

// FIXME: this routine is lossy and must be removed.
void packRGBA8ToRGBA8Unmultiply(const uint8_t* source, uint8_t* destination)
{
    float scaleFactor = 1.0f / (source[3] ? source[3] / 255.0f : 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];
}

void packRGBA8ToUnsignedShort4444(const uint8_t* source, uint16_t* destination)
{
    *destination = (((source[0] & 0xF0) << 8)
                    | ((source[1] & 0xF0) << 4)
                    | (source[2] & 0xF0)
                    | (source[3] >> 4));
}

void packRGBA8ToUnsignedShort4444Premultiply(const uint8_t* source, uint16_t* destination)
{
    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));
}

// FIXME: this routine is lossy and must be removed.
void packRGBA8ToUnsignedShort4444Unmultiply(const uint8_t* source, uint16_t* destination)
{
    float scaleFactor = 1.0f / (source[3] ? source[3] / 255.0f : 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));
}

void packRGBA8ToUnsignedShort5551(const uint8_t* source, uint16_t* destination)
{
    *destination = (((source[0] & 0xF8) << 8)
                    | ((source[1] & 0xF8) << 3)
                    | ((source[2] & 0xF8) >> 2)
                    | (source[3] >> 7));
}

void packRGBA8ToUnsignedShort5551Premultiply(const uint8_t* source, uint16_t* destination)
{
    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));
}

// FIXME: this routine is lossy and must be removed.
void packRGBA8ToUnsignedShort5551Unmultiply(const uint8_t* source, uint16_t* destination)
{
    float scaleFactor = 1.0f / (source[3] ? source[3] / 255.0f : 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));
}

void packRGBA8ToUnsignedShort565(const uint8_t* source, uint16_t* destination)
{
    *destination = (((source[0] & 0xF8) << 8)
                    | ((source[1] & 0xFC) << 3)
                    | ((source[2] & 0xF8) >> 3));
}

void packRGBA8ToUnsignedShort565Premultiply(const uint8_t* source, uint16_t* destination)
{
    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));
}

// FIXME: this routine is lossy and must be removed.
void packRGBA8ToUnsignedShort565Unmultiply(const uint8_t* source, uint16_t* destination)
{
    float scaleFactor = 1.0f / (source[3] ? source[3] / 255.0f : 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));
}

} // anonymous namespace

// This is used whenever unpacking is necessary; i.e., the source data
// is not in RGBA8 format.
template<typename SourceType, typename DestType,
         void unpackingFunc(const SourceType*, uint8_t*),
         void packingFunc(const uint8_t*, DestType*)>
static void doUnpackingAndPacking(const SourceType* sourceData,
                                  unsigned int numElements,
                                  unsigned int sourceElementsPerPixel,
                                  DestType* destinationData,
                                  unsigned int destinationElementsPerPixel)
{
    const SourceType* endPointer = sourceData + numElements;
    uint8_t temporaryRGBAData[4];
    while (sourceData < endPointer) {
        unpackingFunc(sourceData, temporaryRGBAData);
        packingFunc(temporaryRGBAData, destinationData);
        sourceData += sourceElementsPerPixel;
        destinationData += destinationElementsPerPixel;
    }
}

// This handles all conversions with a faster path for RGBA8 source data.
template<typename SourceType, typename DestType, void packingFunc(const SourceType*, DestType*)>
static void doPacking(const SourceType* sourceData,
                      GraphicsContext3D::SourceDataFormat sourceDataFormat,
                      unsigned int numElements,
                      unsigned int sourceElementsPerPixel,
                      DestType* destinationData,
                      unsigned int destinationElementsPerPixel)
{
    switch (sourceDataFormat) {
    case GraphicsContext3D::kSourceFormatRGBA8: {
        const SourceType* endPointer = sourceData + numElements;
        while (sourceData < endPointer) {
            packingFunc(sourceData, destinationData);
            sourceData += sourceElementsPerPixel;
            destinationData += destinationElementsPerPixel;
        }
        break;
    }
    case GraphicsContext3D::kSourceFormatRGB8: {
        doUnpackingAndPacking<SourceType, DestType, unpackRGB8ToRGBA8, packingFunc>(sourceData, numElements, sourceElementsPerPixel, destinationData, destinationElementsPerPixel);
        break;
    }
    case GraphicsContext3D::kSourceFormatBGRA8: {
        doUnpackingAndPacking<SourceType, DestType, unpackBGRA8ToRGBA8, packingFunc>(sourceData, numElements, sourceElementsPerPixel, destinationData, destinationElementsPerPixel);
        break;
    }
    }
}

bool GraphicsContext3D::packPixels(const uint8_t* sourceData,
                                   GraphicsContext3D::SourceDataFormat sourceDataFormat,
                                   unsigned int width,
                                   unsigned int height,
                                   unsigned int destinationFormat,
                                   unsigned int destinationType,
                                   AlphaOp alphaOp,
                                   void* destinationData)
{
    unsigned int sourceElementsPerPixel = 4;
    unsigned int numElements = width * height * sourceElementsPerPixel;
    switch (destinationType) {
    case UNSIGNED_BYTE: {
        uint8_t* destination = static_cast<uint8_t*>(destinationData);
        if (sourceDataFormat == kSourceFormatRGBA8 && destinationFormat == RGBA && alphaOp == kAlphaDoNothing) {
            // No conversion necessary.
            memcpy(destinationData, sourceData, numElements);
            break;
        }
        switch (destinationFormat) {
        case RGB:
            switch (alphaOp) {
            case kAlphaDoNothing:
                doPacking<uint8_t, uint8_t, packRGBA8ToRGB8>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 3);
                break;
            case kAlphaDoPremultiply:
                doPacking<uint8_t, uint8_t, packRGBA8ToRGB8Premultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 3);
                break;
            case kAlphaDoUnmultiply:
                doPacking<uint8_t, uint8_t, packRGBA8ToRGB8Unmultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 3);
                break;
            }
            break;
        case RGBA:
            switch (alphaOp) {
            case kAlphaDoNothing:
                ASSERT(sourceDataFormat != kSourceFormatRGBA8); // Handled above with fast case.
                doPacking<uint8_t, uint8_t, packRGBA8ToRGBA8>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 4);
                break;
            case kAlphaDoPremultiply:
                doPacking<uint8_t, uint8_t, packRGBA8ToRGBA8Premultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 4);
                break;
            case kAlphaDoUnmultiply:
                doPacking<uint8_t, uint8_t, packRGBA8ToRGBA8Unmultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 4);
                break;
            default:
                ASSERT_NOT_REACHED();
            }
            break;
        case ALPHA:
            // From the desktop OpenGL conversion rules (OpenGL 2.1
            // specification, Table 3.15), the alpha channel is chosen
            // from the RGBA data.
            doPacking<uint8_t, uint8_t, packRGBA8ToA8>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
            break;
        case LUMINANCE:
            // From the desktop OpenGL conversion rules (OpenGL 2.1
            // specification, Table 3.15), the red channel is chosen
            // from the RGBA data.
            switch (alphaOp) {
            case kAlphaDoNothing:
                doPacking<uint8_t, uint8_t, packRGBA8ToR8>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
                break;
            case kAlphaDoPremultiply:
                doPacking<uint8_t, uint8_t, packRGBA8ToR8Premultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
                break;
            case kAlphaDoUnmultiply:
                doPacking<uint8_t, uint8_t, packRGBA8ToR8Unmultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
                break;
            }
            break;
        case LUMINANCE_ALPHA:
            // From the desktop OpenGL conversion rules (OpenGL 2.1
            // specification, Table 3.15), the red and alpha channels
            // are chosen from the RGBA data.
            switch (alphaOp) {
            case kAlphaDoNothing:
                doPacking<uint8_t, uint8_t, packRGBA8ToRA8>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 2);
                break;
            case kAlphaDoPremultiply:
                doPacking<uint8_t, uint8_t, packRGBA8ToRA8Premultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 2);
                break;
            case kAlphaDoUnmultiply:
                doPacking<uint8_t, uint8_t, packRGBA8ToRA8Unmultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 2);
                break;
            }
            break;
        }
        break;
    }
    case UNSIGNED_SHORT_4_4_4_4: {
        uint16_t* destination = static_cast<uint16_t*>(destinationData);
        switch (alphaOp) {
        case kAlphaDoNothing:
            doPacking<uint8_t, uint16_t, packRGBA8ToUnsignedShort4444>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
            break;
        case kAlphaDoPremultiply:
            doPacking<uint8_t, uint16_t, packRGBA8ToUnsignedShort4444Premultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
            break;
        case kAlphaDoUnmultiply:
            doPacking<uint8_t, uint16_t, packRGBA8ToUnsignedShort4444Unmultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
            break;
        }
        break;
    }
    case UNSIGNED_SHORT_5_5_5_1: {
        uint16_t* destination = static_cast<uint16_t*>(destinationData);
        switch (alphaOp) {
        case kAlphaDoNothing:
            doPacking<uint8_t, uint16_t, packRGBA8ToUnsignedShort5551>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
            break;
        case kAlphaDoPremultiply:
            doPacking<uint8_t, uint16_t, packRGBA8ToUnsignedShort5551Premultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
            break;
        case kAlphaDoUnmultiply:
            doPacking<uint8_t, uint16_t, packRGBA8ToUnsignedShort5551Unmultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
            break;
        }
        break;
    }
    case UNSIGNED_SHORT_5_6_5: {
        uint16_t* destination = static_cast<uint16_t*>(destinationData);
        switch (alphaOp) {
        case kAlphaDoNothing:
            doPacking<uint8_t, uint16_t, packRGBA8ToUnsignedShort565>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
            break;
        case kAlphaDoPremultiply:
            doPacking<uint8_t, uint16_t, packRGBA8ToUnsignedShort565Premultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
            break;
        case kAlphaDoUnmultiply:
            doPacking<uint8_t, uint16_t, packRGBA8ToUnsignedShort565Unmultiply>(sourceData, sourceDataFormat, numElements, sourceElementsPerPixel, destination, 1);
            break;
        }
        break;
    }
    }
    return true;
}

} // namespace WebCore

#endif // ENABLE(3D_CANVAS)