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/*
* Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#include "config.h"
#include "platform/image-decoders/ImageDecoder.h"
#include "platform/image-decoders/bmp/BMPImageDecoder.h"
#include "platform/image-decoders/gif/GIFImageDecoder.h"
#include "platform/image-decoders/ico/ICOImageDecoder.h"
#include "platform/image-decoders/jpeg/JPEGImageDecoder.h"
#include "platform/image-decoders/png/PNGImageDecoder.h"
#include "platform/image-decoders/webp/WEBPImageDecoder.h"
#include "wtf/PassOwnPtr.h"
namespace WebCore {
static unsigned copyFromSharedBuffer(char* buffer, unsigned bufferLength, const SharedBuffer& sharedBuffer, unsigned offset)
{
unsigned bytesExtracted = 0;
const char* moreData;
while (unsigned moreDataLength = sharedBuffer.getSomeData(moreData, offset)) {
unsigned bytesToCopy = std::min(bufferLength - bytesExtracted, moreDataLength);
memcpy(buffer + bytesExtracted, moreData, bytesToCopy);
bytesExtracted += bytesToCopy;
if (bytesExtracted == bufferLength)
break;
offset += bytesToCopy;
}
return bytesExtracted;
}
inline bool matchesGIFSignature(char* contents)
{
return !memcmp(contents, "GIF87a", 6) || !memcmp(contents, "GIF89a", 6);
}
inline bool matchesPNGSignature(char* contents)
{
return !memcmp(contents, "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A", 8);
}
inline bool matchesJPEGSignature(char* contents)
{
return !memcmp(contents, "\xFF\xD8\xFF", 3);
}
inline bool matchesWebPSignature(char* contents)
{
return !memcmp(contents, "RIFF", 4) && !memcmp(contents + 8, "WEBPVP", 6);
}
inline bool matchesBMPSignature(char* contents)
{
return !memcmp(contents, "BM", 2);
}
inline bool matchesICOSignature(char* contents)
{
return !memcmp(contents, "\x00\x00\x01\x00", 4);
}
inline bool matchesCURSignature(char* contents)
{
return !memcmp(contents, "\x00\x00\x02\x00", 4);
}
PassOwnPtr<ImageDecoder> ImageDecoder::create(const SharedBuffer& data, ImageSource::AlphaOption alphaOption, ImageSource::GammaAndColorProfileOption gammaAndColorProfileOption)
{
static const unsigned longestSignatureLength = sizeof("RIFF????WEBPVP") - 1;
ASSERT(longestSignatureLength == 14);
size_t maxDecodedBytes = blink::Platform::current()->maxDecodedImageBytes();
char contents[longestSignatureLength];
if (copyFromSharedBuffer(contents, longestSignatureLength, data, 0) < longestSignatureLength)
return nullptr;
if (matchesJPEGSignature(contents))
return adoptPtr(new JPEGImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
if (matchesPNGSignature(contents))
return adoptPtr(new PNGImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
if (matchesGIFSignature(contents))
return adoptPtr(new GIFImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
if (matchesICOSignature(contents) || matchesCURSignature(contents))
return adoptPtr(new ICOImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
if (matchesWebPSignature(contents))
return adoptPtr(new WEBPImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
if (matchesBMPSignature(contents))
return adoptPtr(new BMPImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
return nullptr;
}
bool ImageDecoder::frameHasAlphaAtIndex(size_t index) const
{
return !frameIsCompleteAtIndex(index) || m_frameBufferCache[index].hasAlpha();
}
bool ImageDecoder::frameIsCompleteAtIndex(size_t index) const
{
return (index < m_frameBufferCache.size()) &&
(m_frameBufferCache[index].status() == ImageFrame::FrameComplete);
}
unsigned ImageDecoder::frameBytesAtIndex(size_t index) const
{
if (m_frameBufferCache.size() <= index || m_frameBufferCache[index].status() == ImageFrame::FrameEmpty)
return 0;
// FIXME: Use the dimension of the requested frame.
return m_size.area() * sizeof(ImageFrame::PixelData);
}
size_t ImageDecoder::clearCacheExceptFrame(size_t clearExceptFrame)
{
// Don't clear if there are no frames or only one frame.
if (m_frameBufferCache.size() <= 1)
return 0;
size_t frameBytesCleared = 0;
for (size_t i = 0; i < m_frameBufferCache.size(); ++i) {
if (i != clearExceptFrame) {
frameBytesCleared += frameBytesAtIndex(i);
clearFrameBuffer(i);
}
}
return frameBytesCleared;
}
void ImageDecoder::clearFrameBuffer(size_t frameIndex)
{
m_frameBufferCache[frameIndex].clearPixelData();
}
size_t ImageDecoder::findRequiredPreviousFrame(size_t frameIndex, bool frameRectIsOpaque)
{
ASSERT(frameIndex <= m_frameBufferCache.size());
if (!frameIndex) {
// The first frame doesn't rely on any previous data.
return kNotFound;
}
const ImageFrame* currBuffer = &m_frameBufferCache[frameIndex];
if ((frameRectIsOpaque || currBuffer->alphaBlendSource() == ImageFrame::BlendAtopBgcolor)
&& currBuffer->originalFrameRect().contains(IntRect(IntPoint(), size())))
return kNotFound;
// The starting state for this frame depends on the previous frame's
// disposal method.
size_t prevFrame = frameIndex - 1;
const ImageFrame* prevBuffer = &m_frameBufferCache[prevFrame];
ASSERT(prevBuffer->requiredPreviousFrameIndexValid());
switch (prevBuffer->disposalMethod()) {
case ImageFrame::DisposeNotSpecified:
case ImageFrame::DisposeKeep:
// prevFrame will be used as the starting state for this frame.
// FIXME: Be even smarter by checking the frame sizes and/or alpha-containing regions.
return prevFrame;
case ImageFrame::DisposeOverwritePrevious:
// Frames that use the DisposeOverwritePrevious method are effectively
// no-ops in terms of changing the starting state of a frame compared to
// the starting state of the previous frame, so skip over them and
// return the required previous frame of it.
return prevBuffer->requiredPreviousFrameIndex();
case ImageFrame::DisposeOverwriteBgcolor:
// If the previous frame fills the whole image, then the current frame
// can be decoded alone. Likewise, if the previous frame could be
// decoded without reference to any prior frame, the starting state for
// this frame is a blank frame, so it can again be decoded alone.
// Otherwise, the previous frame contributes to this frame.
return (prevBuffer->originalFrameRect().contains(IntRect(IntPoint(), size()))
|| (prevBuffer->requiredPreviousFrameIndex() == kNotFound)) ? kNotFound : prevFrame;
default:
ASSERT_NOT_REACHED();
return kNotFound;
}
}
} // namespace WebCore
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