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/*
* Copyright (c) 2008, 2009, 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:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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 THE COPYRIGHT
* OWNER 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.
*/
#ifndef ICOImageDecoder_h
#define ICOImageDecoder_h
#include "BMPImageReader.h"
#include "PNGImageDecoder.h"
namespace WebCore {
// This class decodes the ICO and CUR image formats.
class ICOImageDecoder : public BMPImageReader {
public:
// See comments on |m_preferredIconSize| below.
ICOImageDecoder(const IntSize& preferredIconSize)
: m_preferredIconSize(preferredIconSize)
, m_imageType(Unknown)
{
m_andMaskState = NotYetDecoded;
}
virtual String filenameExtension() const { return "ico"; }
// BMPImageReader
virtual void decodeImage(SharedBuffer* data);
virtual RGBA32Buffer* frameBufferAtIndex(size_t index);
// ImageDecoder
virtual bool isSizeAvailable() const;
virtual IntSize size() const;
private:
enum ImageType {
Unknown,
BMP,
PNG,
};
// These are based on the Windows ICONDIR and ICONDIRENTRY structs, but
// with unnecessary entries removed.
struct IconDirectory {
uint16_t idCount;
};
struct IconDirectoryEntry {
uint16_t bWidth; // 16 bits so we can represent 256 as 256, not 0
uint16_t bHeight; // "
uint16_t wBitCount;
uint32_t dwImageOffset;
};
// Processes the ICONDIR at the beginning of the data. Returns true if the
// directory could be decoded.
bool processDirectory(SharedBuffer*);
// Processes the ICONDIRENTRY records after the directory. Keeps the
// "best" entry as the one we'll decode. Returns true if the entries could
// be decoded.
bool processDirectoryEntries(SharedBuffer*);
// Reads and returns a directory entry from the current offset into |data|.
IconDirectoryEntry readDirectoryEntry(SharedBuffer*);
// Returns true if |entry| is a preferable icon entry to m_dirEntry.
// Larger sizes, or greater bitdepths at the same size, are preferable.
bool isBetterEntry(const IconDirectoryEntry&) const;
// Called when the image to be decoded is a PNG rather than a BMP.
// Instantiates a PNGImageDecoder, decodes the image, and copies the
// results locally.
void decodePNG(SharedBuffer*);
// The entry size we should prefer. If this is empty, we choose the
// largest available size. If no entries of the desired size are
// available, we pick the next larger size.
IntSize m_preferredIconSize;
// The headers for the ICO.
IconDirectory m_directory;
IconDirectoryEntry m_dirEntry;
// The PNG decoder, if we need to use one.
PNGImageDecoder m_pngDecoder;
// What kind of image data is stored at the entry we're decoding.
ImageType m_imageType;
};
} // namespace WebCore
#endif
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