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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_image_decoders_nsIconDecoder_h
#define mozilla_image_decoders_nsIconDecoder_h
#include "Decoder.h"
#include "StreamingLexer.h"
#include "SurfacePipe.h"
namespace mozilla {
namespace image {
class RasterImage;
////////////////////////////////////////////////////////////////////////////////
// The icon decoder is a decoder specifically tailored for loading icons
// from the OS. We've defined our own little format to represent these icons
// and this decoder takes that format and converts it into 24-bit RGB with
// alpha channel support. It was modeled a bit off the PPM decoder.
//
// The format of the incoming data is as follows:
//
// The first two bytes contain the width and the height of the icon.
// The remaining bytes contain the icon data, 4 bytes per pixel, in
// ARGB order (platform endianness, A in highest bits, B in lowest
// bits), row-primary, top-to-bottom, left-to-right, with
// premultiplied alpha.
//
////////////////////////////////////////////////////////////////////////////////
class nsIconDecoder : public Decoder
{
public:
virtual ~nsIconDecoder();
LexerResult DoDecode(SourceBufferIterator& aIterator,
IResumable* aOnResume) override;
private:
friend class DecoderFactory;
// Decoders should only be instantiated via DecoderFactory.
explicit nsIconDecoder(RasterImage* aImage);
enum class State {
HEADER,
ROW_OF_PIXELS,
FINISH
};
LexerTransition<State> ReadHeader(const char* aData);
LexerTransition<State> ReadRowOfPixels(const char* aData, size_t aLength);
LexerTransition<State> Finish();
StreamingLexer<State> mLexer;
SurfacePipe mPipe;
uint32_t mBytesPerRow;
};
} // namespace image
} // namespace mozilla
#endif // mozilla_image_decoders_nsIconDecoder_h
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