author Bogdan Tara <>
Tue, 22 Oct 2019 09:34:29 +0300
changeset 498482 8e8e5bb63105fd26d10f7cba6adf85a606bceaf0
parent 448947 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Backed out changeset 617d82c93a06 (bug 1590022) for test_fileapi_other.html & test_fileapi_other_worker.html failures CLOSED TREE

/* -*- 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 */

#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 {
  virtual ~nsIconDecoder();

  DecoderType GetType() const override { return DecoderType::ICON; }

  LexerResult DoDecode(SourceBufferIterator& aIterator,
                       IResumable* aOnResume) override;

  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