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The Tor Browser
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nsICODecoder.h (3770B)

      1 /* vim:set tw=80 expandtab softtabstop=4 ts=4 sw=2: */
      2 /* This Source Code Form is subject to the terms of the Mozilla Public
      3 * License, v. 2.0. If a copy of the MPL was not distributed with this
      4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      5 
      6 #ifndef mozilla_image_decoders_nsICODecoder_h
      7 #define mozilla_image_decoders_nsICODecoder_h
      8 
      9 #include "StreamingLexer.h"
     10 #include "Decoder.h"
     11 #include "Downscaler.h"
     12 #include "imgFrame.h"
     13 #include "mozilla/gfx/2D.h"
     14 #include "nsBMPDecoder.h"
     15 #include "nsPNGDecoder.h"
     16 #include "ICOFileHeaders.h"
     17 
     18 namespace mozilla {
     19 namespace image {
     20 
     21 class RasterImage;
     22 
     23 enum class ICOState {
     24  HEADER,
     25  DIR_ENTRY,
     26  FINISHED_DIR_ENTRY,
     27  ITERATE_UNSIZED_DIR_ENTRY,
     28  SKIP_TO_RESOURCE,
     29  FOUND_RESOURCE,
     30  SNIFF_RESOURCE,
     31  READ_RESOURCE,
     32  PREPARE_FOR_MASK,
     33  READ_MASK_ROW,
     34  FINISH_MASK,
     35  SKIP_MASK,
     36  FINISHED_RESOURCE
     37 };
     38 
     39 class nsICODecoder : public Decoder {
     40 public:
     41  virtual ~nsICODecoder() {}
     42 
     43  /// @return The offset from the beginning of the ICO to the first resource.
     44  size_t FirstResourceOffset() const;
     45 
     46  DecoderType GetType() const override { return DecoderType::ICO; }
     47  LexerResult DoDecode(SourceBufferIterator& aIterator,
     48                       IResumable* aOnResume) override;
     49  nsresult FinishInternal() override;
     50  nsresult FinishWithErrorInternal() override;
     51 
     52 private:
     53  friend class DecoderFactory;
     54 
     55  // Decoders should only be instantiated via DecoderFactory.
     56  explicit nsICODecoder(RasterImage* aImage);
     57 
     58  // Flushes the contained decoder to read all available data and sets the
     59  // appropriate errors. Returns true if there are no errors.
     60  bool FlushContainedDecoder();
     61 
     62  // Gets decoder state from the contained decoder so it's visible externally.
     63  nsresult GetFinalStateFromContainedDecoder();
     64 
     65  // Obtains the number of colors from the BPP, mBPP must be filled in
     66  uint16_t GetNumColors();
     67 
     68  LexerTransition<ICOState> ReadHeader(const char* aData);
     69  LexerTransition<ICOState> ReadDirEntry(const char* aData);
     70  LexerTransition<ICOState> IterateUnsizedDirEntry();
     71  LexerTransition<ICOState> FinishDirEntry();
     72  LexerTransition<ICOState> SniffResource(const char* aData);
     73  LexerTransition<ICOState> ReadResource();
     74  LexerTransition<ICOState> ReadBIH(const char* aData);
     75  LexerTransition<ICOState> PrepareForMask();
     76  LexerTransition<ICOState> ReadMaskRow(const char* aData);
     77  LexerTransition<ICOState> FinishMask();
     78  LexerTransition<ICOState> FinishResource();
     79 
     80  struct IconDirEntryEx : public IconDirEntry {
     81    OrientedIntSize mSize;
     82  };
     83 
     84  StreamingLexer<ICOState, 32> mLexer;  // The lexer.
     85  Maybe<Downscaler> mDownscaler;        // The downscaler used for the mask.
     86  RefPtr<Decoder> mContainedDecoder;    // Either a BMP or PNG decoder.
     87  Maybe<SourceBufferIterator>
     88      mReturnIterator;               // Iterator to save return point.
     89  UniquePtr<uint8_t[]> mMaskBuffer;  // A temporary buffer for the alpha mask.
     90  nsTArray<IconDirEntryEx> mDirEntries;  // Valid dir entries with a size.
     91  nsTArray<IconDirEntryEx> mUnsizedDirEntries;  // Dir entries without a size.
     92  IconDirEntryEx* mDirEntry;  // The dir entry for the selected resource.
     93  uint16_t mNumIcons;         // Stores the number of icons in the ICO file.
     94  uint16_t mCurrIcon;  // Stores the current dir entry index we are processing.
     95  uint16_t mBPP;       // The BPP of the resource we're decoding.
     96  uint32_t
     97      mMaskRowSize;  // The size in bytes of each row in the BMP alpha mask.
     98  uint32_t mCurrMaskLine;  // The line of the BMP alpha mask we're processing.
     99  bool mIsCursor;          // Is this ICO a cursor?
    100  bool mHasMaskAlpha;      // Did the BMP alpha mask have any transparency?
    101 };
    102 
    103 }  // namespace image
    104 }  // namespace mozilla
    105 
    106 #endif  // mozilla_image_decoders_nsICODecoder_h