image/decoders/nsICODecoder.h

   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