image/decoders/nsICODecoder.h

   1 /* vim:set tw=80 expandtab softtabstop=4 ts=4 sw=4: */
   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
   7 #ifndef nsICODecoder_h
   8 #define nsICODecoder_h
   9
  10 #include "nsAutoPtr.h"
  11 #include "Decoder.h"
  12 #include "imgFrame.h"
  13 #include "nsBMPDecoder.h"
  14 #include "nsPNGDecoder.h"
  15 #include "ICOFileHeaders.h"
  16
  17 namespace mozilla {
  18 namespace image {
  19
  20 class RasterImage;
  21
  22 class nsICODecoder : public Decoder
  23 {
  24 public:
  25
  26   explicit nsICODecoder(RasterImage* aImage);
  27   virtual ~nsICODecoder();
  28
  29   // Obtains the width of the icon directory entry
  30   uint32_t GetRealWidth() const
  31   {
  32     return mDirEntry.mWidth == 0 ? 256 : mDirEntry.mWidth;
  33   }
  34
  35   // Obtains the height of the icon directory entry
  36   uint32_t GetRealHeight() const
  37   {
  38     return mDirEntry.mHeight == 0 ? 256 : mDirEntry.mHeight;
  39   }
  40
  41   virtual void WriteInternal(const char* aBuffer, uint32_t aCount) MOZ_OVERRIDE;
  42   virtual void FinishInternal() MOZ_OVERRIDE;
  43   virtual nsresult AllocateFrame(const nsIntSize& aTargetSize
  44                                    /* = nsIntSize() */) MOZ_OVERRIDE;
  45
  46 protected:
  47   virtual bool NeedsNewFrame() const MOZ_OVERRIDE;
  48
  49 private:
  50   // Writes to the contained decoder and sets the appropriate errors
  51   // Returns true if there are no errors.
  52   bool WriteToContainedDecoder(const char* aBuffer, uint32_t aCount);
  53
  54   // Processes a single dir entry of the icon resource
  55   void ProcessDirEntry(IconDirEntry& aTarget);
  56   // Sets the hotspot property of if we have a cursor
  57   void SetHotSpotIfCursor();
  58   // Creates a bitmap file header buffer, returns true if successful
  59   bool FillBitmapFileHeaderBuffer(int8_t *bfh);
  60   // Fixes the ICO height to match that of the BIH.
  61   // and also fixes the BIH height to be /2 of what it was.
  62   // See definition for explanation.
  63   // Returns false if invalid information is contained within.
  64   bool FixBitmapHeight(int8_t *bih);
  65   // Fixes the ICO width to match that of the BIH.
  66   // Returns false if invalid information is contained within.
  67   bool FixBitmapWidth(int8_t *bih);
  68   // Extract bitmap info header size count from BMP information header
  69   int32_t ExtractBIHSizeFromBitmap(int8_t *bih);
  70   // Extract bit count from BMP information header
  71   int32_t ExtractBPPFromBitmap(int8_t *bih);
  72   // Calculates the row size in bytes for the AND mask table
  73   uint32_t CalcAlphaRowSize();
  74   // Obtains the number of colors from the BPP, mBPP must be filled in
  75   uint16_t GetNumColors();
  76
  77   uint16_t mBPP; // Stores the images BPP
  78   uint32_t mPos; // Keeps track of the position we have decoded up until
  79   uint16_t mNumIcons; // Stores the number of icons in the ICO file
  80   uint16_t mCurrIcon; // Stores the current dir entry index we are processing
  81   uint32_t mImageOffset; // Stores the offset of the image data we want
  82   uint8_t* mRow;      // Holds one raw line of the image
  83   int32_t mCurLine;   // Line index of the image that's currently being decoded
  84   uint32_t mRowBytes; // How many bytes of the row were already received
  85   int32_t mOldLine;   // Previous index of the line
  86   nsRefPtr<Decoder> mContainedDecoder; // Contains either a BMP or PNG resource
  87   RawAccessFrameRef mRefForContainedDecoder; // Avoid locking off-main-thread
  88
  89   char mDirEntryArray[ICODIRENTRYSIZE]; // Holds the current dir entry buffer
  90   IconDirEntry mDirEntry; // Holds a decoded dir entry
  91   // Holds the potential bytes that can be a PNG signature
  92   char mSignature[PNGSIGNATURESIZE];
  93   // Holds the potential bytes for a bitmap information header
  94   char mBIHraw[40];
  95   // Stores whether or not the icon file we are processing has type 1 (icon)
  96   bool mIsCursor;
  97   // Stores whether or not the contained resource is a PNG
  98   bool mIsPNG;
  99 };
 100
 101 } // namespace image
 102 } // namespace mozilla
 103
 104 #endif // nsICODecoder_h