Pass the destination pointer to next

src/codec/SkSwizzler.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkSwizzler_DEFINED
 #define SkSwizzler_DEFINED
 
@@ skipping 99 matching lines @@
     static int BytesPerPixel(SrcConfig sc) {
         SkASSERT(SkIsAlign8(BitsPerPixel(sc)));
         return BitsPerPixel(sc) >> 3;
     }
 
     /**
      *  Create a new SkSwizzler.
      *  @param SrcConfig Description of the format of the source.
      *  @param SkImageInfo dimensions() describe both the src and the dst.
      *              Other fields describe the dst.
-     *  @param dst Destination to write pixels. Must match info and dstRowBytes
-     *  @param dstRowBytes rowBytes for dst.
      *  @param ZeroInitialized Whether dst is zero-initialized. The
                                implementation may choose to skip writing zeroes
      *                         if set to kYes_ZeroInitialized.
      *  @return A new SkSwizzler or NULL on failure.
      */
     static SkSwizzler* CreateSwizzler(SrcConfig, const SkPMColor* ctable,
-                                      const SkImageInfo&, void* dst,
-                                      size_t dstRowBytes,
-                                      SkCodec::ZeroInitialized);
+                                      const SkImageInfo&, SkCodec::ZeroInitialized);
 
     /**
      * Fill the remainder of the destination with a single color
      *
      * @param dstStartRow
      * The destination row to fill from.
      *
      * @param numRows
      * The number of rows to fill.
      *
@@ skipping 16 matching lines @@
      *
      * If dstInfo.colorType() is kGray, colorOrIndex is always treated as an 8-bit color.
      *
      * Other SkColorTypes are not supported.
      *
      */
     static void Fill(void* dstStartRow, const SkImageInfo& dstInfo, size_t dstRowBytes,
             uint32_t numRows, uint32_t colorOrIndex, const SkPMColor* colorTable);
 
     /**
-     *  Swizzle the next line. Call height times, once for each row of source.
+     *  Swizzle a line. Generally this will be called height times, once
+     *  for each row of source.
+     *  By allowing the caller to pass in the dst pointer, we give the caller
+     *  flexibility to use the swizzler even when the encoded data does not
+     *  store the rows in order.  This also improves usability for scaled and
+     *  subset decodes.
+     *  @param dst Where we write the output.
      *  @param src The next row of the source data.
      *  @return A result code describing if the row was fully opaque, fully
      *          transparent, or neither
      */
-    ResultAlpha next(const uint8_t* SK_RESTRICT src);
-
-    /**
-     *
-     * Alternate version of next that allows the caller to specify the row.
-     * It is very important to only use one version of next.  Since the other
-     * version modifies the dst pointer, it will change the behavior of this
-     * function.  We will check this in Debug mode.
-     *
-     */
-    ResultAlpha next(const uint8_t* SK_RESTRICT src, int y);
-
-    /**
-     *  Update the destination row.
-     *
-     *  Typically this is done by next, but for a client that wants to manually
-     *  modify the destination row (for example, for decoding scanline one at a
-     *  time) they can call this before each call to next.
-     *  TODO: Maybe replace this with a version of next which allows supplying the
-     *  destination?
-     */
-    void setDstRow(void* dst) { fDstRow = dst; }
-
-    /**
-     *  Get the next destination row to decode to
-     */
-    void* getDstRow() {
-        // kDesignateRow_NextMode does not update the fDstRow ptr.  This function is
-        // unnecessary in that case since fDstRow will always be equal to the pointer
-        // passed to CreateSwizzler().
-        SkASSERT(kDesignateRow_NextMode != fNextMode);
-        return fDstRow;
-    }
+    ResultAlpha swizzle(void* dst, const uint8_t* SK_RESTRICT src);
 
 private:
 
-#ifdef SK_DEBUG
-    /*
-     *
-     * Keep track of which version of next the caller is using
-     *
-     */
-    enum NextMode {
-        kUninitialized_NextMode,
-        kConsecutive_NextMode,
-        kDesignateRow_NextMode,
-    };
-
-    NextMode fNextMode;
-#endif
-
     /**
      *  Method for converting raw data to Skia pixels.
      *  @param dstRow Row in which to write the resulting pixels.
      *  @param src Row of src data, in format specified by SrcConfig
      *  @param width Width in pixels
      *  @param deltaSrc if bitsPerPixel % 8 == 0, deltaSrc is bytesPerPixel
      *                  else, deltaSrc is bitsPerPixel
-     *  @param y Line of source.
      *  @param ctable Colors (used for kIndex source).
      */
     typedef ResultAlpha (*RowProc)(void* SK_RESTRICT dstRow,
                                    const uint8_t* SK_RESTRICT src,
-                                   int width, int deltaSrc, int y,
+                                   int width, int deltaSrc,
                                    const SkPMColor ctable[]);
 
     const RowProc       fRowProc;
     const SkPMColor*    fColorTable;      // Unowned pointer
     const int           fDeltaSrc;        // if bitsPerPixel % 8 == 0
                                           //     deltaSrc is bytesPerPixel
                                           // else
                                           //     deltaSrc is bitsPerPixel
     const SkImageInfo   fDstInfo;
-    void*               fDstRow;
-    const size_t        fDstRowBytes;
     int                 fCurrY;
 
     SkSwizzler(RowProc proc, const SkPMColor* ctable, int deltaSrc,
-               const SkImageInfo& info, void* dst, size_t rowBytes);
+               const SkImageInfo& info);
 
 };
 #endif // SkSwizzler_DEFINED