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common/rfb/Decoder.h

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+/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * Copyright 2014 Pierre Ossman for Cendio AB
+ * 
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+#ifndef __RFB_DECODER_H__
+#define __RFB_DECODER_H__
+
+namespace rdr {
+  class InStream;
+  class OutStream;
+}
+
+namespace rfb {
+  class ConnParams;
+  class ModifiablePixelBuffer;
+  class Region;
+
+  struct Rect;
+
+  enum DecoderFlags {
+    // A constant for decoders that don't need anything special
+    DecoderPlain = 0,
+    // All rects for this decoder must be handled in order
+    DecoderOrdered = 1 << 0,
+    // Only some of the rects must be handled in order,
+    // see doesRectsConflict()
+    DecoderPartiallyOrdered = 1 << 1,
+  };
+
+  class Decoder {
+  public:
+    Decoder(enum DecoderFlags flags);
+    virtual ~Decoder();
+
+    // These functions are the main interface to an individual decoder
+
+    // readRect() transfers data for the given rectangle from the
+    // InStream to the OutStream, possibly changing it along the way to
+    // make it easier to decode. This function will always be called in
+    // a serial manner on the main thread.
+    virtual void readRect(const Rect& r, rdr::InStream* is,
+                          const ConnParams& cp, rdr::OutStream* os)=0;
+
+    // These functions will be called from any of the worker threads.
+    // A lock will be held whilst these are called so it is safe to
+    // read and update internal state as necessary.
+
+    // getAffectedRegion() returns the parts of the frame buffer will
+    // be either read from or written do when decoding this rect. The
+    // default implementation simply returns the given rectangle.
+    virtual void getAffectedRegion(const Rect& rect, const void* buffer,
+                                   size_t buflen, const ConnParams& cp,
+                                   Region* region);
+
+    // doesRectsConflict() determines if two rectangles must be decoded
+    // in the order they were received. This will only be called if the
+    // DecoderPartiallyOrdered flag has been set.
+    virtual bool doRectsConflict(const Rect& rectA,
+                                 const void* bufferA,
+                                 size_t buflenA,
+                                 const Rect& rectB,
+                                 const void* bufferB,
+                                 size_t buflenB,
+                                 const ConnParams& cp);
+
+    // decodeRect() decodes the given rectangle with data from the
+    // given buffer, onto the ModifiablePixelBuffer. The PixelFormat of
+    // the PixelBuffer might not match the ConnParams and it is up to
+    // the decoder to do any necessary conversion.
+    virtual void decodeRect(const Rect& r, const void* buffer,
+                            size_t buflen, const ConnParams& cp,
+                            ModifiablePixelBuffer* pb)=0;
+
+  public:
+    static bool supported(int encoding);
+    static Decoder* createDecoder(int encoding);
+
+  public:
+    const enum DecoderFlags flags;
+  };
+}
+
+#endif