diff --git a/common/rfb/rreEncode.h b/common/rfb/rreEncode.h
new file mode 100644
index 0000000..3f83487
--- /dev/null
+++ b/common/rfb/rreEncode.h
@@ -0,0 +1,164 @@
+/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * 
+ * 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.
+ */
+//
+// RRE encoding function.
+//
+// This file is #included after having set the following macros:
+// BPP                - 8, 16 or 32
+//
+// The data argument to RRE_ENCODE contains the pixel data, and it writes the
+// encoded version to the given OutStream.  If the encoded version exceeds w*h
+// it aborts and returns -1, otherwise it returns the number of subrectangles.
+//
+
+#include <rdr/OutStream.h>
+
+namespace rfb {
+
+// CONCAT2E concatenates its arguments, expanding them if they are macros
+
+#ifndef CONCAT2E
+#define CONCAT2(a,b) a##b
+#define CONCAT2E(a,b) CONCAT2(a,b)
+#endif
+
+#define PIXEL_T rdr::CONCAT2E(U,BPP)
+#define WRITE_PIXEL CONCAT2E(writeOpaque,BPP)
+#define RRE_ENCODE CONCAT2E(rreEncode,BPP)
+
+int RRE_ENCODE (PIXEL_T* data, int w, int h, rdr::OutStream* os, PIXEL_T bg);
+
+int RRE_ENCODE (void* data, int w, int h, rdr::OutStream* os)
+{
+  // Find the background colour - count occurrences of up to 4 different pixel
+  // values, and choose the one which occurs most often.
+
+  const int nCols = 4;
+  PIXEL_T pix[nCols];
+  int count[nCols] = { 0, };
+  PIXEL_T* ptr = (PIXEL_T*)data;
+  PIXEL_T* end = ptr + w*h;
+
+  while (ptr < end) {
+    int i;
+    for (i = 0; i < nCols; i++) {
+      if (count[i] == 0)
+        pix[i] = *ptr;
+
+      if (pix[i] == *ptr) {
+        count[i]++;
+        break;
+      }
+    }
+
+    if (i == nCols) break;
+    ptr++;
+  }
+  
+  int bg = 0;
+  for (int i = 1; i < nCols; i++)
+    if (count[i] > count[bg]) bg = i;
+
+  // Now call the function to do the encoding.
+
+  return RRE_ENCODE ((PIXEL_T*)data, w, h, os, pix[bg]);
+}
+
+int RRE_ENCODE (PIXEL_T* data, int w, int h, rdr::OutStream* os, PIXEL_T bg)
+{
+  int oldLen = os->length();
+  os->WRITE_PIXEL(bg);
+
+  int nSubrects = 0;
+
+  for (int y = 0; y < h; y++)
+  {
+    int x = 0;
+    while (x < w) {
+      if (*data == bg) {
+        x++;
+        data++;
+        continue;
+      }
+
+      // Find horizontal subrect first
+      PIXEL_T* ptr = data+1;
+      PIXEL_T* eol = data+w-x;
+      while (ptr < eol && *ptr == *data) ptr++;
+      int sw = ptr - data;
+
+      ptr = data + w;
+      int sh = 1;
+      while (sh < h-y) {
+        eol = ptr + sw;
+        while (ptr < eol)
+          if (*ptr++ != *data) goto endOfHorizSubrect;
+        ptr += w - sw;
+        sh++;
+      }
+    endOfHorizSubrect:
+
+      // Find vertical subrect
+      int vh;
+      for (vh = sh; vh < h-y; vh++)
+        if (data[vh*w] != *data) break;
+
+      if (vh != sh) {
+        ptr = data+1;
+        int vw;
+        for (vw = 1; vw < sw; vw++) {
+          for (int i = 0; i < vh; i++)
+            if (ptr[i*w] != *data) goto endOfVertSubrect;
+          ptr++;
+        }
+      endOfVertSubrect:
+
+        // If vertical subrect bigger than horizontal then use that.
+        if (sw*sh < vw*vh) {
+          sw = vw;
+          sh = vh;
+        }
+      }
+
+      nSubrects++;
+      os->WRITE_PIXEL(*data);
+      os->writeU16(x);
+      os->writeU16(y);
+      os->writeU16(sw);
+      os->writeU16(sh);
+      if (os->length() > oldLen + w*h) return -1;
+
+      ptr = data+w;
+      PIXEL_T* eor = data+w*sh;
+      while (ptr < eor) {
+        eol = ptr + sw;
+        while (ptr < eol) *ptr++ = bg;
+        ptr += w - sw;
+      }
+      x += sw;
+      data += sw;
+    }
+  }
+
+  return nSubrects;
+}
+
+#undef PIXEL_T
+#undef WRITE_PIXEL
+#undef RRE_ENCODE
+}