Add Rich Geldreich's ETC1 compressor.

CLTool/src/clwin32.cpp

@@ -60,7 +60,7 @@
 void PrintUsage() {
   fprintf(stderr, "Usage: tc [OPTIONS] imagefile\n");
   fprintf(stderr, "\n");
-  fprintf(stderr, "\t-f\t\tFormat to use. Either \"BPTC\" or \"PVRTC\". Default: BPTC\n");
+  fprintf(stderr, "\t-f\t\tFormat to use. Either \"ETC1\", \"BPTC\" or \"PVRTC\". Default: BPTC\n");
   fprintf(stderr, "\t-l\t\tSave an output log.\n");
   fprintf(stderr, "\t-q <quality>\tSet compression quality level. Default: 50\n");
   fprintf(stderr, "\t-n <num>\tCompress the image num times and give the average time and PSNR. Default: 1\n");
@@ -137,6 +137,8 @@ int _tmain(int argc, _TCHAR* argv[])
         } else if(!strcmp(argv[fileArg], "PVRTCLib")) {
           format = eCompressionFormat_PVRTC;
           bUsePVRTexLib = true;
+        } else if(!strcmp(argv[fileArg], "ETC1")) {
+          format = eCompressionFormat_ETC1;
         }
       }
 
@@ -275,6 +277,8 @@ int _tmain(int argc, _TCHAR* argv[])
     strcat_s(basename, "-bc7.png");
   } else if(format == eCompressionFormat_PVRTC) {
     strcat_s(basename, "-pvrtc.png");
+  } else if(format == eCompressionFormat_ETC1) {
+    strcat_s(basename, "-etc1.png");
   }
 
   ImageFile cImgFile (basename, eFileFormat_PNG, *ci);

CMakeLists.txt

@@ -93,7 +93,7 @@ SET(CMAKE_MODULE_PATH "${FasTC_SOURCE_DIR}/CMakeModules" ${CMAKE_MODULE_PATH})
 FIND_PACKAGE(PVRTexLib)
 
 SET(FASTC_DIRECTORIES
-  Base Core IO BPTCEncoder PVRTCEncoder DXTEncoder
+  Base Core IO BPTCEncoder PVRTCEncoder DXTEncoder ETCEncoder
 )
 
 FOREACH(DIR ${FASTC_DIRECTORIES})

Core/CMakeLists.txt

@@ -77,6 +77,7 @@ ENDIF()
 INCLUDE_DIRECTORIES( ${FasTC_SOURCE_DIR}/Base/include )
 INCLUDE_DIRECTORIES( ${FasTC_SOURCE_DIR} )
 
+INCLUDE_DIRECTORIES( ${FasTC_SOURCE_DIR}/ETCEncoder/include )
 INCLUDE_DIRECTORIES( ${FasTC_SOURCE_DIR}/DXTEncoder/include )
 
 INCLUDE_DIRECTORIES( ${FasTC_SOURCE_DIR}/PVRTCEncoder/include )
@@ -162,6 +163,7 @@ ADD_LIBRARY( FasTCCore
 
 TARGET_LINK_LIBRARIES( FasTCCore FasTCBase )
 TARGET_LINK_LIBRARIES( FasTCCore FasTCIO )
+TARGET_LINK_LIBRARIES( FasTCCore ETCEncoder )
 TARGET_LINK_LIBRARIES( FasTCCore DXTEncoder )
 TARGET_LINK_LIBRARIES( FasTCCore BPTCEncoder )
 TARGET_LINK_LIBRARIES( FasTCCore PVRTCEncoder )

Core/include/CompressedImage.h

@@ -49,6 +49,7 @@
 enum ECompressionFormat {
   eCompressionFormat_DXT1,
   eCompressionFormat_DXT5,
+  eCompressionFormat_ETC1,
   eCompressionFormat_BPTC,
   eCompressionFormat_PVRTC,
 

Core/src/CompressedImage.cpp

@@ -54,6 +54,7 @@
 #include "BC7Compressor.h"
 #include "PVRTCCompressor.h"
 #include "DXTCompressor.h"
+#include "ETCCompressor.h"
 
 CompressedImage::CompressedImage( const CompressedImage &other )
   : Image(other)
@@ -116,6 +117,10 @@ bool CompressedImage::DecompressImage(unsigned char *outBuf, unsigned int outBuf
       DXTC::DecompressDXT1(dj);
       break;
 
+    case eCompressionFormat_ETC1:
+      ETCC::Decompress(dj);
+      break;
+
     case eCompressionFormat_PVRTC:
     {
 #ifndef NDEBUG
@@ -168,6 +173,7 @@ uint32 CompressedImage::GetCompressedSize(uint32 uncompressedSize, ECompressionF
   default:
     assert(!"Not implemented!");
     // Fall through V
+  case eCompressionFormat_ETC1:
   case eCompressionFormat_DXT1:
   case eCompressionFormat_PVRTC:
     cmpDataSzNeeded = uncompressedSize / 8;

Core/src/TexComp.cpp

@@ -50,6 +50,7 @@
 #include <cassert>
 #include <iostream>
 
+#include "ETCCompressor.h"
 #include "DXTCompressor.h"
 #include "BC7Compressor.h"
 #include "CompressionFuncs.h"
@@ -102,7 +103,8 @@ static  CompressionFuncWithStats ChooseFuncFromSettingsWithStats(const SCompress
        return BC7C::CompressWithStats;
     }
     break;
-
+    
+    case eCompressionFormat_ETC1:
     case eCompressionFormat_DXT1:
     case eCompressionFormat_DXT5:
     case eCompressionFormat_PVRTC:
@@ -149,6 +151,9 @@ static CompressionFunc ChooseFuncFromSettings(const SCompressionSettings &s) {
       }
     }
 
+    case eCompressionFormat_ETC1:
+      return ETCC::Compress_RG;
+
     default:
     {
       assert(!"Not implemented!");

ETCEncoder/CMakeLists.txt

@@ -0,0 +1,64 @@
+# FasTC
+# Copyright (c) 2012 University of North Carolina at Chapel Hill. All rights reserved.
+#
+# Permission to use, copy, modify, and distribute this software and its documentation for educational, 
+# research, and non-profit purposes, without fee, and without a written agreement is hereby granted, 
+# provided that the above copyright notice, this paragraph, and the following four paragraphs appear 
+# in all copies.
+#
+# Permission to incorporate this software into commercial products may be obtained by contacting the 
+# authors or the Office of Technology Development at the University of North Carolina at Chapel Hill <otd@unc.edu>.
+#
+# This software program and documentation are copyrighted by the University of North Carolina at Chapel Hill. 
+# The software program and documentation are supplied "as is," without any accompanying services from the 
+# University of North Carolina at Chapel Hill or the authors. The University of North Carolina at Chapel Hill 
+# and the authors do not warrant that the operation of the program will be uninterrupted or error-free. The 
+# end-user understands that the program was developed for research purposes and is advised not to rely 
+# exclusively on the program for any reason.
+#
+# IN NO EVENT SHALL THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE AUTHORS BE LIABLE TO ANY PARTY FOR 
+# DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE 
+# USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE 
+# AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS SPECIFICALLY DISCLAIM ANY WARRANTIES, INCLUDING, 
+# BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND ANY 
+# STATUTORY WARRANTY OF NON-INFRINGEMENT. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY 
+# OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS HAVE NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, 
+# ENHANCEMENTS, OR MODIFICATIONS.
+#
+# Please send all BUG REPORTS to <pavel@cs.unc.edu>.
+#
+# The authors may be contacted via:
+#
+# Pavel Krajcevski
+# Dept of Computer Science
+# 201 S Columbia St
+# Frederick P. Brooks, Jr. Computer Science Bldg
+# Chapel Hill, NC 27599-3175
+# USA
+# 
+# <http://gamma.cs.unc.edu/FasTC/>
+
+INCLUDE_DIRECTORIES(${FasTC_SOURCE_DIR}/Base/include)
+
+INCLUDE_DIRECTORIES(${FasTC_SOURCE_DIR}/ETCEncoder/include)
+INCLUDE_DIRECTORIES(${FasTC_BINARY_DIR}/ETCEncoder/include)
+
+SET( HEADERS
+  include/ETCCompressor.h
+  src/rg_etc1.h
+)
+
+SET( SOURCES
+  src/Compressor.cpp
+  src/Decompressor.cpp
+  src/rg_etc1.cpp
+)
+
+ADD_LIBRARY( ETCEncoder
+  ${HEADERS}
+  ${SOURCES}
+)
+
+TARGET_LINK_LIBRARIES( ETCEncoder FasTCBase )

ETCEncoder/include/ETCCompressor.h

@@ -0,0 +1,74 @@
+/* FasTC
+ * Copyright (c) 2013 University of North Carolina at Chapel Hill.
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation for educational, research, and non-profit purposes, without
+ * fee, and without a written agreement is hereby granted, provided that the
+ * above copyright notice, this paragraph, and the following four paragraphs
+ * appear in all copies.
+ *
+ * Permission to incorporate this software into commercial products may be
+ * obtained by contacting the authors or the Office of Technology Development
+ * at the University of North Carolina at Chapel Hill <otd@unc.edu>.
+ *
+ * This software program and documentation are copyrighted by the University of
+ * North Carolina at Chapel Hill. The software program and documentation are
+ * supplied "as is," without any accompanying services from the University of
+ * North Carolina at Chapel Hill or the authors. The University of North
+ * Carolina at Chapel Hill and the authors do not warrant that the operation of
+ * the program will be uninterrupted or error-free. The end-user understands
+ * that the program was developed for research purposes and is advised not to
+ * rely exclusively on the program for any reason.
+ *
+ * IN NO EVENT SHALL THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE
+ * AUTHORS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL,
+ * OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF
+ * THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF NORTH CAROLINA
+ * AT CHAPEL HILL OR THE AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS SPECIFICALLY
+ * DISCLAIM ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND ANY 
+ * STATUTORY WARRANTY OF NON-INFRINGEMENT. THE SOFTWARE PROVIDED HEREUNDER IS ON
+ * AN "AS IS" BASIS, AND THE UNIVERSITY  OF NORTH CAROLINA AT CHAPEL HILL AND
+ * THE AUTHORS HAVE NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, 
+ * ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Please send all BUG REPORTS to <pavel@cs.unc.edu>.
+ *
+ * The authors may be contacted via:
+ *
+ * Pavel Krajcevski
+ * Dept of Computer Science
+ * 201 S Columbia St
+ * Frederick P. Brooks, Jr. Computer Science Bldg
+ * Chapel Hill, NC 27599-3175
+ * USA
+ * 
+ * <http://gamma.cs.unc.edu/FasTC/>
+ */
+
+#ifndef ETCENCODER_INCLUDE_ETCCOMPRESSOR_H_
+#define ETCENCODER_INCLUDE_ETCCOMPRESSOR_H_
+
+#include "CompressionJob.h"
+#include "TexCompTypes.h"
+
+namespace ETCC {
+
+  // Takes a stream of compressed ETC1 data and decompresses it into R8G8B8A8
+  // format. The width and height must be specified in order to properly
+  // decompress the data.
+  void Decompress(const DecompressionJob &);
+
+  // Takes a stream of uncompressed RGBA8 data and compresses it into ETC1
+  // version one. The width and height must be specified in order to properly
+  // decompress the data. This uses the library created by Rich Geldreich found here:
+  // https://code.google.com/p/rg-etc1
+  void Compress_RG(const CompressionJob &);
+
+}  // namespace PVRTCC
+
+#endif  // ETCENCODER_INCLUDE_ETCCOMPRESSOR_H_

ETCEncoder/src/Compressor.cpp

@@ -0,0 +1,83 @@
+/* FasTC
+ * Copyright (c) 2013 University of North Carolina at Chapel Hill.
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation for educational, research, and non-profit purposes, without
+ * fee, and without a written agreement is hereby granted, provided that the
+ * above copyright notice, this paragraph, and the following four paragraphs
+ * appear in all copies.
+ *
+ * Permission to incorporate this software into commercial products may be
+ * obtained by contacting the authors or the Office of Technology Development
+ * at the University of North Carolina at Chapel Hill <otd@unc.edu>.
+ *
+ * This software program and documentation are copyrighted by the University of
+ * North Carolina at Chapel Hill. The software program and documentation are
+ * supplied "as is," without any accompanying services from the University of
+ * North Carolina at Chapel Hill or the authors. The University of North
+ * Carolina at Chapel Hill and the authors do not warrant that the operation of
+ * the program will be uninterrupted or error-free. The end-user understands
+ * that the program was developed for research purposes and is advised not to
+ * rely exclusively on the program for any reason.
+ *
+ * IN NO EVENT SHALL THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE
+ * AUTHORS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL,
+ * OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF
+ * THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF NORTH CAROLINA
+ * AT CHAPEL HILL OR THE AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS SPECIFICALLY
+ * DISCLAIM ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND ANY 
+ * STATUTORY WARRANTY OF NON-INFRINGEMENT. THE SOFTWARE PROVIDED HEREUNDER IS ON
+ * AN "AS IS" BASIS, AND THE UNIVERSITY  OF NORTH CAROLINA AT CHAPEL HILL AND
+ * THE AUTHORS HAVE NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, 
+ * ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Please send all BUG REPORTS to <pavel@cs.unc.edu>.
+ *
+ * The authors may be contacted via:
+ *
+ * Pavel Krajcevski
+ * Dept of Computer Science
+ * 201 S Columbia St
+ * Frederick P. Brooks, Jr. Computer Science Bldg
+ * Chapel Hill, NC 27599-3175
+ * USA
+ * 
+ * <http://gamma.cs.unc.edu/FasTC/>
+ */
+
+#include "rg_etc1.h"
+#include "ETCCompressor.h"
+
+namespace ETCC {
+
+  void Compress_RG(const CompressionJob &cj) {
+
+    rg_etc1::etc1_pack_params params;
+    params.m_quality = rg_etc1::cLowQuality;
+    rg_etc1::pack_etc1_block_init();
+
+    // Assume block-stream order
+    uint32 blockSizeX = cj.width / 4;
+    uint32 blockSizeY = cj.height / 4;
+
+    for(uint32 j = 0; j < blockSizeY; j++)
+    for(uint32 i = 0; i < blockSizeX; i++) {
+      uint32 pixels[16];
+      uint32 blockIdx = j*blockSizeX + i;
+
+      for(uint32 y = 0; y < 4; y++) {
+        for(uint32 x = 0; x < 4; x++) {
+          const uint32 *in = reinterpret_cast<const uint32 *>(cj.inBuf);
+          pixels[y*4 + x] = in[(j*4 + y)*cj.width + (i*4 + x)];
+        }
+      }
+
+      pack_etc1_block(cj.outBuf + blockIdx * 8, pixels, params);
+    }
+  }
+}  // namespace PVRTCC

ETCEncoder/src/Decompressor.cpp

@@ -0,0 +1,77 @@
+/* FasTC
+ * Copyright (c) 2013 University of North Carolina at Chapel Hill.
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation for educational, research, and non-profit purposes, without
+ * fee, and without a written agreement is hereby granted, provided that the
+ * above copyright notice, this paragraph, and the following four paragraphs
+ * appear in all copies.
+ *
+ * Permission to incorporate this software into commercial products may be
+ * obtained by contacting the authors or the Office of Technology Development
+ * at the University of North Carolina at Chapel Hill <otd@unc.edu>.
+ *
+ * This software program and documentation are copyrighted by the University of
+ * North Carolina at Chapel Hill. The software program and documentation are
+ * supplied "as is," without any accompanying services from the University of
+ * North Carolina at Chapel Hill or the authors. The University of North
+ * Carolina at Chapel Hill and the authors do not warrant that the operation of
+ * the program will be uninterrupted or error-free. The end-user understands
+ * that the program was developed for research purposes and is advised not to
+ * rely exclusively on the program for any reason.
+ *
+ * IN NO EVENT SHALL THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE
+ * AUTHORS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL,
+ * OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF
+ * THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF NORTH CAROLINA
+ * AT CHAPEL HILL OR THE AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS SPECIFICALLY
+ * DISCLAIM ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND ANY 
+ * STATUTORY WARRANTY OF NON-INFRINGEMENT. THE SOFTWARE PROVIDED HEREUNDER IS ON
+ * AN "AS IS" BASIS, AND THE UNIVERSITY  OF NORTH CAROLINA AT CHAPEL HILL AND
+ * THE AUTHORS HAVE NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, 
+ * ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Please send all BUG REPORTS to <pavel@cs.unc.edu>.
+ *
+ * The authors may be contacted via:
+ *
+ * Pavel Krajcevski
+ * Dept of Computer Science
+ * 201 S Columbia St
+ * Frederick P. Brooks, Jr. Computer Science Bldg
+ * Chapel Hill, NC 27599-3175
+ * USA
+ * 
+ * <http://gamma.cs.unc.edu/FasTC/>
+ */
+
+#include "rg_etc1.h"
+#include "ETCCompressor.h"
+
+namespace ETCC {
+
+  void Decompress(const DecompressionJob &cj) {
+
+    uint32 blocksX = cj.width / 4;
+    uint32 blocksY = cj.width / 4;
+
+    for(uint32 j = 0; j < blocksX; j++) {
+      for(uint32 i = 0; i < blocksY; i++) {
+        uint32 pixels[16];
+        uint32 blockIdx = j*blocksX + i;
+        rg_etc1::unpack_etc1_block(cj.inBuf + blockIdx * 8, pixels);
+        for(uint32 y = 0; y < 4; y++)
+        for(uint32 x = 0; x < 4; x++) {
+          uint32 *out = reinterpret_cast<uint32 *>(cj.outBuf);
+          out[(j*4 + y)*cj.width + (i*4 + x)] = pixels[y*4 + x];
+        }
+      }
+    }
+  }
+
+}  // namespace PVRTCC

ETCEncoder/src/rg_etc1.h

@@ -0,0 +1,76 @@
+// File: rg_etc1.h - Fast, high quality ETC1 block packer/unpacker - Rich Geldreich <richgel99@gmail.com>
+// Please see ZLIB license at the end of this file.
+#pragma once
+
+namespace rg_etc1
+{
+   // Unpacks an 8-byte ETC1 compressed block to a block of 4x4 32bpp RGBA pixels.
+   // Returns false if the block is invalid. Invalid blocks will still be unpacked with clamping.
+   // This function is thread safe, and does not dynamically allocate any memory.
+   // If preserve_alpha is true, the alpha channel of the destination pixels will not be overwritten. Otherwise, alpha will be set to 255.
+   bool unpack_etc1_block(const void *pETC1_block, unsigned int* pDst_pixels_rgba, bool preserve_alpha = false);
+
+   // Quality setting = the higher the quality, the slower. 
+   // To pack large textures, it is highly recommended to call pack_etc1_block() in parallel, on different blocks, from multiple threads (particularly when using cHighQuality).
+   enum etc1_quality
+   { 
+      cLowQuality,
+      cMediumQuality,
+      cHighQuality,
+   };
+      
+   struct etc1_pack_params
+   {
+      etc1_quality m_quality;
+      bool m_dithering;
+                              
+      inline etc1_pack_params() 
+      {
+         clear();
+      }
+
+      void clear()
+      {
+         m_quality = cHighQuality;
+         m_dithering = false;
+      }
+   };
+
+   // Important: pack_etc1_block_init() must be called before calling pack_etc1_block().
+   void pack_etc1_block_init();
+
+   // Packs a 4x4 block of 32bpp RGBA pixels to an 8-byte ETC1 block.
+   // 32-bit RGBA pixels must always be arranged as (R,G,B,A) (R first, A last) in memory, independent of platform endianness. A should always be 255.
+   // Returns squared error of result.
+   // This function is thread safe, and does not dynamically allocate any memory.
+   // pack_etc1_block() does not currently support "perceptual" colorspace metrics - it primarily optimizes for RGB RMSE.
+   unsigned int pack_etc1_block(void* pETC1_block, const unsigned int* pSrc_pixels_rgba, etc1_pack_params& pack_params);
+            
+} // namespace rg_etc1
+
+//------------------------------------------------------------------------------
+//
+// rg_etc1 uses the ZLIB license:
+// http://opensource.org/licenses/Zlib
+//
+// Copyright (c) 2012 Rich Geldreich
+//
+// This software is provided 'as-is', without any express or implied
+// warranty.  In no event will the authors be held liable for any damages
+// arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented; you must not
+// claim that you wrote the original software. If you use this software
+// in a product, an acknowledgment in the product documentation would be
+// appreciated but is not required.
+//
+// 2. Altered source versions must be plainly marked as such, and must not be
+// misrepresented as being the original software.
+//
+// 3. This notice may not be removed or altered from any source distribution.
+//
+//------------------------------------------------------------------------------