text: ///////////////////////////////////////////////////////////////////////////
  //
  // Copyright (c) 2004, Industrial Light & Magic, a division of Lucas
  // Digital Ltd. LLC
  // 
  // All rights reserved.
  // 
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  // *       Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  // *       Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  // *       Neither the name of Industrial Light & Magic nor the names of
  // its contributors may be used to endorse or promote products derived
  // from this software without specific prior written permission. 
  // 
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  //
  ///////////////////////////////////////////////////////////////////////////
  
  
  //-----------------------------------------------------------------------------
  //
  //	Miscellaneous stuff related to tiled files
  //
  //-----------------------------------------------------------------------------
  
  #include <ImfTiledMisc.h>
  #include "Iex.h"
  #include <ImfMisc.h>
  #include <ImfChannelList.h>
  #include <ImfTileDescription.h>
  #include <algorithm>
  
  #include "ImfNamespace.h"
  
  OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_ENTER
  
  using IMATH_NAMESPACE::Box2i;
  using IMATH_NAMESPACE::V2i;
  
  
  int
  levelSize (int min, int max, int l, LevelRoundingMode rmode)
  {
      if (l < 0)
  	throw IEX_NAMESPACE::ArgExc ("Argument not in valid range.");
  
      int a = max - min + 1;
      int b = (1 << l);
      int size = a / b;
  
      if (rmode == ROUND_UP && size * b < a)
  	size += 1;
  
      return std::max (size, 1);
  }
  
  
  Box2i
  dataWindowForLevel (const TileDescription &tileDesc,
  		    int minX, int maxX,
  		    int minY, int maxY,
  		    int lx, int ly)
  {
      V2i levelMin = V2i (minX, minY);
  
      V2i levelMax = levelMin +
  		   V2i (levelSize (minX, maxX, lx, tileDesc.roundingMode) - 1,
  			levelSize (minY, maxY, ly, tileDesc.roundingMode) - 1);
  
      return Box2i(levelMin, levelMax);
  }
  
  
  Box2i
  dataWindowForTile (const TileDescription &tileDesc,
  		   int minX, int maxX,
  		   int minY, int maxY,
  		   int dx, int dy,
  		   int lx, int ly)
  {
      V2i tileMin = V2i (minX + dx * tileDesc.xSize,
  		       minY + dy * tileDesc.ySize);
  
      V2i tileMax = tileMin + V2i (tileDesc.xSize - 1, tileDesc.ySize - 1);
  
      V2i levelMax = dataWindowForLevel
  		       (tileDesc, minX, maxX, minY, maxY, lx, ly).max;
  
      tileMax = V2i (std::min (tileMax[0], levelMax[0]),
  		   std::min (tileMax[1], levelMax[1]));
  
      return Box2i (tileMin, tileMax);
  }
  
  
  size_t
  calculateBytesPerPixel (const Header &header)
  {
      const ChannelList &channels = header.channels();
  
      size_t bytesPerPixel = 0;
  
      for (ChannelList::ConstIterator c = channels.begin();
  	 c != channels.end();
  	 ++c)
      {
  	bytesPerPixel += pixelTypeSize (c.channel().type);
      }
  
      return bytesPerPixel;
  }
  
  
  void
  calculateBytesPerLine (const Header &header,
                         char* sampleCountBase,
                         int sampleCountXStride,
                         int sampleCountYStride,
                         int minX, int maxX,
                         int minY, int maxY,
                         std::vector<int>& xOffsets,
                         std::vector<int>& yOffsets,
                         std::vector<Int64>& bytesPerLine)
  {
      const ChannelList &channels = header.channels();
  
      int pos = 0;
      for (ChannelList::ConstIterator c = channels.begin();
           c != channels.end();
           ++c, ++pos)
      {
          int xOffset = xOffsets[pos];
          int yOffset = yOffsets[pos];
          int i = 0;
          for (int y = minY - yOffset; y <= maxY - yOffset; y++, i++)
              for (int x = minX - xOffset; x <= maxX - xOffset; x++)
              {
                  bytesPerLine[i] += sampleCount(sampleCountBase,
                                                 sampleCountXStride,
                                                 sampleCountYStride,
                                                 x, y)
                                     * pixelTypeSize (c.channel().type);
              }
      }
  }
  
  
  namespace {
  
  int
  floorLog2 (int x)
  {
      //
      // For x > 0, floorLog2(y) returns floor(log(x)/log(2)).
      //
  
      int y = 0;
  
      while (x > 1)
      {
  	y +=  1;
  	x >>= 1;
      }
  
      return y;
  }
  
  
  int
  ceilLog2 (int x)
  {
      //
      // For x > 0, ceilLog2(y) returns ceil(log(x)/log(2)).
      //
  
      int y = 0;
      int r = 0;
  
      while (x > 1)
      {
  	if (x & 1)
  	    r = 1;
  
  	y +=  1;
  	x >>= 1;
      }
  
      return y + r;
  }
  
  
  int
  roundLog2 (int x, LevelRoundingMode rmode)
  {
      return (rmode == ROUND_DOWN)? floorLog2 (x): ceilLog2 (x);
  }
  
  
  int
  calculateNumXLevels (const TileDescription& tileDesc,
  		     int minX, int maxX,
  		     int minY, int maxY)
  {
      int num = 0;
  
      switch (tileDesc.mode)
      {
        case ONE_LEVEL:
  
  	num = 1;
  	break;
  
        case MIPMAP_LEVELS:
  
  	{
  	  int w = maxX - minX + 1;
  	  int h = maxY - minY + 1;
  	  num = roundLog2 (std::max (w, h), tileDesc.roundingMode) + 1;
  	}
          break;
  
        case RIPMAP_LEVELS:
  
  	{
  	  int w = maxX - minX + 1;
  	  num = roundLog2 (w, tileDesc.roundingMode) + 1;
  	}
  	break;
  
        default:
  
  	throw IEX_NAMESPACE::ArgExc ("Unknown LevelMode format.");
      }
  
      return num;
  }
  
  
  int
  calculateNumYLevels (const TileDescription& tileDesc,
  		     int minX, int maxX,
  		     int minY, int maxY)
  {
      int num = 0;
  
      switch (tileDesc.mode)
      {
        case ONE_LEVEL:
  
  	num = 1;
  	break;
  
        case MIPMAP_LEVELS:
  
  	{
  	  int w = maxX - minX + 1;
  	  int h = maxY - minY + 1;
  	  num = roundLog2 (std::max (w, h), tileDesc.roundingMode) + 1;
  	}
          break;
  
        case RIPMAP_LEVELS:
  
  	{
  	  int h = maxY - minY + 1;
  	  num = roundLog2 (h, tileDesc.roundingMode) + 1;
  	}
  	break;
  
        default:
  
  	throw IEX_NAMESPACE::ArgExc ("Unknown LevelMode format.");
      }
  
      return num;
  }
  
  
  void
  calculateNumTiles (int *numTiles,
  		   int numLevels,
  		   int min, int max,
  		   int size,
  		   LevelRoundingMode rmode)
  {
      for (int i = 0; i < numLevels; i++)
      {
  	numTiles[i] = (levelSize (min, max, i, rmode) + size - 1) / size;
      }
  }
  
  } // namespace
  
  
  void
  precalculateTileInfo (const TileDescription& tileDesc,
  		      int minX, int maxX,
  		      int minY, int maxY,
  		      int *&numXTiles, int *&numYTiles,
  		      int &numXLevels, int &numYLevels)
  {
      numXLevels = calculateNumXLevels(tileDesc, minX, maxX, minY, maxY);
      numYLevels = calculateNumYLevels(tileDesc, minX, maxX, minY, maxY);
      
      numXTiles = new int[numXLevels];
      numYTiles = new int[numYLevels];
  
      calculateNumTiles (numXTiles,
  		       numXLevels,
  		       minX, maxX,
  		       tileDesc.xSize,
  		       tileDesc.roundingMode);
  
      calculateNumTiles (numYTiles,
  		       numYLevels,
  		       minY, maxY,
  		       tileDesc.ySize,
  		       tileDesc.roundingMode);
  }
  
  
  int
  getTiledChunkOffsetTableSize(const Header& header)
  {
      //
      // Save the dataWindow information
      //
  
      const Box2i &dataWindow = header.dataWindow();
      
      //
      // Precompute level and tile information.
      //
  
      int* numXTiles;
      int* numYTiles;
      int numXLevels;
      int numYLevels;
      precalculateTileInfo (header.tileDescription(),
                            dataWindow.min.x, dataWindow.max.x,
                            dataWindow.min.y, dataWindow.max.y,
                            numXTiles, numYTiles,
                            numXLevels, numYLevels);
  
      //
      // Calculate lineOffsetSize.
      //
      Int64 lineOffsetSize = 0;
      const TileDescription &desc = header.tileDescription();
      switch (desc.mode)
      {
          case ONE_LEVEL:
          case MIPMAP_LEVELS:
              for (int i = 0; i < numXLevels; i++)
              {
                  lineOffsetSize += static_cast<Int64>(numXTiles[i]) * static_cast<Int64>(numYTiles[i]);
                  if ( lineOffsetSize > static_cast<Int64>(std::numeric_limits<int>::max()) )
                  {
                      throw IEX_NAMESPACE::LogicExc("Maximum number of tiles exceeded");
                  }
              }
             break;
          case RIPMAP_LEVELS:
              for (int i = 0; i < numXLevels; i++)
              {
                  for (int j = 0; j < numYLevels; j++)
                  {
                       lineOffsetSize += static_cast<Int64>(numXTiles[i]) * static_cast<Int64>(numYTiles[j]);
                       if ( lineOffsetSize > static_cast<Int64>(std::numeric_limits<int>::max()) )
                       {
                          throw IEX_NAMESPACE::LogicExc("Maximum number of tiles exceeded");
                       }
                  }
              }
             break;
          case NUM_LEVELMODES :
              throw IEX_NAMESPACE::LogicExc("Bad level mode getting chunk offset table size");
      }
  
      delete[] numXTiles;
      delete[] numYTiles;
  
      return static_cast<int>(lineOffsetSize);
  }
  
  
  OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT
  