public void ReadHeader()
{
List <long> tileOffsets = new List <long>();
_mapFile.StreamReader.Position = ZoomIntervalConfig.AbsStartPositionSubFile;
MinX = (int)MapFile.GetTileX((double)_mapFile.Header.MinLon, ZoomIntervalConfig.BaseZoomLevel);
MaxX = (int)MapFile.GetTileX((double)_mapFile.Header.MaxLon, ZoomIntervalConfig.BaseZoomLevel);
MinY = (int)MapFile.GetTileY((double)_mapFile.Header.MaxLat, ZoomIntervalConfig.BaseZoomLevel);
MaxY = (int)MapFile.GetTileY((double)_mapFile.Header.MinLat, ZoomIntervalConfig.BaseZoomLevel);
if (_mapFile.Header.DebugInformationPresent)
{
TileIndexSignature = _mapFile.ReadFixedString(16);
}
else
{
TileIndexSignature = null;
}
long hTiles = MaxX - MinX + 1;
long vTiles = MaxY - MinY + 1;
long blockCount = hTiles * vTiles;
long endOfIndex = ZoomIntervalConfig.AbsStartPositionSubFile + (blockCount * 5);
//tile entries
byte[] buffer = new byte[8];
while (_mapFile.StreamReader.Position < endOfIndex)
{
Array.Clear(buffer, 0, 8);
_mapFile.StreamReader.Read(buffer, 3, 5);
long offset;
if ((buffer[3] & 0x80) == 0x80)
{
//in water
offset = 0;
}
else
{
offset = BitConverter.ToInt64(MapFile.ReverseBytes(buffer, 0, 8), 0);
}
tileOffsets.Add(offset);
}
_tileAbsOffsets = tileOffsets.ToArray();
}
private static double toRelTileX(double longitude, long tileX, int zoom)
{
return((MapFile.GetTileX(longitude / 1000000.0, zoom) - tileX) * 256.0);
}