/Main/src/DynamicDataDisplay.Maps/Servers/FileServers/ReadonlyTileCache.cs

  1using System;
  2using System.Collections.Generic;
  3using System.Linq;
  4using System.Text;
  5using System.Collections;
  6using System.Diagnostics;
  7
  8namespace Microsoft.Research.DynamicDataDisplay.Charts.Maps
  9{
 10	[Serializable]
 11	[DebuggerDisplay("Count = {Count}")]
 12	public sealed class ReadonlyTileCache
 13	{
 14		private readonly Dictionary<TileIndex, ulong> cache = new Dictionary<TileIndex, ulong>(new TileIndex.TileIndexEqualityComparer());
 15
 16		public ReadonlyTileCache() { }
 17
 18		public ReadonlyTileCache(Dictionary<TileIndex, ulong> dictionary)
 19		{
 20			this.cache = dictionary;
 21
 22			CalcMinMaxLevels();
 23		}
 24
 25		private const int levelDelta = 3;
 26		private const int levelSize = 8; // 3 << 2
 27
 28		public void CalcMinMaxLevels()
 29		{
 30			minLevel = Int32.MaxValue;
 31			maxLevel = Int32.MinValue;
 32
 33			foreach (var key in cache.Keys)
 34			{
 35				int level = (int)key.Level + levelDelta;
 36
 37				if (minLevel > level)
 38					minLevel = level;
 39				if (maxLevel < level)
 40					maxLevel = level;
 41			}
 42		}
 43
 44		private int minLevel = 0;
 45		public int MinLevel
 46		{
 47			get { return minLevel; }
 48		}
 49
 50		private int maxLevel = Int32.MaxValue;
 51		public int MaxLevel
 52		{
 53			get { return maxLevel; }
 54		}
 55
 56		public void Add(TileIndex id, bool exists)
 57		{
 58			ulong cacheLine = 0;
 59			TileIndex parent = id.GetLowerTile(levelDelta);
 60
 61			cache.TryGetValue(parent, out cacheLine);
 62
 63			int x = id.X - parent.X * levelSize;
 64			int y = id.Y - parent.Y * levelSize;
 65
 66			int position = x * levelSize + y;
 67			if (exists)
 68			{
 69				cacheLine |= ((ulong)1) << position;
 70			}
 71			else
 72			{
 73				cacheLine &= ~(((ulong)1) << position);
 74			}
 75
 76			cache[parent] = cacheLine;
 77		}
 78
 79		public bool Contains(TileIndex id)
 80		{
 81			int level = (int)id.Level;
 82			if (level < minLevel || level > maxLevel)
 83				return false;
 84
 85			TileIndex parent = id.GetLowerTile(levelDelta);
 86
 87			ulong cacheLine;
 88			if (cache.TryGetValue(parent, out cacheLine))
 89			{
 90				int x = id.X - parent.X * levelSize;
 91				int y = id.Y - parent.Y * levelSize;
 92
 93				int position = x * levelSize + y;
 94
 95				return (cacheLine & ((ulong)1 << position)) != 0;
 96			}
 97			return false;
 98		}
 99
100		public int Count
101		{
102			get { return cache.Count; }
103		}
104	}
105}