Started Rewriting LinkData

Created NewLinkData and replaced references to the original LinkData.
Moved it to the mod_pocketDim.core package. Added Point4D, an immutable
point type for 3D integer coordinates with an added dimension ID.

StevenDimDoors/mod_pocketDim/util/Point4D.java

@@ -0,0 +1,131 @@
+package StevenDimDoors.mod_pocketDim.util;
+
+public final class Point4D
+{
+	private final int x;
+	private final int y;
+	private final int z;
+	private final int dimension;
+	
+	public Point4D(int x, int y, int z, int dimension)
+	{
+		this.x = x;
+		this.y = y;
+		this.z = z;
+		this.dimension = dimension;
+	}
+
+	public int getX()
+	{
+		return x;
+	}
+
+	public int getY()
+	{
+		return y;
+	}
+
+	public int getZ()
+	{
+		return z;
+	}
+
+	public int getDimension()
+	{
+		return dimension;
+	}
+	
+	@Override
+	public int hashCode()
+	{
+		//Time for some witchcraft.
+		//The code here is inspired by a discussion on Stack Overflow regarding hash codes for 3D.
+		//Source: http://stackoverflow.com/questions/9858376/hashcode-for-3d-integer-coordinates-with-high-spatial-coherence
+		
+		//I believe that most of the time, any points we might be hashing will be in close proximity to each other.
+		//For instance, points that are within the same chunk or within a few neighboring chunks. Only the low-order
+		//bits of each component would differ. I'll use 8 bits from Y and the 12 bits from X and Z. ~SenseiKiwi
+		
+		int bit;
+		int hash;
+		int index;
+		
+		hash = 0;
+		index = 0;
+		for (bit = 0; bit < 8; bit++)
+		{
+			hash |= ((y >> bit) & 1) << index;
+			index++;
+			hash |= ((x >> bit) & 1) << index;
+			index++;
+			hash |= ((z >> bit) & 1) << index;
+			index++;
+		}
+		for (; bit < 12; bit++)
+		{
+			hash |= ((x >> bit) & 1) << index;
+			index++;
+			hash |= ((z >> bit) & 1) << index;
+			index++;
+		}
+		return hash;
+	}
+	
+	public long longHashCode()
+	{
+		//Time for some witchcraft.
+		//The code here is inspired by a discussion on Stack Overflow regarding hash codes for 3D.
+		//Source: http://stackoverflow.com/questions/9858376/hashcode-for-3d-integer-coordinates-with-high-spatial-coherence
+		
+		//Use 8 bits from Y and 24 bits from X and Z. Mix in 8 bits from the destination dim ID too - that means
+		//even if you aligned two doors perfectly between two pockets, it's unlikely they would lead to the same dungeon.
+		
+		int bit;
+		int index;
+		long hash;
+		
+		hash = 0;
+		index = 0;
+		for (bit = 0; bit < 8; bit++)
+		{
+			hash |= ((dimension >> bit) & 1) << index;
+			index++;
+			hash |= ((x >> bit) & 1) << index;
+			index++;
+			hash |= ((y >> bit) & 1) << index;
+			index++;
+			hash |= ((z >> bit) & 1) << index;
+			index++;
+		}
+		for (; bit < 24; bit++)
+		{
+			hash |= ((x >> bit) & 1) << index;
+			index++;
+			hash |= ((z >> bit) & 1) << index;
+			index++;
+		}
+		return hash;
+	}
+
+	@Override
+	public boolean equals(Object obj)
+	{
+		return equals((Point4D) obj);
+	}
+	
+	public boolean equals(Point4D other)
+	{
+		if (this == other)
+			return true;
+		if (other == null)
+			return false;
+		
+		return (x == other.x && y == other.y && z == other.z && dimension == other.dimension);
+	}
+
+	@Override
+	public String toString()
+	{
+		return "(" + x + ", " + y + ", " + z + ", " + dimension + ")";
+	}
+}