Initial commit

1 files changed, 77 insertions, 0 deletions

diff --git a/Minecraft.World/JavaIntHash.h b/Minecraft.World/JavaIntHash.h
new file mode 100644
index 00000000..447b8052
--- /dev/null
+++ b/Minecraft.World/JavaIntHash.h
@@ -0,0 +1,77 @@
+#pragma once
+
+// Java doesn't have a default hash value for ints, however, the hashmap itself does some "supplemental" hashing, so
+// our ints actually get hashed by code as implemented below. std templates *do* have a standard hash for ints, but it
+// would appear to be a bit expensive so matching the java one for now anyway. This code implements the supplemental
+// hashing that happens in java so we can match what their maps are doing with ints.
+
+typedef struct
+{
+	int operator() (const int &k) const
+	{
+		int h = k;
+        h += ~(h << 9);
+        h ^=  (((unsigned int)h) >> 14);
+        h +=  (h << 4);
+        h ^=  (((unsigned int)h) >> 10);
+		return h;
+	}
+
+} IntKeyHash;
+
+typedef struct
+{
+	bool operator() (const int &x, const int &y) const { return x==y; }
+} IntKeyEq;
+
+
+// This hash functor is taken from the IntHashMap java class used by the game, so that we can use a standard std hashmap with this hash rather
+// than implement the class itself
+typedef struct
+{
+	int operator() (const int &k) const
+	{
+		unsigned int h = (unsigned int)k;
+        h ^= (h >> 20) ^ (h >> 12);
+        return (int)(h ^ (h >> 7) ^ (h >> 4));
+	}
+} IntKeyHash2;
+
+
+// This hash functor is taken from the LongHashMap java class used by the game, so that we can use a standard std hashmap with this hash rather
+// than implement the class itself
+typedef struct
+{
+	int hash(const int &k) const
+	{
+		unsigned int h = (unsigned int)k;
+        h ^= (h >> 20) ^ (h >> 12);
+        return (int)(h ^ (h >> 7) ^ (h >> 4));
+	}
+
+	int operator() (const __int64 &k) const
+	{
+		return hash((int) ( k ^ (((__uint64)k) >> 32 )));
+	}
+} LongKeyHash;
+
+typedef struct
+{
+	bool operator() (const __int64 &x, const __int64 &y) const { return x==y; }
+} LongKeyEq;
+
+typedef struct
+{
+	int operator() (const eINSTANCEOF &k) const
+	{
+		unsigned int h = (unsigned int)k;
+        h ^= (h >> 20) ^ (h >> 12);
+        return (int)(h ^ (h >> 7) ^ (h >> 4));
+	}
+} eINSTANCEOFKeyHash;
+
+typedef struct
+{
+	bool operator() (const eINSTANCEOF &x, const eINSTANCEOF &y) const { return x==y; }
+} eINSTANCEOFKeyEq;
+