Add NodeCoord (in preparation for future changes)

BlockPos.h

@@ -4,18 +4,25 @@
 
 #include <cstdlib>
 #include <limits>
+#include <climits>
 
 struct BlockPos {
-	int x;
-	int y;
-	int z;
-#if SIZE_MAX > (1LL << 36)
-	std::size_t hash(void) const { return databasePos(); }
-#else
-	std::size_t hash(void) const { return databasePos() % SIZE_MAX; }
-#endif
-	BlockPos() : x(0), y(0), z(0) {}
-	BlockPos(int _x, int _y, int _z) : x(_x), y(_y), z(_z) {}
+	int dimension[3];
+	// Unfortunately, static member references are not supported (even though static member pointers are...)
+	// I'd like to have:
+	//	static int BlockPos::&x = dimension[0];
+	// (which would avoid the extra object size associated with non-static members)
+	int &x = dimension[0];
+	int &y = dimension[1];
+	int &z = dimension[2];
+//#if SIZE_MAX > (1LL << 36)
+//	std::size_t hash(void) const { return databasePos(); }
+//#else
+//	std::size_t hash(void) const { return databasePos() % SIZE_MAX; }
+//#endif
+	BlockPos() : dimension{0, 0, 0} {}
+	BlockPos(int _x, int _y, int _z) : dimension{_x, _y, _z} {}
+	BlockPos(const BlockPos &pos) : dimension{pos.x, pos.y, pos.z} {}
 	BlockPos(int64_t i) { setFromDBPos(i); }
 	int64_t databasePos(void) const { return getDBPos(); }
 
@@ -24,6 +31,9 @@ struct BlockPos {
 	void operator=(const BlockPos &p) { x = p.x; y = p.y; z = p.z; }
 	void operator=(int64_t i) { setFromDBPos(i); }
 
+	static const int Any = INT_MIN;
+	static const int Invalid = INT_MAX;
+
 protected:
 // Include code copied from the minetest codebase.
 // Defines (at least) the following functions:
@@ -33,6 +43,54 @@ protected:
 
 };
 
+struct NodeCoord : BlockPos
+{
+	bool isBlock[3];
+	// Unfortunately, static member references are not supported (even though static member pointers are...)
+	bool &xBlock = isBlock[0];
+	bool &yBlock = isBlock[1];
+	bool &zBlock = isBlock[2];
+
+	NodeCoord() : BlockPos(), isBlock{false, false, false} {}
+	NodeCoord(int _x, int _y, int _z) : BlockPos(_x, _y, _z), isBlock{false, false, false} {}
+	NodeCoord(const BlockPos &pos, bool node = false) : BlockPos(pos), isBlock{pos.x == Any ? false : !node, pos.y == Any ? false : !node, pos.z == Any ? false : !node} {}
+	NodeCoord(const NodeCoord &coord) : BlockPos(coord), isBlock{coord.xBlock, coord.yBlock, coord.zBlock} {}
+	NodeCoord(int64_t i) : isBlock{true, true, true} { setFromDBPos(i); }
+
+	size_t hash(void) const;
+
+	bool operator==(const NodeCoord &coord) const;
+	void operator=(const BlockPos &coord) { x = coord.x; y = coord.y; z = coord.z; xBlock = true; yBlock = true; zBlock = true; }
+	void operator=(const NodeCoord &coord) { x = coord.x; y = coord.y; z = coord.z; xBlock = coord.xBlock; yBlock = coord.yBlock; zBlock = coord.zBlock; }
+};
+
+// Use this for map or set storage only...
+struct NodeCoordHashed : NodeCoord
+{
+private:
+	size_t m_hash;
+public:
+	struct Hash {
+		size_t operator()(const NodeCoordHashed &h) const { return h.hash(); }
+	};
+	NodeCoordHashed(const BlockPos &pos) : NodeCoord(pos) { rehash(); }
+	NodeCoordHashed(const NodeCoord &coord) : NodeCoord(coord) { rehash(); }
+	void rehash(void) { m_hash = NodeCoord::hash(); }
+	unsigned hash(void) { rehash(); return m_hash; }
+	unsigned hash(void) const { return m_hash; }
+	bool operator==(const NodeCoordHashed &coord) const { if (m_hash != coord.m_hash) return false; return NodeCoord::operator==(coord); }
+	void operator=(const NodeCoord &coord) { NodeCoord::operator=(coord); rehash(); }
+	bool operator<(const NodeCoordHashed &coord) { return m_hash < coord.m_hash; }
+};
+
+namespace std {
+	template<>
+	struct hash<NodeCoordHashed>
+	{
+		size_t operator()(const NodeCoordHashed &nch) const { return nch.hash(); }
+	};
+}
+
 // operator< should order the positions in the
 // order the corresponding pixels are generated:
 // First (most significant): z coordinate, descending (i.e. reversed)
@@ -55,7 +113,7 @@ inline bool BlockPos::operator<(const BlockPos& p) const
 	return false;
 }
 
-inline bool BlockPos::operator==(const BlockPos& p) const
+inline bool BlockPos::operator==(const BlockPos &p) const
 {
 	if (z != p.z)
 		return false;
@@ -66,4 +124,30 @@ inline bool BlockPos::operator==(const BlockPos& p) const
 	return true;
 }
 
+inline size_t NodeCoord::hash(void) const
+{
+	size_t hash = 0xd3adb33f;
+	for (int i=0; i<3; i++)
+		// Nothing too fancy...
+		hash = ((hash << 8) | (hash >> 24)) ^ (dimension[i] ^ (isBlock[i] ? 0x50000000 : 0));
+	return hash;
+}
+
+inline bool NodeCoord::operator==(const NodeCoord &coord) const
+{
+	if (z != coord.z)
+		return false;
+	if (y != coord.y)
+		return false;
+	if (x != coord.x)
+		return false;
+	if (zBlock != coord.zBlock)
+		return false;
+	if (yBlock != coord.yBlock)
+		return false;
+	if (xBlock != coord.xBlock)
+		return false;
+	return true;
+}
+
 #endif // BLOCKPOS_H