BAN: Add basic hashing functionality

BAN/include/BAN/Hash.h

@@ -0,0 +1,50 @@
+#pragma once
+
+#include <BAN/Traits.h>
+#include <stddef.h>
+#include <stdint.h>
+
+namespace BAN
+{
+
+	template<typename T>
+	struct hash;
+
+	using hash_t = uint32_t;
+
+	inline constexpr hash_t u32_hash(uint32_t val)
+	{
+		val = ((val >> 16) ^ val) * 0x119de1f3;
+		val = ((val >> 16) ^ val) * 0x119de1f3;
+		val = ((val >> 16) ^ val);
+		return val;
+	}
+
+	inline constexpr hash_t u64_hash(uint64_t val)
+	{
+		hash_t low = u32_hash(val);
+		hash_t high = u32_hash(val >> 32);
+		return low ^ high;
+	}
+
+	template<integral T>
+	struct hash<T>
+	{
+		constexpr hash_t operator()(T val) const
+		{
+			if constexpr(sizeof(val) <= sizeof(uint32_t))
+				return u32_hash(val);
+			return u64_hash(val);
+		}
+	};
+
+	template<pointer T>
+	struct hash<T>
+	{
+		constexpr hash_t operator()(T val) const
+		{
+			return hash<uintptr_t>()((uintptr_t)val);
+		}
+	};
+
+}