1 files changed, 58 insertions, 0 deletions
diff --git a/include/odhtdb/Hash.hpp b/include/odhtdb/Hash.hpp
new file mode 100644
index 0000000..9dce168
--- /dev/null
+++ b/include/odhtdb/Hash.hpp
@@ -0,0 +1,58 @@
+#pragma once
+
+#include "utils.hpp"
+#include <stdexcept>
+#include <unordered_map>
+#include <unordered_set>
+
+namespace odhtdb
+{
+    const int HASH_BYTE_SIZE = 32;
+    
+    // Source: https://stackoverflow.com/a/11414104 (public license)
+    static size_t fnvHash(const unsigned char *key, int len)
+    {
+        size_t h = 2166136261;
+        for (int i = 0; i < len; i++)
+            h = (h * 16777619) ^ key[i];
+        return h;
+    }
+    
+    class HashException : public std::runtime_error
+    {
+    public:
+        HashException(const std::string &errMsg) : std::runtime_error(errMsg) {}
+    };
+    
+    class Hash
+    {
+    public:
+        Hash();
+        // Throws HashException on failure
+        Hash(const void *input, const size_t inputSize);
+        Hash(const Hash &other);
+        
+        void* getData() const { return (void*)data; }
+        size_t getSize() const { return HASH_BYTE_SIZE; }
+        
+        size_t operator()() const;
+        bool operator==(const Hash &other) const;
+        
+        std::string toString() const;
+    private:
+        char data[HASH_BYTE_SIZE];
+    };
+    
+    struct HashHasher
+    {
+        size_t operator()(const Hash &hash) const
+        {
+            return hash();
+        }
+    };
+    
+    template <typename ValueType>
+    using MapHash = std::unordered_map<Hash, ValueType, HashHasher>;
+    
+    using SetHash = std::unordered_set<Hash, HashHasher>;
+}