Change signature hash function

Author: tdermendjiev

src/NativeScript/Calling/FFICache.h

@@ -13,33 +13,27 @@
 #include <vector>
 
 namespace NativeScript {
-    
-    struct SignatureHash {
-        
-        std::size_t operator()(std::vector<const ffi_type*> signature) const {
-            std::size_t seed = 0;
-            
-            
-            for(size_t i = 0; i < signature.size(); i++) {
-                seed <<= 4;
-                seed |= signature[i]->type;
-            }
-            return seed;
+
+struct SignatureHash {
+
+    std::size_t operator()(std::vector<const ffi_type*> signature) const {
+        std::size_t seed = 2166136261;
+
+        for (size_t i = 0; i < signature.size(); i++) {
+            seed = (seed ^ reinterpret_cast<size_t>(signature[i])) * 16777619U;
         }
-        
-    };
-    
-    class FFICache {
-        
-    public:
-        
-        std::unordered_map<std::vector<const ffi_type*>, std::shared_ptr<ffi_cif>, SignatureHash> cifCache;
-        
-        static FFICache *global(); 
-        
-    };
-    
-}
+        return seed;
+    }
+};
+
+class FFICache {
+
+public:
+    std::unordered_map<std::vector<const ffi_type*>, std::shared_ptr<ffi_cif>, SignatureHash> cifCache;
+
+    static FFICache* global();
+};
 
+} // namespace NativeScript
 
 #endif /* FFICache_h */