medfall

commit fe92c9f6e9b0b3aa94a11e53547f96a54f3b6cf9
parent 1fd5e48ec77dab6949e13c32dfcc860852224b60
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Mon May 15 03:31:42 +0300

Add stringhash.h

Diffstat:
stringhash.h
 | 
66
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+), 0 deletions(-)
diff --git a/stringhash.h b/stringhash.h
@@ -0,0 +1,66 @@
+#pragma once
+
+#include "intrinsics.h"
+
+constexpr static inline u32 fnv1a( const char * str, size_t n ) {
+	return n == 0 ? 0x811C9DC5 : ( fnv1a( str + 1, n - 1 ) ^ u32( str[ 0 ] ) ) * 0x01000193;
+}
+
+template< size_t N >
+constexpr static inline u32 fnv1a( const char ( & str )[ N ] ) {
+	return fnv1a( str, N );
+}
+
+struct StringHash {
+	const char * str;
+	u32 hash;
+
+	StringHash() { }
+
+	template< size_t N >
+	StringHash( const char ( & s )[ N ] ) {
+		str = s;
+		hash = fnv1a( s );
+	}
+};
+
+template< typename T, size_t N >
+class StaticMap {
+	struct Node {
+		StringHash key;
+		T value;
+	};
+
+	Node nodes[ N ];
+	size_t nodes_in_use = 0;
+
+	bool get( StringHash key, T * x ) {
+		for( size_t i = 0; i < nodes_in_use; i++ ) {
+			if( nodes[ i ].key.hash == key.hash ) {
+				if( x != NULL ) *x = nodes[ i ].value;
+				return true;
+			}
+		}
+		return false;
+	}
+
+public:
+	void add( StringHash key, const T & value ) {
+		ASSERT( nodes_in_use < N );
+		ASSERT( !get( key, NULL ) );
+
+		Node node;
+		node.key = key;
+		node.value = value;
+		nodes[ nodes_in_use ] = node;
+
+		nodes_in_use++;
+	}
+
+	T get( StringHash key ) {
+		T res;
+		bool ok = get( key, &res );
+		ASSERT( ok );
+		return res;
+	}
+};