public: crclib: optimize COM_HashKey, implement typical djb hashing as this function is used for hashtables with string lookup

public/crclib.c

@@ -457,10 +457,11 @@ returns hash key for string
 */
 uint COM_HashKey( const char *string, uint hashSize )
 {
-	uint	i, hashKey = 0;
+	int hashKey = 5381;
+	unsigned char i;
 
-	for( i = 0; string[i]; i++ )
+	while(( i = *string++ ))
-		hashKey = (hashKey + i) * 37 + Q_tolower( string[i] );
+		hashKey = ( hashKey << 5 ) + hashKey + ( i & 0xDF );
 
-	return (hashKey % hashSize);
+	return hashKey & ( hashSize - 1 );
 }