protected int hash(Object key) {
        // same as JDK 1.4
        /*int h = key.hashCode();
        h += ~(h << 9);
        h ^= (h >>> 14);
        h += (h << 4);
        h ^= (h >>> 10);*/
        return key.hashCode();
    }
Gets the hash code for the key specified.
This implementation uses the additional hashing routine from JDK1.4.
Subclasses can override this to return alternate hash codes.

@param key the key to get a hash code for
@return the hash code
jphp-runtime/src/php/runtime/memory/support/ArrayMemoryMap.java