+/* data structures for hashtables ********************************************
+
+
+ All utf-symbols, javastrings and classes are stored in global hashtables,
+ so every symbol exists only once. Equal symbols have identical pointers.
+ The functions for adding hashtable elements search the table for the
+ element with the specified name/text and return it on success. Otherwise a
+ new hashtable element is created.
+
+ The hashtables use external linking for handling collisions. The hashtable
+ structure contains a pointer <ptr> to the array of hashtable slots. The
+ number of hashtable slots and therefore the size of this array is specified
+ by the element <size> of hashtable structure. <entries> contains the number
+ of all hashtable elements stored in the table, including those in the
+ external chains.
+ The hashtable element structures (utf, literalstring, classinfo) contain
+ both a pointer to the next hashtable element as a link for the external hash
+ chain and the key of the element. The key is computed from the text of
+ the string or the classname by using up to 8 characters.
+
+ If the number of entries in the hashtable exceeds twice the size of the
+ hashtableslot-array it is supposed that the average length of the
+ external chains has reached a value beyond 2. Therefore the functions for
+ adding hashtable elements (utf_new, class_new, literalstring_new) double
+ the hashtableslot-array. In this restructuring process all elements have
+ to be inserted into the new hashtable and new external chains must be built.
+
+
+example for the layout of a hashtable:
+
+hashtable.ptr--> +-------------------+
+ | |
+ ...
+ | |
+ +-------------------+ +-------------------+ +-------------------+
+ | hashtable element |-->| hashtable element |-->| hashtable element |-->NULL
+ +-------------------+ +-------------------+ +-------------------+
+ | hashtable element |
+ +-------------------+ +-------------------+
+ | hashtable element |-->| hashtable element |-->NULL
+ +-------------------+ +-------------------+
+ | hashtable element |-->NULL
+ +-------------------+
+ | |
+ ...
+ | |
+ +-------------------+