--- /dev/null
+/***********************************************************
+* Artsoft Retro-Game Library *
+*----------------------------------------------------------*
+* (c) 1994-2003 Artsoft Entertainment *
+* Holger Schemel *
+* Detmolder Strasse 189 *
+* 33604 Bielefeld *
+* Germany *
+* e-mail: info@artsoft.org *
+*----------------------------------------------------------*
+* hash.h *
+***********************************************************/
+
+/*
+ * Copyright (C) 2002 Christopher Clark <firstname.lastname@cl.cam.ac.uk>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies of the Software and its documentation and acknowledgment shall be
+ * given in the documentation and software packages that this Software was
+ * used.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * */
+
+#ifndef HASH_H
+#define HASH_H
+
+
+/* Example of use:
+ *
+ * struct hashtable *h;
+ * struct some_key *k;
+ * struct some_value *v;
+ *
+ * static unsigned int hash_from_key_fn( void *k );
+ * static int keys_equal_fn ( void *key1, void *key2 );
+ *
+ * h = create_hashtable(16, 0.75, hash_from_key_fn, keys_equal_fn);
+ * k = (struct some_key *) malloc(sizeof(struct some_key));
+ * v = (struct some_value *) malloc(sizeof(struct some_value));
+ *
+ * (initialise k and v to suitable values)
+ *
+ * if (! hashtable_insert(h,k,v) )
+ * { exit(-1); }
+ *
+ * if (NULL == (found = hashtable_search(h,k) ))
+ * { printf("not found!"); }
+ *
+ * if (NULL == (found = hashtable_remove(h,k) ))
+ * { printf("Not found\n"); }
+ *
+ */
+
+/* Macros may be used to define type-safe(r) hashtable access functions, with
+ * methods specialized to take known key and value types as parameters.
+ *
+ * Example:
+ *
+ * Insert this at the start of your file:
+ *
+ * DEFINE_HASHTABLE_INSERT(insert_some, struct some_key, struct some_value);
+ * DEFINE_HASHTABLE_SEARCH(search_some, struct some_key, struct some_value);
+ * DEFINE_HASHTABLE_REMOVE(remove_some, struct some_key, struct some_value);
+ *
+ * This defines the functions 'insert_some', 'search_some' and 'remove_some'.
+ * These operate just like hashtable_insert etc., with the same parameters,
+ * but their function signatures have 'struct some_key *' rather than
+ * 'void *', and hence can generate compile time errors if your program is
+ * supplying incorrect data as a key (and similarly for value).
+ *
+ * Note that the hash and key equality functions passed to create_hashtable
+ * still take 'void *' parameters instead of 'some key *'. This shouldn't be
+ * a difficult issue as they're only defined and passed once, and the other
+ * functions will ensure that only valid keys are supplied to them.
+ *
+ * The cost for this checking is increased code size and runtime overhead
+ * - if performance is important, it may be worth switching back to the
+ * unsafe methods once your program has been debugged with the safe methods.
+ * This just requires switching to some simple alternative defines - eg:
+ * #define insert_some hashtable_insert
+ *
+ */
+
+
+/*****************************************************************************/
+struct entry
+{
+ void *k, *v;
+ unsigned int h;
+ struct entry *next;
+};
+
+struct hashtable {
+ unsigned int tablelength;
+ struct entry **table;
+ unsigned int entrycount;
+ unsigned int loadlimit;
+ unsigned int (*hashfn) (void *k);
+ int (*eqfn) (void *k1, void *k2);
+};
+
+/*****************************************************************************/
+struct hashtable_itr
+{
+ struct hashtable *h;
+ struct entry *e;
+ unsigned int index;
+};
+
+
+/*****************************************************************************
+ * create_hashtable
+
+ * @name create_hashtable
+ * @param minsize minimum initial size of hashtable
+ * @param maxloadfactor maximum ratio entries / tablesize
+ * @param hashfunction function for hashing keys
+ * @param key_eq_fn function for determining key equality
+ * @return newly created hashtable or NULL on failure
+ */
+
+struct hashtable *
+create_hashtable(unsigned int minsize, float maxloadfactor,
+ unsigned int (*hashfunction) (void*),
+ int (*key_eq_fn) (void*,void*));
+
+/*****************************************************************************
+ * hashtable_insert
+
+ * @name hashtable_insert
+ * @param h the hashtable to insert into
+ * @param k the key - hashtable claims ownership and will free on removal
+ * @param v the value - does not claim ownership
+ * @return non-zero for successful insertion
+ *
+ * This function will cause the table to expand if the insertion would take
+ * the ratio of entries to table size over the maximum load factor.
+ *
+ * This function does not check for repeated insertions with a duplicate key.
+ * The value returned when using a duplicate key is undefined -- when
+ * the hashtable changes size, the order of retrieval of duplicate key
+ * entries is reversed.
+ * If in doubt, remove before insert.
+ */
+
+int
+hashtable_insert(struct hashtable *h, void *k, void *v);
+
+#define DEFINE_HASHTABLE_INSERT(fnname, keytype, valuetype) \
+int fnname (struct hashtable *h, keytype *k, valuetype *v) \
+{ \
+ return hashtable_insert(h,k,v); \
+}
+
+/*****************************************************************************
+ * hashtable_change
+
+ * @name hashtable_change
+ * @param h the hashtable to search
+ * @param k the key of the entry to change
+ * @param v the new value
+ * @return non-zero for successful change
+ */
+
+int
+hashtable_change(struct hashtable *h, void *k, void *v);
+
+#define DEFINE_HASHTABLE_CHANGE(fnname, keytype, valuetype) \
+int fnname (struct hashtable *h, keytype *k, valuetype *v) \
+{ \
+ return hashtable_change(h,k,v); \
+}
+
+/*****************************************************************************
+ * hashtable_search
+
+ * @name hashtable_search
+ * @param h the hashtable to search
+ * @param k the key to search for - does not claim ownership
+ * @return the value associated with the key, or NULL if none found
+ */
+
+void *
+hashtable_search(struct hashtable *h, void *k);
+
+#define DEFINE_HASHTABLE_SEARCH(fnname, keytype, valuetype) \
+valuetype * fnname (struct hashtable *h, keytype *k) \
+{ \
+ return (valuetype *) (hashtable_search(h,k)); \
+}
+
+/*****************************************************************************
+ * hashtable_remove
+
+ * @name hashtable_remove
+ * @param h the hashtable to remove the item from
+ * @param k the key to search for - does not claim ownership
+ * @return the value associated with the key, or NULL if none found
+ */
+
+void * /* returns value */
+hashtable_remove(struct hashtable *h, void *k);
+
+#define DEFINE_HASHTABLE_REMOVE(fnname, keytype, valuetype) \
+valuetype * fnname (struct hashtable *h, keytype *k) \
+{ \
+ return (valuetype *) (hashtable_remove(h,k)); \
+}
+
+
+/*****************************************************************************
+ * hashtable_count
+
+ * @name hashtable_count
+ * @return the number of items stored in the hashtable
+ */
+unsigned int
+hashtable_count(struct hashtable *h);
+
+
+/*****************************************************************************
+ * hashtable_destroy
+
+ * @name hashtable_destroy
+ * @param free_values whether to call 'free' on the remaining values
+ */
+
+void
+hashtable_destroy(struct hashtable *h, int free_values);
+
+
+/*****************************************************************************/
+/* hashtable_iterator
+ */
+
+struct hashtable_itr *
+hashtable_iterator(struct hashtable *h);
+
+/*****************************************************************************/
+/* hashtable_iterator_key
+ * - return the value of the (key,value) pair at the current position */
+
+extern inline void *
+hashtable_iterator_key(struct hashtable_itr *i)
+{
+ return i->e->k;
+}
+
+/*****************************************************************************/
+/* value - return the value of the (key,value) pair at the current position */
+
+extern inline void *
+hashtable_iterator_value(struct hashtable_itr *i)
+{
+ return i->e->v;
+}
+
+/*****************************************************************************/
+/* advance - advance the iterator to the next element
+ * returns zero if advanced to end of table */
+
+int
+hashtable_iterator_advance(struct hashtable_itr *itr);
+
+#endif
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