update

git-svn-id: http://svn.openzap.org/svn/openzap/trunk@5 a93c3328-9c30-0410-af19-c9cd2b2d52af

libs/freetdm/src/include/hashtable.h

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+/* Copyright (C) 2002 Christopher Clark <firstname.lastname@cl.cam.ac.uk> */
+
+#ifndef __HASHTABLE_CWC22_H__
+#define __HASHTABLE_CWC22_H__
+
+struct hashtable;
+
+/* 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, 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
+ *
+ */
+
+/*****************************************************************************
+ * create_hashtable
+   
+ * @name                    create_hashtable
+ * @param   minsize         minimum initial size of hashtable
+ * @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,
+                 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_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
+ * @param   h   the hashtable
+ * @return      the number of items stored in the hashtable
+ */
+unsigned int
+hashtable_count(struct hashtable *h);
+
+
+/*****************************************************************************
+ * hashtable_destroy
+   
+ * @name        hashtable_destroy
+ * @param   h   the hashtable
+ * @param       free_values     whether to call 'free' on the remaining values
+ */
+
+void
+hashtable_destroy(struct hashtable *h, int free_values);
+
+#endif /* __HASHTABLE_CWC22_H__ */
+
+/*
+ * Copyright (c) 2002, Christopher Clark
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 
+ * * Neither the name of the original author; nor the names of any contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ * 
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER
+ * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/