/* Copyright (C) 2002 Christopher Clark */ #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, value_free_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 * @param value_free_fn function to free value (on removal/destroing) * @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*), void (*value_free_fn)(void *v)); /***************************************************************************** * 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 * @param free_value whether to free value (thus it would return NULL) * @return the value associated with the key, or NULL if none found */ void * /* returns value */ hashtable_remove(struct hashtable *h, void *k, int free_value); #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 'value_free_fn' on the remaining values */ void hashtable_destroy(struct hashtable *h, int free_values); /* hashtable_enum_fn: * should return 0 when finished and no more enumeration needed */ typedef int (*hashtable_enum_fn)(void * key, void * value, void * user_data); void hashtable_enumerate(struct hashtable * h, hashtable_enum_fn enum_fn, void * user_data); #endif /* __HASHTABLE_CWC22_H__ */ /* * Copyright (C) 2002 Christopher Clark * * 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 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. * */