/* * A hash table (hashtab) maintains associations between * key values and datum values.  The type of the key values * and the type of the datum values is arbitrary.  The * functions for hash computation and key comparison are * provided by the creator of the table. * * Author : Stephen Smalley, <sds@epoch.ncsc.mil> */#ifndef _SS_HASHTAB_H_#define _SS_HASHTAB_H_#define HASHTAB_MAX_NODES	0xffffffffstruct hashtab_node {	void *key;	void *datum;	struct hashtab_node *next;};struct hashtab {	struct hashtab_node **htable;	/* hash table */	u32 size;			/* number of slots in hash table */	u32 nel;			/* number of elements in hash table */	u32 (*hash_value)(struct hashtab *h, void *key);					/* hash function */	int (*keycmp)(struct hashtab *h, void *key1, void *key2);					/* key comparison function */};struct hashtab_info {	u32 slots_used;	u32 max_chain_len;};/* * Creates a new hash table with the specified characteristics. * * Returns NULL if insufficent space is available or * the new hash table otherwise. */struct hashtab *hashtab_create(u32 (*hash_value)(struct hashtab *h, void *key),                               int (*keycmp)(struct hashtab *h, void *key1, void *key2),                               u32 size);/* * Inserts the specified (key, datum) pair into the specified hash table. * * Returns -ENOMEM on memory allocation error, * -EEXIST if there is already an entry with the same key, * -EINVAL for general errors or * 0 otherwise. */int hashtab_insert(struct hashtab *h, void *k, void *d);/* * Removes the entry with the specified key from the hash table. * Applies the specified destroy function to (key,datum,args) for * the entry. * * Returns -ENOENT if no entry has the specified key, * -EINVAL for general errors or *0 otherwise. */int hashtab_remove(struct hashtab *h, void *k,		   void (*destroy)(void *k, void *d, void *args),		   void *args);/* * Insert or replace the specified (key, datum) pair in the specified * hash table.  If an entry for the specified key already exists, * then the specified destroy function is applied to (key,datum,args) * for the entry prior to replacing the entry's contents. * * Returns -ENOMEM if insufficient space is available, * -EINVAL for general errors or * 0 otherwise. */int hashtab_replace(struct hashtab *h, void *k, void *d,		    void (*destroy)(void *k, void *d, void *args),		    void *args);/* * Searches for the entry with the specified key in the hash table. * * Returns NULL if no entry has the specified key or * the datum of the entry otherwise. */void *hashtab_search(struct hashtab *h, void *k);/* * Destroys the specified hash table. */void hashtab_destroy(struct hashtab *h);/* * Applies the specified apply function to (key,datum,args) * for each entry in the specified hash table. * * The order in which the function is applied to the entries * is dependent upon the internal structure of the hash table. * * If apply returns a non-zero status, then hashtab_map will cease * iterating through the hash table and will propagate the error * return to its caller. */int hashtab_map(struct hashtab *h,		int (*apply)(void *k, void *d, void *args),		void *args);/* * Same as hashtab_map, except that if apply returns a non-zero status, * then the (key,datum) pair will be removed from the hashtab and the * destroy function will be applied to (key,datum,args). */void hashtab_map_remove_on_error(struct hashtab *h,                                 int (*apply)(void *k, void *d, void *args),                                 void (*destroy)(void *k, void *d, void *args),                                 void *args);/* Fill info with some hash table statistics */void hashtab_stat(struct hashtab *h, struct hashtab_info *info);#endif	/* _SS_HASHTAB_H */