1 /* Author : Stephen Smalley, <sds@tycho.nsa.gov> */ 2 3 /* FLASK */ 4 5 /* 6 * A hash table (hashtab) maintains associations between 7 * key values and datum values. The type of the key values 8 * and the type of the datum values is arbitrary. The 9 * functions for hash computation and key comparison are 10 * provided by the creator of the table. 11 */ 12 13 #ifndef _SEPOL_POLICYDB_HASHTAB_H_ 14 #define _SEPOL_POLICYDB_HASHTAB_H_ 15 16 #include <sepol/errcodes.h> 17 18 #include <stdint.h> 19 #include <stdio.h> 20 21 #ifdef __cplusplus 22 extern "C" { 23 #endif 24 25 typedef char *hashtab_key_t; /* generic key type */ 26 typedef const char *const_hashtab_key_t; /* constant generic key type */ 27 typedef void *hashtab_datum_t; /* generic datum type */ 28 29 typedef struct hashtab_node *hashtab_ptr_t; 30 31 typedef struct hashtab_node { 32 hashtab_key_t key; 33 hashtab_datum_t datum; 34 hashtab_ptr_t next; 35 } hashtab_node_t; 36 37 typedef struct hashtab_val { 38 hashtab_ptr_t *htable; /* hash table */ 39 unsigned int size; /* number of slots in hash table */ 40 uint32_t nel; /* number of elements in hash table */ 41 unsigned int (*hash_value) (struct hashtab_val * h, const_hashtab_key_t key); /* hash function */ 42 int (*keycmp) (struct hashtab_val * h, const_hashtab_key_t key1, const_hashtab_key_t key2); /* key comparison function */ 43 } hashtab_val_t; 44 45 typedef hashtab_val_t *hashtab_t; 46 47 /* 48 Creates a new hash table with the specified characteristics. 49 50 Returns NULL if insufficient space is available or 51 the new hash table otherwise. 52 */ 53 extern hashtab_t hashtab_create(unsigned int (*hash_value) (hashtab_t h, 54 const_hashtab_key_t 55 key), 56 int (*keycmp) (hashtab_t h, 57 const_hashtab_key_t key1, 58 const_hashtab_key_t key2), 59 unsigned int size); 60 /* 61 Inserts the specified (key, datum) pair into the specified hash table. 62 63 Returns SEPOL_ENOMEM if insufficient space is available or 64 SEPOL_EEXIST if there is already an entry with the same key or 65 SEPOL_OK otherwise. 66 */ 67 extern int hashtab_insert(hashtab_t h, hashtab_key_t k, hashtab_datum_t d); 68 69 /* 70 Removes the entry with the specified key from the hash table. 71 Applies the specified destroy function to (key,datum,args) for 72 the entry. 73 74 Returns SEPOL_ENOENT if no entry has the specified key or 75 SEPOL_OK otherwise. 76 */ 77 extern int hashtab_remove(hashtab_t h, hashtab_key_t k, 78 void (*destroy) (hashtab_key_t k, 79 hashtab_datum_t d, 80 void *args), void *args); 81 82 /* 83 Searches for the entry with the specified key in the hash table. 84 85 Returns NULL if no entry has the specified key or 86 the datum of the entry otherwise. 87 */ 88 extern hashtab_datum_t hashtab_search(hashtab_t h, const_hashtab_key_t k); 89 90 /* 91 Destroys the specified hash table. 92 */ 93 extern void hashtab_destroy(hashtab_t h); 94 95 /* 96 Applies the specified apply function to (key,datum,args) 97 for each entry in the specified hash table. 98 99 The order in which the function is applied to the entries 100 is dependent upon the internal structure of the hash table. 101 102 If apply returns a non-zero status, then hashtab_map will cease 103 iterating through the hash table and will propagate the error 104 return to its caller. 105 */ 106 extern int hashtab_map(hashtab_t h, 107 int (*apply) (hashtab_key_t k, 108 hashtab_datum_t d, 109 void *args), void *args); 110 111 extern void hashtab_hash_eval(hashtab_t h, char *tag); 112 113 #ifdef __cplusplus 114 } 115 #endif 116 117 #endif 118