1
2/* Author : Stephen Smalley, <sds@epoch.ncsc.mil> */
3
4/* FLASK */
5
6/*
7 * A hash table (hashtab) maintains associations between
8 * key values and datum values.  The type of the key values
9 * and the type of the datum values is arbitrary.  The
10 * functions for hash computation and key comparison are
11 * provided by the creator of the table.
12 */
13
14#ifndef _NEWROLE_HASHTAB_H_
15#define _NEWROLE_HASHTAB_H_
16
17#include <stdint.h>
18#include <errno.h>
19#include <stdio.h>
20
21typedef char *hashtab_key_t;	/* generic key type */
22typedef void *hashtab_datum_t;	/* generic datum type */
23
24typedef struct hashtab_node *hashtab_ptr_t;
25
26typedef struct hashtab_node {
27	hashtab_key_t key;
28	hashtab_datum_t datum;
29	hashtab_ptr_t next;
30} hashtab_node_t;
31
32typedef struct hashtab_val {
33	hashtab_ptr_t *htable;	/* hash table */
34	unsigned int size;	/* number of slots in hash table */
35	uint32_t nel;		/* number of elements in hash table */
36	unsigned int (*hash_value) (struct hashtab_val * h, hashtab_key_t key);	/* hash function */
37	int (*keycmp) (struct hashtab_val * h, hashtab_key_t key1, hashtab_key_t key2);	/* key comparison function */
38} hashtab_val_t;
39
40typedef hashtab_val_t *hashtab_t;
41
42/* Define status codes for hash table functions */
43#define HASHTAB_SUCCESS     0
44#define HASHTAB_OVERFLOW    -ENOMEM
45#define HASHTAB_PRESENT     -EEXIST
46#define HASHTAB_MISSING     -ENOENT
47
48/*
49   Creates a new hash table with the specified characteristics.
50
51   Returns NULL if insufficent space is available or
52   the new hash table otherwise.
53 */
54extern hashtab_t hashtab_create(unsigned int (*hash_value) (hashtab_t h,
55							    const hashtab_key_t
56							    key),
57				int (*keycmp) (hashtab_t h,
58					       const hashtab_key_t key1,
59					       const hashtab_key_t key2),
60				unsigned int size);
61/*
62   Inserts the specified (key, datum) pair into the specified hash table.
63
64   Returns HASHTAB_OVERFLOW if insufficient space is available or
65   HASHTAB_PRESENT  if there is already an entry with the same key or
66   HASHTAB_SUCCESS otherwise.
67 */
68extern int hashtab_insert(hashtab_t h, hashtab_key_t k, hashtab_datum_t d);
69
70/*
71   Removes the entry with the specified key from the hash table.
72   Applies the specified destroy function to (key,datum,args) for
73   the entry.
74
75   Returns HASHTAB_MISSING if no entry has the specified key or
76   HASHTAB_SUCCESS otherwise.
77 */
78extern int hashtab_remove(hashtab_t h, hashtab_key_t k,
79			  void (*destroy) (hashtab_key_t k,
80					   hashtab_datum_t d,
81					   void *args), void *args);
82
83/*
84   Insert or replace the specified (key, datum) pair in the specified
85   hash table.  If an entry for the specified key already exists,
86   then the specified destroy function is applied to (key,datum,args)
87   for the entry prior to replacing the entry's contents.
88
89   Returns HASHTAB_OVERFLOW if insufficient space is available or
90   HASHTAB_SUCCESS otherwise.
91 */
92extern int hashtab_replace(hashtab_t h, hashtab_key_t k, hashtab_datum_t d,
93			   void (*destroy) (hashtab_key_t k,
94					    hashtab_datum_t d,
95					    void *args), void *args);
96
97/*
98   Searches for the entry with the specified key in the hash table.
99
100   Returns NULL if no entry has the specified key or
101   the datum of the entry otherwise.
102 */
103extern hashtab_datum_t hashtab_search(hashtab_t h, const hashtab_key_t k);
104
105/*
106   Destroys the specified hash table.
107 */
108extern void hashtab_destroy(hashtab_t h);
109
110/*
111   Applies the specified apply function to (key,datum,args)
112   for each entry in the specified hash table.
113
114   The order in which the function is applied to the entries
115   is dependent upon the internal structure of the hash table.
116
117   If apply returns a non-zero status, then hashtab_map will cease
118   iterating through the hash table and will propagate the error
119   return to its caller.
120 */
121extern int hashtab_map(hashtab_t h,
122		       int (*apply) (hashtab_key_t k,
123				     hashtab_datum_t d,
124				     void *args), void *args);
125
126/*
127   Same as hashtab_map, except that if apply returns a non-zero status,
128   then the (key,datum) pair will be removed from the hashtab and the
129   destroy function will be applied to (key,datum,args).
130 */
131extern void hashtab_map_remove_on_error(hashtab_t h,
132					int (*apply) (hashtab_key_t k,
133						      hashtab_datum_t d,
134						      void *args),
135					void (*destroy) (hashtab_key_t k,
136							 hashtab_datum_t d,
137							 void *args),
138					void *args);
139
140extern void hashtab_hash_eval(hashtab_t h, char *tag);
141
142#endif
143