1/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to. The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 * must display the following acknowledgement:
32 * "This product includes cryptographic software written by
33 * Eric Young (eay@cryptsoft.com)"
34 * The word 'cryptographic' can be left out if the rouines from the library
35 * being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 * the apps directory (application code) you must include an acknowledgement:
38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed. i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.] */
56
57#ifndef OPENSSL_HEADER_LHASH_H
58#define OPENSSL_HEADER_LHASH_H
59
60#include <openssl/base.h>
61#include <openssl/type_check.h>
62
63#if defined(__cplusplus)
64extern "C" {
65#endif
66
67
68// lhash is a traditional, chaining hash table that automatically expands and
69// contracts as needed. One should not use the lh_* functions directly, rather
70// use the type-safe macro wrappers:
71//
72// A hash table of a specific type of object has type |LHASH_OF(type)|. This
73// can be defined (once) with |DEFINE_LHASH_OF(type)| and declared where needed
74// with |DECLARE_LHASH_OF(type)|. For example:
75//
76// struct foo {
77// int bar;
78// };
79//
80// DEFINE_LHASH_OF(struct foo)
81//
82// Although note that the hash table will contain /pointers/ to |foo|.
83//
84// A macro will be defined for each of the lh_* functions below. For
85// LHASH_OF(foo), the macros would be lh_foo_new, lh_foo_num_items etc.
86
87
88#define LHASH_OF(type) struct lhash_st_##type
89
90#define DECLARE_LHASH_OF(type) LHASH_OF(type);
91
92
93// lhash_item_st is an element of a hash chain. It points to the opaque data
94// for this element and to the next item in the chain. The linked-list is NULL
95// terminated.
96typedef struct lhash_item_st {
97 void *data;
98 struct lhash_item_st *next;
99 // hash contains the cached, hash value of |data|.
100 uint32_t hash;
101} LHASH_ITEM;
102
103// lhash_cmp_func is a comparison function that returns a value equal, or not
104// equal, to zero depending on whether |*a| is equal, or not equal to |*b|,
105// respectively. Note the difference between this and |stack_cmp_func| in that
106// this takes pointers to the objects directly.
107//
108// This function's actual type signature is int (*)(const T*, const T*). The
109// low-level |lh_*| functions will be passed a type-specific wrapper to call it
110// correctly.
111typedef int (*lhash_cmp_func)(const void *a, const void *b);
112typedef int (*lhash_cmp_func_helper)(lhash_cmp_func func, const void *a,
113 const void *b);
114
115// lhash_hash_func is a function that maps an object to a uniformly distributed
116// uint32_t.
117//
118// This function's actual type signature is uint32_t (*)(const T*). The
119// low-level |lh_*| functions will be passed a type-specific wrapper to call it
120// correctly.
121typedef uint32_t (*lhash_hash_func)(const void *a);
122typedef uint32_t (*lhash_hash_func_helper)(lhash_hash_func func, const void *a);
123
124typedef struct lhash_st _LHASH;
125
126// lh_new returns a new, empty hash table or NULL on error.
127OPENSSL_EXPORT _LHASH *lh_new(lhash_hash_func hash, lhash_cmp_func comp);
128
129// lh_free frees the hash table itself but none of the elements. See
130// |lh_doall|.
131OPENSSL_EXPORT void lh_free(_LHASH *lh);
132
133// lh_num_items returns the number of items in |lh|.
134OPENSSL_EXPORT size_t lh_num_items(const _LHASH *lh);
135
136// lh_retrieve finds an element equal to |data| in the hash table and returns
137// it. If no such element exists, it returns NULL.
138OPENSSL_EXPORT void *lh_retrieve(const _LHASH *lh, const void *data,
139 lhash_hash_func_helper call_hash_func,
140 lhash_cmp_func_helper call_cmp_func);
141
142// lh_retrieve_key finds an element matching |key|, given the specified hash and
143// comparison function. This differs from |lh_retrieve| in that the key may be a
144// different type than the values stored in |lh|. |key_hash| and |cmp_key| must
145// be compatible with the functions passed into |lh_new|.
146OPENSSL_EXPORT void *lh_retrieve_key(const _LHASH *lh, const void *key,
147 uint32_t key_hash,
148 int (*cmp_key)(const void *key,
149 const void *value));
150
151// lh_insert inserts |data| into the hash table. If an existing element is
152// equal to |data| (with respect to the comparison function) then |*old_data|
153// will be set to that value and it will be replaced. Otherwise, or in the
154// event of an error, |*old_data| will be set to NULL. It returns one on
155// success or zero in the case of an allocation error.
156OPENSSL_EXPORT int lh_insert(_LHASH *lh, void **old_data, void *data,
157 lhash_hash_func_helper call_hash_func,
158 lhash_cmp_func_helper call_cmp_func);
159
160// lh_delete removes an element equal to |data| from the hash table and returns
161// it. If no such element is found, it returns NULL.
162OPENSSL_EXPORT void *lh_delete(_LHASH *lh, const void *data,
163 lhash_hash_func_helper call_hash_func,
164 lhash_cmp_func_helper call_cmp_func);
165
166// lh_doall_arg calls |func| on each element of the hash table and also passes
167// |arg| as the second argument.
168// TODO(fork): rename this
169OPENSSL_EXPORT void lh_doall_arg(_LHASH *lh, void (*func)(void *, void *),
170 void *arg);
171
172// lh_strhash is the default hash function which processes NUL-terminated
173// strings.
174OPENSSL_EXPORT uint32_t lh_strhash(const char *c);
175
176#define DEFINE_LHASH_OF(type) \
177 DECLARE_LHASH_OF(type) \
178 \
179 typedef int (*lhash_##type##_cmp_func)(const type *, const type *); \
180 typedef uint32_t (*lhash_##type##_hash_func)(const type *); \
181 \
182 OPENSSL_INLINE int lh_##type##_call_cmp_func(lhash_cmp_func func, \
183 const void *a, const void *b) { \
184 return ((lhash_##type##_cmp_func)func)((const type *)a, (const type *)b); \
185 } \
186 \
187 OPENSSL_INLINE uint32_t lh_##type##_call_hash_func(lhash_hash_func func, \
188 const void *a) { \
189 return ((lhash_##type##_hash_func)func)((const type *)a); \
190 } \
191 \
192 OPENSSL_INLINE LHASH_OF(type) * \
193 lh_##type##_new(lhash_##type##_hash_func hash, \
194 lhash_##type##_cmp_func comp) { \
195 return (LHASH_OF(type) *)lh_new((lhash_hash_func)hash, \
196 (lhash_cmp_func)comp); \
197 } \
198 \
199 OPENSSL_INLINE void lh_##type##_free(LHASH_OF(type) *lh) { \
200 lh_free((_LHASH *)lh); \
201 } \
202 \
203 OPENSSL_INLINE size_t lh_##type##_num_items(const LHASH_OF(type) *lh) { \
204 return lh_num_items((const _LHASH *)lh); \
205 } \
206 \
207 OPENSSL_INLINE type *lh_##type##_retrieve(const LHASH_OF(type) *lh, \
208 const type *data) { \
209 return (type *)lh_retrieve((const _LHASH *)lh, data, \
210 lh_##type##_call_hash_func, \
211 lh_##type##_call_cmp_func); \
212 } \
213 \
214 typedef struct { \
215 int (*cmp_key)(const void *key, const type *value); \
216 const void *key; \
217 } LHASH_CMP_KEY_##type; \
218 \
219 OPENSSL_INLINE int lh_##type##_call_cmp_key(const void *key, \
220 const void *value) { \
221 const LHASH_CMP_KEY_##type *cb = (const LHASH_CMP_KEY_##type *)key; \
222 return cb->cmp_key(cb->key, (const type *)value); \
223 } \
224 \
225 OPENSSL_INLINE type *lh_##type##_retrieve_key( \
226 const LHASH_OF(type) *lh, const void *key, uint32_t key_hash, \
227 int (*cmp_key)(const void *key, const type *value)) { \
228 LHASH_CMP_KEY_##type cb = {cmp_key, key}; \
229 return (type *)lh_retrieve_key((const _LHASH *)lh, &cb, key_hash, \
230 lh_##type##_call_cmp_key); \
231 } \
232 \
233 OPENSSL_INLINE int lh_##type##_insert(LHASH_OF(type) *lh, type **old_data, \
234 type *data) { \
235 void *old_data_void = NULL; \
236 int ret = \
237 lh_insert((_LHASH *)lh, &old_data_void, data, \
238 lh_##type##_call_hash_func, lh_##type##_call_cmp_func); \
239 *old_data = (type *)old_data_void; \
240 return ret; \
241 } \
242 \
243 OPENSSL_INLINE type *lh_##type##_delete(LHASH_OF(type) *lh, \
244 const type *data) { \
245 return (type *)lh_delete((_LHASH *)lh, data, lh_##type##_call_hash_func, \
246 lh_##type##_call_cmp_func); \
247 } \
248 \
249 typedef struct { \
250 void (*doall)(type *); \
251 void (*doall_arg)(type *, void *); \
252 void *arg; \
253 } LHASH_DOALL_##type; \
254 \
255 OPENSSL_INLINE void lh_##type##_call_doall(void *value, void *arg) { \
256 const LHASH_DOALL_##type *cb = (const LHASH_DOALL_##type *)arg; \
257 cb->doall((type *)value); \
258 } \
259 \
260 OPENSSL_INLINE void lh_##type##_call_doall_arg(void *value, void *arg) { \
261 const LHASH_DOALL_##type *cb = (const LHASH_DOALL_##type *)arg; \
262 cb->doall_arg((type *)value, cb->arg); \
263 } \
264 \
265 OPENSSL_INLINE void lh_##type##_doall(LHASH_OF(type) *lh, \
266 void (*func)(type *)) { \
267 LHASH_DOALL_##type cb = {func, NULL, NULL}; \
268 lh_doall_arg((_LHASH *)lh, lh_##type##_call_doall, &cb); \
269 } \
270 \
271 OPENSSL_INLINE void lh_##type##_doall_arg( \
272 LHASH_OF(type) *lh, void (*func)(type *, void *), void *arg) { \
273 LHASH_DOALL_##type cb = {NULL, func, arg}; \
274 lh_doall_arg((_LHASH *)lh, lh_##type##_call_doall_arg, &cb); \
275 }
276
277
278#if defined(__cplusplus)
279} // extern C
280#endif
281
282#endif // OPENSSL_HEADER_LHASH_H
283