1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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.
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).
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.
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
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)"
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
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.] */
57 #ifndef OPENSSL_HEADER_LHASH_H
58 #define OPENSSL_HEADER_LHASH_H
60 #include <openssl/base.h>
61 #include <openssl/type_check.h>
63 #if defined(__cplusplus)
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:
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:
80 // DEFINE_LHASH_OF(struct foo);
82 // Although note that the hash table will contain /pointers/ to |foo|.
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.
88 #define LHASH_OF(type) struct lhash_st_##type
90 #define DEFINE_LHASH_OF(type) LHASH_OF(type) { int dummy; }
92 #define DECLARE_LHASH_OF(type) LHASH_OF(type);
94 // The make_macros.sh script in this directory parses the following lines and
95 // generates the lhash_macros.h file that contains macros for the following
98 // LHASH_OF:ASN1_OBJECT
99 // LHASH_OF:CONF_VALUE
100 // LHASH_OF:CRYPTO_BUFFER
101 // LHASH_OF:SSL_SESSION
104 #include <openssl/lhash_macros.h>
108 // lhash_item_st is an element of a hash chain. It points to the opaque data
109 // for this element and to the next item in the chain. The linked-list is NULL
111 typedef struct lhash_item_st {
113 struct lhash_item_st *next;
114 // hash contains the cached, hash value of |data|.
118 // lhash_cmp_func is a comparison function that returns a value equal, or not
119 // equal, to zero depending on whether |*a| is equal, or not equal to |*b|,
120 // respectively. Note the difference between this and |stack_cmp_func| in that
121 // this takes pointers to the objects directly.
122 typedef int (*lhash_cmp_func)(const void *a, const void *b);
124 // lhash_hash_func is a function that maps an object to a uniformly distributed
126 typedef uint32_t (*lhash_hash_func)(const void *a);
128 typedef struct lhash_st _LHASH;
130 // lh_new returns a new, empty hash table or NULL on error.
131 OPENSSL_EXPORT _LHASH *lh_new(lhash_hash_func hash, lhash_cmp_func comp);
133 // lh_free frees the hash table itself but none of the elements. See
135 OPENSSL_EXPORT void lh_free(_LHASH *lh);
137 // lh_num_items returns the number of items in |lh|.
138 OPENSSL_EXPORT size_t lh_num_items(const _LHASH *lh);
140 // lh_retrieve finds an element equal to |data| in the hash table and returns
141 // it. If no such element exists, it returns NULL.
142 OPENSSL_EXPORT void *lh_retrieve(const _LHASH *lh, const void *data);
144 // lh_insert inserts |data| into the hash table. If an existing element is
145 // equal to |data| (with respect to the comparison function) then |*old_data|
146 // will be set to that value and it will be replaced. Otherwise, or in the
147 // event of an error, |*old_data| will be set to NULL. It returns one on
148 // success or zero in the case of an allocation error.
149 OPENSSL_EXPORT int lh_insert(_LHASH *lh, void **old_data, void *data);
151 // lh_delete removes an element equal to |data| from the hash table and returns
152 // it. If no such element is found, it returns NULL.
153 OPENSSL_EXPORT void *lh_delete(_LHASH *lh, const void *data);
155 // lh_doall calls |func| on each element of the hash table.
156 // TODO(fork): rename this
157 OPENSSL_EXPORT void lh_doall(_LHASH *lh, void (*func)(void *));
159 // lh_doall_arg calls |func| on each element of the hash table and also passes
160 // |arg| as the second argument.
161 // TODO(fork): rename this
162 OPENSSL_EXPORT void lh_doall_arg(_LHASH *lh, void (*func)(void *, void *),
165 // lh_strhash is the default hash function which processes NUL-terminated
167 OPENSSL_EXPORT uint32_t lh_strhash(const char *c);
170 #if defined(__cplusplus)
174 #endif // OPENSSL_HEADER_LHASH_H