1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) 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 (at) 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 (at) 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 (at) 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) 64 extern "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 DEFINE_LHASH_OF(type) LHASH_OF(type) { int dummy; } 91 92 #define DECLARE_LHASH_OF(type) LHASH_OF(type); 93 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 96 * types of stacks: 97 * 98 * LHASH_OF:ASN1_OBJECT 99 * LHASH_OF:CONF_VALUE 100 * LHASH_OF:CRYPTO_BUFFER 101 * LHASH_OF:SSL_SESSION */ 102 103 #define IN_LHASH_H 104 #include <openssl/lhash_macros.h> 105 #undef IN_LHASH_H 106 107 108 /* 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 110 * terminated. */ 111 typedef struct lhash_item_st { 112 void *data; 113 struct lhash_item_st *next; 114 /* hash contains the cached, hash value of |data|. */ 115 uint32_t hash; 116 } LHASH_ITEM; 117 118 /* 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); 123 124 /* lhash_hash_func is a function that maps an object to a uniformly distributed 125 * uint32_t. */ 126 typedef uint32_t (*lhash_hash_func)(const void *a); 127 128 typedef struct lhash_st { 129 /* num_items contains the total number of items in the hash table. */ 130 size_t num_items; 131 /* buckets is an array of |num_buckets| pointers. Each points to the head of 132 * a chain of LHASH_ITEM objects that have the same hash value, mod 133 * |num_buckets|. */ 134 LHASH_ITEM **buckets; 135 /* num_buckets contains the length of |buckets|. This value is always >= 136 * kMinNumBuckets. */ 137 size_t num_buckets; 138 /* callback_depth contains the current depth of |lh_doall| or |lh_doall_arg| 139 * calls. If non-zero then this suppresses resizing of the |buckets| array, 140 * which would otherwise disrupt the iteration. */ 141 unsigned callback_depth; 142 143 lhash_cmp_func comp; 144 lhash_hash_func hash; 145 } _LHASH; 146 147 /* lh_new returns a new, empty hash table or NULL on error. */ 148 OPENSSL_EXPORT _LHASH *lh_new(lhash_hash_func hash, lhash_cmp_func comp); 149 150 /* lh_free frees the hash table itself but none of the elements. See 151 * |lh_doall|. */ 152 OPENSSL_EXPORT void lh_free(_LHASH *lh); 153 154 /* lh_num_items returns the number of items in |lh|. */ 155 OPENSSL_EXPORT size_t lh_num_items(const _LHASH *lh); 156 157 /* lh_retrieve finds an element equal to |data| in the hash table and returns 158 * it. If no such element exists, it returns NULL. */ 159 OPENSSL_EXPORT void *lh_retrieve(const _LHASH *lh, const void *data); 160 161 /* lh_insert inserts |data| into the hash table. If an existing element is 162 * equal to |data| (with respect to the comparison function) then |*old_data| 163 * will be set to that value and it will be replaced. Otherwise, or in the 164 * event of an error, |*old_data| will be set to NULL. It returns one on 165 * success or zero in the case of an allocation error. */ 166 OPENSSL_EXPORT int lh_insert(_LHASH *lh, void **old_data, void *data); 167 168 /* lh_delete removes an element equal to |data| from the hash table and returns 169 * it. If no such element is found, it returns NULL. */ 170 OPENSSL_EXPORT void *lh_delete(_LHASH *lh, const void *data); 171 172 /* lh_doall calls |func| on each element of the hash table. 173 * TODO(fork): rename this */ 174 OPENSSL_EXPORT void lh_doall(_LHASH *lh, void (*func)(void *)); 175 176 /* lh_doall_arg calls |func| on each element of the hash table and also passes 177 * |arg| as the second argument. 178 * TODO(fork): rename this */ 179 OPENSSL_EXPORT void lh_doall_arg(_LHASH *lh, void (*func)(void *, void *), 180 void *arg); 181 182 /* lh_strhash is the default hash function which processes NUL-terminated 183 * strings. */ 184 OPENSSL_EXPORT uint32_t lh_strhash(const char *c); 185 186 187 #if defined(__cplusplus) 188 } /* extern C */ 189 #endif 190 191 #endif /* OPENSSL_HEADER_LHASH_H */ 192
