1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) * All rights reserved. 2 * 3 * This package is an SSL implementation written 4 * by Eric Young (eay (at) cryptsoft.com). 5 * The implementation was written so as to conform with Netscapes SSL. 6 * 7 * This library is free for commercial and non-commercial use as long as 8 * the following conditions are aheared to. The following conditions 9 * apply to all code found in this distribution, be it the RC4, RSA, 10 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 11 * included with this distribution is covered by the same copyright terms 12 * except that the holder is Tim Hudson (tjh (at) cryptsoft.com). 13 * 14 * Copyright remains Eric Young's, and as such any Copyright notices in 15 * the code are not to be removed. 16 * If this package is used in a product, Eric Young should be given attribution 17 * as the author of the parts of the library used. 18 * This can be in the form of a textual message at program startup or 19 * in documentation (online or textual) provided with the package. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 3. All advertising materials mentioning features or use of this software 30 * must display the following acknowledgement: 31 * "This product includes cryptographic software written by 32 * Eric Young (eay (at) cryptsoft.com)" 33 * The word 'cryptographic' can be left out if the rouines from the library 34 * being used are not cryptographic related :-). 35 * 4. If you include any Windows specific code (or a derivative thereof) from 36 * the apps directory (application code) you must include an acknowledgement: 37 * "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)" 38 * 39 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 40 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 42 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 43 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 44 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 45 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 46 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 47 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 48 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 49 * SUCH DAMAGE. 50 * 51 * The licence and distribution terms for any publically available version or 52 * derivative of this code cannot be changed. i.e. this code cannot simply be 53 * copied and put under another distribution licence 54 * [including the GNU Public Licence.] */ 55 56 #ifndef OPENSSL_HEADER_LHASH_H 57 #define OPENSSL_HEADER_LHASH_H 58 59 #include <openssl/base.h> 60 #include <openssl/type_check.h> 61 62 #if defined(__cplusplus) 63 extern "C" { 64 #endif 65 66 67 /* lhash is a traditional, chaining hash table that automatically expands and 68 * contracts as needed. One should not use the lh_* functions directly, rather 69 * use the type-safe macro wrappers: 70 * 71 * A hash table of a specific type of object has type |LHASH_OF(type)|. This 72 * can be defined (once) with |DEFINE_LHASH_OF(type)| and declared where needed 73 * with |DECLARE_LHASH_OF(type)|. For example: 74 * 75 * struct foo { 76 * int bar; 77 * }; 78 * 79 * DEFINE_LHASH_OF(struct foo); 80 * 81 * Although note that the hash table will contain /pointers/ to |foo|. 82 * 83 * A macro will be defined for each of the lh_* functions below. For 84 * LHASH_OF(foo), the macros would be lh_foo_new, lh_foo_num_items etc. */ 85 86 87 #define LHASH_OF(type) struct lhash_st_##type 88 89 #define DEFINE_LHASH_OF(type) LHASH_OF(type) { int dummy; } 90 91 #define DECLARE_LHASH_OF(type) LHASH_OF(type); 92 93 /* The make_macros.sh script in this directory parses the following lines and 94 * generates the lhash_macros.h file that contains macros for the following 95 * types of stacks: 96 * 97 * LHASH_OF:ASN1_OBJECT 98 * LHASH_OF:CONF_VALUE 99 * LHASH_OF:SSL_SESSION */ 100 101 #define IN_LHASH_H 102 #include <openssl/lhash_macros.h> 103 #undef IN_LHASH_H 104 105 106 /* lhash_item_st is an element of a hash chain. It points to the opaque data 107 * for this element and to the next item in the chain. The linked-list is NULL 108 * terminated. */ 109 typedef struct lhash_item_st { 110 void *data; 111 struct lhash_item_st *next; 112 /* hash contains the cached, hash value of |data|. */ 113 uint32_t hash; 114 } LHASH_ITEM; 115 116 /* lhash_cmp_func is a comparison function that returns a value equal, or not 117 * equal, to zero depending on whether |*a| is equal, or not equal to |*b|, 118 * respectively. Note the difference between this and |stack_cmp_func| in that 119 * this takes pointers to the objects directly. */ 120 typedef int (*lhash_cmp_func)(const void *a, const void *b); 121 122 /* lhash_hash_func is a function that maps an object to a uniformly distributed 123 * uint32_t. */ 124 typedef uint32_t (*lhash_hash_func)(const void *a); 125 126 typedef struct lhash_st { 127 /* num_items contains the total number of items in the hash table. */ 128 size_t num_items; 129 /* buckets is an array of |num_buckets| pointers. Each points to the head of 130 * a chain of LHASH_ITEM objects that have the same hash value, mod 131 * |num_buckets|. */ 132 LHASH_ITEM **buckets; 133 /* num_buckets contains the length of |buckets|. This value is always >= 134 * kMinNumBuckets. */ 135 size_t num_buckets; 136 /* callback_depth contains the current depth of |lh_doall| or |lh_doall_arg| 137 * calls. If non-zero then this suppresses resizing of the |buckets| array, 138 * which would otherwise disrupt the iteration. */ 139 unsigned callback_depth; 140 141 lhash_cmp_func comp; 142 lhash_hash_func hash; 143 } _LHASH; 144 145 /* lh_new returns a new, empty hash table or NULL on error. If |comp| is NULL, 146 * |strcmp| will be used. If |hash| is NULL, a generic hash function will be 147 * used. */ 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_STACK_H */ 192
