/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ #ifndef OPENSSL_HEADER_LHASH_H #define OPENSSL_HEADER_LHASH_H #include #include #if defined(__cplusplus) extern "C" { #endif /* lhash is a traditional, chaining hash table that automatically expands and * contracts as needed. One should not use the lh_* functions directly, rather * use the type-safe macro wrappers: * * A hash table of a specific type of object has type |LHASH_OF(type)|. This * can be defined (once) with |DEFINE_LHASH_OF(type)| and declared where needed * with |DECLARE_LHASH_OF(type)|. For example: * * struct foo { * int bar; * }; * * DEFINE_LHASH_OF(struct foo); * * Although note that the hash table will contain /pointers/ to |foo|. * * A macro will be defined for each of the lh_* functions below. For * LHASH_OF(foo), the macros would be lh_foo_new, lh_foo_num_items etc. */ #define LHASH_OF(type) struct lhash_st_##type #define DEFINE_LHASH_OF(type) LHASH_OF(type) { int dummy; } #define DECLARE_LHASH_OF(type) LHASH_OF(type); /* The make_macros.sh script in this directory parses the following lines and * generates the lhash_macros.h file that contains macros for the following * types of stacks: * * LHASH_OF:ASN1_OBJECT * LHASH_OF:CONF_VALUE * LHASH_OF:EX_CLASS_ITEM * LHASH_OF:SSL_SESSION */ #define IN_LHASH_H #include #undef IN_LHASH_H /* lhash_item_st is an element of a hash chain. It points to the opaque data * for this element and to the next item in the chain. The linked-list is NULL * terminated. */ typedef struct lhash_item_st { void *data; struct lhash_item_st *next; /* hash contains the cached, hash value of |data|. */ uint32_t hash; } LHASH_ITEM; /* lhash_cmp_func is a comparison function that returns a value equal, or not * equal, to zero depending on whether |*a| is equal, or not equal to |*b|, * respectively. Note the difference between this and |stack_cmp_func| in that * this takes pointers to the objects directly. */ typedef int (*lhash_cmp_func)(const void *a, const void *b); /* lhash_hash_func is a function that maps an object to a uniformly distributed * uint32_t. */ typedef uint32_t (*lhash_hash_func)(const void *a); typedef struct lhash_st { /* num_items contains the total number of items in the hash table. */ size_t num_items; /* buckets is an array of |num_buckets| pointers. Each points to the head of * a chain of LHASH_ITEM objects that have the same hash value, mod * |num_buckets|. */ LHASH_ITEM **buckets; /* num_buckets contains the length of |buckets|. This value is always >= * kMinNumBuckets. */ size_t num_buckets; /* callback_depth contains the current depth of |lh_doall| or |lh_doall_arg| * calls. If non-zero then this suppresses resizing of the |buckets| array, * which would otherwise disrupt the iteration. */ unsigned callback_depth; lhash_cmp_func comp; lhash_hash_func hash; } _LHASH; /* lh_new returns a new, empty hash table or NULL on error. If |comp| is NULL, * |strcmp| will be used. If |hash| is NULL, a generic hash function will be * used. */ OPENSSL_EXPORT _LHASH *lh_new(lhash_hash_func hash, lhash_cmp_func comp); /* lh_free frees the hash table itself but none of the elements. See * |lh_doall|. */ OPENSSL_EXPORT void lh_free(_LHASH *lh); /* lh_num_items returns the number of items in |lh|. */ OPENSSL_EXPORT size_t lh_num_items(const _LHASH *lh); /* lh_retrieve finds an element equal to |data| in the hash table and returns * it. If no such element exists, it returns NULL. */ OPENSSL_EXPORT void *lh_retrieve(const _LHASH *lh, const void *data); /* lh_insert inserts |data| into the hash table. If an existing element is * equal to |data| (with respect to the comparison function) then |*old_data| * will be set to that value and it will be replaced. Otherwise, or in the * event of an error, |*old_data| will be set to NULL. It returns one on * success or zero in the case of an allocation error. */ OPENSSL_EXPORT int lh_insert(_LHASH *lh, void **old_data, void *data); /* lh_delete removes an element equal to |data| from the hash table and returns * it. If no such element is found, it returns NULL. */ OPENSSL_EXPORT void *lh_delete(_LHASH *lh, const void *data); /* lh_doall calls |func| on each element of the hash table. * TODO(fork): rename this */ OPENSSL_EXPORT void lh_doall(_LHASH *lh, void (*func)(void *)); /* lh_doall_arg calls |func| on each element of the hash table and also passes * |arg| as the second argument. * TODO(fork): rename this */ OPENSSL_EXPORT void lh_doall_arg(_LHASH *lh, void (*func)(void *, void *), void *arg); /* lh_strhash is the default hash function which processes NUL-terminated * strings. */ OPENSSL_EXPORT uint32_t lh_strhash(const char *c); #if defined(__cplusplus) } /* extern C */ #endif #endif /* OPENSSL_HEADER_STACK_H */