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