133 lines
4.6 KiB
C
133 lines
4.6 KiB
C
/*
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* (c) Thomas Pornin 2002
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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 above 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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* 4. The name of the authors may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#ifndef UCPP__NHASH__
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#define UCPP__NHASH__
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/*
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* Each item stored in the hash table should be a structure beginning
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* with the following header.
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*/
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typedef struct hash_item_header_ {
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char *ident;
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struct hash_item_header_ *left, *right;
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} hash_item_header;
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/*
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* This macro takes as argument a pointer to a hash table item (a
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* structure beginning with `hash_item_header') and returns a pointer to
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* the item name. This name should be considered as read-only. The
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* retrieved pointer can become invalid whenever a new item is inserted
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* in or removed from the table.
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*/
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#define HASH_ITEM_NAME(s) (((hash_item_header *)(s))->ident + sizeof(unsigned))
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/*
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* Number of lists for the primary hash step. Can be reduced to save more
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* memory, or increased to speed things up. It should be a power of 2
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* greater or equal than 2 and smaller than UINT_MAX.
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*/
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#define HTT_NUM_TREES 128
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/*
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* Type for a hash table.
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*/
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typedef struct {
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void (*deldata)(void *);
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hash_item_header *tree[HTT_NUM_TREES];
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} HTT;
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/*
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* Type for a reduced version of HTT with only two binary trees. That
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* version has a lower initialization time and is suitable for situation
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* where only a limited number of elements will be stored, but new tables
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* need frequent initializations.
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*/
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typedef struct {
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void (*deldata)(void *);
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hash_item_header *tree[2];
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} HTT2;
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/*
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* Initialize a hash table. The `deldata' parameter should point to a
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* function which will be invoked on any item removed from the table;
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* that function should take care of the release of memory allocated for
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* that item (except the hash_item_header contents, which are handled
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* internally).
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*/
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void HTT_init(HTT *htt, void (*deldata)(void *));
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/*
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* Link an item into the hash table under the given name. If another
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* item of identical name is already present in the table, a pointer to
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* that item is returned; otherwise, the new item is linked into the
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* table and NULL is returned. The object pointed to by `item' is
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* linked from the table, but not the string pointed to by `name'.
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*/
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void *HTT_put(HTT *htt, void *item, char *name);
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/*
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* Retrieve an item by name from the hash table. NULL is returned if
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* the object is not found.
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*/
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void *HTT_get(HTT *htt, char *name);
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/*
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* Remove an item from the hash table. 1 is returned if the item was
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* removed, 0 if it was not found.
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*/
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int HTT_del(HTT *htt, char *name);
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/*
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* For all items stored within the hash table, invoke the provided
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* function with the item as parameter. The function may abort the
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* scan by performing a longjmp() to a context encapsulating the
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* call to that function.
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*/
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void HTT_scan(HTT *htt, void (*action)(void *));
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/*
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* Release the whole table contents. After a call to this function,
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* the table is ready to accept new items.
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*/
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void HTT_kill(HTT *htt);
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/*
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* The following functions are identical to the HTT_*() functions, except
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* that they operate on the reduced HTT2 tables.
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*/
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void HTT2_init(HTT2 *htt, void (*deldata)(void *));
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void *HTT2_put(HTT2 *htt, void *item, char *name);
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void *HTT2_get(HTT2 *htt, char *name);
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int HTT2_del(HTT2 *htt, char *name);
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void HTT2_scan(HTT2 *htt, void (*action)(void *));
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void HTT2_kill(HTT2 *htt);
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#endif
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