Home | History | Annotate | Download | only in cso_cache 
      1 /**************************************************************************
      2  *
      3  * Copyright 2007 VMware, Inc.
      4  * All Rights Reserved.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the
      8  * "Software"), to deal in the Software without restriction, including
      9  * without limitation the rights to use, copy, modify, merge, publish,
     10  * distribute, sub license, and/or sell copies of the Software, and to
     11  * permit persons to whom the Software is furnished to do so, subject to
     12  * the following conditions:
     13  *
     14  * The above copyright notice and this permission notice (including the
     15  * next paragraph) shall be included in all copies or substantial portions
     16  * of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
     21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
     22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  **************************************************************************/
     27 
     28 /**
     29  * @file
     30  * Hash table implementation.
     31  *
     32  * This file provides a hash implementation that is capable of dealing
     33  * with collisions. It stores colliding entries in linked list. All
     34  * functions operating on the hash return an iterator. The iterator
     35  * itself points to the collision list. If there wasn't any collision
     36  * the list will have just one entry, otherwise client code should
     37  * iterate over the entries to find the exact entry among ones that
     38  * had the same key (e.g. memcmp could be used on the data to check
     39  * that)
     40  *
     41  * @author Zack Rusin <zackr (at) vmware.com>
     42  */
     43 
     44 #ifndef CSO_HASH_H
     45 #define CSO_HASH_H
     46 
     47 #include "pipe/p_compiler.h"
     48 
     49 #ifdef	__cplusplus
     50 extern "C" {
     51 #endif
     52 
     53 
     54 struct cso_node {
     55    struct cso_node *next;
     56    unsigned key;
     57    void *value;
     58 };
     59 
     60 struct cso_hash {
     61    union {
     62       struct cso_hash_data *d;
     63       struct cso_node      *e;
     64    } data;
     65 };
     66 
     67 struct cso_hash_iter {
     68    struct cso_hash *hash;
     69    struct cso_node  *node;
     70 };
     71 
     72 
     73 struct cso_hash *cso_hash_create(void);
     74 void             cso_hash_delete(struct cso_hash *hash);
     75 
     76 
     77 int              cso_hash_size(struct cso_hash *hash);
     78 
     79 
     80 /**
     81  * Adds a data with the given key to the hash. If entry with the given
     82  * key is already in the hash, this current entry is instered before it
     83  * in the collision list.
     84  * Function returns iterator pointing to the inserted item in the hash.
     85  */
     86 struct cso_hash_iter cso_hash_insert(struct cso_hash *hash, unsigned key,
     87                                      void *data);
     88 /**
     89  * Removes the item pointed to by the current iterator from the hash.
     90  * Note that the data itself is not erased and if it was a malloc'ed pointer
     91  * it will have to be freed after calling this function by the callee.
     92  * Function returns iterator pointing to the item after the removed one in
     93  * the hash.
     94  */
     95 struct cso_hash_iter cso_hash_erase(struct cso_hash *hash, struct cso_hash_iter iter);
     96 
     97 void  *cso_hash_take(struct cso_hash *hash, unsigned key);
     98 
     99 
    100 
    101 struct cso_hash_iter cso_hash_first_node(struct cso_hash *hash);
    102 
    103 /**
    104  * Return an iterator pointing to the first entry in the collision list.
    105  */
    106 struct cso_hash_iter cso_hash_find(struct cso_hash *hash, unsigned key);
    107 
    108 /**
    109  * Returns true if a value with the given key exists in the hash
    110  */
    111 boolean   cso_hash_contains(struct cso_hash *hash, unsigned key);
    112 
    113 
    114 unsigned  cso_hash_iter_key(struct cso_hash_iter iter);
    115 
    116 
    117 struct cso_hash_iter cso_hash_iter_next(struct cso_hash_iter iter);
    118 struct cso_hash_iter cso_hash_iter_prev(struct cso_hash_iter iter);
    119 
    120 
    121 /**
    122  * Convenience routine to iterate over the collision list while doing a memory
    123  * comparison to see which entry in the list is a direct copy of our template
    124  * and returns that entry.
    125  */
    126 void *cso_hash_find_data_from_template( struct cso_hash *hash,
    127 				        unsigned hash_key,
    128 				        void *templ,
    129 				        int size );
    130 
    131 static inline int
    132 cso_hash_iter_is_null(struct cso_hash_iter iter)
    133 {
    134    if (!iter.node || iter.node == iter.hash->data.e)
    135       return 1;
    136    return 0;
    137 }
    138 
    139 static inline void *
    140 cso_hash_iter_data(struct cso_hash_iter iter)
    141 {
    142    if (!iter.node || iter.hash->data.e == iter.node)
    143       return 0;
    144    return iter.node->value;
    145 }
    146 
    147 #ifdef	__cplusplus
    148 }
    149 #endif
    150 
    151 #endif
    152