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      1 /**************************************************************************
      2  *
      3  * Copyright 2008 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
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     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
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     24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  **************************************************************************/
     27 
     28 /**
     29  * @file
     30  * General purpose hash table implementation.
     31  *
     32  * Just uses the cso_hash for now, but it might be better switch to a linear
     33  * probing hash table implementation at some point -- as it is said they have
     34  * better lookup and cache performance and it appears to be possible to write
     35  * a lock-free implementation of such hash tables .
     36  *
     37  * @author Jos Fonseca <jfonseca (at) vmware.com>
     38  */
     39 
     40 
     41 #include "pipe/p_compiler.h"
     42 #include "util/u_debug.h"
     43 
     44 #include "cso_cache/cso_hash.h"
     45 
     46 #include "util/u_memory.h"
     47 #include "util/u_hash_table.h"
     48 
     49 
     50 struct util_hash_table
     51 {
     52    struct cso_hash *cso;
     53 
     54    /** Hash function */
     55    unsigned (*hash)(void *key);
     56 
     57    /** Compare two keys */
     58    int (*compare)(void *key1, void *key2);
     59 
     60    /* TODO: key, value destructors? */
     61 };
     62 
     63 
     64 struct util_hash_table_item
     65 {
     66    void *key;
     67    void *value;
     68 };
     69 
     70 
     71 static inline struct util_hash_table_item *
     72 util_hash_table_item(struct cso_hash_iter iter)
     73 {
     74    return (struct util_hash_table_item *)cso_hash_iter_data(iter);
     75 }
     76 
     77 
     78 struct util_hash_table *
     79 util_hash_table_create(unsigned (*hash)(void *key),
     80                        int (*compare)(void *key1, void *key2))
     81 {
     82    struct util_hash_table *ht;
     83 
     84    ht = MALLOC_STRUCT(util_hash_table);
     85    if (!ht)
     86       return NULL;
     87 
     88    ht->cso = cso_hash_create();
     89    if(!ht->cso) {
     90       FREE(ht);
     91       return NULL;
     92    }
     93 
     94    ht->hash = hash;
     95    ht->compare = compare;
     96 
     97    return ht;
     98 }
     99 
    100 
    101 static inline struct cso_hash_iter
    102 util_hash_table_find_iter(struct util_hash_table *ht,
    103                           void *key,
    104                           unsigned key_hash)
    105 {
    106    struct cso_hash_iter iter;
    107    struct util_hash_table_item *item;
    108 
    109    iter = cso_hash_find(ht->cso, key_hash);
    110    while (!cso_hash_iter_is_null(iter)) {
    111       item = (struct util_hash_table_item *)cso_hash_iter_data(iter);
    112       if (!ht->compare(item->key, key))
    113          break;
    114       iter = cso_hash_iter_next(iter);
    115    }
    116 
    117    return iter;
    118 }
    119 
    120 
    121 static inline struct util_hash_table_item *
    122 util_hash_table_find_item(struct util_hash_table *ht,
    123                           void *key,
    124                           unsigned key_hash)
    125 {
    126    struct cso_hash_iter iter;
    127    struct util_hash_table_item *item;
    128 
    129    iter = cso_hash_find(ht->cso, key_hash);
    130    while (!cso_hash_iter_is_null(iter)) {
    131       item = (struct util_hash_table_item *)cso_hash_iter_data(iter);
    132       if (!ht->compare(item->key, key))
    133          return item;
    134       iter = cso_hash_iter_next(iter);
    135    }
    136 
    137    return NULL;
    138 }
    139 
    140 
    141 enum pipe_error
    142 util_hash_table_set(struct util_hash_table *ht,
    143                     void *key,
    144                     void *value)
    145 {
    146    unsigned key_hash;
    147    struct util_hash_table_item *item;
    148    struct cso_hash_iter iter;
    149 
    150    assert(ht);
    151    if (!ht)
    152       return PIPE_ERROR_BAD_INPUT;
    153 
    154    key_hash = ht->hash(key);
    155 
    156    item = util_hash_table_find_item(ht, key, key_hash);
    157    if (item) {
    158       /* TODO: key/value destruction? */
    159       item->value = value;
    160       return PIPE_OK;
    161    }
    162 
    163    item = MALLOC_STRUCT(util_hash_table_item);
    164    if (!item)
    165       return PIPE_ERROR_OUT_OF_MEMORY;
    166 
    167    item->key = key;
    168    item->value = value;
    169 
    170    iter = cso_hash_insert(ht->cso, key_hash, item);
    171    if(cso_hash_iter_is_null(iter)) {
    172       FREE(item);
    173       return PIPE_ERROR_OUT_OF_MEMORY;
    174    }
    175 
    176    return PIPE_OK;
    177 }
    178 
    179 
    180 void *
    181 util_hash_table_get(struct util_hash_table *ht,
    182                     void *key)
    183 {
    184    unsigned key_hash;
    185    struct util_hash_table_item *item;
    186 
    187    assert(ht);
    188    if (!ht)
    189       return NULL;
    190 
    191    key_hash = ht->hash(key);
    192 
    193    item = util_hash_table_find_item(ht, key, key_hash);
    194    if (!item)
    195       return NULL;
    196 
    197    return item->value;
    198 }
    199 
    200 
    201 void
    202 util_hash_table_remove(struct util_hash_table *ht,
    203                        void *key)
    204 {
    205    unsigned key_hash;
    206    struct cso_hash_iter iter;
    207    struct util_hash_table_item *item;
    208 
    209    assert(ht);
    210    if (!ht)
    211       return;
    212 
    213    key_hash = ht->hash(key);
    214 
    215    iter = util_hash_table_find_iter(ht, key, key_hash);
    216    if(cso_hash_iter_is_null(iter))
    217       return;
    218 
    219    item = util_hash_table_item(iter);
    220    assert(item);
    221    FREE(item);
    222 
    223    cso_hash_erase(ht->cso, iter);
    224 }
    225 
    226 
    227 void
    228 util_hash_table_clear(struct util_hash_table *ht)
    229 {
    230    struct cso_hash_iter iter;
    231    struct util_hash_table_item *item;
    232 
    233    assert(ht);
    234    if (!ht)
    235       return;
    236 
    237    iter = cso_hash_first_node(ht->cso);
    238    while (!cso_hash_iter_is_null(iter)) {
    239       item = (struct util_hash_table_item *)cso_hash_take(ht->cso, cso_hash_iter_key(iter));
    240       FREE(item);
    241       iter = cso_hash_first_node(ht->cso);
    242    }
    243 }
    244 
    245 
    246 enum pipe_error
    247 util_hash_table_foreach(struct util_hash_table *ht,
    248                      enum pipe_error (*callback)
    249                         (void *key, void *value, void *data),
    250                      void *data)
    251 {
    252    struct cso_hash_iter iter;
    253    struct util_hash_table_item *item;
    254    enum pipe_error result;
    255 
    256    assert(ht);
    257    if (!ht)
    258       return PIPE_ERROR_BAD_INPUT;
    259 
    260    iter = cso_hash_first_node(ht->cso);
    261    while (!cso_hash_iter_is_null(iter)) {
    262       item = (struct util_hash_table_item *)cso_hash_iter_data(iter);
    263       result = callback(item->key, item->value, data);
    264       if(result != PIPE_OK)
    265 	 return result;
    266       iter = cso_hash_iter_next(iter);
    267    }
    268 
    269    return PIPE_OK;
    270 }
    271 
    272 
    273 void
    274 util_hash_table_destroy(struct util_hash_table *ht)
    275 {
    276    struct cso_hash_iter iter;
    277    struct util_hash_table_item *item;
    278 
    279    assert(ht);
    280    if (!ht)
    281       return;
    282 
    283    iter = cso_hash_first_node(ht->cso);
    284    while (!cso_hash_iter_is_null(iter)) {
    285       item = (struct util_hash_table_item *)cso_hash_iter_data(iter);
    286       FREE(item);
    287       iter = cso_hash_iter_next(iter);
    288    }
    289 
    290    cso_hash_delete(ht->cso);
    291 
    292    FREE(ht);
    293 }
    294