1/*
2 * Copyright © 2008 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 */
23
24/**
25 * \file hash_table.c
26 * \brief Implementation of a generic, opaque hash table data type.
27 *
28 * \author Ian Romanick <ian.d.romanick@intel.com>
29 */
30
31#include "main/imports.h"
32#include "main/simple_list.h"
33#include "hash_table.h"
34
35struct node {
36   struct node *next;
37   struct node *prev;
38};
39
40struct hash_table {
41    hash_func_t    hash;
42    hash_compare_func_t  compare;
43
44    unsigned num_buckets;
45    struct node buckets[1];
46};
47
48
49struct hash_node {
50    struct node link;
51    const void *key;
52    void *data;
53};
54
55
56struct hash_table *
57hash_table_ctor(unsigned num_buckets, hash_func_t hash,
58                hash_compare_func_t compare)
59{
60    struct hash_table *ht;
61    unsigned i;
62
63
64    if (num_buckets < 16) {
65        num_buckets = 16;
66    }
67
68    ht = malloc(sizeof(*ht) + ((num_buckets - 1)
69				     * sizeof(ht->buckets[0])));
70    if (ht != NULL) {
71        ht->hash = hash;
72        ht->compare = compare;
73        ht->num_buckets = num_buckets;
74
75        for (i = 0; i < num_buckets; i++) {
76            make_empty_list(& ht->buckets[i]);
77        }
78    }
79
80    return ht;
81}
82
83
84void
85hash_table_dtor(struct hash_table *ht)
86{
87   hash_table_clear(ht);
88   free(ht);
89}
90
91
92void
93hash_table_clear(struct hash_table *ht)
94{
95   struct node *node;
96   struct node *temp;
97   unsigned i;
98
99
100   for (i = 0; i < ht->num_buckets; i++) {
101      foreach_s(node, temp, & ht->buckets[i]) {
102	 remove_from_list(node);
103	 free(node);
104      }
105
106      assert(is_empty_list(& ht->buckets[i]));
107   }
108}
109
110
111void *
112hash_table_find(struct hash_table *ht, const void *key)
113{
114    const unsigned hash_value = (*ht->hash)(key);
115    const unsigned bucket = hash_value % ht->num_buckets;
116    struct node *node;
117
118    foreach(node, & ht->buckets[bucket]) {
119       struct hash_node *hn = (struct hash_node *) node;
120
121       if ((*ht->compare)(hn->key, key) == 0) {
122	  return hn->data;
123       }
124    }
125
126    return NULL;
127}
128
129
130void
131hash_table_insert(struct hash_table *ht, void *data, const void *key)
132{
133    const unsigned hash_value = (*ht->hash)(key);
134    const unsigned bucket = hash_value % ht->num_buckets;
135    struct hash_node *node;
136
137    node = calloc(1, sizeof(*node));
138
139    node->data = data;
140    node->key = key;
141
142    insert_at_head(& ht->buckets[bucket], & node->link);
143}
144
145void
146hash_table_remove(struct hash_table *ht, const void *key)
147{
148    const unsigned hash_value = (*ht->hash)(key);
149    const unsigned bucket = hash_value % ht->num_buckets;
150    struct node *node;
151
152    foreach(node, & ht->buckets[bucket]) {
153       struct hash_node *hn = (struct hash_node *) node;
154
155       if ((*ht->compare)(hn->key, key) == 0) {
156	  remove_from_list(node);
157	  free(node);
158	  return;
159       }
160    }
161}
162
163unsigned
164hash_table_string_hash(const void *key)
165{
166    const char *str = (const char *) key;
167    unsigned hash = 5381;
168
169
170    while (*str != '\0') {
171        hash = (hash * 33) + *str;
172        str++;
173    }
174
175    return hash;
176}
177
178
179unsigned
180hash_table_pointer_hash(const void *key)
181{
182   return (unsigned)((uintptr_t) key / sizeof(void *));
183}
184
185
186int
187hash_table_pointer_compare(const void *key1, const void *key2)
188{
189   return key1 == key2 ? 0 : 1;
190}
191