1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
/* Copyright (C) 2002 Christopher Clark <firstname.lastname@cl.cam.ac.uk> */
#ifndef __HASHTABLE_CWC22_H__
#define __HASHTABLE_CWC22_H__
struct hashtable;
/* Example of use:
*
* struct hashtable *h;
* struct some_key *k;
* struct some_value *v;
*
* static unsigned int hash_from_key_fn( void *k );
* static int keys_equal_fn ( void *key1, void *key2 );
*
* h = create_hashtable(16, hash_from_key_fn, keys_equal_fn, value_free_fn);
* k = (struct some_key *) malloc(sizeof(struct some_key));
* v = (struct some_value *) malloc(sizeof(struct some_value));
*
* (initialise k and v to suitable values)
*
* if (! hashtable_insert(h,k,v) )
* { exit(-1); }
*
* if (NULL == (found = hashtable_search(h,k) ))
* { printf("not found!"); }
*
* if (NULL == (found = hashtable_remove(h,k) ))
* { printf("Not found\n"); }
*
*/
/* Macros may be used to define type-safe(r) hashtable access functions, with
* methods specialized to take known key and value types as parameters.
*
* Example:
*
* Insert this at the start of your file:
*
* DEFINE_HASHTABLE_INSERT(insert_some, struct some_key, struct some_value);
* DEFINE_HASHTABLE_SEARCH(search_some, struct some_key, struct some_value);
* DEFINE_HASHTABLE_REMOVE(remove_some, struct some_key, struct some_value);
*
* This defines the functions 'insert_some', 'search_some' and 'remove_some'.
* These operate just like hashtable_insert etc., with the same parameters,
* but their function signatures have 'struct some_key *' rather than
* 'void *', and hence can generate compile time errors if your program is
* supplying incorrect data as a key (and similarly for value).
*
* Note that the hash and key equality functions passed to create_hashtable
* still take 'void *' parameters instead of 'some key *'. This shouldn't be
* a difficult issue as they're only defined and passed once, and the other
* functions will ensure that only valid keys are supplied to them.
*
* The cost for this checking is increased code size and runtime overhead
* - if performance is important, it may be worth switching back to the
* unsafe methods once your program has been debugged with the safe methods.
* This just requires switching to some simple alternative defines - eg:
* #define insert_some hashtable_insert
*
*/
/*****************************************************************************
* create_hashtable
* @name create_hashtable
* @param minsize minimum initial size of hashtable
* @param hashfunction function for hashing keys
* @param key_eq_fn function for determining key equality
* @param value_free_fn function to free value (on removal/destroing)
* @return newly created hashtable or NULL on failure
*/
struct hashtable *
create_hashtable(unsigned int minsize,
unsigned int (*hashfunction) (void*),
int (*key_eq_fn) (void*,void*),
void (*value_free_fn)(void *v));
/*****************************************************************************
* hashtable_insert
* @name hashtable_insert
* @param h the hashtable to insert into
* @param k the key - hashtable claims ownership and will free on removal
* @param v the value - does not claim ownership
* @return non-zero for successful insertion
*
* This function will cause the table to expand if the insertion would take
* the ratio of entries to table size over the maximum load factor.
*
* This function does not check for repeated insertions with a duplicate key.
* The value returned when using a duplicate key is undefined -- when
* the hashtable changes size, the order of retrieval of duplicate key
* entries is reversed.
* If in doubt, remove before insert.
*/
int
hashtable_insert(struct hashtable *h, void *k, void *v);
#define DEFINE_HASHTABLE_INSERT(fnname, keytype, valuetype) \
int fnname (struct hashtable *h, keytype *k, valuetype *v) \
{ \
return hashtable_insert(h,k,v); \
}
/*****************************************************************************
* hashtable_search
* @name hashtable_search
* @param h the hashtable to search
* @param k the key to search for - does not claim ownership
* @return the value associated with the key, or NULL if none found
*/
void *
hashtable_search(struct hashtable *h, void *k);
#define DEFINE_HASHTABLE_SEARCH(fnname, keytype, valuetype) \
valuetype * fnname (struct hashtable *h, keytype *k) \
{ \
return (valuetype *) (hashtable_search(h,k)); \
}
/*****************************************************************************
* hashtable_remove
* @name hashtable_remove
* @param h the hashtable to remove the item from
* @param k the key to search for - does not claim ownership
* @param free_value whether to free value (thus it would return NULL)
* @return the value associated with the key, or NULL if none found
*/
void * /* returns value */
hashtable_remove(struct hashtable *h, void *k, int free_value);
#define DEFINE_HASHTABLE_REMOVE(fnname, keytype, valuetype) \
valuetype * fnname (struct hashtable *h, keytype *k) \
{ \
return (valuetype *) (hashtable_remove(h,k)); \
}
/*****************************************************************************
* hashtable_count
* @name hashtable_count
* @param h the hashtable
* @return the number of items stored in the hashtable
*/
unsigned int
hashtable_count(struct hashtable *h);
/*****************************************************************************
* hashtable_destroy
* @name hashtable_destroy
* @param h the hashtable
* @param free_values whether to call 'value_free_fn' on the remaining values
*/
void
hashtable_destroy(struct hashtable *h, int free_values);
/* hashtable_enum_fn:
* should return 0 when finished and no more enumeration needed
*/
typedef int (*hashtable_enum_fn)(void * key, void * value, void * user_data);
void hashtable_enumerate(struct hashtable * h, hashtable_enum_fn enum_fn, void * user_data);
#endif /* __HASHTABLE_CWC22_H__ */
/*
* Copyright (C) 2002 Christopher Clark <firstname.lastname@cl.cam.ac.uk>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
* */
|
