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Commit | Line | Data |
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b93ad422 | 1 | /* $Header$ |
2 | * | |
3 | * Generic hash table routines. Uses integer keys to store char * values. | |
4 | */ | |
5 | ||
6 | #include <ctype.h> | |
7 | #include "sms_app.h" | |
8 | #define NULL 0 | |
9 | ||
10 | ||
11 | /* Create a hash table. The size is just a hint, not a maximum. */ | |
12 | ||
13 | struct hash *create_hash(size) | |
14 | int size; | |
15 | { | |
16 | struct hash *h; | |
17 | ||
18 | h = (struct hash *) malloc(sizeof(struct hash)); | |
19 | h->size = size; | |
20 | h->data = (struct bucket **) malloc(size * sizeof(char *)); | |
21 | bzero(h->data, size * sizeof(char *)); | |
22 | return(h); | |
23 | } | |
24 | ||
25 | /* Lookup an object in the hash table. Returns the value associated with | |
26 | * the key, or NULL (thus NULL is not a very good value to store...) | |
27 | */ | |
28 | ||
29 | char *hash_lookup(h, key) | |
30 | struct hash *h; | |
31 | register int key; | |
32 | { | |
33 | register struct bucket *b; | |
34 | ||
35 | b = h->data[key % h->size]; | |
36 | while (b && b->key != key) | |
37 | b = b->next; | |
38 | if (b && b->key == key) | |
39 | return(b->data); | |
40 | else | |
41 | return(NULL); | |
42 | } | |
43 | ||
44 | ||
45 | /* Update an existing object in the hash table. Returns 1 if the object | |
46 | * existed, or 0 if not. | |
47 | */ | |
48 | ||
49 | int hash_update(h, key, value) | |
50 | struct hash *h; | |
51 | register int key; | |
52 | char *value; | |
53 | { | |
54 | register struct bucket *b; | |
55 | ||
56 | b = h->data[key % h->size]; | |
57 | while (b && b->key != key) | |
58 | b = b->next; | |
59 | if (b && b->key == key) { | |
60 | b->data = value; | |
61 | return(1); | |
62 | } else | |
63 | return(0); | |
64 | } | |
65 | ||
66 | ||
67 | /* Store an item in the hash table. Returns 0 if the key was not previously | |
68 | * there, or 1 if it was. | |
69 | */ | |
70 | ||
71 | int hash_store(h, key, value) | |
72 | struct hash *h; | |
73 | register int key; | |
74 | char *value; | |
75 | { | |
76 | register struct bucket *b, **p; | |
77 | ||
78 | p = &(h->data[key % h->size]); | |
79 | if (*p == NULL) { | |
80 | b = *p = (struct bucket *) malloc(sizeof(struct bucket)); | |
81 | b->next = NULL; | |
82 | b->key = key; | |
83 | b->data = value; | |
84 | return(0); | |
85 | } | |
86 | ||
87 | for (b = *p; b && b->key != key; b = *p) | |
88 | p = (struct bucket **) *p; | |
89 | if (b && b->key == key) { | |
90 | b->data = value; | |
91 | return(1); | |
92 | } | |
93 | b = *p = (struct bucket *) malloc(sizeof(struct bucket)); | |
94 | b->next = NULL; | |
95 | b->key = key; | |
96 | b->data = value; | |
97 | return(0); | |
98 | } | |
99 | ||
100 | ||
101 | /* Search through the hash table for a given value. For each piece of | |
102 | * data with that value, call the callback proc with the corresponding key. | |
103 | */ | |
104 | ||
105 | hash_search(h, value, callback) | |
106 | struct hash *h; | |
107 | register char *value; | |
108 | void (*callback)(); | |
109 | { | |
110 | register struct bucket *b, **p; | |
111 | ||
112 | for (p = &(h->data[h->size - 1]); p >= h->data; p--) { | |
113 | for (b = *p; b; b = b->next) { | |
114 | if (b->data == value) | |
115 | (*callback)(b->key); | |
116 | } | |
117 | } | |
118 | } | |
119 | ||
120 | ||
0efcee1f | 121 | /* Step through the hash table, calling the callback proc with each key. |
122 | */ | |
123 | ||
07d9123c | 124 | hash_step(h, callback, hint) |
0efcee1f | 125 | struct hash *h; |
126 | void (*callback)(); | |
07d9123c | 127 | char *hint; |
0efcee1f | 128 | { |
129 | register struct bucket *b, **p; | |
130 | ||
131 | for (p = &(h->data[h->size - 1]); p >= h->data; p--) { | |
132 | for (b = *p; b; b = b->next) { | |
07d9123c | 133 | (*callback)(b->key, b->data, hint); |
0efcee1f | 134 | } |
135 | } | |
136 | } | |
137 | ||
138 | ||
b93ad422 | 139 | /* Deallocate all of the memory associated with a table */ |
140 | ||
141 | hash_destroy(h) | |
142 | struct hash *h; | |
143 | { | |
144 | register struct bucket *b, **p, *b1; | |
145 | ||
146 | for (p = &(h->data[h->size - 1]); p >= h->data; p--) { | |
147 | for (b = *p; b; b = b1) { | |
148 | b1 = b->next; | |
149 | free(b); | |
150 | } | |
151 | } | |
152 | } |