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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. | |
babbc197 | 4 | * |
5 | * (c) Copyright 1988 by the Massachusetts Institute of Technology. | |
6 | * For copying and distribution information, please see the file | |
7 | * <mit-copyright.h>. | |
b93ad422 | 8 | */ |
9 | ||
babbc197 | 10 | #include <mit-copyright.h> |
b93ad422 | 11 | #include <ctype.h> |
8defc06b | 12 | #include <moira.h> |
8fd777cf | 13 | #include <string.h> |
a43ce477 | 14 | #include <stdlib.h> |
d9e7aa31 | 15 | |
a43ce477 | 16 | #ifndef NULL |
b93ad422 | 17 | #define NULL 0 |
a43ce477 | 18 | #endif |
8e24e9aa | 19 | #define hash_func(h, key) (key >= 0 ? (key % h->size) : (-key % h->size)) |
b93ad422 | 20 | |
21 | /* Create a hash table. The size is just a hint, not a maximum. */ | |
22 | ||
5eaef520 | 23 | struct hash *create_hash(int size) |
b93ad422 | 24 | { |
5eaef520 | 25 | struct hash *h; |
26 | ||
27 | h = malloc(sizeof(struct hash)); | |
28 | if (!h) | |
29 | return NULL; | |
30 | h->size = size; | |
31 | h->data = malloc(size * sizeof(char *)); | |
32 | if (!h->data) | |
33 | { | |
34 | free(h); | |
35 | return NULL; | |
7b0a0eca | 36 | } |
5eaef520 | 37 | memset(h->data, 0, size * sizeof(char *)); |
38 | return h; | |
b93ad422 | 39 | } |
40 | ||
41 | /* Lookup an object in the hash table. Returns the value associated with | |
42 | * the key, or NULL (thus NULL is not a very good value to store...) | |
43 | */ | |
44 | ||
44d12d58 | 45 | char *hash_lookup(struct hash *h, int key) |
b93ad422 | 46 | { |
44d12d58 | 47 | struct bucket *b; |
5eaef520 | 48 | |
49 | b = h->data[hash_func(h, key)]; | |
50 | while (b && b->key != key) | |
51 | b = b->next; | |
52 | if (b && b->key == key) | |
53 | return b->data; | |
54 | else | |
55 | return NULL; | |
b93ad422 | 56 | } |
57 | ||
58 | ||
59 | /* Update an existing object in the hash table. Returns 1 if the object | |
60 | * existed, or 0 if not. | |
61 | */ | |
62 | ||
44d12d58 | 63 | int hash_update(struct hash *h, int key, char *value) |
b93ad422 | 64 | { |
44d12d58 | 65 | struct bucket *b; |
5eaef520 | 66 | |
67 | b = h->data[hash_func(h, key)]; | |
68 | while (b && b->key != key) | |
69 | b = b->next; | |
70 | if (b && b->key == key) | |
71 | { | |
72 | b->data = value; | |
73 | return 1; | |
74 | } | |
75 | else | |
76 | return 0; | |
b93ad422 | 77 | } |
78 | ||
79 | ||
80 | /* Store an item in the hash table. Returns 0 if the key was not previously | |
7b0a0eca | 81 | * there, 1 if it was, or -1 if we ran out of memory. |
b93ad422 | 82 | */ |
83 | ||
44d12d58 | 84 | int hash_store(struct hash *h, int key, char *value) |
b93ad422 | 85 | { |
44d12d58 | 86 | struct bucket *b, **p; |
5eaef520 | 87 | |
88 | p = &(h->data[hash_func(h, key)]); | |
89 | if (!*p) | |
90 | { | |
91 | b = *p = malloc(sizeof(struct bucket)); | |
92 | if (!b) | |
93 | return -1; | |
94 | b->next = NULL; | |
95 | b->key = key; | |
96 | b->data = value; | |
97 | return 0; | |
b93ad422 | 98 | } |
99 | ||
5eaef520 | 100 | for (b = *p; b && b->key != key; b = *p) |
101 | p = (struct bucket **) *p; | |
102 | if (b && b->key == key) | |
103 | { | |
104 | b->data = value; | |
105 | return 1; | |
b93ad422 | 106 | } |
5eaef520 | 107 | b = *p = malloc(sizeof(struct bucket)); |
108 | if (!b) | |
109 | return -1; | |
110 | b->next = NULL; | |
111 | b->key = key; | |
112 | b->data = value; | |
113 | return 0; | |
b93ad422 | 114 | } |
115 | ||
116 | ||
117 | /* Search through the hash table for a given value. For each piece of | |
118 | * data with that value, call the callback proc with the corresponding key. | |
119 | */ | |
120 | ||
44d12d58 | 121 | hash_search(struct hash *h, char *value, void (*callback)()) |
b93ad422 | 122 | { |
44d12d58 | 123 | struct bucket *b, **p; |
5eaef520 | 124 | |
125 | for (p = &(h->data[h->size - 1]); p >= h->data; p--) | |
126 | { | |
127 | for (b = *p; b; b = b->next) | |
128 | { | |
129 | if (b->data == value) | |
130 | (*callback)(b->key); | |
b93ad422 | 131 | } |
132 | } | |
133 | } | |
134 | ||
135 | ||
0efcee1f | 136 | /* Step through the hash table, calling the callback proc with each key. |
137 | */ | |
138 | ||
5eaef520 | 139 | hash_step(struct hash *h, void (*callback)(), char *hint) |
0efcee1f | 140 | { |
44d12d58 | 141 | struct bucket *b, **p; |
0efcee1f | 142 | |
5eaef520 | 143 | for (p = &(h->data[h->size - 1]); p >= h->data; p--) |
144 | { | |
145 | for (b = *p; b; b = b->next) | |
146 | (*callback)(b->key, b->data, hint); | |
0efcee1f | 147 | } |
148 | } | |
149 | ||
150 | ||
b93ad422 | 151 | /* Deallocate all of the memory associated with a table */ |
152 | ||
5eaef520 | 153 | hash_destroy(struct hash *h) |
b93ad422 | 154 | { |
44d12d58 | 155 | struct bucket *b, **p, *b1; |
5eaef520 | 156 | |
157 | for (p = &(h->data[h->size - 1]); p >= h->data; p--) | |
158 | { | |
159 | for (b = *p; b; b = b1) | |
160 | { | |
161 | b1 = b->next; | |
162 | free(b); | |
b93ad422 | 163 | } |
164 | } | |
165 | } |