Commit | Line | Data |
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460b9539 | 1 | /* |
2 | * This file is part of DisOrder | |
5aff007d | 3 | * Copyright (C) 2005-2008 Richard Kettlewell |
460b9539 | 4 | * |
e7eb3a27 | 5 | * This program is free software: you can redistribute it and/or modify |
460b9539 | 6 | * it under the terms of the GNU General Public License as published by |
e7eb3a27 | 7 | * the Free Software Foundation, either version 3 of the License, or |
460b9539 | 8 | * (at your option) any later version. |
e7eb3a27 RK |
9 | * |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
460b9539 | 15 | * You should have received a copy of the GNU General Public License |
e7eb3a27 | 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
460b9539 | 17 | */ |
132a5a4a RK |
18 | /** @file lib/hash.c |
19 | * @brief A simple hash table | |
20 | */ | |
05b75f8d | 21 | #include "common.h" |
460b9539 | 22 | |
23 | #include "hash.h" | |
24 | #include "mem.h" | |
25 | #include "log.h" | |
9faa7a88 | 26 | #include "kvp.h" |
460b9539 | 27 | |
28 | struct entry { | |
29 | struct entry *next; /* next entry same key */ | |
30 | size_t h; /* hash of KEY */ | |
31 | const char *key; /* key of this entry */ | |
32 | void *value; /* value of this entry */ | |
33 | }; | |
34 | ||
35 | struct hash { | |
36 | size_t nslots; /* number of slots */ | |
37 | size_t nitems; /* total number of entries */ | |
38 | struct entry **slots; /* table of slots */ | |
39 | size_t valuesize; /* size of a value */ | |
40 | }; | |
41 | ||
42 | static size_t hashfn(const char *key) { | |
43 | size_t i = 0; | |
44 | ||
45 | while(*key) | |
46 | i = 33 * i + (unsigned char)*key++; | |
47 | return i; | |
48 | } | |
49 | ||
50 | static void grow(hash *h) { | |
51 | size_t n, newnslots; | |
52 | struct entry **newslots, *e, *f; | |
53 | ||
54 | /* Allocate a new, larger array */ | |
55 | newnslots = 2 * h->nslots; | |
56 | newslots = xcalloc(newnslots, sizeof (struct entry *)); | |
57 | /* Copy everything to it */ | |
58 | for(n = 0; n < h->nslots; ++n) { | |
59 | for(e = h->slots[n]; e; e = f) { | |
60 | f = e->next; | |
61 | e->next = newslots[e->h & (newnslots - 1)]; | |
62 | newslots[e->h & (newnslots - 1)] = e; | |
63 | } | |
64 | } | |
65 | h->slots = newslots; | |
66 | h->nslots = newnslots; | |
67 | } | |
68 | ||
69 | hash *hash_new(size_t valuesize) { | |
70 | hash *h = xmalloc(sizeof *h); | |
71 | ||
72 | h->nslots = 256; | |
73 | h->slots = xcalloc(h->nslots, sizeof (struct slot *)); | |
74 | h->valuesize = valuesize; | |
75 | return h; | |
76 | } | |
77 | ||
78 | int hash_add(hash *h, const char *key, const void *value, int mode) { | |
79 | size_t n = hashfn(key); | |
80 | struct entry *e; | |
81 | ||
82 | for(e = h->slots[n & (h->nslots - 1)]; e; e = e->next) | |
83 | if(e->h == n || !strcmp(e->key, key)) | |
84 | break; | |
85 | if(e) { | |
86 | /* This key is already present. */ | |
87 | if(mode == HASH_INSERT) return -1; | |
88 | if(value) memcpy(e->value, value, h->valuesize); | |
89 | return 0; | |
90 | } else { | |
91 | /* This key is absent. */ | |
92 | if(mode == HASH_REPLACE) return -1; | |
93 | if(h->nitems >= h->nslots) /* bound mean chain length */ | |
94 | grow(h); | |
95 | e = xmalloc(sizeof *e); | |
96 | e->next = h->slots[n & (h->nslots - 1)]; | |
97 | e->h = n; | |
98 | e->key = xstrdup(key); | |
99 | e->value = xmalloc(h->valuesize); | |
100 | if(value) memcpy(e->value, value, h->valuesize); | |
101 | h->slots[n & (h->nslots - 1)] = e; | |
102 | ++h->nitems; | |
103 | return 0; | |
104 | } | |
105 | } | |
106 | ||
107 | int hash_remove(hash *h, const char *key) { | |
108 | size_t n = hashfn(key); | |
109 | struct entry *e, **ee; | |
110 | ||
111 | for(ee = &h->slots[n & (h->nslots - 1)]; (e = *ee); ee = &e->next) | |
112 | if(e->h == n || !strcmp(e->key, key)) | |
113 | break; | |
114 | if(e) { | |
115 | *ee = e->next; | |
116 | --h->nitems; | |
117 | return 0; | |
118 | } else | |
119 | return -1; | |
120 | } | |
121 | ||
122 | void *hash_find(hash *h, const char *key) { | |
123 | size_t n = hashfn(key); | |
124 | struct entry *e; | |
125 | ||
126 | for(e = h->slots[n & (h->nslots - 1)]; e; e = e->next) | |
127 | if(e->h == n || !strcmp(e->key, key)) | |
128 | return e->value; | |
129 | return 0; | |
130 | } | |
131 | ||
132 | int hash_foreach(hash *h, | |
133 | int (*callback)(const char *key, void *value, void *u), | |
134 | void *u) { | |
135 | size_t n; | |
136 | int ret; | |
137 | struct entry *e, *f; | |
138 | ||
139 | for(n = 0; n < h->nslots; ++n) | |
140 | for(e = h->slots[n]; e; e = f) { | |
141 | f = e->next; | |
142 | if((ret = callback(e->key, e->value, u))) | |
143 | return ret; | |
144 | } | |
145 | return 0; | |
146 | } | |
147 | ||
148 | size_t hash_count(hash *h) { | |
149 | return h->nitems; | |
150 | } | |
151 | ||
152 | char **hash_keys(hash *h) { | |
153 | size_t n; | |
154 | char **vec = xcalloc(h->nitems + 1, sizeof (char *)), **vp = vec; | |
155 | struct entry *e; | |
156 | ||
157 | for(n = 0; n < h->nslots; ++n) | |
158 | for(e = h->slots[n]; e; e = e->next) | |
159 | *vp++ = (char *)e->key; | |
160 | *vp = 0; | |
161 | return vec; | |
162 | } | |
163 | ||
164 | /* | |
165 | Local Variables: | |
166 | c-basic-offset:2 | |
167 | comment-column:40 | |
168 | fill-column:79 | |
169 | indent-tabs-mode:nil | |
170 | End: | |
171 | */ |