460b9539 |
1 | /* |
2 | * This file is part of DisOrder |
3 | * Copyright (C) 2005, 2006 Richard Kettlewell |
4 | * |
5 | * This program is free software; you can redistribute it and/or modify |
6 | * it under the terms of the GNU General Public License as published by |
7 | * the Free Software Foundation; either version 2 of the License, or |
8 | * (at your option) any later version. |
9 | * |
10 | * This program is distributed in the hope that it will be useful, but |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | * General Public License for more details. |
14 | * |
15 | * You should have received a copy of the GNU General Public License |
16 | * along with this program; if not, write to the Free Software |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
18 | * USA |
19 | */ |
20 | |
21 | #include <config.h> |
22 | #include "types.h" |
23 | |
24 | #include <string.h> |
25 | |
26 | #include "hash.h" |
27 | #include "mem.h" |
28 | #include "log.h" |
29 | |
30 | struct entry { |
31 | struct entry *next; /* next entry same key */ |
32 | size_t h; /* hash of KEY */ |
33 | const char *key; /* key of this entry */ |
34 | void *value; /* value of this entry */ |
35 | }; |
36 | |
37 | struct hash { |
38 | size_t nslots; /* number of slots */ |
39 | size_t nitems; /* total number of entries */ |
40 | struct entry **slots; /* table of slots */ |
41 | size_t valuesize; /* size of a value */ |
42 | }; |
43 | |
44 | static size_t hashfn(const char *key) { |
45 | size_t i = 0; |
46 | |
47 | while(*key) |
48 | i = 33 * i + (unsigned char)*key++; |
49 | return i; |
50 | } |
51 | |
52 | static void grow(hash *h) { |
53 | size_t n, newnslots; |
54 | struct entry **newslots, *e, *f; |
55 | |
56 | /* Allocate a new, larger array */ |
57 | newnslots = 2 * h->nslots; |
58 | newslots = xcalloc(newnslots, sizeof (struct entry *)); |
59 | /* Copy everything to it */ |
60 | for(n = 0; n < h->nslots; ++n) { |
61 | for(e = h->slots[n]; e; e = f) { |
62 | f = e->next; |
63 | e->next = newslots[e->h & (newnslots - 1)]; |
64 | newslots[e->h & (newnslots - 1)] = e; |
65 | } |
66 | } |
67 | h->slots = newslots; |
68 | h->nslots = newnslots; |
69 | } |
70 | |
71 | hash *hash_new(size_t valuesize) { |
72 | hash *h = xmalloc(sizeof *h); |
73 | |
74 | h->nslots = 256; |
75 | h->slots = xcalloc(h->nslots, sizeof (struct slot *)); |
76 | h->valuesize = valuesize; |
77 | return h; |
78 | } |
79 | |
80 | int hash_add(hash *h, const char *key, const void *value, int mode) { |
81 | size_t n = hashfn(key); |
82 | struct entry *e; |
83 | |
84 | for(e = h->slots[n & (h->nslots - 1)]; e; e = e->next) |
85 | if(e->h == n || !strcmp(e->key, key)) |
86 | break; |
87 | if(e) { |
88 | /* This key is already present. */ |
89 | if(mode == HASH_INSERT) return -1; |
90 | if(value) memcpy(e->value, value, h->valuesize); |
91 | return 0; |
92 | } else { |
93 | /* This key is absent. */ |
94 | if(mode == HASH_REPLACE) return -1; |
95 | if(h->nitems >= h->nslots) /* bound mean chain length */ |
96 | grow(h); |
97 | e = xmalloc(sizeof *e); |
98 | e->next = h->slots[n & (h->nslots - 1)]; |
99 | e->h = n; |
100 | e->key = xstrdup(key); |
101 | e->value = xmalloc(h->valuesize); |
102 | if(value) memcpy(e->value, value, h->valuesize); |
103 | h->slots[n & (h->nslots - 1)] = e; |
104 | ++h->nitems; |
105 | return 0; |
106 | } |
107 | } |
108 | |
109 | int hash_remove(hash *h, const char *key) { |
110 | size_t n = hashfn(key); |
111 | struct entry *e, **ee; |
112 | |
113 | for(ee = &h->slots[n & (h->nslots - 1)]; (e = *ee); ee = &e->next) |
114 | if(e->h == n || !strcmp(e->key, key)) |
115 | break; |
116 | if(e) { |
117 | *ee = e->next; |
118 | --h->nitems; |
119 | return 0; |
120 | } else |
121 | return -1; |
122 | } |
123 | |
124 | void *hash_find(hash *h, const char *key) { |
125 | size_t n = hashfn(key); |
126 | struct entry *e; |
127 | |
128 | for(e = h->slots[n & (h->nslots - 1)]; e; e = e->next) |
129 | if(e->h == n || !strcmp(e->key, key)) |
130 | return e->value; |
131 | return 0; |
132 | } |
133 | |
134 | int hash_foreach(hash *h, |
135 | int (*callback)(const char *key, void *value, void *u), |
136 | void *u) { |
137 | size_t n; |
138 | int ret; |
139 | struct entry *e, *f; |
140 | |
141 | for(n = 0; n < h->nslots; ++n) |
142 | for(e = h->slots[n]; e; e = f) { |
143 | f = e->next; |
144 | if((ret = callback(e->key, e->value, u))) |
145 | return ret; |
146 | } |
147 | return 0; |
148 | } |
149 | |
150 | size_t hash_count(hash *h) { |
151 | return h->nitems; |
152 | } |
153 | |
154 | char **hash_keys(hash *h) { |
155 | size_t n; |
156 | char **vec = xcalloc(h->nitems + 1, sizeof (char *)), **vp = vec; |
157 | struct entry *e; |
158 | |
159 | for(n = 0; n < h->nslots; ++n) |
160 | for(e = h->slots[n]; e; e = e->next) |
161 | *vp++ = (char *)e->key; |
162 | *vp = 0; |
163 | return vec; |
164 | } |
165 | |
166 | /* |
167 | Local Variables: |
168 | c-basic-offset:2 |
169 | comment-column:40 |
170 | fill-column:79 |
171 | indent-tabs-mode:nil |
172 | End: |
173 | */ |