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1 | /* |
2 | * This file is part of DisOrder |
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3 | * Copyright (C) 2005-2008 Richard Kettlewell |
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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" |
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29 | #include "kvp.h" |
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30 | |
31 | struct entry { |
32 | struct entry *next; /* next entry same key */ |
33 | size_t h; /* hash of KEY */ |
34 | const char *key; /* key of this entry */ |
35 | void *value; /* value of this entry */ |
36 | }; |
37 | |
38 | struct hash { |
39 | size_t nslots; /* number of slots */ |
40 | size_t nitems; /* total number of entries */ |
41 | struct entry **slots; /* table of slots */ |
42 | size_t valuesize; /* size of a value */ |
43 | }; |
44 | |
45 | static size_t hashfn(const char *key) { |
46 | size_t i = 0; |
47 | |
48 | while(*key) |
49 | i = 33 * i + (unsigned char)*key++; |
50 | return i; |
51 | } |
52 | |
53 | static void grow(hash *h) { |
54 | size_t n, newnslots; |
55 | struct entry **newslots, *e, *f; |
56 | |
57 | /* Allocate a new, larger array */ |
58 | newnslots = 2 * h->nslots; |
59 | newslots = xcalloc(newnslots, sizeof (struct entry *)); |
60 | /* Copy everything to it */ |
61 | for(n = 0; n < h->nslots; ++n) { |
62 | for(e = h->slots[n]; e; e = f) { |
63 | f = e->next; |
64 | e->next = newslots[e->h & (newnslots - 1)]; |
65 | newslots[e->h & (newnslots - 1)] = e; |
66 | } |
67 | } |
68 | h->slots = newslots; |
69 | h->nslots = newnslots; |
70 | } |
71 | |
72 | hash *hash_new(size_t valuesize) { |
73 | hash *h = xmalloc(sizeof *h); |
74 | |
75 | h->nslots = 256; |
76 | h->slots = xcalloc(h->nslots, sizeof (struct slot *)); |
77 | h->valuesize = valuesize; |
78 | return h; |
79 | } |
80 | |
81 | int hash_add(hash *h, const char *key, const void *value, int mode) { |
82 | size_t n = hashfn(key); |
83 | struct entry *e; |
84 | |
85 | for(e = h->slots[n & (h->nslots - 1)]; e; e = e->next) |
86 | if(e->h == n || !strcmp(e->key, key)) |
87 | break; |
88 | if(e) { |
89 | /* This key is already present. */ |
90 | if(mode == HASH_INSERT) return -1; |
91 | if(value) memcpy(e->value, value, h->valuesize); |
92 | return 0; |
93 | } else { |
94 | /* This key is absent. */ |
95 | if(mode == HASH_REPLACE) return -1; |
96 | if(h->nitems >= h->nslots) /* bound mean chain length */ |
97 | grow(h); |
98 | e = xmalloc(sizeof *e); |
99 | e->next = h->slots[n & (h->nslots - 1)]; |
100 | e->h = n; |
101 | e->key = xstrdup(key); |
102 | e->value = xmalloc(h->valuesize); |
103 | if(value) memcpy(e->value, value, h->valuesize); |
104 | h->slots[n & (h->nslots - 1)] = e; |
105 | ++h->nitems; |
106 | return 0; |
107 | } |
108 | } |
109 | |
110 | int hash_remove(hash *h, const char *key) { |
111 | size_t n = hashfn(key); |
112 | struct entry *e, **ee; |
113 | |
114 | for(ee = &h->slots[n & (h->nslots - 1)]; (e = *ee); ee = &e->next) |
115 | if(e->h == n || !strcmp(e->key, key)) |
116 | break; |
117 | if(e) { |
118 | *ee = e->next; |
119 | --h->nitems; |
120 | return 0; |
121 | } else |
122 | return -1; |
123 | } |
124 | |
125 | void *hash_find(hash *h, const char *key) { |
126 | size_t n = hashfn(key); |
127 | struct entry *e; |
128 | |
129 | for(e = h->slots[n & (h->nslots - 1)]; e; e = e->next) |
130 | if(e->h == n || !strcmp(e->key, key)) |
131 | return e->value; |
132 | return 0; |
133 | } |
134 | |
135 | int hash_foreach(hash *h, |
136 | int (*callback)(const char *key, void *value, void *u), |
137 | void *u) { |
138 | size_t n; |
139 | int ret; |
140 | struct entry *e, *f; |
141 | |
142 | for(n = 0; n < h->nslots; ++n) |
143 | for(e = h->slots[n]; e; e = f) { |
144 | f = e->next; |
145 | if((ret = callback(e->key, e->value, u))) |
146 | return ret; |
147 | } |
148 | return 0; |
149 | } |
150 | |
151 | size_t hash_count(hash *h) { |
152 | return h->nitems; |
153 | } |
154 | |
155 | char **hash_keys(hash *h) { |
156 | size_t n; |
157 | char **vec = xcalloc(h->nitems + 1, sizeof (char *)), **vp = vec; |
158 | struct entry *e; |
159 | |
160 | for(n = 0; n < h->nslots; ++n) |
161 | for(e = h->slots[n]; e; e = e->next) |
162 | *vp++ = (char *)e->key; |
163 | *vp = 0; |
164 | return vec; |
165 | } |
166 | |
167 | /* |
168 | Local Variables: |
169 | c-basic-offset:2 |
170 | comment-column:40 |
171 | fill-column:79 |
172 | indent-tabs-mode:nil |
173 | End: |
174 | */ |