| 1 | /* |
| 2 | * This file is part of DisOrder |
| 3 | * Copyright (C) 2005-2008 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 | */ |