src/dict-splay.c

   1 /* dict-splay.c - Abstract dictionary type
   2  * Copyright 2000-2004 srvx Development Team
   3  *
   4  * This file is part of srvx.
   5  *
   6  * srvx is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include "common.h"
  18 #include "dict.h"
  19
  20 /*
  21  *    Create new dictionary.
  22  */
  23 dict_t
  24 dict_new(void)
  25 {
  26     dict_t dict = calloc(1, sizeof(*dict));
  27     return dict;
  28 }
  29
  30 /*
  31  *    Return number of entries in the dictionary.
  32  */
  33 unsigned int
  34 dict_size(dict_t dict)
  35 {
  36     return dict->count;
  37 }
  38
  39 /*
  40  *    Set the function to be called when freeing a key structure.
  41  *    If the function is NULL, just forget about the pointer.
  42  */
  43 void
  44 dict_set_free_keys(dict_t dict, free_f free_keys)
  45 {
  46     dict->free_keys = free_keys;
  47 }
  48
  49 /*
  50  *    Set the function to free data.
  51  * If the function is NULL, just forget about the pointer.
  52  */
  53 void
  54 dict_set_free_data(dict_t dict, free_f free_data)
  55 {
  56     dict->free_data = free_data;
  57 }
  58
  59 const char *
  60 dict_foreach(dict_t dict, dict_iterator_f it_f, void *extra)
  61 {
  62     dict_iterator_t it;
  63
  64     for (it=dict_first(dict); it; it=iter_next(it)) {
  65         if (it_f(iter_key(it), iter_data(it), extra)) return iter_key(it);
  66     }
  67     return NULL;
  68 }
  69
  70 /*
  71  *   This function finds a node and pulls it to the top of the tree.
  72  *   This helps balance the tree and auto-cache things you search for.
  73  */
  74 static struct dict_node*
  75 dict_splay(struct dict_node *node, const char *key)
  76 {
  77     struct dict_node N, *l, *r, *y;
  78     if (!node) return NULL;
  79     N.l = N.r = NULL;
  80     l = r = &N;
  81
  82     while (1) {
  83         int res = irccasecmp(key, node->key);
  84         if (!res) break;
  85         if (res < 0) {
  86             if (!node->l) break;
  87             res = irccasecmp(key, node->l->key);
  88             if (res < 0) {
  89                 y = node->l;
  90                 node->l = y->r;
  91                 y->r = node;
  92                 node = y;
  93                 if (!node->l) break;
  94             }
  95             r->l = node;
  96             r = node;
  97             node = node->l;
  98         } else { /* res > 0 */
  99             if (!node->r) break;
 100             res = irccasecmp(key, node->r->key);
 101             if (res > 0) {
 102                 y = node->r;
 103                 node->r = y->l;
 104                 y->l = node;
 105                 node = y;
 106                 if (!node->r) break;
 107             }
 108             l->r = node;
 109             l = node;
 110             node = node->r;
 111         }
 112     }
 113     l->r = node->l;
 114     r->l = node->r;
 115     node->l = N.r;
 116     node->r = N.l;
 117     return node;
 118 }
 119
 120 /*
 121  *    Free node.  Free data/key using free_f functions.
 122  */
 123 static void
 124 dict_dispose_node(struct dict_node *node, free_f free_keys, free_f free_data)
 125 {
 126     if (free_keys && node->key)
 127         free_keys((void*)node->key);
 128     if (free_data && node->data)
 129         free_data(node->data);
 130     free(node);
 131 }
 132
 133 /*
 134  *    Insert an entry into the dictionary.
 135  *    Key ordering (and uniqueness) is determined by case-insensitive
 136  *    string comparison.
 137  */
 138 void
 139 dict_insert(dict_t dict, const char *key, void *data)
 140 {
 141     struct dict_node *new_node;
 142     if (!key)
 143         return;
 144     new_node = malloc(sizeof(struct dict_node));
 145     new_node->key = key;
 146     new_node->data = data;
 147     if (dict->root) {
 148         int res;
 149         dict->root = dict_splay(dict->root, key);
 150         res = irccasecmp(key, dict->root->key);
 151         if (res < 0) {
 152             /* insert just "before" current root */
 153             new_node->l = dict->root->l;
 154             new_node->r = dict->root;
 155             dict->root->l = NULL;
 156             if (dict->root->prev) {
 157                 dict->root->prev->next = new_node;
 158             } else {
 159                 dict->first = new_node;
 160             }
 161             new_node->prev = dict->root->prev;
 162             new_node->next = dict->root;
 163             dict->root->prev = new_node;
 164             dict->root = new_node;
 165         } else if (res > 0) {
 166             /* insert just "after" current root */
 167             new_node->r = dict->root->r;
 168             new_node->l = dict->root;
 169             dict->root->r = NULL;
 170             if (dict->root->next) {
 171                 dict->root->next->prev = new_node;
 172             } else {
 173                 dict->last = new_node;
 174             }
 175             new_node->next = dict->root->next;
 176             new_node->prev = dict->root;
 177             dict->root->next = new_node;
 178             dict->root = new_node;
 179         } else {
 180             /* maybe we don't want to overwrite it .. oh well */
 181             if (dict->free_data) dict->free_data(dict->root->data);
 182             if (dict->free_keys) dict->free_keys((void*)dict->root->key);
 183             free(new_node);
 184             dict->root->key = key;
 185             dict->root->data = data;
 186             /* decrement the count since we dropped the node */
 187             dict->count--;
 188         }
 189     } else {
 190         new_node->l = new_node->r = NULL;
 191         new_node->next = new_node->prev = NULL;
 192         dict->root = dict->first = dict->last = new_node;
 193     }
 194     dict->count++;
 195 }
 196
 197 /*
 198  *    Remove an entry from the dictionary.
 199  *    Return non-zero if it was found, or zero if the key was not in the
 200  *    dictionary.
 201  */
 202 int
 203 dict_remove2(dict_t dict, const char *key, int no_dispose)
 204 {
 205     struct dict_node *new_root;
 206
 207     if (!dict->root)
 208         return 0;
 209     dict->root = dict_splay(dict->root, key);
 210     if (irccasecmp(key, dict->root->key))
 211         return 0;
 212
 213     if (!dict->root->l) {
 214         new_root = dict->root->r;
 215     } else {
 216         new_root = dict_splay(dict->root->l, key);
 217         new_root->r = dict->root->r;
 218     }
 219     if (dict->root->prev) dict->root->prev->next = dict->root->next;
 220     if (dict->first == dict->root) dict->first = dict->first->next;
 221     if (dict->root->next) dict->root->next->prev = dict->root->prev;
 222     if (dict->last == dict->root) dict->last = dict->last->prev;
 223     if (no_dispose) {
 224         free(dict->root);
 225     } else {
 226         dict_dispose_node(dict->root, dict->free_keys, dict->free_data);
 227     }
 228     dict->root = new_root;
 229     dict->count--;
 230     return 1;
 231 }
 232
 233 /*
 234  *    Find an entry in the dictionary.
 235  *    If "found" is non-NULL, set it to non-zero if the key was found.
 236  *    Return the data associated with the key (or NULL if the key was
 237  *    not found).
 238  */
 239 void*
 240 dict_find(dict_t dict, const char *key, int *found)
 241 {
 242     int was_found;
 243     if (!dict || !dict->root || !key) {
 244         if (found)
 245             *found = 0;
 246         return NULL;
 247     }
 248     dict->root = dict_splay(dict->root, key);
 249     was_found = !irccasecmp(key, dict->root->key);
 250     if (found)
 251         *found = was_found;
 252     return was_found ? dict->root->data : NULL;
 253 }
 254
 255 /*
 256  *    Delete an entire dictionary.
 257  */
 258 void
 259 dict_delete(dict_t dict)
 260 {
 261     dict_iterator_t it, next;
 262     if (!dict)
 263         return;
 264     for (it=dict_first(dict); it; it=next) {
 265         next = iter_next(it);
 266         dict_dispose_node(it, dict->free_keys, dict->free_data);
 267     }
 268     free(dict);
 269 }
 270
 271 struct dict_sanity_struct {
 272     unsigned int node_count;
 273     struct dict_node *bad_node;
 274     char error[128];
 275 };
 276
 277 static int
 278 dict_sanity_check_node(struct dict_node *node, struct dict_sanity_struct *dss)
 279 {
 280     if (!node->key) {
 281         snprintf(dss->error, sizeof(dss->error), "Node %p had null key", node);
 282         return 1;
 283     }
 284     if (node->l) {
 285         if (dict_sanity_check_node(node->l, dss)) return 1;
 286         if (irccasecmp(node->l->key, node->key) >= 0) {
 287             snprintf(dss->error, sizeof(dss->error), "Node %p's left child's key '%s' >= its key '%s'", node, node->l->key, node->key);
 288             return 1;
 289         }
 290     }
 291     if (node->r) {
 292         if (dict_sanity_check_node(node->r, dss)) return 1;
 293         if (irccasecmp(node->key, node->r->key) >= 0) {
 294             snprintf(dss->error, sizeof(dss->error), "Node %p's right child's key '%s' <= its key '%s'", node, node->r->key, node->key);
 295             return 1;
 296         }
 297     }
 298     dss->node_count++;
 299     return 0;
 300 }
 301
 302 /*
 303  *    Perform sanity checks on the dict's internal structure.
 304  */
 305 char *
 306 dict_sanity_check(dict_t dict)
 307 {
 308     struct dict_sanity_struct dss;
 309     dss.node_count = 0;
 310     dss.bad_node = 0;
 311     dss.error[0] = 0;
 312     if (dict->root && dict_sanity_check_node(dict->root, &dss)) {
 313         return strdup(dss.error);
 314     } else if (dss.node_count != dict->count) {
 315         snprintf(dss.error, sizeof(dss.error), "Counted %d nodes but expected %d.", dss.node_count, dict->count);
 316         return strdup(dss.error);
 317     } else {
 318         return 0;
 319     }
 320 }