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 x3.
   5  *
   6  * x3 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 3 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     int res;
  79
  80     if (!node) return NULL;
  81     N.l = N.r = NULL;
  82     l = r = &N;
  83
  84     while (1) {
  85         verify(node);
  86         res = irccasecmp(key, node->key);
  87         if (!res) break;
  88         if (res < 0) {
  89             if (!node->l) break;
  90             res = irccasecmp(key, node->l->key);
  91             if (res < 0) {
  92                 y = node->l;
  93                 node->l = y->r;
  94                 y->r = node;
  95                 node = y;
  96                 if (!node->l) break;
  97             }
  98             r->l = node;
  99             r = node;
 100             node = node->l;
 101         } else { /* res > 0 */
 102             if (!node->r) break;
 103             res = irccasecmp(key, node->r->key);
 104             if (res > 0) {
 105                 y = node->r;
 106                 node->r = y->l;
 107                 y->l = node;
 108                 node = y;
 109                 if (!node->r) break;
 110             }
 111             l->r = node;
 112             l = node;
 113             node = node->r;
 114         }
 115     }
 116     l->r = node->l;
 117     r->l = node->r;
 118     node->l = N.r;
 119     node->r = N.l;
 120     return node;
 121 }
 122
 123 /*
 124  *    Free node.  Free data/key using free_f functions.
 125  */
 126 static void
 127 dict_dispose_node(struct dict_node *node, free_f free_keys, free_f free_data)
 128 {
 129     if (free_keys && node->key) {
 130         if (free_keys == free)
 131             free((void*)node->key);
 132         else
 133             free_keys((void*)node->key);
 134     }
 135     if (free_data && node->data) {
 136         if (free_data == free)
 137             free(node->data);
 138         else
 139             free_data(node->data);
 140     }
 141     free(node);
 142 }
 143
 144 /*
 145  *    Insert an entry into the dictionary.
 146  *    Key ordering (and uniqueness) is determined by case-insensitive
 147  *    string comparison.
 148  */
 149 void
 150 dict_insert(dict_t dict, const char *key, void *data)
 151 {
 152     struct dict_node *new_node;
 153     if (!key)
 154         return;
 155     verify(dict);
 156     new_node = malloc(sizeof(struct dict_node));
 157     new_node->key = key;
 158     new_node->data = data;
 159     if (dict->root) {
 160         int res;
 161         dict->root = dict_splay(dict->root, key);
 162         res = irccasecmp(key, dict->root->key);
 163         if (res < 0) {
 164             /* insert just "before" current root */
 165             new_node->l = dict->root->l;
 166             new_node->r = dict->root;
 167             dict->root->l = NULL;
 168             if (dict->root->prev) {
 169                 dict->root->prev->next = new_node;
 170             } else {
 171                 dict->first = new_node;
 172             }
 173             new_node->prev = dict->root->prev;
 174             new_node->next = dict->root;
 175             dict->root->prev = new_node;
 176             dict->root = new_node;
 177         } else if (res > 0) {
 178             /* insert just "after" current root */
 179             new_node->r = dict->root->r;
 180             new_node->l = dict->root;
 181             dict->root->r = NULL;
 182             if (dict->root->next) {
 183                 dict->root->next->prev = new_node;
 184             } else {
 185                 dict->last = new_node;
 186             }
 187             new_node->next = dict->root->next;
 188             new_node->prev = dict->root;
 189             dict->root->next = new_node;
 190             dict->root = new_node;
 191         } else {
 192             /* maybe we don't want to overwrite it .. oh well */
 193             if (dict->free_data) {
 194                 if (dict->free_data == free)
 195                     free(dict->root->data);
 196                 else
 197                     dict->free_data(dict->root->data);
 198             }
 199             if (dict->free_keys) {
 200                 if (dict->free_keys == free)
 201                     free((void*)dict->root->key);
 202                 else
 203                     dict->free_keys((void*)dict->root->key);
 204             }
 205             free(new_node);
 206             dict->root->key = key;
 207             dict->root->data = data;
 208             /* decrement the count since we dropped the node */
 209             dict->count--;
 210         }
 211     } else {
 212         new_node->l = new_node->r = NULL;
 213         new_node->next = new_node->prev = NULL;
 214         dict->root = dict->first = dict->last = new_node;
 215     }
 216     dict->count++;
 217 }
 218
 219 /*
 220  *    Remove an entry from the dictionary.
 221  *    Return non-zero if it was found, or zero if the key was not in the
 222  *    dictionary.
 223  */
 224 int
 225 dict_remove2(dict_t dict, const char *key, int no_dispose)
 226 {
 227     struct dict_node *new_root, *old_root;
 228
 229     if (!dict->root)
 230         return 0;
 231     verify(dict);
 232     dict->root = dict_splay(dict->root, key);
 233     if (irccasecmp(key, dict->root->key))
 234         return 0;
 235
 236     if (!dict->root->l) {
 237         new_root = dict->root->r;
 238     } else {
 239         new_root = dict_splay(dict->root->l, key);
 240         new_root->r = dict->root->r;
 241     }
 242     if (dict->root->prev) dict->root->prev->next = dict->root->next;
 243     if (dict->first == dict->root) dict->first = dict->first->next;
 244     if (dict->root->next) dict->root->next->prev = dict->root->prev;
 245     if (dict->last == dict->root) dict->last = dict->last->prev;
 246     old_root = dict->root;
 247     dict->root = new_root;
 248     dict->count--;
 249     if (no_dispose) {
 250         free(old_root);
 251     } else {
 252         dict_dispose_node(old_root, dict->free_keys, dict->free_data);
 253     }
 254     return 1;
 255 }
 256
 257 /*
 258  *    Find an entry in the dictionary.
 259  *    If "found" is non-NULL, set it to non-zero if the key was found.
 260  *    Return the data associated with the key (or NULL if the key was
 261  *    not found).
 262  */
 263 void*
 264 dict_find(dict_t dict, const char *key, int *found)
 265 {
 266     int was_found;
 267     if (!dict || !dict->root || !key) {
 268         if (found)
 269             *found = 0;
 270         return NULL;
 271     }
 272     verify(dict);
 273     dict->root = dict_splay(dict->root, key);
 274     was_found = !irccasecmp(key, dict->root->key);
 275     if (found)
 276         *found = was_found;
 277     return was_found ? dict->root->data : NULL;
 278 }
 279
 280 /*
 281  *    Delete an entire dictionary.
 282  */
 283 void
 284 dict_delete(dict_t dict)
 285 {
 286     dict_iterator_t it, next;
 287     if (!dict)
 288         return;
 289     for (it=dict_first(dict); it; it=next) {
 290         next = iter_next(it);
 291         dict_dispose_node(it, dict->free_keys, dict->free_data);
 292     }
 293     free(dict);
 294 }
 295
 296 struct dict_sanity_struct {
 297     unsigned int node_count;
 298     struct dict_node *bad_node;
 299     char error[128];
 300 };
 301
 302 static int
 303 dict_sanity_check_node(struct dict_node *node, struct dict_sanity_struct *dss)
 304 {
 305     verify(node);
 306     if (!node->key) {
 307         snprintf(dss->error, sizeof(dss->error), "Node %p had null key", (void*)node);
 308         return 1;
 309     }
 310     if (node->l) {
 311         if (dict_sanity_check_node(node->l, dss)) return 1;
 312         if (irccasecmp(node->l->key, node->key) >= 0) {
 313             snprintf(dss->error, sizeof(dss->error), "Node %p's left child's key '%s' >= its key '%s'", (void*)node, node->l->key, node->key);
 314             return 1;
 315         }
 316     }
 317     if (node->r) {
 318         if (dict_sanity_check_node(node->r, dss)) return 1;
 319         if (irccasecmp(node->key, node->r->key) >= 0) {
 320             snprintf(dss->error, sizeof(dss->error), "Node %p's right child's key '%s' <= its key '%s'", (void*)node, node->r->key, node->key);
 321             return 1;
 322         }
 323     }
 324     dss->node_count++;
 325     return 0;
 326 }
 327
 328 /*
 329  *    Perform sanity checks on the dict's internal structure.
 330  */
 331 char *
 332 dict_sanity_check(dict_t dict)
 333 {
 334     struct dict_sanity_struct dss;
 335     dss.node_count = 0;
 336     dss.bad_node = 0;
 337     dss.error[0] = 0;
 338     verify(dict);
 339     if (dict->root && dict_sanity_check_node(dict->root, &dss)) {
 340         return strdup(dss.error);
 341     } else if (dss.node_count != dict->count) {
 342         snprintf(dss.error, sizeof(dss.error), "Counted %d nodes but expected %d.", dss.node_count, dict->count);
 343         return strdup(dss.error);
 344     } else {
 345         return 0;
 346     }
 347 }