elemental-ircd/src/irc_dictionary.c

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2007-12-02 15:06:25 +00:00
/*
* charybdis: an advanced ircd
* irc_dictionary.c: Dictionary-based information storage.
*
* Copyright (c) 2007 William Pitcock <nenolod -at- sacredspiral.co.uk>
* Copyright (c) 2007 Jilles Tjoelker <jilles -at- stack.nl>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice is present in all copies.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "stdinc.h"
#include "match.h"
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#include "client.h"
#include "setup.h"
#include "irc_dictionary.h"
static rb_bh *elem_heap = NULL;
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struct Dictionary
{
DCF compare_cb;
struct DictionaryElement *root, *head, *tail;
unsigned int count;
char *id;
unsigned int dirty:1;
};
/*
* irc_dictionary_create(DCF compare_cb)
*
* Dictionary object factory.
*
* Inputs:
* - function to use for comparing two entries in the dtree
*
* Outputs:
* - on success, a new dictionary object.
*
* Side Effects:
* - if services runs out of memory and cannot allocate the object,
* the program will abort.
*/
struct Dictionary *irc_dictionary_create(DCF compare_cb)
{
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struct Dictionary *dtree = (struct Dictionary *) rb_malloc(sizeof(struct Dictionary));
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dtree->compare_cb = compare_cb;
if (!elem_heap)
elem_heap = rb_bh_create(sizeof(struct DictionaryElement), 1024, "dictionary_elem_heap");
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return dtree;
}
/*
* irc_dictionary_create_named(const char *name,
* DCF compare_cb)
*
* Dictionary object factory.
*
* Inputs:
* - dictionary name
* - function to use for comparing two entries in the dtree
*
* Outputs:
* - on success, a new dictionary object.
*
* Side Effects:
* - if services runs out of memory and cannot allocate the object,
* the program will abort.
*/
struct Dictionary *irc_dictionary_create_named(const char *name,
DCF compare_cb)
{
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struct Dictionary *dtree = (struct Dictionary *) rb_malloc(sizeof(struct Dictionary));
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dtree->compare_cb = compare_cb;
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dtree->id = rb_strdup(name);
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if (!elem_heap)
elem_heap = rb_bh_create(sizeof(struct DictionaryElement), 1024, "dictionary_elem_heap");
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return dtree;
}
/*
* irc_dictionary_set_comparator_func(struct Dictionary *dict,
* DCF compare_cb)
*
* Resets the comparator function used by the dictionary code for
* updating the DTree structure.
*
* Inputs:
* - dictionary object
* - new comparator function (passed as functor)
*
* Outputs:
* - nothing
*
* Side Effects:
* - the dictionary comparator function is reset.
*/
void irc_dictionary_set_comparator_func(struct Dictionary *dict,
DCF compare_cb)
{
s_assert(dict != NULL);
s_assert(compare_cb != NULL);
dict->compare_cb = compare_cb;
}
/*
* irc_dictionary_get_comparator_func(struct Dictionary *dict)
*
* Returns the current comparator function used by the dictionary.
*
* Inputs:
* - dictionary object
*
* Outputs:
* - comparator function (returned as functor)
*
* Side Effects:
* - none
*/
DCF
irc_dictionary_get_comparator_func(struct Dictionary *dict)
{
s_assert(dict != NULL);
return dict->compare_cb;
}
/*
* irc_dictionary_get_linear_index(struct Dictionary *dict,
* const char *key)
*
* Gets a linear index number for key.
*
* Inputs:
* - dictionary tree object
* - pointer to data
*
* Outputs:
* - position, from zero.
*
* Side Effects:
* - rebuilds the linear index if the tree is marked as dirty.
*/
int
irc_dictionary_get_linear_index(struct Dictionary *dict, const char *key)
{
struct DictionaryElement *elem;
s_assert(dict != NULL);
s_assert(key != NULL);
elem = irc_dictionary_find(dict, key);
if (elem == NULL)
return -1;
if (!dict->dirty)
return elem->position;
else
{
struct DictionaryElement *delem;
int i;
for (delem = dict->head, i = 0; delem != NULL; delem = delem->next, i++)
delem->position = i;
dict->dirty = FALSE;
}
return elem->position;
}
/*
* irc_dictionary_retune(struct Dictionary *dict, const char *key)
*
* Retunes the tree, self-optimizing for the element which belongs to key.
*
* Inputs:
* - node to begin search from
*
* Outputs:
* - none
*
* Side Effects:
* - a new root node is nominated.
*/
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static void
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irc_dictionary_retune(struct Dictionary *dict, const char *key)
{
struct DictionaryElement n, *tn, *left, *right, *node;
int ret;
s_assert(dict != NULL);
if (dict->root == NULL)
return;
/*
* we initialize n with known values, since it's on stack
* memory. otherwise the dict would become corrupted.
*
* n is used for temporary storage while the tree is retuned.
* -nenolod
*/
n.left = n.right = NULL;
left = right = &n;
/* this for(;;) loop is the main workhorse of the rebalancing */
for (node = dict->root; ; )
{
if ((ret = dict->compare_cb(key, node->key)) == 0)
break;
if (ret < 0)
{
if (node->left == NULL)
break;
if ((ret = dict->compare_cb(key, node->left->key)) < 0)
{
tn = node->left;
node->left = tn->right;
tn->right = node;
node = tn;
if (node->left == NULL)
break;
}
right->left = node;
right = node;
node = node->left;
}
else
{
if (node->right == NULL)
break;
if ((ret = dict->compare_cb(key, node->right->key)) > 0)
{
tn = node->right;
node->right = tn->left;
tn->left = node;
node = tn;
if (node->right == NULL)
break;
}
left->right = node;
left = node;
node = node->right;
}
}
left->right = node->left;
right->left = node->right;
node->left = n.right;
node->right = n.left;
dict->root = node;
}
/*
* irc_dictionary_link(struct Dictionary *dict,
* struct DictionaryElement *delem)
*
* Links a dictionary tree element to the dictionary.
*
* When we add new nodes to the tree, it becomes the
* next nominated root. This is perhaps not a wise
* optimization because of automatic retuning, but
* it keeps the code simple.
*
* Inputs:
* - dictionary tree
* - dictionary tree element
*
* Outputs:
* - nothing
*
* Side Effects:
* - a node is linked to the dictionary tree
*/
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static void
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irc_dictionary_link(struct Dictionary *dict,
struct DictionaryElement *delem)
{
s_assert(dict != NULL);
s_assert(delem != NULL);
dict->dirty = TRUE;
dict->count++;
if (dict->root == NULL)
{
delem->left = delem->right = NULL;
delem->next = delem->prev = NULL;
dict->head = dict->tail = dict->root = delem;
}
else
{
int ret;
irc_dictionary_retune(dict, delem->key);
if ((ret = dict->compare_cb(delem->key, dict->root->key)) < 0)
{
delem->left = dict->root->left;
delem->right = dict->root;
dict->root->left = NULL;
if (dict->root->prev)
dict->root->prev->next = delem;
else
dict->head = delem;
delem->prev = dict->root->prev;
delem->next = dict->root;
dict->root->prev = delem;
dict->root = delem;
}
else if (ret > 0)
{
delem->right = dict->root->right;
delem->left = dict->root;
dict->root->right = NULL;
if (dict->root->next)
dict->root->next->prev = delem;
else
dict->tail = delem;
delem->next = dict->root->next;
delem->prev = dict->root;
dict->root->next = delem;
dict->root = delem;
}
else
{
dict->root->key = delem->key;
dict->root->data = delem->data;
dict->count--;
rb_bh_free(elem_heap, delem);
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}
}
}
/*
* irc_dictionary_unlink_root(struct Dictionary *dict)
*
* Unlinks the root dictionary tree element from the dictionary.
*
* Inputs:
* - dictionary tree
*
* Outputs:
* - nothing
*
* Side Effects:
* - the root node is unlinked from the dictionary tree
*/
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static void
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irc_dictionary_unlink_root(struct Dictionary *dict)
{
struct DictionaryElement *delem, *nextnode, *parentofnext;
dict->dirty = TRUE;
delem = dict->root;
if (delem == NULL)
return;
if (dict->root->left == NULL)
dict->root = dict->root->right;
else if (dict->root->right == NULL)
dict->root = dict->root->left;
else
{
/* Make the node with the next highest key the new root.
* This node has a NULL left pointer. */
nextnode = delem->next;
s_assert(nextnode->left == NULL);
if (nextnode == delem->right)
{
dict->root = nextnode;
dict->root->left = delem->left;
}
else
{
parentofnext = delem->right;
while (parentofnext->left != NULL && parentofnext->left != nextnode)
parentofnext = parentofnext->left;
s_assert(parentofnext->left == nextnode);
parentofnext->left = nextnode->right;
dict->root = nextnode;
dict->root->left = delem->left;
dict->root->right = delem->right;
}
}
/* linked list */
if (delem->prev != NULL)
delem->prev->next = delem->next;
if (dict->head == delem)
dict->head = delem->next;
if (delem->next)
delem->next->prev = delem->prev;
if (dict->tail == delem)
dict->tail = delem->prev;
dict->count--;
}
/*
* irc_dictionary_destroy(struct Dictionary *dtree,
* void (*destroy_cb)(dictionary_elem_t *delem, void *privdata),
* void *privdata);
*
* Recursively destroys all nodes in a dictionary tree.
*
* Inputs:
* - dictionary tree object
* - optional iteration callback
* - optional opaque/private data to pass to callback
*
* Outputs:
* - nothing
*
* Side Effects:
* - on success, a dtree and optionally it's children are destroyed.
*
* Notes:
* - if this is called without a callback, the objects bound to the
* DTree will not be destroyed.
*/
void irc_dictionary_destroy(struct Dictionary *dtree,
void (*destroy_cb)(struct DictionaryElement *delem, void *privdata),
void *privdata)
{
struct DictionaryElement *n, *tn;
s_assert(dtree != NULL);
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RB_DLINK_FOREACH_SAFE(n, tn, dtree->head)
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{
if (destroy_cb != NULL)
(*destroy_cb)(n, privdata);
rb_bh_free(elem_heap, n);
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}
rb_free(dtree);
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}
/*
* irc_dictionary_foreach(struct Dictionary *dtree,
* void (*destroy_cb)(dictionary_elem_t *delem, void *privdata),
* void *privdata);
*
* Iterates over all entries in a DTree.
*
* Inputs:
* - dictionary tree object
* - optional iteration callback
* - optional opaque/private data to pass to callback
*
* Outputs:
* - nothing
*
* Side Effects:
* - on success, a dtree is iterated
*/
void irc_dictionary_foreach(struct Dictionary *dtree,
int (*foreach_cb)(struct DictionaryElement *delem, void *privdata),
void *privdata)
{
struct DictionaryElement *n, *tn;
s_assert(dtree != NULL);
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RB_DLINK_FOREACH_SAFE(n, tn, dtree->head)
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{
/* delem_t is a subclass of node_t. */
struct DictionaryElement *delem = (struct DictionaryElement *) n;
if (foreach_cb != NULL)
(*foreach_cb)(delem, privdata);
}
}
/*
* irc_dictionary_search(struct Dictionary *dtree,
* void (*destroy_cb)(struct DictionaryElement *delem, void *privdata),
* void *privdata);
*
* Searches all entries in a DTree using a custom callback.
*
* Inputs:
* - dictionary tree object
* - optional iteration callback
* - optional opaque/private data to pass to callback
*
* Outputs:
* - on success, the requested object
* - on failure, NULL.
*
* Side Effects:
* - a dtree is iterated until the requested conditions are met
*/
void *irc_dictionary_search(struct Dictionary *dtree,
void *(*foreach_cb)(struct DictionaryElement *delem, void *privdata),
void *privdata)
{
struct DictionaryElement *n, *tn;
void *ret = NULL;
s_assert(dtree != NULL);
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RB_DLINK_FOREACH_SAFE(n, tn, dtree->head)
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{
/* delem_t is a subclass of node_t. */
struct DictionaryElement *delem = (struct DictionaryElement *) n;
if (foreach_cb != NULL)
ret = (*foreach_cb)(delem, privdata);
if (ret)
break;
}
return ret;
}
/*
* irc_dictionary_foreach_start(struct Dictionary *dtree,
* struct DictionaryIter *state);
*
* Initializes a static DTree iterator.
*
* Inputs:
* - dictionary tree object
* - static DTree iterator
*
* Outputs:
* - nothing
*
* Side Effects:
* - the static iterator, &state, is initialized.
*/
void irc_dictionary_foreach_start(struct Dictionary *dtree,
struct DictionaryIter *state)
{
s_assert(dtree != NULL);
s_assert(state != NULL);
state->cur = NULL;
state->next = NULL;
/* find first item */
state->cur = dtree->head;
if (state->cur == NULL)
return;
/* make state->cur point to first item and state->next point to
* second item */
state->next = state->cur;
irc_dictionary_foreach_next(dtree, state);
}
/*
* irc_dictionary_foreach_cur(struct Dictionary *dtree,
* struct DictionaryIter *state);
*
* Returns the data from the current node being iterated by the
* static iterator.
*
* Inputs:
* - dictionary tree object
* - static DTree iterator
*
* Outputs:
* - reference to data in the current dtree node being iterated
*
* Side Effects:
* - none
*/
void *irc_dictionary_foreach_cur(struct Dictionary *dtree,
struct DictionaryIter *state)
{
s_assert(dtree != NULL);
s_assert(state != NULL);
return state->cur != NULL ? state->cur->data : NULL;
}
/*
* irc_dictionary_foreach_next(struct Dictionary *dtree,
* struct DictionaryIter *state);
*
* Advances a static DTree iterator.
*
* Inputs:
* - dictionary tree object
* - static DTree iterator
*
* Outputs:
* - nothing
*
* Side Effects:
* - the static iterator, &state, is advanced to a new DTree node.
*/
void irc_dictionary_foreach_next(struct Dictionary *dtree,
struct DictionaryIter *state)
{
s_assert(dtree != NULL);
s_assert(state != NULL);
if (state->cur == NULL)
{
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ilog(L_MAIN, "irc_dictionary_foreach_next(): called again after iteration finished on dtree<%p>", (void *)dtree);
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return;
}
state->cur = state->next;
if (state->next == NULL)
return;
state->next = state->next->next;
}
/*
* irc_dictionary_find(struct Dictionary *dtree, const char *key)
*
* Looks up a DTree node by name.
*
* Inputs:
* - dictionary tree object
* - name of node to lookup
*
* Outputs:
* - on success, the dtree node requested
* - on failure, NULL
*
* Side Effects:
* - none
*/
struct DictionaryElement *irc_dictionary_find(struct Dictionary *dict, const char *key)
{
s_assert(dict != NULL);
s_assert(key != NULL);
/* retune for key, key will be the tree's root if it's available */
irc_dictionary_retune(dict, key);
if (dict->root && !dict->compare_cb(key, dict->root->key))
return dict->root;
return NULL;
}
/*
* irc_dictionary_add(struct Dictionary *dtree, const char *key, void *data)
*
* Creates a new DTree node and binds data to it.
*
* Inputs:
* - dictionary tree object
* - name for new DTree node
* - data to bind to the new DTree node
*
* Outputs:
* - on success, a new DTree node
* - on failure, NULL
*
* Side Effects:
* - data is inserted into the DTree.
*/
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struct DictionaryElement *irc_dictionary_add(struct Dictionary *dict, const char *key, void *data)
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{
struct DictionaryElement *delem;
s_assert(dict != NULL);
s_assert(key != NULL);
s_assert(data != NULL);
s_assert(irc_dictionary_find(dict, key) == NULL);
delem = rb_bh_alloc(elem_heap);
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delem->key = key;
delem->data = data;
/* TBD: is this needed? --nenolod */
if (delem->key == NULL)
{
rb_bh_free(elem_heap, delem);
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return NULL;
}
irc_dictionary_link(dict, delem);
return delem;
}
/*
* irc_dictionary_delete(struct Dictionary *dtree, const char *key)
*
* Deletes data from a dictionary tree.
*
* Inputs:
* - dictionary tree object
* - name of DTree node to delete
*
* Outputs:
* - on success, the remaining data that needs to be mowgli_freed
* - on failure, NULL
*
* Side Effects:
* - data is removed from the DTree.
*
* Notes:
* - the returned data needs to be mowgli_freed/released manually!
*/
void *irc_dictionary_delete(struct Dictionary *dtree, const char *key)
{
struct DictionaryElement *delem = irc_dictionary_find(dtree, key);
void *data;
if (delem == NULL)
return NULL;
data = delem->data;
irc_dictionary_unlink_root(dtree);
rb_bh_free(elem_heap, delem);
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return data;
}
/*
* irc_dictionary_retrieve(struct Dictionary *dtree, const char *key)
*
* Retrieves data from a dictionary.
*
* Inputs:
* - dictionary tree object
* - name of node to lookup
*
* Outputs:
* - on success, the data bound to the DTree node.
* - on failure, NULL
*
* Side Effects:
* - none
*/
void *irc_dictionary_retrieve(struct Dictionary *dtree, const char *key)
{
struct DictionaryElement *delem = irc_dictionary_find(dtree, key);
if (delem != NULL)
return delem->data;
return NULL;
}
/*
* irc_dictionary_size(struct Dictionary *dict)
*
* Returns the size of a dictionary.
*
* Inputs:
* - dictionary tree object
*
* Outputs:
* - size of dictionary
*
* Side Effects:
* - none
*/
unsigned int irc_dictionary_size(struct Dictionary *dict)
{
s_assert(dict != NULL);
return dict->count;
}
/* returns the sum of the depths of the subtree rooted in delem at depth depth */
static int
stats_recurse(struct DictionaryElement *delem, int depth, int *pmaxdepth)
{
int result;
if (depth > *pmaxdepth)
*pmaxdepth = depth;
result = depth;
if (delem->left)
result += stats_recurse(delem->left, depth + 1, pmaxdepth);
if (delem->right)
result += stats_recurse(delem->right, depth + 1, pmaxdepth);
return result;
}
/*
* irc_dictionary_stats(struct Dictionary *dict, void (*cb)(const char *line, void *privdata), void *privdata)
*
* Returns the size of a dictionary.
*
* Inputs:
* - dictionary tree object
* - callback
* - data for callback
*
* Outputs:
* - none
*
* Side Effects:
* - callback called with stats text
*/
void irc_dictionary_stats(struct Dictionary *dict, void (*cb)(const char *line, void *privdata), void *privdata)
{
char str[256];
int sum, maxdepth;
s_assert(dict != NULL);
if (dict->id != NULL)
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rb_snprintf(str, sizeof str, "Dictionary stats for %s (%d)",
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dict->id, dict->count);
else
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rb_snprintf(str, sizeof str, "Dictionary stats for <%p> (%d)",
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(void *)dict, dict->count);
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cb(str, privdata);
maxdepth = 0;
sum = stats_recurse(dict->root, 0, &maxdepth);
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rb_snprintf(str, sizeof str, "Depth sum %d Avg depth %d Max depth %d", sum, sum / dict->count, maxdepth);
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cb(str, privdata);
return;
}