/External/Mysql-5.0/include/my_trie.h
http://awoe.googlecode.com/ · C++ Header · 141 lines · 76 code · 17 blank · 48 comment · 14 complexity · 05ba1fa605bf9d7d63d6d4135b1ea41a MD5 · raw file
- /* Copyright (C) 2005 MySQL AB
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; version 2 of the License.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- #ifndef _trie_h
- #define _trie_h
- #ifdef __cplusplus
- extern "C" {
- #endif
- typedef struct st_trie_node
- {
- uint16 leaf; /* Depth from root node if match, 0 else */
- uchar c; /* Label on this edge */
- struct st_trie_node *next; /* Next label */
- struct st_trie_node *links; /* Array of edges leaving this node */
- struct st_trie_node *fail; /* AC failure function */
- } TRIE_NODE;
- typedef struct st_trie
- {
- TRIE_NODE root;
- MEM_ROOT mem_root;
- CHARSET_INFO *charset;
- uint32 nnodes;
- uint32 nwords;
- } TRIE;
- typedef struct st_ac_trie_state
- {
- TRIE *trie;
- TRIE_NODE *node;
- } AC_TRIE_STATE;
- extern TRIE *trie_init (TRIE *trie, CHARSET_INFO *charset);
- extern void trie_free (TRIE *trie);
- extern my_bool trie_insert (TRIE *trie, const uchar *key, uint keylen);
- extern my_bool ac_trie_prepare (TRIE *trie);
- extern void ac_trie_init (TRIE *trie, AC_TRIE_STATE *state);
- /* `trie_goto' is internal function and shouldn't be used. */
- static inline TRIE_NODE *trie_goto (TRIE_NODE *root, TRIE_NODE *node, uchar c)
- {
- TRIE_NODE *next;
- DBUG_ENTER("trie_goto");
- for (next= node->links; next; next= next->next)
- if (next->c == c)
- DBUG_RETURN(next);
- if (root == node)
- DBUG_RETURN(root);
- DBUG_RETURN(NULL);
- }
- /*
- SYNOPSIS
- int ac_trie_next (AC_TRIE_STATE *state, uchar *c);
- state - valid pointer to `AC_TRIE_STATE'
- c - character to lookup
- DESCRIPTION
- Implementation of search using Aho-Corasick automaton.
- Performs char-by-char search.
- RETURN VALUE
- `ac_trie_next' returns length of matched word or 0.
- */
- static inline int ac_trie_next (AC_TRIE_STATE *state, uchar *c)
- {
- TRIE_NODE *root, *node;
- DBUG_ENTER("ac_trie_next");
- DBUG_ASSERT(state && c);
- root= &state->trie->root;
- node= state->node;
- while (! (state->node= trie_goto(root, node, *c)))
- node= node->fail;
- DBUG_RETURN(state->node->leaf);
- }
- /*
- SYNOPSIS
- my_bool trie_search (TRIE *trie, const uchar *key, uint keylen);
- trie - valid pointer to `TRIE'
- key - valid pointer to key to insert
- keylen - non-0 key length
- DESCRIPTION
- Performs key lookup in trie.
- RETURN VALUE
- `trie_search' returns `true' if key is in `trie'. Otherwise,
- `false' is returned.
- NOTES
- Consecutive search here is "best by test". arrays are very short, so
- binary search or hashing would add too much complexity that would
- overweight speed gain. Especially because compiler can optimize simple
- consecutive loop better (tested)
- */
- static inline my_bool trie_search (TRIE *trie, const uchar *key, uint keylen)
- {
- TRIE_NODE *node;
- uint k;
- DBUG_ENTER("trie_search");
- DBUG_ASSERT(trie && key && keylen);
- node= &trie->root;
- for (k= 0; k < keylen; k++)
- {
- uchar p;
- if (! (node= node->links))
- DBUG_RETURN(FALSE);
- p= key[k];
- while (p != node->c)
- if (! (node= node->next))
- DBUG_RETURN(FALSE);
- }
- DBUG_RETURN(node->leaf > 0);
- }
- #ifdef __cplusplus
- }
- #endif
- #endif