mirror of
https://github.com/UberGames/RPG-X2.git
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141 lines
3.6 KiB
C
141 lines
3.6 KiB
C
/* Copyright (C) 2005 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#ifndef _trie_h
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#define _trie_h
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef struct st_trie_node
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{
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uint16 leaf; /* Depth from root node if match, 0 else */
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uchar c; /* Label on this edge */
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struct st_trie_node *next; /* Next label */
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struct st_trie_node *links; /* Array of edges leaving this node */
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struct st_trie_node *fail; /* AC failure function */
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} TRIE_NODE;
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typedef struct st_trie
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{
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TRIE_NODE root;
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MEM_ROOT mem_root;
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CHARSET_INFO *charset;
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uint32 nnodes;
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uint32 nwords;
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} TRIE;
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typedef struct st_ac_trie_state
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{
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TRIE *trie;
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TRIE_NODE *node;
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} AC_TRIE_STATE;
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extern TRIE *trie_init (TRIE *trie, CHARSET_INFO *charset);
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extern void trie_free (TRIE *trie);
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extern my_bool trie_insert (TRIE *trie, const uchar *key, uint keylen);
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extern my_bool ac_trie_prepare (TRIE *trie);
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extern void ac_trie_init (TRIE *trie, AC_TRIE_STATE *state);
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/* `trie_goto' is internal function and shouldn't be used. */
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static inline TRIE_NODE *trie_goto (TRIE_NODE *root, TRIE_NODE *node, uchar c)
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{
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TRIE_NODE *next;
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DBUG_ENTER("trie_goto");
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for (next= node->links; next; next= next->next)
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if (next->c == c)
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DBUG_RETURN(next);
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if (root == node)
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DBUG_RETURN(root);
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DBUG_RETURN(NULL);
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}
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/*
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SYNOPSIS
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int ac_trie_next (AC_TRIE_STATE *state, uchar *c);
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state - valid pointer to `AC_TRIE_STATE'
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c - character to lookup
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DESCRIPTION
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Implementation of search using Aho-Corasick automaton.
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Performs char-by-char search.
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RETURN VALUE
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`ac_trie_next' returns length of matched word or 0.
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*/
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static inline int ac_trie_next (AC_TRIE_STATE *state, uchar *c)
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{
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TRIE_NODE *root, *node;
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DBUG_ENTER("ac_trie_next");
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DBUG_ASSERT(state && c);
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root= &state->trie->root;
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node= state->node;
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while (! (state->node= trie_goto(root, node, *c)))
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node= node->fail;
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DBUG_RETURN(state->node->leaf);
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}
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/*
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SYNOPSIS
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my_bool trie_search (TRIE *trie, const uchar *key, uint keylen);
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trie - valid pointer to `TRIE'
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key - valid pointer to key to insert
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keylen - non-0 key length
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DESCRIPTION
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Performs key lookup in trie.
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RETURN VALUE
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`trie_search' returns `true' if key is in `trie'. Otherwise,
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`false' is returned.
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NOTES
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Consecutive search here is "best by test". arrays are very short, so
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binary search or hashing would add too much complexity that would
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overweight speed gain. Especially because compiler can optimize simple
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consecutive loop better (tested)
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*/
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static inline my_bool trie_search (TRIE *trie, const uchar *key, uint keylen)
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{
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TRIE_NODE *node;
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uint k;
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DBUG_ENTER("trie_search");
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DBUG_ASSERT(trie && key && keylen);
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node= &trie->root;
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for (k= 0; k < keylen; k++)
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{
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uchar p;
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if (! (node= node->links))
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DBUG_RETURN(FALSE);
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p= key[k];
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while (p != node->c)
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if (! (node= node->next))
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DBUG_RETURN(FALSE);
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}
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DBUG_RETURN(node->leaf > 0);
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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