added mysql source for win build
--HG-- branch : trunk
This commit is contained in:
Vendored
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/* 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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/*
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Implementation of trie and Aho-Corasick automaton.
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Supports only charsets that can be compared byte-wise.
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TODO:
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Add character frequencies. Can increase lookup speed
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up to 30%.
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Implement character-wise comparision.
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*/
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#include "mysys_priv.h"
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#include <m_string.h>
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#include <my_trie.h>
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#include <my_base.h>
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/*
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SYNOPSIS
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TRIE *trie_init (TRIE *trie, CHARSET_INFO *charset);
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DESCRIPTION
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Allocates or initializes a `TRIE' object. If `trie' is a `NULL'
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pointer, the function allocates, initializes, and returns a new
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object. Otherwise, the object is initialized and the address of
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the object is returned. If `trie_init()' allocates a new object,
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it will be freed when `trie_free()' is called.
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RETURN VALUE
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An initialized `TRIE*' object. `NULL' if there was insufficient
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memory to allocate a new object.
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*/
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TRIE *trie_init (TRIE *trie, CHARSET_INFO *charset)
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{
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MEM_ROOT mem_root;
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DBUG_ENTER("trie_init");
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DBUG_ASSERT(charset);
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init_alloc_root(&mem_root,
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(sizeof(TRIE_NODE) * 128) + ALLOC_ROOT_MIN_BLOCK_SIZE,
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sizeof(TRIE_NODE) * 128);
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if (! trie)
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{
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if (! (trie= (TRIE *)alloc_root(&mem_root, sizeof(TRIE))))
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{
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free_root(&mem_root, MYF(0));
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DBUG_RETURN(NULL);
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}
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}
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memcpy(&trie->mem_root, &mem_root, sizeof(MEM_ROOT));
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trie->root.leaf= 0;
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trie->root.c= 0;
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trie->root.next= NULL;
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trie->root.links= NULL;
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trie->root.fail= NULL;
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trie->charset= charset;
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trie->nnodes= 0;
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trie->nwords= 0;
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DBUG_RETURN(trie);
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}
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/*
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SYNOPSIS
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void trie_free (TRIE *trie);
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trie - valid pointer to `TRIE'
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DESCRIPTION
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Frees the memory allocated for a `trie'.
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RETURN VALUE
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None.
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*/
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void trie_free (TRIE *trie)
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{
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MEM_ROOT mem_root;
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DBUG_ENTER("trie_free");
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DBUG_ASSERT(trie);
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memcpy(&mem_root, &trie->mem_root, sizeof(MEM_ROOT));
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free_root(&mem_root, MYF(0));
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DBUG_VOID_RETURN;
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}
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/*
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SYNOPSIS
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my_bool trie_insert (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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Inserts new key into trie.
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RETURN VALUE
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Upon successful completion, `trie_insert' returns `FALSE'. Otherwise
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`TRUE' is returned.
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NOTES
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If this function fails you must assume `trie' is broken.
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However it can be freed with trie_free().
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*/
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my_bool trie_insert (TRIE *trie, const uchar *key, uint keylen)
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{
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TRIE_NODE *node;
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TRIE_NODE *next;
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uchar p;
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uint k;
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DBUG_ENTER("trie_insert");
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DBUG_ASSERT(trie && key && keylen);
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node= &trie->root;
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trie->root.fail= NULL;
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for (k= 0; k < keylen; k++)
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{
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p= key[k];
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for (next= node->links; next; next= next->next)
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if (next->c == p)
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break;
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if (! next)
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{
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TRIE_NODE *tmp= (TRIE_NODE *)alloc_root(&trie->mem_root,
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sizeof(TRIE_NODE));
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if (! tmp)
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DBUG_RETURN(TRUE);
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tmp->leaf= 0;
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tmp->c= p;
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tmp->links= tmp->fail= tmp->next= NULL;
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trie->nnodes++;
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if (! node->links)
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{
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node->links= tmp;
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}
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else
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{
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for (next= node->links; next->next; next= next->next) /* no-op */;
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next->next= tmp;
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}
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node= tmp;
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}
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else
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{
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node= next;
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}
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}
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node->leaf= keylen;
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trie->nwords++;
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DBUG_RETURN(FALSE);
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}
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/*
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SYNOPSIS
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my_bool trie_prepare (TRIE *trie);
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trie - valid pointer to `TRIE'
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DESCRIPTION
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Constructs Aho-Corasick automaton.
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RETURN VALUE
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Upon successful completion, `trie_prepare' returns `FALSE'. Otherwise
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`TRUE' is returned.
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*/
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my_bool ac_trie_prepare (TRIE *trie)
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{
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TRIE_NODE **tmp_nodes;
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TRIE_NODE *node;
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uint32 fnode= 0;
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uint32 lnode= 0;
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DBUG_ENTER("trie_prepare");
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DBUG_ASSERT(trie);
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tmp_nodes= (TRIE_NODE **)my_malloc(trie->nnodes * sizeof(TRIE_NODE *), MYF(0));
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if (! tmp_nodes)
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DBUG_RETURN(TRUE);
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trie->root.fail= &trie->root;
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for (node= trie->root.links; node; node= node->next)
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{
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node->fail= &trie->root;
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tmp_nodes[lnode++]= node;
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}
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while (fnode < lnode)
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{
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TRIE_NODE *current= (TRIE_NODE *)tmp_nodes[fnode++];
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for (node= current->links; node; node= node->next)
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{
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TRIE_NODE *fail= current->fail;
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tmp_nodes[lnode++]= node;
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while (! (node->fail= trie_goto(&trie->root, fail, node->c)))
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fail= fail->fail;
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}
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}
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my_free((uchar*)tmp_nodes, MYF(0));
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DBUG_RETURN(FALSE);
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}
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/*
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SYNOPSIS
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void ac_trie_init (TRIE *trie, AC_TRIE_STATE *state);
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trie - valid pointer to `TRIE'
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state - value pointer to `AC_TRIE_STATE'
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DESCRIPTION
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Initializes `AC_TRIE_STATE' object.
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*/
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void ac_trie_init (TRIE *trie, AC_TRIE_STATE *state)
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{
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DBUG_ENTER("ac_trie_init");
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DBUG_ASSERT(trie && state);
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state->trie= trie;
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state->node= &trie->root;
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DBUG_VOID_RETURN;
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}
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