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152
myisam/ft_parser.c
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152
myisam/ft_parser.c
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/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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; either version 2 of the License, or
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(at your option) any later version.
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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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/* Written by Sergei A. Golubchik, who has a shared copyright to this code */
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#include "ftdefs.h"
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#ifdef EVAL_RUN
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#ifdef PIVOT_STAT
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ulong collstat=0;
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#endif
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#endif /* EVAL_RUN */
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typedef struct st_ft_docstat {
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FT_WORD *list;
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uint uniq;
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double sum;
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#ifdef EVAL_RUN
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uint words, totlen;
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double max, nsum, nsum2;
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#endif /* EVAL_RUN */
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MI_INFO *info;
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uint keynr;
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byte *keybuf;
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} FT_DOCSTAT;
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static int FT_WORD_cmp(FT_WORD *w1, FT_WORD *w2)
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{
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return _mi_compare_text(default_charset_info,
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(uchar*) w1->pos,w1->len,
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(uchar*) w2->pos, w2->len,0);
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}
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static int walk_and_copy(FT_WORD *word,uint32 count,FT_DOCSTAT *docstat)
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{
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if(is_stopword(word->pos, word->len))
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return 0;
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word->weight=LWS_IN_USE;
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#ifdef EVAL_RUN
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word->cnt= (uchar) count;
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if(docstat->max < word->weight) docstat->max=word->weight;
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docstat->words+=count;
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docstat->totlen+=word->len;
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#endif /* EVAL_RUN */
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docstat->sum+=word->weight;
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memcpy_fixed((docstat->list)++,word,sizeof(FT_WORD));
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return 0;
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}
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/* transforms tree of words into the array, applying normalization */
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FT_WORD * ft_linearize(MI_INFO *info, uint keynr, byte *keybuf, TREE *wtree)
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{
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FT_WORD *wlist,*p;
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FT_DOCSTAT docstat;
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if ((wlist=(FT_WORD *) my_malloc(sizeof(FT_WORD)*
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(1+wtree->elements_in_tree),MYF(0))))
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{
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docstat.info=info;
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docstat.keynr=keynr;
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docstat.keybuf=keybuf;
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docstat.list=wlist;
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docstat.uniq=wtree->elements_in_tree;
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#ifdef EVAL_RUN
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docstat.nsum=docstat.nsum2=docstat.max=docstat.words=docstat.totlen=
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#endif /* EVAL_RUN */
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docstat.sum=0;
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tree_walk(wtree,(tree_walk_action)&walk_and_copy,&docstat,left_root_right);
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}
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delete_tree(wtree);
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free(wtree);
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if(wlist==NULL)
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return NULL;
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docstat.list->pos=NULL;
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for(p=wlist;p->pos;p++)
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{
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p->weight=PRENORM_IN_USE;
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#ifdef EVAL_RUN
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docstat.nsum+=p->weight;
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docstat.nsum2+=p->weight*p->weight;
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#endif /* EVAL_RUN */
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}
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#ifdef EVAL_RUN
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#ifdef PIVOT_STAT
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collstat+=PIVOT_STAT;
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#endif
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#endif /* EVAL_RUN */
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for(p=wlist;p->pos;p++)
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{
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p->weight/=NORM_IN_USE;
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}
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return wlist;
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}
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#ifdef HYPHEN_IS_DELIM
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#define word_char(X) (isalnum(X) || (X)=='_' || (X)=='\'')
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#else
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#define word_char(X) (isalnum(X) || (X)=='_' || (X)=='\'' || (X)=='-')
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#endif
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/* this is rather dumb first version of the parser */
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TREE * ft_parse(TREE *wtree, byte *doc, int doclen)
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{
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byte *end=doc+doclen;
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FT_WORD w;
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if(!wtree)
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{
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if(!(wtree=(TREE *)my_malloc(sizeof(TREE),MYF(0)))) return NULL;
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init_tree(wtree,0,sizeof(FT_WORD),(qsort_cmp)&FT_WORD_cmp,0,NULL);
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}
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w.weight=0;
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while(doc<end)
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{
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for(;doc<end;doc++)
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if(word_char(*doc)) break;
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for(w.pos=doc; doc<end; doc++)
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if(!word_char(*doc)) break;
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if((w.len=doc-w.pos) < MIN_WORD_LEN) continue;
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if(!tree_insert(wtree, &w, 0))
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{
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delete_tree(wtree);
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free(wtree);
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return NULL;
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}
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}
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return wtree;
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}
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