156 lines
5 KiB
C++
156 lines
5 KiB
C++
/* Copyright (C) 2005 J.F.Dockes
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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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*
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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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*
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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
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* Free Software Foundation, Inc.,
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include "autoconfig.h"
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#include MEMORY_INCLUDE
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#include "debuglog.h"
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#include "utf8iter.h"
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#include "smallut.h"
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#include "chrono.h"
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#include "textsplit.h"
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#include "xmacros.h"
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#include "rcldb.h"
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#include "stemdb.h"
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#include "expansiondbs.h"
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using namespace std;
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namespace Rcl {
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/**
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* Create all expansion dbs used to transform user input term to widen a query
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* We use Xapian synonyms subsets to store the expansions.
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*/
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bool createExpansionDbs(Xapian::WritableDatabase& wdb,
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const vector<string>& langs)
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{
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LOGDEB(("StemDb::createExpansionDbs: languages: %s\n",
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stringsToString(langs).c_str()));
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Chrono cron;
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// Erase and recreate all the expansion groups
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// If langs is empty and we don't need casediac expansion, then no need to
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// walk the big list
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if (langs.empty()) {
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if (o_index_stripchars)
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return true;
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}
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// Stem dbs
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vector<XapWritableComputableSynFamMember> stemdbs;
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// Note: tried to make this to work with stack-allocated objects, couldn't.
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// Looks like a bug in copy constructors somewhere, can't guess where
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vector<STD_SHARED_PTR<SynTermTransStem> > stemmers;
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for (unsigned int i = 0; i < langs.size(); i++) {
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stemmers.push_back(STD_SHARED_PTR<SynTermTransStem>
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(new SynTermTransStem(langs[i])));
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stemdbs.push_back(
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XapWritableComputableSynFamMember(wdb, synFamStem, langs[i],
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stemmers.back().get()));
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stemdbs.back().recreate();
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}
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// Unaccented stem dbs
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vector<XapWritableComputableSynFamMember> unacstemdbs;
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// We can reuse the same stemmer pointers, the objects are stateless.
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if (!o_index_stripchars) {
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for (unsigned int i = 0; i < langs.size(); i++) {
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unacstemdbs.push_back(
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XapWritableComputableSynFamMember(wdb, synFamStemUnac, langs[i],
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stemmers.back().get()));
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unacstemdbs.back().recreate();
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}
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}
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SynTermTransUnac transunac(UNACOP_UNACFOLD);
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XapWritableComputableSynFamMember
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diacasedb(wdb, synFamDiCa, "all", &transunac);
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if (!o_index_stripchars)
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diacasedb.recreate();
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// Walk the list of all terms, and stem/unac each.
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string ermsg;
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try {
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Xapian::TermIterator it = wdb.allterms_begin();
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// We'd want to skip to the first non-prefixed term, but this is a bit
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// complicated, so we just jump over most of the prefixed term and then
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// skip the rest one by one.
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it.skip_to(wrap_prefix("Z"));
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for ( ;it != wdb.allterms_end(); it++) {
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if (has_prefix(*it))
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continue;
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// Detect and skip CJK terms.
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Utf8Iter utfit(*it);
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if (utfit.eof()) // Empty term?? Seems to happen.
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continue;
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if (TextSplit::isCJK(*utfit)) {
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// LOGDEB(("stemskipped: Skipping CJK\n"));
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continue;
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}
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string lower = *it;
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// If the index is raw, compute the case-folded term which
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// is the input to the stem db, and add a synonym from the
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// stripped term to the cased and accented one, for accent
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// and case expansion at query time
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if (!o_index_stripchars) {
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unacmaybefold(*it, lower, "UTF-8", UNACOP_FOLD);
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diacasedb.addSynonym(*it);
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}
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// Dont' apply stemming to terms which don't look like
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// natural language words.
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if (!Db::isSpellingCandidate(*it)) {
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LOGDEB1(("createExpansionDbs: skipped: [%s]\n", (*it).c_str()));
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continue;
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}
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// Create stemming synonym for every language. The input is the
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// lowercase accented term
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for (unsigned int i = 0; i < langs.size(); i++) {
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stemdbs[i].addSynonym(lower);
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}
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// For a raw index, also maybe create a stem expansion for
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// the unaccented term. While this may be incorrect, it is
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// also necessary for searching in a diacritic-unsensitive
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// way on a raw index
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if (!o_index_stripchars) {
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string unac;
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unacmaybefold(lower, unac, "UTF-8", UNACOP_UNAC);
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if (unac != lower) {
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for (unsigned int i = 0; i < langs.size(); i++) {
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unacstemdbs[i].addSynonym(unac);
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}
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}
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}
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}
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} XCATCHERROR(ermsg);
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if (!ermsg.empty()) {
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LOGERR(("Db::createStemDb: map build failed: %s\n", ermsg.c_str()));
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return false;
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}
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LOGDEB(("StemDb::createExpansionDbs: done: %.2f S\n", cron.secs()));
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return true;
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}
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}
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