cppjieba/src/MPSegment.hpp
2015-10-08 17:08:57 +08:00

115 lines
2.9 KiB
C++

#ifndef CPPJIEBA_MPSEGMENT_H
#define CPPJIEBA_MPSEGMENT_H
#include <algorithm>
#include <set>
#include <cassert>
#include "limonp/Logger.hpp"
#include "DictTrie.hpp"
#include "SegmentBase.hpp"
namespace CppJieba {
class MPSegment: public SegmentBase {
public:
MPSegment(const string& dictPath, const string& userDictPath = "") {
dictTrie_ = new DictTrie(dictPath, userDictPath);
isNeedDestroy_ = true;
LogInfo("MPSegment init(%s) ok", dictPath.c_str());
}
MPSegment(const DictTrie* dictTrie)
: dictTrie_(dictTrie), isNeedDestroy_(false) {
assert(dictTrie_);
}
~MPSegment() {
if (isNeedDestroy_) {
delete dictTrie_;
}
}
void cut(const string& sentence,
vector<string>& words,
size_t max_word_len = MAX_WORD_LENGTH) const {
PreFilter pre_filter(symbols_, sentence);
PreFilter::Range range;
vector<Unicode> uwords;
uwords.reserve(sentence.size());
while (pre_filter.HasNext()) {
range = pre_filter.Next();
cut(range.begin, range.end, uwords, max_word_len);
}
TransCode::encode(uwords, words);
}
void cut(Unicode::const_iterator begin,
Unicode::const_iterator end,
vector<Unicode>& words,
size_t max_word_len = MAX_WORD_LENGTH) const {
vector<Dag> dags;
dictTrie_->find(begin,
end,
dags,
max_word_len);
CalcDP(dags);
CutByDag(dags, words);
}
const DictTrie* getDictTrie() const {
return dictTrie_;
}
bool isUserDictSingleChineseWord(const Rune & value) const {
return dictTrie_->isUserDictSingleChineseWord(value);
}
private:
void CalcDP(vector<Dag>& dags) const {
size_t nextPos;
const DictUnit* p;
double val;
for (vector<Dag>::reverse_iterator rit = dags.rbegin(); rit != dags.rend(); rit++) {
rit->pInfo = NULL;
rit->weight = MIN_DOUBLE;
assert(!rit->nexts.empty());
for (LocalVector<pair<size_t, const DictUnit*> >::const_iterator it = rit->nexts.begin(); it != rit->nexts.end(); it++) {
nextPos = it->first;
p = it->second;
val = 0.0;
if (nextPos + 1 < dags.size()) {
val += dags[nextPos + 1].weight;
}
if (p) {
val += p->weight;
} else {
val += dictTrie_->getMinWeight();
}
if (val > rit->weight) {
rit->pInfo = p;
rit->weight = val;
}
}
}
}
void CutByDag(const vector<Dag>& dags,
vector<Unicode>& words) const {
size_t i = 0;
while (i < dags.size()) {
const DictUnit* p = dags[i].pInfo;
if (p) {
words.push_back(p->word);
i += p->word.size();
} else { //single chinese word
words.push_back(Unicode(1, dags[i].rune));
i++;
}
}
}
const DictTrie* dictTrie_;
bool isNeedDestroy_;
}; // class MPSegment
} // namespace CppJieba
#endif