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ukui-search/libchinese-segmentation/cppjieba/segment-trie/segment-trie.cpp

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/*
* Copyright (C) 2022, KylinSoft Co., Ltd.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
* Authors: jixiaoxu <jixiaoxu@kylinos.cn>
*
*/
#include <cmath>
#include "segment-trie.h"
DictTrie::DictTrie(const vector<string> file_paths, string dat_cache_path)
: StorageBase<DatMemElem, false, DictCacheFileHeader>(file_paths, dat_cache_path)
{
this->Init();
}
DictTrie::DictTrie(const string &dict_path, const string &user_dict_paths, const string &dat_cache_path)
: StorageBase<DatMemElem, false, DictCacheFileHeader>(vector<string>{dict_path, user_dict_paths}, dat_cache_path)
{
this->Init();
}
void DictTrie::LoadSourceFile(const string &dat_cache_file, const string &md5)
{
DictCacheFileHeader header;
assert(sizeof(header.md5_hex) == md5.size());
memcpy(&header.md5_hex[0], md5.c_str(), md5.size());
int offset(0), elements_num(0), write_bytes(0), data_trie_size(0);
string tmp_filepath = string(dat_cache_file) + "_XXXXXX";
umask(S_IWGRP | S_IWOTH);
const int fd =mkstemp((char *)tmp_filepath.data());
assert(fd >= 0);
fchmod(fd, 0644);
write_bytes = write(fd, (const char *)&header, sizeof(DictCacheFileHeader));
this->PreLoad();
this->LoadDefaultDict(fd, write_bytes, offset, elements_num);
this->LoadUserDict(fd, write_bytes, offset, elements_num);
write_bytes += write(fd, this->GetDataTrieArray(), this->GetDataTrieTotalSize());
lseek(fd, sizeof(header.md5_hex), SEEK_SET);
write(fd, &elements_num, sizeof(int));
write(fd, &offset, sizeof(int));
data_trie_size = this->GetDataTrieSize();
write(fd, &data_trie_size, sizeof(int));
write(fd, &m_min_weight, sizeof(double));
close(fd);
assert((size_t)write_bytes == sizeof(DictCacheFileHeader) + offset + this->GetDataTrieTotalSize());
const auto rename_ret = rename(tmp_filepath.c_str(), dat_cache_file.c_str());
assert(0 == rename_ret);
}
const DatMemElem * DictTrie::Find(const string &key) const
{
int result = this->ExactMatchSearch(key.c_str(), key.size());
if (result < 0)
return nullptr;
return &this->GetElementPtr()[result];
}
void DictTrie::FindDatDag(RuneStrArray::const_iterator begin, RuneStrArray::const_iterator end, vector<DatDag> &res, size_t max_word_len) const {
res.clear();
res.resize(end - begin);
string text_str;
EncodeRunesToString(begin, end, text_str);
static const size_t max_num = 128;
result_pair_type result_pairs[max_num] = {};
for (size_t i = 0, begin_pos = 0; i < size_t(end - begin); i++) {
std::size_t num_results = this->CommonPrefixSearch(&text_str[begin_pos], &result_pairs[0], max_num);
res[i].nexts.push_back(pair<size_t, const DatMemElem *>(i + 1, nullptr));
for (std::size_t idx = 0; idx < num_results; ++idx) {
auto & match = result_pairs[idx];
if ((match.value < 0) || ((size_t)match.value >= this->GetCacheFileHeaderPtr()->elements_size)) {
continue;
}
auto const char_num = Utf8CharNum(&text_str[begin_pos], match.length);
if (char_num > max_word_len) {
continue;
}
const DatMemElem * pValue = &this->GetElementPtr()[match.value];
if (1 == char_num) {
res[i].nexts[0].second = pValue;
continue;
}
res[i].nexts.push_back(pair<size_t, const DatMemElem *>(i + char_num, pValue));
}
begin_pos += limonp::UnicodeToUtf8Bytes((begin + i)->rune);
}
}
void DictTrie::FindWordRange(RuneStrArray::const_iterator begin, RuneStrArray::const_iterator end, vector<WordRange> &words, size_t max_word_len) const {
string text_str;
EncodeRunesToString(begin, end, text_str);
static const size_t max_num = 128;
result_pair_type result_pairs[max_num] = {};//存放字典查询结果
size_t str_size = end - begin;
double max_weight[str_size];//存放逆向路径最大weight
for (size_t i = 0; i<str_size; i++) {
max_weight[i] = -3.14e+100;
}
size_t max_next[str_size];//存放动态规划后的分词结果
//memset(max_next,-1,str_size*sizeof(size_t));
double val(0);
for (size_t i = 0, begin_pos = text_str.size(); i < str_size; i++) {
size_t nextPos = str_size - i;//逆向计算
begin_pos -= (end - i - 1)->len;
std::size_t num_results = this->CommonPrefixSearch(&text_str[begin_pos], &result_pairs[0], max_num);
if (0 == num_results) {//字典不存在则单独分词
val = GetMinWeight();
if (nextPos < str_size) {
val += max_weight[nextPos];
}
if ((nextPos <= str_size) && (val > max_weight[nextPos - 1])) {
max_weight[nextPos - 1] = val;
max_next[nextPos - 1] = nextPos;
}
} else {//字典存在则根据查询结果数量计算最大概率路径
for (std::size_t idx = 0; idx < num_results; ++idx) {
auto & match = result_pairs[idx];
if ((match.value < 0) || ((uint32_t)match.value >= this->GetCacheFileHeaderPtr()->elements_size)) {
continue;
}
auto const char_num = Utf8CharNum(&text_str[begin_pos], match.length);
if (char_num > max_word_len) {
continue;
}
auto * pValue = &this->GetElementPtr()[match.value];
val = pValue->weight;
if (1 == char_num) {
if (nextPos < str_size) {
val += max_weight[nextPos];
}
if ((nextPos <= str_size) && (val > max_weight[nextPos - 1])) {
max_weight[nextPos - 1] = val;
max_next[nextPos - 1] = nextPos;
}
} else {
if (nextPos - 1 + char_num < str_size) {
val += max_weight[nextPos - 1 + char_num];
}
if ((nextPos - 1 + char_num <= str_size) && (val > max_weight[nextPos - 1])) {
max_weight[nextPos - 1] = val;
max_next[nextPos - 1] = nextPos - 1 + char_num;
}
}
}
}
}
for (size_t i = 0; i < str_size;) {//统计动态规划结果
assert(max_next[i] > i);
assert(max_next[i] <= str_size);
WordRange wr(begin + i, begin + max_next[i] - 1);
words.push_back(wr);
i = max_next[i];
}
}
bool DictTrie::IsUserDictSingleChineseWord(const Rune &word) const {
return IsIn(m_user_dict_single_chinese_word, word);
}
void DictTrie::PreLoad()
{
ifstream ifs(DICT_PATH);
string line;
vector<string> buf;
for (; getline(ifs, line);) {
if (limonp::StartsWith(line, "#") or line.empty()) {
continue;
}
limonp::Split(line, buf, " ");
if (buf.size() != 3)
continue;
m_freq_sum += atof(buf[1].c_str());
}
}
void DictTrie::LoadDefaultDict(const int &fd, int &write_bytes, int &offset, int &elements_num)
{
ifstream ifs(DICT_PATH);
string line;
vector<string> buf;
for (; getline(ifs, line);) {
if (limonp::StartsWith(line, "#") or line.empty()) {
continue;
}
limonp::Split(line, buf, " ");
if (buf.size() != 3)
continue;
DatMemElem node_info;
node_info.weight = log(atof(buf[1].c_str()) / m_freq_sum);
node_info.SetTag(buf[2]);
this->Update(buf[0].c_str(), buf[0].size(), elements_num);
offset += (sizeof(DatMemElem));
elements_num++;
if (m_min_weight > node_info.weight) {
m_min_weight = node_info.weight;
}
write_bytes += write(fd, &node_info, sizeof(DatMemElem));
}
}
void DictTrie::LoadUserDict(const int &fd, int &write_bytes, int &offset, int &elements_num)
{
ifstream ifs(USER_DICT_PATH);
string line;
vector<string> buf;
for (; getline(ifs, line);) {
if (limonp::StartsWith(line, "#") or line.empty()) {
continue;
}
limonp::Split(line, buf, " ");
if (buf.size() != 3)
continue;
DatMemElem node_info;
assert(m_freq_sum > 0.0);
const int freq = atoi(buf[1].c_str());
node_info.weight = log(1.0 * freq / m_freq_sum);
node_info.SetTag(buf[2]);
this->Update(buf[0].c_str(), buf[0].size(), elements_num);
offset += (sizeof(DatMemElem));
elements_num++;
write_bytes += write(fd, &node_info, sizeof(DatMemElem));
if (Utf8CharNum(buf[0]) == 1) {
RuneArray word;
if (DecodeRunesInString(buf[0], word)) {
m_user_dict_single_chinese_word.insert(word[0]);
}
}
}
}
inline double DictTrie::GetMinWeight() const
{
return this->GetCacheFileHeaderPtr()->min_weight;
}
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