quick_classic_builder.cpp

/*
 * Copyright (C) 2012  Wan Leung Wong <me at wanleung dot com>
 *
 * This file is part of libcangjie.
 *
 * libcangjie is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * libcangjie 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libcangjie.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <iostream>
#include <iomanip>
#include <string>
#include <db_cxx.h>
#include <fstream>
#include <vector>
#include <sstream>
#include "util.h"

using namespace std;

std::vector<std::string> &split(const std::string &s, char delim, std::vector<std::string> &elems) {
    std::stringstream ss(s);
    std::string item;
    while(std::getline(ss, item, delim)) {
        elems.push_back(item);
    }
    return elems;
}


std::vector<std::string> split(const std::string &s, char delim) {
    std::vector<std::string> elems;
    return split(s, delim, elems);
}

int main(int argc, const char* argv[]) {

  if (argc !=3) {
      cout << "usage: "<< argv[0] << " <filename> <db filename>" << endl;
      return 1;
  }

  const char* kDatabaseName = argv[2];
  const char* filename = argv[1];

  DbEnv env(0);
  Db* pdb;

  string line;

  bool datamode = false;

  try {

    env.set_error_stream(&cerr);
    env.open("./", DB_CREATE | DB_INIT_MPOOL, 0);

    pdb = new Db(&env, 0);
    // If you want to support duplicated records and make duplicated
    // records sorted by data, you need to call:
    //   pdb->set_flags(DB_DUPSORT);
    // Note that only Btree-typed database supports sorted duplicated
    // records

    // If the database does not exist, create it.  If it exists, clear
    // its content after openning.
    //pdb->set_flags( DB_DUP );// | DB_DUPSORT);
    pdb->open(NULL, kDatabaseName, NULL, DB_BTREE, DB_CREATE | DB_TRUNCATE, 0);


    ifstream myfile (filename);
    if (myfile.is_open()) {
        while ( myfile.good() ) {
            getline (myfile,line);

            // Ignore empty and commented lines
            if ((line.length() == 0) || (startswith(line, std::string("#")))) {
                continue;
            }

            if (!datamode) {
                if ("BEGIN_TABLE" == line ) {
                    datamode = true;
                }
                continue;
            }
            
            if ("END_TABLE" == line) {
                datamode = false;
                continue;
            }

            std::vector<std::string> cj = split(line, '\t'); 

            int freq = atoi(cj[2].c_str());

            Dbt key(const_cast<char*>(cj[1].data()), cj[1].size());
            Dbt value(&freq, sizeof(int));
            pdb->put(NULL, &key, &value, 0);
        }
        myfile.close();
    } else {
        cout << "Unable to open file";
    }

    // You need to set ulen and flags=DB_DBT_USERMEM to prevent Dbt
    // from allocate its own memory but use the memory provided by you.

    if (pdb != NULL) {
      pdb->close(0);
      delete pdb;
    }
    env.close(0);

  } catch (DbException& e) {
    cerr << "DbException: " << e.what() << endl;
    return -1;
  } catch (std::exception& e) {
    cerr << e.what() << endl;
    return -1;
  }

  return 0;
}