libsvm_converter.cpp

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// Jubatus: Online machine learning framework for distributed environment
// Copyright (C) 2011 Preferred Networks and Nippon Telegraph and Telephone Corporation.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License version 2.1 as published by the Free Software Foundation.
//
// This library 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 this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

#include <sstream>
#include <string>
#include "jubatus/util/lang/cast.h"
#include "datum.hpp"
#include "exception.hpp"
#include "libsvm_converter.hpp"

namespace jubatus {
namespace core {
namespace fv_converter {

void libsvm_converter::convert(
    const std::string& line,
    datum& ret_datum,
    std::string& ret_label) {
  std::string label;
  std::istringstream in(line);
  in >> label;
  datum::nv_t num_values;

  std::string s;
  while (in) {
    in >> s;
    if (!in) {
      break;
    }
    size_t p = s.find(':');
    if (p == std::string::npos) {
      throw JUBATUS_EXCEPTION(
          converter_exception("invalid libsvm format: " + s));
    }
    std::string id = s.substr(0, p);
    float val = jubatus::util::lang::lexical_cast<float>(s.substr(p + 1));
    num_values.push_back(make_pair(id, val));
  }

  ret_label.swap(label);
  ret_datum.string_values_.clear();
  ret_datum.num_values_.swap(num_values);
}

}  // namespace fv_converter
}  // namespace core
}  // namespace jubatus