basic-file-backed-feature-extractor.H

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#ifndef RERANKER_BASIC_FILE_BACKED_FEATURE_EXTRACTOR_H_
#define RERANKER_BASIC_FILE_BACKED_FEATURE_EXTRACTOR_H_

#include <cstdlib>
#include <string>
#include <vector>

#include "abstract-file-backed-feature-extractor.H"

namespace reranker {

using std::string;
using std::vector;

class BasicFileBackedFeatureExtractor :
      public AbstractFileBackedFeatureExtractor {
 public:
  BasicFileBackedFeatureExtractor() : AbstractFileBackedFeatureExtractor() {
  }
  virtual ~BasicFileBackedFeatureExtractor() { }

  virtual void Extract(Candidate &candidate,
                       FeatureVector<int,double> &features) { }

  virtual void ExtractSymbolic(Candidate &candidate,
                               FeatureVector<string,double> &symbolic_features);
 protected:
  virtual void ExtractFeatureValuePair(const string &s,
                                       string &feature, double &value) {
    size_t equals_pos = s.find_last_of("=");
    bool found_equals = equals_pos != string::npos;
    value =
        found_equals && equals_pos < s.length() - 1 ?
        atof(s.substr(equals_pos + 1, s.length() - (equals_pos + 1)).c_str()) :
        1.0;
    feature = found_equals ? s.substr(0, equals_pos) : s;
  }
};

}  // namespace reranker

#endif