mosesdecoder/mert/Vocabulary.h

#ifndef MERT_VOCABULARY_H_
#define MERT_VOCABULARY_H_

#include <map>
#include <string>

namespace mert {

/**
 * A embarrassingly simple map to handle vocabularies to calculate
 * various scores such as BLEU.
 *
 * TODO: replace this with more efficient data structure.
 */
class Vocabulary {
 public:
  typedef std::map<std::string, int>::iterator iterator;
  typedef std::map<std::string, int>::const_iterator const_iterator;

  Vocabulary() {}
  virtual ~Vocabulary() {}

  /** Returns the assiged id for given "token". */
  int Encode(const std::string& token) {
    iterator it = m_vocab.find(token);
    int encoded_token;
    if (it == m_vocab.end()) {
      // Add an new entry to the vocaburary.
      encoded_token = static_cast<int>(m_vocab.size());
      m_vocab[token] = encoded_token;
    } else {
      encoded_token = it->second;
    }
    return encoded_token;
  }

  /**
   * Return true iff the specified "str" is found in the container.
   */
  bool Lookup(const std::string&str , int* v) const {
    const_iterator it = m_vocab.find(str);
    if (it == m_vocab.end()) return false;
    *v = it->second;
    return true;
  }

  void clear() { m_vocab.clear(); }

  bool empty() const { return m_vocab.empty(); }

  size_t size() const { return m_vocab.size(); }

  iterator find(const std::string& str) { return m_vocab.find(str); }
  const_iterator find(const std::string& str) const { return m_vocab.find(str); }

  int& operator[](const std::string& str) { return m_vocab[str]; }

  iterator begin() { return m_vocab.begin(); }
  const_iterator begin() const { return m_vocab.begin(); }
  iterator end() { return m_vocab.end(); }
  const_iterator end() const { return m_vocab.end(); }

 private:
  std::map<std::string, int> m_vocab;
};

class VocabularyFactory {
 public:
  static Vocabulary* GetVocabulary();
  static void SetVocabulary(Vocabulary* vocab);

 private:
  VocabularyFactory() {}
  virtual ~VocabularyFactory() {}
};

} // namespace mert

#endif  // MERT_VOCABULARY_H_