facade.hh
#ifndef LM_FACADE_H
#define LM_FACADE_H
#include "lm/virtual_interface.hh"
#include "util/string_piece.hh"
#include <string>
namespace lm {
namespace base {
// Common model interface that depends on knowing the specific classes.
// Curiously recurring template pattern.
template <class Child, class StateT, class VocabularyT> class ModelFacade : public Model {
public:
typedef StateT State;
typedef VocabularyT Vocabulary;
/* Translate from void* to State */
FullScoreReturn BaseFullScore(const void *in_state, const WordIndex new_word, void *out_state) const {
return static_cast<const Child*>(this)->FullScore(
*reinterpret_cast<const State*>(in_state),
new_word,
*reinterpret_cast<State*>(out_state));
}
FullScoreReturn BaseFullScoreForgotState(const WordIndex *context_rbegin, const WordIndex *context_rend, const WordIndex new_word, void *out_state) const {
return static_cast<const Child*>(this)->FullScoreForgotState(
context_rbegin,
context_rend,
new_word,
*reinterpret_cast<State*>(out_state));
}
// Default Score function calls FullScore. Model can override this.
float Score(const State &in_state, const WordIndex new_word, State &out_state) const {
return static_cast<const Child*>(this)->FullScore(in_state, new_word, out_state).prob;
}
float BaseScore(const void *in_state, const WordIndex new_word, void *out_state) const {
return static_cast<const Child*>(this)->Score(
*reinterpret_cast<const State*>(in_state),
new_word,
*reinterpret_cast<State*>(out_state));
}
const State &BeginSentenceState() const { return begin_sentence_; }
const State &NullContextState() const { return null_context_; }
const Vocabulary &GetVocabulary() const { return *static_cast<const Vocabulary*>(&BaseVocabulary()); }
protected:
ModelFacade() : Model(sizeof(State)) {}
virtual ~ModelFacade() {}
// begin_sentence and null_context can disappear after. vocab should stay.
void Init(const State &begin_sentence, const State &null_context, const Vocabulary &vocab, unsigned char order) {
begin_sentence_ = begin_sentence;
null_context_ = null_context;
begin_sentence_memory_ = &begin_sentence_;
null_context_memory_ = &null_context_;
base_vocab_ = &vocab;
order_ = order;
}
private:
State begin_sentence_, null_context_;
};
} // mamespace base
} // namespace lm
#endif // LM_FACADE_H