// online2/online-timing.h
  
  // Copyright 2014   Johns Hopkins University (author: Daniel Povey)
  
  // See ../../COPYING for clarification regarding multiple authors
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //  http://www.apache.org/licenses/LICENSE-2.0
  //
  // THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
  // WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
  // MERCHANTABLITY OR NON-INFRINGEMENT.
  // See the Apache 2 License for the specific language governing permissions and
  // limitations under the License.
  
  
  #ifndef KALDI_ONLINE2_ONLINE_TIMING_H_
  #define KALDI_ONLINE2_ONLINE_TIMING_H_
  
  #include <string>
  #include <vector>
  #include <deque>
  
  #include "base/timer.h"
  #include "base/kaldi-error.h"
  
  namespace kaldi {
  /// @addtogroup  onlinedecoding OnlineDecoding
  /// @{
  
  
  class OnlineTimer;
  
  /// class OnlineTimingStats stores statistics from timing of online decoding,
  /// which will enable the Print() function to print out the averate real-time
  /// factor and average delay per utterance.  See class OnlineTimer.
  class OnlineTimingStats {
   public:
    OnlineTimingStats();
    /// Here, if "online == false" we take into account that the setup was used in
    /// not-really-online mode where the chunk length was the whole file.  We need
    /// to change the way we interpret the stats and print results, in this case.
    void Print(bool online = true);
   protected:
    friend class OnlineTimer;
    int32 num_utts_;
    // all times are in seconds.
    double total_audio_; // total time of audio.
    double total_time_taken_;  // total time spent processing the audio.
    double total_time_waited_; // total time we pretended to wait (but just
                               // increased the waited_ counter)... zero if you
                               // called SleepUntil instead of WaitUntil().
    double max_delay_; // maximum delay at utterance end.
    std::string max_delay_utt_;
  };
  
  
  
  /// class OnlineTimer is used to test real-time decoding algorithms and evaluate
  /// how long the decoding of a particular utterance would take.  The 'obvious'
  /// way to evaluate this would be to measure the wall-clock time, and if we're
  /// processing the data in chunks, to sleep() until a given chunk would become
  /// available in a real-time application-- e.g. say we need to process a chunk
  /// that ends half a second into the utterance, we would sleep until half a
  /// second had elapsed since the start of the utterance.  In this code we
  /// have the option to not actually sleep: we can simulate the effect of
  /// sleeping by just incrementing
  /// a variable that says how long we would have slept; and we add this to
  /// wall-clock times obtained from Timer::Elapsed().
  /// The usage of this class will be something like as follows:
  /// \code
  /// OnlineTimingStats stats;
  /// while (.. process different utterances..) {
  ///   OnlineTimer this_utt_timer(utterance_id);
  ///   while (...process chunks of this utterance..) {
  ///      double num_secs_elapsed = 0.01 * num_frames;
  ///      this_utt_timer.WaitUntil(num_secs_elapsed);
  ///   }
  ///   this_utt_timer.OutputStats(&stats);
  /// \endcode
  /// This assumes that the value provided to the last WaitUntil()
  /// call was the length of the utterance.
  
  class OnlineTimer {
   public:
    OnlineTimer(const std::string &utterance_id);
  
    /// The call to SleepUntil(t) will sleep until cur_utterance_length seconds
    /// after this object was initialized, or return immediately if we've
    /// already passed that time.
    void SleepUntil(double cur_utterance_length);
  
    /// The call to WaitUntil(t) simulates the effect of sleeping until
    /// cur_utterance_length seconds after this object was initialized; 
    /// but instead of actually sleeping, it increases a counter.
    void WaitUntil(double cur_utterance_length);
    
    /// This call, which should be made after decoding is done,
    /// writes the stats to the object that accumulates them.
    void OutputStats(OnlineTimingStats *stats);
  
    /// Returns the simulated time elapsed in seconds since the timer was started;
    /// this equals waited_ plus the real time elapsed.
    double Elapsed();
    
   private:
    std::string utterance_id_;
    Timer timer_;
    // all times are in seconds.
    double waited_;
    double utterance_length_;
  };
  
  
  /// @} End of "addtogroup onlinedecoding"
  }  // namespace kaldi
  
  
  
  #endif  // KALDI_ONLINE2_ONLINE_TIMING_