// base/timer.cc
  
  // Copyright 2018  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.
  
  #include "base/timer.h"
  #include "base/kaldi-error.h"
  #include <algorithm>
  #include <iomanip>
  #include <map>
  #include <unordered_map>
  
  namespace kaldi {
  
  class ProfileStats {
   public:
    void AccStats(const char *function_name, double elapsed) {
      std::unordered_map<const char*, ProfileStatsEntry>::iterator
          iter = map_.find(function_name);
      if (iter == map_.end()) {
        map_[function_name] = ProfileStatsEntry(function_name);
        map_[function_name].total_time = elapsed;
      } else {
        iter->second.total_time += elapsed;
      }
    }
    ~ProfileStats() {
      // This map makes sure we agglomerate the time if there were any duplicate
      // addresses of strings.
      std::unordered_map<std::string, double> total_time;
      for (auto iter = map_.begin(); iter != map_.end(); iter++)
        total_time[iter->second.name] += iter->second.total_time;
  
      ReverseSecondComparator comp;
      std::vector<std::pair<std::string, double> > pairs(total_time.begin(),
                                                         total_time.end());
      std::sort(pairs.begin(), pairs.end(), comp);
      for (size_t i = 0; i < pairs.size(); i++) {
        KALDI_LOG << "Time taken in " << pairs[i].first << " is "
                  << std::fixed << std::setprecision(2) << pairs[i].second << "s.";
      }
    }
   private:
  
    struct ProfileStatsEntry {
      std::string name;
      double total_time;
      ProfileStatsEntry() { }
      ProfileStatsEntry(const char *name): name(name) { }
    };
  
    struct ReverseSecondComparator {
      bool operator () (const std::pair<std::string, double> &a,
                        const std::pair<std::string, double> &b) {
        return a.second > b.second;
      }
    };
  
    // Note: this map is keyed on the address of the string, there is no proper
    // hash function.  The assumption is that the strings are compile-time
    // constants.
    std::unordered_map<const char*, ProfileStatsEntry> map_;
  };
  
  ProfileStats g_profile_stats;
  
  Profiler::~Profiler() {
    g_profile_stats.AccStats(name_, tim_.Elapsed());
  }
  
  }  // namespace kaldi