Repo created

libs/base/stats.hpp

@@ -0,0 +1,128 @@
+#pragma once
+
+#include "base/logging.hpp"
+
+#include <queue>
+#include <sstream>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace base
+{
+
+template <typename T>
+class NoopStats
+{
+public:
+  NoopStats() {}
+  void operator()(T const &) {}
+  std::string GetStatsStr() const { return ""; }
+};
+
+template <typename T>
+class AverageStats
+{
+public:
+  AverageStats() = default;
+  template <class ContT>
+  explicit AverageStats(ContT const & cont)
+  {
+    for (auto const & e : cont)
+      (*this)(e);
+  }
+
+  void operator()(T const & x)
+  {
+    ++m_count;
+    if (x > m_max)
+      m_max = x;
+    m_sum += x;
+  }
+
+  std::string ToString() const
+  {
+    std::ostringstream out;
+    out << "N = " << m_count << "; Total = " << m_sum << "; Max = " << m_max << "; Avg = " << GetAverage();
+    return out.str();
+  }
+
+  double GetAverage() const { return m_count == 0 ? 0.0 : m_sum / static_cast<double>(m_count); }
+  uint32_t GetCount() const { return m_count; }
+
+private:
+  uint32_t m_count = 0;
+  T m_max = 0;
+  T m_sum = 0;
+};
+
+template <class T>
+class StatsCollector
+{
+  std::vector<std::pair<std::string, AverageStats<T>>> m_vec;
+
+public:
+  explicit StatsCollector(std::initializer_list<std::string> init)
+  {
+    for (auto & name : init)
+      m_vec.push_back({std::move(name), {}});
+  }
+  ~StatsCollector()
+  {
+    for (auto const & e : m_vec)
+      LOG_SHORT(LINFO, (e.first, ":", e.second.ToString()));
+  }
+
+  AverageStats<T> & Get(size_t i) { return m_vec[i].second; }
+};
+
+template <class Key>
+class TopStatsCounter
+{
+  std::unordered_map<Key, size_t> m_data;
+
+public:
+  void Add(Key const & key) { ++m_data[key]; }
+
+  void PrintTop(size_t count) const
+  {
+    ASSERT(count > 0, ());
+
+    using PtrT = std::pair<Key const, size_t> const *;
+    struct GreaterNumber
+    {
+      bool operator()(PtrT l, PtrT r) const { return l->second > r->second; }
+    };
+
+    std::priority_queue<PtrT, std::vector<PtrT>, GreaterNumber> queue;
+
+    for (auto const & p : m_data)
+    {
+      if (queue.size() >= count)
+      {
+        if (queue.top()->second >= p.second)
+          continue;
+        queue.pop();
+      }
+
+      queue.push(&p);
+    }
+
+    std::vector<PtrT> vec;
+    vec.reserve(count);
+
+    while (!queue.empty())
+    {
+      vec.push_back(queue.top());
+      queue.pop();
+    }
+
+    for (auto i = vec.rbegin(); i != vec.rend(); ++i)
+    {
+      PtrT const p = *i;
+      LOG_SHORT(LINFO, (p->first, ":", p->second));
+    }
+  }
+};
+
+}  // namespace base