remove uses of using namespace std::chrono

dlib/dnn/trainer.h

@@ -310,15 +310,14 @@ namespace dlib
  epoch_iteration < max_num_epochs && learning_rate >= min_learning_rate; 
  ++epoch_iteration)
  {
- using namespace std::chrono;
- last_time = system_clock::now();
+ last_time = std::chrono::system_clock::now();
  clear_average_loss();
  for (; epoch_pos < data.size() && learning_rate >= min_learning_rate; epoch_pos += mini_batch_size)
  {
  if (verbose)
  {
- auto now_time = system_clock::now();
- if (now_time-last_time > seconds(20))
+ auto now_time = std::chrono::system_clock::now();
+ if (now_time-last_time > std::chrono::seconds(20))
  {
  last_time = now_time;
  auto iter = epoch_iteration + epoch_pos/(double)data.size();
@@ -368,15 +367,14 @@ namespace dlib
  epoch_iteration < max_num_epochs && learning_rate >= min_learning_rate; 
  ++epoch_iteration)
  {
- using namespace std::chrono;
- last_time = system_clock::now();
+ last_time = std::chrono::system_clock::now();
  clear_average_loss();
  for (; epoch_pos < data.size() && learning_rate >= min_learning_rate; epoch_pos += mini_batch_size)
  {
  if (verbose)
  {
- auto now_time = system_clock::now();
- if (now_time-last_time > seconds(20))
+ auto now_time = std::chrono::system_clock::now();
+ if (now_time-last_time > std::chrono::seconds(20))
  {
  last_time = now_time;
  auto iter = epoch_iteration + epoch_pos/(double)data.size();
@@ -1266,9 +1264,8 @@ namespace dlib
  {
  if (verbose)
  {
- using namespace std::chrono;
- auto now_time = system_clock::now();
- if (now_time-last_time > seconds(40))
+ auto now_time = std::chrono::system_clock::now();
+ if (now_time-last_time > std::chrono::seconds(40))
  {
  last_time = now_time;
  std::cout << "step#: " << rpad(cast_to_string(train_one_step_calls),epoch_string_pad) << " " 

dlib/global_optimization/find_max_global.h

@@ -177,7 +177,7 @@ template <typename T> static auto go(T&& f, const matrix<double, 0, 1>& a) -> de
 
  running_stats_decayed<double> objective_funct_eval_time(functions.size()*5);
  std::mutex eval_time_mutex;
- using namespace std::chrono;
+ using std::chrono::steady_clock, std::chrono::duration_cast, std::chrono::nanoseconds;
 
  const auto time_to_stop = steady_clock::now() + max_runtime;
  //atomic<bool> doesn't support .fetch_or, use std::atomic<int> instead

dlib/media/ffmpeg_demuxer.h

@@ -4,6 +4,7 @@
 #ifndef DLIB_FFMPEG_DEMUXER
 #define DLIB_FFMPEG_DEMUXER
 
+#include <chrono>
 #include <queue>
 #include <functional>
 #include <unordered_map>
@@ -995,8 +996,8 @@ namespace dlib
  Callback&& clb
  )
  {
- using namespace std::chrono;
  using namespace details;
+ using std::chrono::system_clock, std::chrono::duration_cast, std::chrono::nanoseconds;
 
  const auto send_packet = [&](extract_state& state)
  {
@@ -1232,8 +1233,8 @@ namespace dlib
 
  inline bool demuxer::open(const args& a)
  {
- using namespace std::chrono;
  using namespace details;
+ using std::chrono::system_clock;
 
  details::register_ffmpeg();
 

dlib/media/ffmpeg_muxer.h

@@ -4,6 +4,7 @@
 #ifndef DLIB_VIDEO_MUXER
 #define DLIB_VIDEO_MUXER
 
+#include <chrono>
 #include <queue>
 #include <functional>
 #include <unordered_map>
@@ -1016,7 +1017,6 @@ namespace dlib
  Callback&& clb
  )
  {
- using namespace std::chrono;
  using namespace details;
 
  if (!is_open())
@@ -1212,8 +1212,8 @@ namespace dlib
 
  inline bool muxer::open(const args& a)
  {
- using namespace std::chrono;
  using namespace details;
+ using std::chrono::system_clock;
 
  st = {};
  st.args_ = a;

dlib/media/ffmpeg_utils.h

@@ -807,8 +807,8 @@ namespace dlib
  frame& dst
  )
  {
- using namespace std::chrono;
  using namespace details;
+ using std::chrono::system_clock;
 
  DLIB_CASSERT(src.is_audio(), "src.is_audio() == false");
 
@@ -896,7 +896,7 @@ namespace dlib
  frame&& in
  )
  {
- using namespace std::chrono;
+ using std::chrono::system_clock;
  DLIB_ASSERT(in.is_audio(), "this isn't an audio frame");
 
  std::vector<frame> outs;

dlib/timing.h

@@ -98,7 +98,7 @@ namespace dlib
 
  inline uint64_t ts()
  {
- using namespace std::chrono;
+ using std::chrono::duration_cast, std::chrono::duration, std::chrono::high_resolution_clock;
  return duration_cast<duration<double,std::nano>>(high_resolution_clock::now().time_since_epoch()).count();
  }