Refactor package using C++17 API

[RyuYamamoto]

Hi,

Now C++17 is available, so I'm thinking that I should try to replace code that could be replaced with latest function.

For example, I think the part that loads multiple PCDs with pointcloud_map_loader could be replaced with std::filesystem available from C++17.
https://github.com/autowarefoundation/autoware.universe/blob/main/map/map_loader/src/pointcloud_map_loader/pointcloud_map_loader_node.cpp#L72-L89

I haven't looked at the other parts that could be replaced yet, but is it no problem if I send PullRequest if I found something that could be fixed?
(If you know other parts in package of autoware.universe that could replaced , I would appreciate it if you could tell me.)

[kenji-miyake]

@RyuYamamoto Yes, it's super nice!!!
Regarding other features, I think many Boost dependencies such as optional can be replaced with std.

[RyuYamamoto]

Thanks for the reply and sharing the info.
sure, boost can be replaced by some std functions. I will try to check autoware packages!

[kenji-miyake]

boost::mutex
https://github.com/autowarefoundation/autoware.universe/blob/e07f8c715bcbf03d48ac5d20391bc78842fbafa1/sensing/pointcloud_preprocessor/src/crop_box_filter/crop_box_filter_nodelet.cpp#L96

[RyuYamamoto]

maybe can replace boost::filesystem to std::filesystem in system_monitor packages.
https://github.com/autowarefoundation/autoware.universe/blob/main/system/system_monitor/include/system_monitor/system_monitor_utility.hpp#L32

[TakaHoribe]

This must be super nice work.

[RyuYamamoto]

Probably , some of system_monitor packages can be replaced boost:filesystem to std::filesystem.

https://github.com/autowarefoundation/autoware.universe/blob/1bab84e75e6a6b750b5781212b04702b7646616f/system/system_monitor/src/cpu_monitor/raspi_cpu_monitor.cpp#L30
https://github.com/autowarefoundation/autoware.universe/blob/8db33518a31bd7cd56cf9aedab9c19c82282bcea/system/system_monitor/src/ntp_monitor/ntp_monitor.cpp#L34
https://github.com/autowarefoundation/autoware.universe/blob/de8deed8e45177298fe34fbdbf46f7aafead7316/system/system_monitor/src/gpu_monitor/tegra_gpu_monitor.cpp#L33
https://github.com/autowarefoundation/autoware.universe/blob/1bab84e75e6a6b750b5781212b04702b7646616f/system/system_monitor/src/cpu_monitor/intel_cpu_monitor.cpp#L39

etc...