Improve performance of type name demangling

[jacobperron]

Feature description

It was noticed in the addition of #266, that there was a performance hit, possibly due to the use of the regex library. See #266 (comment) for a discussion.

A simple benchmark is timing the rcl graph tests before and after applying the change:

for i in {1..10}; do; /usr/bin/time -o time.txt -a --format "%E" build/rcl/test/test_graph__rmw_fastrtps_cpp; done
cat time.txt

On my machine,
before: 03.06 seconds
after: 04.28 seconds

Implementation considerations

We should try replacing the usage of regex and cutting down on string copies (as suggested) to see if performance can be improved.

[jacobperron]

Closed by #488

[jacobperron]

I've compared the usage of std::regex_replace with an implementation based on std::string::replace (code) and the latter is significantly faster (~23x). But, after replacing all usage of regex_replace with my custom function in rmw_fastrtps I didn't notice any performance improvement. The regex calls must not be the culprit for the performance degradation.

[clalancette]

I've compared the usage of std::regex_replace with an implementation based on std::string::replace (code) and the latter is significantly faster (~23x). But, after replacing all usage of regex_replace with my custom function in rmw_fastrtps I didn't notice any performance improvement. The regex calls must not be the culprit for the performance degradation.

Good to know. I'm still in favor of doing this, but we can defer to later (and we'll have to figure out the other performance degradation).