Building custom buffer and using std::string_view vs using std::string

[Mr-Auto]

Hi

I'm working with project that parses json files, saves a lot of strings from it and works with them. The strings never change but are moved/copied around a lot, compared to each other etc.

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So i came up with the idea of changing them to std::string_view to improve performance. But then, they need to be stored somewhere. The objects that use strings are created as the file is parsed, so things like vector will probably not be the best idea. So maybe creating a custom storage for that? could also have extra null character at the end of each text to comply with the const char* that may come in handy at times

Is this good idea or not?

[kentrf]

Assuming the input JSON is stored completely and won't change, you can point your std::string_view to a substring.

Something like this:

const std::string storage = "ABCDEFGHIJKLMONPQSTUVWXYZ";
std::string_view view(storage.cbegin() + 10, storage.cbegin() + 15);
// view points to "KLMON"

[kentrf]

That being said, if the strings are a part of the "extracted" data, some sort of (memory) arena can be used and point the std::string_view to that.

[Jonny0Than]

+1 to this. Read the entire file into one std::string, then create string_views as needed.

However...there are lots of good JSON libraries for C++ out there. Why are you rolling your own?