Question

I have a file path, gotten from the __FILE__ macro, and I want to extract 2 pieces from it.

The format is: /some/path/to/a/file/AAA/xxx/BBB.cc. I want the AAA and BBB path. xxx is generally src, inc, tst, etc, and the file extension is generally .cc, but not guaranteed.

I know I can use string.find() or even splitting the string into an array on the / character, but neither seem efficient, given the number of searches that would be needed. I thought about sscanf and feel that is probably the best approach, however, I have not been able to define the format such that it will skip the majority of the beginning and get the pieces I need. How could I use sscanf to do this, or is there a better way?

Thanks for the help.

Answer 1

Use rfind, so that you can start at the end and work backwards:

string s = "/some/path/to/a/file/AAA/xxx/BBB.cc";

unsigned int a = s.rfind('.');
unsigned int b = s.rfind('/');
string BBB = s.substr(b+1,a-b-1);

a = s.rfind('/',b-1);
b = s.rfind('/',a-1);  
string AAA = s.substr(b+1,a-b-1);