How to extract the leftover substring from strrchr() or strchr()?

Question

Let's say I have the following string which looks like a file path:

 char *filepath = "this/is/my/path/to/file.jpg";

I can use strrchr() to extract file.jpg as follows:

 char *filename =  strrchr(filepath, '/') + 1;

Now I need to extract and store the rest of the string this/is/my/path/to. How do I do that in the most effective manner? Please note that I would like to avoid using strtok()or regex or big iterative loops.

It will be very nice if:

I can apply the same the substring extraction technique to strchr() where I have extracted the substring this using strchr(filepath, '/') and now I need to extract the rest of the substring is/my/path/to/file.jpg

Answer 1

Copy everything up to the file name, then append a '\0' :

int   pathLen = filename - filepath;
char *path = (char *) malloc(pathLen + 1);
memcpy(path, filepath, pathLen);
path[pathLen] = '\0';

...

free(path);

Answer 2

If your string is in writable memory (ie, not a string literal) you can do this

char *p =  strrchr(filepath, '/');
*p = '\0';
char *filename = p + 1;

this will give you filepath pointing at "this/is/my/path/to" and filename pointing at "file.jpg". Without any copying.