SD log position

im starter of pixhawk.
anyway i want to know where is the code related to LASTLOG.txt (in SDcard)

where can i find this ??

im using eclipse and ArduCopter version is 3.5.7.
i already know that i can see datalogs in missionplanner’s datafrash.
but i want to import data in new textfile in SDcard,
thats why im asking.
once know the code (make LASTLOG.txt) than i can study myself.

here is my workspace.