Function patallocstr 

pub fn patallocstr(
    prog: &Patprog,
    string: &str,
    stringlen: i32,
    unmetalen: i32,
    force: i32,
    patstralloc: &mut patstralloc,
) -> Option<String>

Port of char *patallocstr(Patprog prog, char *string, int stringlen, int unmetalen, int force, Patstralloc patstralloc) from Src/pattern.c:2132.

Sets up patstralloc for a match attempt: when force is set or the input contains Meta bytes (or PAT_HAS_EXCLUDP demands a full-path copy), allocates an un-metafied scratch buffer and stashes pointer/length info on patstralloc. Returns the allocated buffer or None if no allocation was needed.