canon_path Function

public function canon_path(path)

Canonicalize path for comparison * Handles path string redundancies * Does not test existence of path

To be replaced by realpath/_fullname in stdlib_os

FIXME: Lot’s of ugly hacks following here

Arguments

Type IntentOptional Attributes Name
character(len=*), intent(in) :: path

Return Value character(len=:), allocatable


Contents

Source Code

canon_path

Source Code

function canon_path(path)
    character(len=*), intent(in) :: path
    character(len=:), allocatable :: canon_path
    character(len=:), allocatable :: nixpath

    integer :: istart, iend, nn, last
    logical :: is_path, absolute

    nixpath = unix_path(path)

    istart = 0
    nn = 0
    iend = 0
    absolute = nixpath(1:1) == "/"
    if (absolute) then
        canon_path = "/"
    else
        canon_path = ""
    end if

    do while(iend < len(nixpath))
        call next(nixpath, istart, iend, is_path)
        if (is_path) then
            select case(nixpath(istart:iend))
            case(".", "") ! always drop empty paths
            case("..")
                if (nn > 0) then
                    last = scan(canon_path(:len(canon_path)-1), "/", back=.true.)
                    canon_path = canon_path(:last)
                    nn = nn - 1
                else
                    if (.not. absolute) then
                        canon_path = canon_path // nixpath(istart:iend) // "/"
                    end if
                end if
            case default
                nn = nn + 1
                canon_path = canon_path // nixpath(istart:iend) // "/"
            end select
        end if
    end do

    if (len(canon_path) == 0) canon_path = "."
    if (len(canon_path) > 1 .and. canon_path(len(canon_path):) == "/") then
        canon_path = canon_path(:len(canon_path)-1)
    end if

contains

    subroutine next(string, istart, iend, is_path)
        character(len=*), intent(in) :: string
        integer, intent(inout) :: istart
        integer, intent(inout) :: iend
        logical, intent(inout) :: is_path

        integer :: ii, nn
        character :: tok

        nn = len(string)

        if (iend >= nn) then
            istart = nn
            iend = nn
            return
        end if

        ii = min(iend + 1, nn)
        tok = string(ii:ii)

        is_path = tok /= '/'

        if (.not.is_path) then
            is_path = .false.
            istart = ii
            iend = ii
            return
        end if

        istart = ii
        do ii = min(iend + 1, nn), nn
            tok = string(ii:ii)
            select case(tok)
            case('/')
                exit
            case default
                iend = ii
                cycle
            end select
        end do

    end subroutine next
end function canon_path