module fileutils

!-----------------------------------------------------------------------
!BOP
!
! !MODULE: fileutils
!
! !DESCRIPTION:
! Module containing file I/O utilities
!
! !USES:
  use clm_varctl,  only : iulog
  use shr_sys_mod, only : shr_sys_abort
!
! !PUBLIC TYPES:
  implicit none
  save
!
! !PUBLIC MEMBER FUNCTIONS:
  public :: get_filename  !Returns filename given full pathname
  public :: opnfil        !Open local unformatted or formatted file
  public :: getfil        !Obtain local copy of file
  public :: relavu        !Close and release Fortran unit no longer in use
  public :: getavu        !Get next available Fortran unit number
!
! !REVISION HISTORY:
! Created by Mariana Vertenstein
!
!
! !PRIVATE MEMBER FUNCTIONS: None
!EOP
!-----------------------------------------------------------------------

contains

!-----------------------------------------------------------------------
!BOP
!
! !IROUTINE: get_filename
!
! !INTERFACE:
  character(len=256) function get_filename (fulpath)
!
! !DESCRIPTION:
! Returns filename given full pathname
!
! !ARGUMENTS:
    implicit none
    character(len=*), intent(in)  :: fulpath !full pathname
!
! !REVISION HISTORY:
! Created by Mariana Vertenstein
!
!
! !LOCAL VARIABLES:
!EOP
    integer i               !loop index
    integer klen            !length of fulpath character string
!------------------------------------------------------------------------

    klen = len_trim(fulpath)
    do i = klen, 1, -1
       if (fulpath(i:i) == '/') go to 10
    end do
    i = 0
10  get_filename = fulpath(i+1:klen)

    return
  end function get_filename

!------------------------------------------------------------------------
!BOP
!
! !IROUTINE: getfil
!
! !INTERFACE:
   subroutine getfil (fulpath, locfn, iflag)
!
! !DESCRIPTION:
! Obtain local copy of file
! First check current working directory
! Next check full pathname[fulpath] on disk
! 
! !USES:
     use shr_file_mod, only: shr_file_get
! !ARGUMENTS:
     implicit none
     character(len=*), intent(in)  :: fulpath !Archival or permanent disk full pathname
     character(len=*), intent(out) :: locfn   !output local file name
     integer, optional, intent(in) :: iflag   !0=>abort if file not found 1=>do not abort
!
! !REVISION HISTORY:
! Created by Mariana Vertenstein
!
!
! !LOCAL VARIABLES:
!EOP
     integer i               !loop index
     integer klen            !length of fulpath character string
     logical lexist          !true if local file exists
!------------------------------------------------------------------------

     ! get local file name from full name

     locfn = get_filename( fulpath )
     if (len_trim(locfn) == 0) then
	write(iulog,*)'(GETFIL): local filename has zero length'
        call shr_sys_abort
     else
        write(iulog,*)'(GETFIL): attempting to find local file ',  &
             trim(locfn)
     endif

     ! first check if file is in current working directory.

     inquire (file=locfn,exist=lexist)
     if (lexist) then
        write(iulog,*) '(GETFIL): using ',trim(locfn), &
             ' in current working directory'
        RETURN
     endif

     ! second check for full pathname on disk
     locfn = fulpath

     inquire (file=fulpath,exist=lexist)
     if (lexist) then
        write(iulog,*) '(GETFIL): using ',trim(fulpath)
        RETURN
     else
        write(iulog,*)'(GETFIL): failed getting file from full path: ', fulpath
        if (present(iflag) .and. iflag==0) then
           call shr_sys_abort ('GETFIL: FAILED to get '//trim(fulpath))
        else
           RETURN
        endif
     endif

   end subroutine getfil

!------------------------------------------------------------------------
!BOP
!
! !IROUTINE: opnfil
!
! !INTERFACE:
   subroutine opnfil (locfn, iun, form)
!
! !DESCRIPTION:
! Open file locfn in unformatted or formatted form on unit iun
!
! !ARGUMENTS:
!
     implicit none
     character(len=*), intent(in):: locfn  !file name
     integer, intent(in):: iun             !fortran unit number
     character(len=1), intent(in):: form   !file format: u = unformatted,
                                           !f = formatted
!
! !REVISION HISTORY:
! Created by Mariana Vertenstein
!
!
! !LOCAL VARIABLES:
!EOP
     integer ioe             !error return from fortran open
     character(len=11) ft    !format type: formatted. unformatted
!------------------------------------------------------------------------

     if (len_trim(locfn) == 0) then
        write(iulog,*)'(OPNFIL): local filename has zero length'
        call shr_sys_abort
     endif
     if (form=='u' .or. form=='U') then
        ft = 'unformatted'
     else
        ft = 'formatted  '
     end if
     open (unit=iun,file=locfn,status='unknown',form=ft,iostat=ioe)
     if (ioe /= 0) then
        write(iulog,*)'(OPNFIL): failed to open file ',trim(locfn),        &
             &     ' on unit ',iun,' ierr=',ioe
        call shr_sys_abort
     else
        write(iulog,*)'(OPNFIL): Successfully opened file ',trim(locfn),   &
             &     ' on unit= ',iun
     end if

   end subroutine opnfil

!------------------------------------------------------------------------
!BOP
!
! !IROUTINE: getavu
!
! !INTERFACE:
  integer function getavu()
!
! !DESCRIPTION:
! Get next available Fortran unit number.
!
! !USES:
   use shr_file_mod, only : shr_file_getUnit
!
! !ARGUMENTS:
    implicit none
!
! !REVISION HISTORY:
! Created by Gordon Bonan
! Modified for clm2 by Mariana Vertenstein
!
!
! !LOCAL VARIABLES:
!EOP
!------------------------------------------------------------------------

    getavu = shr_file_getunit()

  end function getavu

!------------------------------------------------------------------------
!BOP
!
! !IROUTINE: relavu
!
! !INTERFACE:
  subroutine relavu (iunit)
!
! !DESCRIPTION:
! Close and release Fortran unit no longer in use!
!
! !USES:
   use shr_file_mod, only : shr_file_freeUnit
!
! !ARGUMENTS:
    implicit none
    integer, intent(in) :: iunit    !Fortran unit number
!
! !REVISION HISTORY:
! Created by Gordon Bonan
!
!EOP
!------------------------------------------------------------------------

    close(iunit)
    call shr_file_freeUnit(iunit)

  end subroutine relavu

end module fileutils