program convert_ocean_i8_to_i4

! Reads an oceanic restart file written by the CSIRO Mk3 GCM when using
! 64-bit integers, and writes the data out using 32-bit integers.
!
! Note:   This program must be compiled using -r8
!
! Usage:   convert_ocean_i8_to_i4 <input_file> <output_file>
!
! Steve Phipps   28 April 2003

  implicit none

  ! Define constants
  integer, parameter :: inunit=10, outunit=11, ntb=689060

  ! Declare variables
  character(len=80) :: infile, outfile
  integer(kind=8) :: itt
  real, dimension(ntb-1) :: data

  ! Get names of input and output files
  call getarg(1, infile)
  call getarg(2, outfile)

  ! Open input and output files
  open(unit=inunit, file=infile, status='old', form='unformatted', &
       action='read')
  open(unit=outunit, file=outfile, status='new', form='unformatted', &
       action='write')

  ! Read data from input file and write immediately to output file
  read (inunit) itt, data
  write (*, *) "itt = ", itt
  write (outunit) int(itt, 4), data

  ! Close input and output files
  close (unit=inunit)
  close (unit=outunit)

end program convert_ocean_i8_to_i4