! +-======-+ 
!  Copyright (c) 2003-2007 United States Government as represented by 
!  the Admistrator of the National Aeronautics and Space Administration.  
!  All Rights Reserved.
!  
!  THIS OPEN  SOURCE  AGREEMENT  ("AGREEMENT") DEFINES  THE  RIGHTS  OF USE,
!  REPRODUCTION,  DISTRIBUTION,  MODIFICATION AND REDISTRIBUTION OF CERTAIN 
!  COMPUTER SOFTWARE ORIGINALLY RELEASED BY THE UNITED STATES GOVERNMENT AS 
!  REPRESENTED BY THE GOVERNMENT AGENCY LISTED BELOW ("GOVERNMENT AGENCY").  
!  THE UNITED STATES GOVERNMENT, AS REPRESENTED BY GOVERNMENT AGENCY, IS AN 
!  INTENDED  THIRD-PARTY  BENEFICIARY  OF  ALL  SUBSEQUENT DISTRIBUTIONS OR 
!  REDISTRIBUTIONS  OF THE  SUBJECT  SOFTWARE.  ANYONE WHO USES, REPRODUCES, 
!  DISTRIBUTES, MODIFIES  OR REDISTRIBUTES THE SUBJECT SOFTWARE, AS DEFINED 
!  HEREIN, OR ANY PART THEREOF,  IS,  BY THAT ACTION, ACCEPTING IN FULL THE 
!  RESPONSIBILITIES AND OBLIGATIONS CONTAINED IN THIS AGREEMENT.
!  
!  Government Agency: National Aeronautics and Space Administration
!  Government Agency Original Software Designation: GSC-15354-1
!  Government Agency Original Software Title:  GEOS-5 GCM Modeling Software
!  User Registration Requested.  Please Visit http://opensource.gsfc.nasa.gov
!  Government Agency Point of Contact for Original Software:  
!  			Dale Hithon, SRA Assistant, (301) 286-2691
!  
! +-======-+ 
program endian_convert
  implicit none
  
  real, pointer :: var(:)

  integer :: i, bpos, epos, status
  integer :: rsize
  character(128) :: str, f_in, f_out
  integer*4 :: ftell
  external  :: ftell

  integer*4 :: iargc
  external  :: iargc

! Begin

  if (iargc() /= 2) then
     call getarg(0,str)
     write(*,*) "Usage:",trim(str)," <big_endian_in> <native_out>"
     call exit(2)
  end if

  call getarg(1,f_in)
  call getarg(2,f_out)

  open(unit=10, file=trim(f_in),  form='unformatted', convert="big_endian")
  open(unit=20, file=trim(f_out), form='unformatted', convert="native")

  print *,'Converting File: ',trim(f_in)

  bpos=0
  do 
     read(10, end=100, err=200) ! skip to next record
     epos = ftell(10)          ! ending position of file pointer
     backspace(10)
     
     rsize = (epos-bpos)/4-2   ! record size (in 4 byte words; 
                               ! 2 is the number of fortran control words)
     bpos=epos
     allocate(var(rsize), stat=status)
     if (status  /= 0) then
        print *, 'Error: allocation ', rsize, ' failed!'
        call exit(11)
     end if

     read (10) var
     write(20) var
     deallocate(var)
  end do

100 continue
  close(10)
  close(20)
  stop

200 print *,'Error reading file ',trim(f_in)
    call exit(11)

end