#! /bin/sh
#
#    Last change: Mihai Dima 2001
#
if [ $# -lt 7 ]
then
  echo " "
  echo "            *****     GAD2EXT     *****      "
  echo " "
  echo " The program transforms a GRADS file in an EXTRA file"
  echo " "
  echo " Syntax:"
  echo " "
  echo " gad2ext <x_dim> <ydim> <input_undef> <output_undef>"
  echo "         <start_date> <increment> <input_file>"
  echo " "
  exit 0
else
 echo " "
 echo "            *****     GAD2EXT     *****      "
 echo " "
 echo "Input file (GRADS)="$7
 echo "Output file (EXTRA)="$8
 cp $7 fort.1
fi
cat > gad2ext.f << EOF
      PROGRAM GAD2EXTX
      implicit none
      integer mxdim, nx,ny,dt,date,var,level,len,
     $     day,month,year,i,irec,ireal,j,rec
      parameter(mxdim=22000)
      real data(mxdim),udefi
      REAL odata(mxdim),udefo

C      data nx,ny,date,dt/ 148,74,1,100/
C      data udefi,udefo,level/ 0.9.e+10,0.9e+10,9999/
      ireal=4
c     -->  Read command inputs:
      read(5,*,end=10) nx,ny,udefi,udefo,date,dt
 10   continue
      print *,'nx=',nx,' ny=',ny
      print *,' udefi=',udefi,' udefo=',udefo
      print *,'date=',date,' dt=',dt
C      stop 'OK!'
      len=nx*ny
c     --> open files
      OPEN(1,form='unformatted',access='direct',recl=ireal*len)
c      OPEN(1,form='unformatted',access='direct',recl=1)
      OPEN(2,form='unformatted')

      level=9999
      var=nx*1000+1
      irec=1
      print*,'Using: date=',date,'  var=',var,'  level = ',level,
     $     '  len=',len,' delta t = ',dt
      print*, 'Input  undef = ',udefi,',  Extra file undef = ',udefo
c      rewind 1

c -------Start while-not-end-of-file unit 9:
 20   continue
         read(1,err=99,rec=irec) (data(i),i=1,len)
c      print*,'OK!'
      
c        --> Correct udef:
         do i=1,len
            if(abs(data(i)-udefi).lt.0.00001*abs(udefi)) then
               odata(i)=udefo
            else 
               odata(i)=data(i)
            endif
         enddo
c        --> Write Extra data record
         write(2) date,var,level,len
         write(2) ((odata(i+j*nx),i=1,nx),j=ny-1,0,-1)
         irec=irec+1
c        --> Compute new date
         date=date+dt
         month=mod(date,10000)/100
         year=date/10000
         day=mod(date,100)
         if(day.gt.30) month=month+1
         if(month.gt.12) year=year+1
         month=mod(month-1,12)+1
         day=mod(day-1,30)+1
         date=year*10000+month*100+day
      goto 20
 99   continue
      print*,irec-1,' records written.'
c ------End while loop
      print*, '----- normal end of gad2extx -----'
      stop
      end
EOF
f77 gad2ext.f -o gad2ext.x
gad2ext.x $7 << M
$1
$2
$3
$4
$5
$6
M
cp fort.2 $7.ext
rm fort.1 fort.2
rm gad2ext.x gad2ext.f
exit