nxtwin.f

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C> @file
C> @brief Computes the start and end indices of the next window.
C>
C> @author J. Woollen @date 1994-01-06
 
C> Given indices within the internal jump/link table which
C> point to the start and end of an "rpc" window (which is an iteration of
C> an 8-bit or 16-bit delayed replication sequence), this subroutine
C> computes the start and end indices of the next window.
C>
C> @note See getwin() for an explanation of "windows" within the
C> context of a bufr data subset.
C>
C> @param[in] LUN - integer: i/o stream index into internal memory arrays.
C> @param[inout] IWIN - integer:
C>  - on input, contains starting index of current window iteration.
C>  - on output, contains starting index of next window iteration.
C> @param[inout] JWIN - integer:
C>  - on input, contains ending index of current window iteration.
C>  - on output, contains ending index of next window iteration.
C>
C> @author J. Woollen @date 1994-01-06
      SUBROUTINE nxtwin(LUN,IWIN,JWIN)
 
      USE moda_usrint
 
      CHARACTER*128 BORT_STR
 
C----------------------------------------------------------------------
C----------------------------------------------------------------------
 
      IF(jwin.EQ.nval(lun)) THEN
         iwin = 0
         GOTO 100
      ENDIF
 
C  FIND THE NEXT SEQUENTIAL WINDOW
C  -------------------------------
 
      node = inv(iwin,lun)
      IF(lstjpb(node,lun,'RPC').NE.node) GOTO 900
      IF(val(jwin,lun).EQ.0) THEN
         iwin = 0
      ELSE
         iwin = jwin
         jwin = iwin+nint(val(iwin,lun))
      ENDIF
 
C  EXITS
C  -----
 
100   RETURN
900   WRITE(bort_str,'("BUFRLIB: NXTWIN - LSTJPB FOR NODE",I6," '//
     . '(LSTJPB=",I5,") DOES NOT EQUAL VALUE OF NODE, NOT RPC (IWIN '//
     . '=",I8,")")') node,lstjpb(node,lun,'RPC'),iwin
      CALL bort(bort_str)
      END