hwrf-baseline-20111205-1743/ungrib/src/ngl/g2/gf_unpack4.f

   1       subroutine gf_unpack4(cgrib,lcgrib,iofst,ipdsnum,ipdstmpl,
   2      &                      mappdslen,coordlist,numcoord,ierr)
   3 !$$$  SUBPROGRAM DOCUMENTATION BLOCK
   4 !                .      .    .                                       .
   5 ! SUBPROGRAM:    gf_unpack4
   6 !   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2000-05-26
   7 !
   8 ! ABSTRACT: This subroutine unpacks Section 4 (Product Definition Section)
   9 !   starting at octet 6 of that Section.
  10 !
  11 ! PROGRAM HISTORY LOG:
  12 ! 2000-05-26  Gilbert
  13 ! 2002-01-24  Gilbert  - Changed to dynamically allocate arrays
  14 !                        and to pass pointers to those arrays through
  15 !                        the argument list.
  16 !
  17 ! USAGE:    CALL gf_unpack4(cgrib,lcgrib,iofst,ipdsnum,ipdstmpl,mappdslen,
  18 !    &                   coordlist,numcoord,ierr)
  19 !   INPUT ARGUMENT LIST:
  20 !     cgrib    - Character array that contains the GRIB2 message
  21 !     lcgrib   - Length (in bytes) of GRIB message array cgrib.
  22 !     iofst    - Bit offset of the beginning of Section 4.
  23 !
  24 !   OUTPUT ARGUMENT LIST:
  25 !     iofst    - Bit offset of the end of Section 4, returned.
  26 !     ipdsnum  - Product Definition Template Number ( see Code Table 4.0)
  27 !     ipdstmpl - Pointer to integer array containing the data values for
  28 !                the specified Product Definition
  29 !                Template ( N=ipdsnum ).  Each element of this integer
  30 !                array contains an entry (in the order specified) of Product
  31 !                Defintion Template 4.N
  32 !     mappdslen- Number of elements in ipdstmpl().  i.e. number of entries
  33 !                in Product Defintion Template 4.N  ( N=ipdsnum ).
  34 !     coordlist- Pointer to real array containing floating point values
  35 !                intended to document
  36 !                the vertical discretisation associated to model data
  37 !                on hybrid coordinate vertical levels.  (part of Section 4)
  38 !     numcoord - number of values in array coordlist.
  39 !     ierr     - Error return code.
  40 !                0 = no error
  41 !                5 = "GRIB" message contains an undefined Product Definition
  42 !                    Template.
  43 !                6 = memory allocation error
  44 !
  45 ! REMARKS: Uses Fortran 90 module pdstemplates and module re_alloc.
  46 !
  47 ! ATTRIBUTES:
  48 !   LANGUAGE: Fortran 90
  49 !   MACHINE:  IBM SP
  50 !
  51 !$$$
  52
  53       use pdstemplates
  54       use re_alloc        !  needed for subroutine realloc
  55
  56       character(len=1),intent(in) :: cgrib(lcgrib)
  57       integer,intent(in) :: lcgrib
  58       integer,intent(inout) :: iofst
  59       real,pointer,dimension(:) :: coordlist
  60       integer,pointer,dimension(:) :: ipdstmpl
  61       integer,intent(out) :: ipdsnum
  62       integer,intent(out) :: ierr,numcoord
  63
  64       real(4),allocatable :: coordieee(:)
  65       integer,allocatable :: mappds(:)
  66       integer :: mappdslen
  67       logical needext
  68
  69       ierr=0
  70       nullify(ipdstmpl,coordlist)
  71
  72       call gbyte(cgrib,lensec,iofst,32)        ! Get Length of Section
  73       iofst=iofst+32
  74       iofst=iofst+8     ! skip section number
  75       allocate(mappds(lensec))
  76
  77       call gbyte(cgrib,numcoord,iofst,16)    ! Get num of coordinate values
  78       iofst=iofst+16
  79       call gbyte(cgrib,ipdsnum,iofst,16)    ! Get Prod. Def Template num.
  80       iofst=iofst+16
  81       !   Get Product Definition Template
  82       call getpdstemplate(ipdsnum,mappdslen,mappds,needext,iret)
  83       if (iret.ne.0) then
  84         ierr=5
  85         if( allocated(mappds) ) deallocate(mappds)
  86         return
  87       endif
  88       !
  89       !   Unpack each value into array ipdstmpl from the
  90       !   the appropriate number of octets, which are specified in
  91       !   corresponding entries in array mappds.
  92       !
  93       istat=0
  94       if (mappdslen.gt.0) allocate(ipdstmpl(mappdslen),stat=istat)
  95       if (istat.ne.0) then
  96          ierr=6
  97          nullify(ipdstmpl)
  98          if( allocated(mappds) ) deallocate(mappds)
  99          return
 100       endif
 101       do i=1,mappdslen
 102         nbits=iabs(mappds(i))*8
 103         if ( mappds(i).ge.0 ) then
 104           call gbyte(cgrib,ipdstmpl(i),iofst,nbits)
 105         else
 106           call gbyte(cgrib,isign,iofst,1)
 107           call gbyte(cgrib,ipdstmpl(i),iofst+1,nbits-1)
 108           if (isign.eq.1) ipdstmpl(i)=-ipdstmpl(i)
 109         endif
 110         iofst=iofst+nbits
 111       enddo
 112       !
 113       !   Check to see if the Product Definition Template needs to be
 114       !   extended.
 115       !   The number of values in a specific template may vary
 116       !   depending on data specified in the "static" part of the
 117       !   template.
 118       !
 119       if ( needext ) then
 120         call extpdstemplate(ipdsnum,ipdstmpl,newmappdslen,mappds)
 121         call realloc(ipdstmpl,mappdslen,newmappdslen,istat)
 122         !   Unpack the rest of the Product Definition Template
 123         do i=mappdslen+1,newmappdslen
 124           nbits=iabs(mappds(i))*8
 125           if ( mappds(i).ge.0 ) then
 126             call gbyte(cgrib,ipdstmpl(i),iofst,nbits)
 127           else
 128             call gbyte(cgrib,isign,iofst,1)
 129             call gbyte(cgrib,ipdstmpl(i),iofst+1,nbits-1)
 130             if (isign.eq.1) ipdstmpl(i)=-ipdstmpl(i)
 131           endif
 132           iofst=iofst+nbits
 133         enddo
 134         mappdslen=newmappdslen
 135       endif
 136       if( allocated(mappds) ) deallocate(mappds)
 137       !
 138       !   Get Optional list of vertical coordinate values
 139       !   after the Product Definition Template, if necessary.
 140       !
 141       nullify(coordlist)
 142       if ( numcoord .ne. 0 ) then
 143          allocate (coordieee(numcoord),stat=istat1)
 144          allocate(coordlist(numcoord),stat=istat)
 145          if ((istat1+istat).ne.0) then
 146             ierr=6
 147             nullify(coordlist)
 148             if( allocated(coordieee) ) deallocate(coordieee)
 149             return
 150          endif
 151         call gbytes(cgrib,coordieee,iofst,32,0,numcoord)
 152         call rdieee(coordieee,coordlist,numcoord)
 153         deallocate (coordieee)
 154         iofst=iofst+(32*numcoord)
 155       endif
 156
 157       return    ! End of Section 4 processing
 158       end
 159