module drstemplates
!$$$  SUBPROGRAM DOCUMENTATION BLOCK
!                .      .    .                                       .
! MODULE:    drstemplates 
!   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2001-04-03
!
! ABSTRACT: This Fortran Module contains info on all the available 
!   GRIB2 Data Representation Templates used in Section 5 (DRS).
!   Each Template has three parts: The number of entries in the template
!   (mapgridlen);  A map of the template (mapgrid), which contains the
!   number of octets in which to pack each of the template values; and
!   a logical value (needext) that indicates whether the Template needs 
!   to be extended.  In some cases the number of entries in a template 
!   can vary depending upon values specified in the "static" part of 
!   the template.  ( See Template 5.1 as an example )
!
!   This module also contains two subroutines.  Subroutine getdrstemplate
!   returns the octet map for a specified Template number, and
!   subroutine extdrstemplate will calculate the extended octet map
!   of an appropriate template given values for the "static" part of the 
!   template.  See docblocks below for the arguments and usage of these 
!   routines.
!
!   NOTE:  Array mapgrid contains the number of octets in which the 
!   corresponding template values will be stored.  A negative value in
!   mapgrid is used to indicate that the corresponding template entry can
!   contain negative values.  This information is used later when packing
!   (or unpacking) the template data values.  Negative data values in GRIB
!   are stored with the left most bit set to one, and a negative number
!   of octets value in mapgrid() indicates that this possibility should
!   be considered.  The number of octets used to store the data value
!   in this case would be the absolute value of the negative value in 
!   mapgrid().
!  
!
! PROGRAM HISTORY LOG:
! 2000-05-11  Gilbert
! 2002-12-11  Gilbert - Added templates for JPEG2000 and PNG encoding
!
! USAGE:    use drstemplates
!
! ATTRIBUTES:
!   LANGUAGE: Fortran 90
!   MACHINE:  IBM SP
!
!$$$

      integer,parameter :: MAXLEN=200,MAXTEMP=9

      type drstemplate
          integer :: template_num
          integer :: mapdrslen
          integer,dimension(MAXLEN) :: mapdrs
          logical :: needext
      end type drstemplate

      type(drstemplate),dimension(MAXTEMP) :: templates

      data templates(1)%template_num /0/     !  Simple Packing
      data templates(1)%mapdrslen /5/ 
      data templates(1)%needext /.false./
      data (templates(1)%mapdrs(j),j=1,5) 
     &                             /4,-2,-2,1,1/

      data templates(2)%template_num /2/     !  Complex Packing
      data templates(2)%mapdrslen /16/
      data templates(2)%needext /.false./
      data (templates(2)%mapdrs(j),j=1,16)
     &                        /4,-2,-2,1,1,1,1,4,4,4,1,1,4,1,4,1/

      data templates(3)%template_num /3/     !  Complex Packing - Spatial Diff
      data templates(3)%mapdrslen /18/
      data templates(3)%needext /.false./
      data (templates(3)%mapdrs(j),j=1,18)
     &                        /4,-2,-2,1,1,1,1,4,4,4,1,1,4,1,4,1,1,1/

      data templates(4)%template_num /50/     !  Simple Packing - Spectral Data
      data templates(4)%mapdrslen /5/
      data templates(4)%needext /.false./
      data (templates(4)%mapdrs(j),j=1,5)
     &                         /4,-2,-2,1,4/

      data templates(5)%template_num /51/    !  Complex Packing - Spectral Data
      data templates(5)%mapdrslen /10/
      data templates(5)%needext /.false./
      data (templates(5)%mapdrs(j),j=1,10)
     &                         /4,-2,-2,1,-4,2,2,2,4,1/

      data templates(6)%template_num /40000/     !  JPEG2000 Encoding
      data templates(6)%mapdrslen /7/ 
      data templates(6)%needext /.false./
      data (templates(6)%mapdrs(j),j=1,7) 
     &                             /4,-2,-2,1,1,1,1/

      data templates(7)%template_num /40010/     !  PNG Encoding
      data templates(7)%mapdrslen /5/ 
      data templates(7)%needext /.false./
      data (templates(7)%mapdrs(j),j=1,5) 
     &                             /4,-2,-2,1,1/

      data templates(8)%template_num /40/     !  JPEG2000 Encoding
      data templates(8)%mapdrslen /7/ 
      data templates(8)%needext /.false./
      data (templates(8)%mapdrs(j),j=1,7) 
     &                             /4,-2,-2,1,1,1,1/

      data templates(9)%template_num /41/     !  PNG Encoding
      data templates(9)%mapdrslen /5/ 
      data templates(9)%needext /.false./
      data (templates(9)%mapdrs(j),j=1,5) 
     &                             /4,-2,-2,1,1/

!      data templates(5)%template_num /1/      !  Simple Packing - Matrix
!      data templates(5)%mapdrslen /15/ 
!      data templates(5)%needext /.true./
!      data (templates(5)%mapdrs(j),j=1,15)
!     &                        /4,-2,-2,1,1,1,4,2,2,1,1,1,1,1,1/


      contains

         integer function getdrsindex(number)
!$$$  SUBPROGRAM DOCUMENTATION BLOCK
!                .      .    .                                       .
! SUBPROGRAM:    getdrsindex 
!   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2001-06-28
!
! ABSTRACT: This function returns the index of specified Data 
!   Representation Template 5.NN (NN=number) in array templates.
!
! PROGRAM HISTORY LOG:
! 2001-06-28  Gilbert
!
! USAGE:    index=getdrsindex(number)
!   INPUT ARGUMENT LIST:
!     number   - NN, indicating the number of the Data Representation 
!                Template 5.NN that is being requested.
!
! RETURNS:  Index of DRT 5.NN in array templates, if template exists.
!           = -1, otherwise.
!
! REMARKS: None
!
! ATTRIBUTES:
!   LANGUAGE: Fortran 90
!   MACHINE:  IBM SP
!
!$$$
           integer,intent(in) :: number

           getdrsindex=-1

           do j=1,MAXTEMP
              if (number.eq.templates(j)%template_num) then
                 getdrsindex=j
                 return
              endif
           enddo

         end function


         subroutine getdrstemplate(number,nummap,map,needext,iret)
!$$$  SUBPROGRAM DOCUMENTATION BLOCK
!                .      .    .                                       .
! SUBPROGRAM:    getdrstemplate 
!   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2000-05-11
!
! ABSTRACT: This subroutine returns DRS template information for a 
!   specified Data Representation Template 5.NN.
!   The number of entries in the template is returned along with a map
!   of the number of octets occupied by each entry.  Also, a flag is
!   returned to indicate whether the template would need to be extended.
!
! PROGRAM HISTORY LOG:
! 2000-05-11  Gilbert
!
! USAGE:    CALL getdrstemplate(number,nummap,map,needext,iret)
!   INPUT ARGUMENT LIST:
!     number   - NN, indicating the number of the Data Representation 
!                Template 5.NN that is being requested.
!
!   OUTPUT ARGUMENT LIST:      
!     nummap   - Number of entries in the Template
!     map()    - An array containing the number of octets that each 
!                template entry occupies when packed up into the DRS.
!     needext  - Logical variable indicating whether the Data Representation
!                Template has to be extended.  
!     ierr     - Error return code.
!                0 = no error
!                1 = Undefined Data Representation Template number.
!
! REMARKS: None
!
! ATTRIBUTES:
!   LANGUAGE: Fortran 90
!   MACHINE:  IBM SP
!
!$$$
           integer,intent(in) :: number
           integer,intent(out) :: nummap,map(*),iret
           logical,intent(out) :: needext

           iret=0

           index=getdrsindex(number)

           if (index.ne.-1) then
              nummap=templates(index)%mapdrslen
              needext=templates(index)%needext
              map(1:nummap)=templates(index)%mapdrs(1:nummap)
           else
             nummap=0
             needext=.false.
             print *,'getdrstemplate: DRS Template ',number,
     &               ' not defined.'
             iret=1
           endif

         end subroutine

         subroutine extdrstemplate(number,list,nummap,map)
!$$$  SUBPROGRAM DOCUMENTATION BLOCK
!                .      .    .                                       .
! SUBPROGRAM:    extdrstemplate 
!   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2000-05-11
!
! ABSTRACT: This subroutine generates the remaining octet map for a
!   given Data Representation Template, if required.  Some Templates can
!   vary depending on data values given in an earlier part of the 
!   Template, and it is necessary to know some of the earlier entry
!   values to generate the full octet map of the Template.
!
! PROGRAM HISTORY LOG:
! 2000-05-11  Gilbert
!
! USAGE:    CALL extdrstemplate(number,list,nummap,map)
!   INPUT ARGUMENT LIST:
!     number   - NN, indicating the number of the Data Representation 
!                Template 5.NN that is being requested.
!     list()   - The list of values for each entry in the 
!                the Data Representation Template 5.NN.
!
!   OUTPUT ARGUMENT LIST:      
!     nummap   - Number of entries in the Template
!     map()    - An array containing the number of octets that each 
!                template entry occupies when packed up into the GDS.
!
! ATTRIBUTES:
!   LANGUAGE: Fortran 90
!   MACHINE:  IBM SP
!
!$$$
           integer,intent(in) :: number,list(*)
           integer,intent(out) :: nummap,map(*)

           index=getdrsindex(number)
           if (index.eq.-1) return

           if ( .not. templates(index)%needext ) return
           nummap=templates(index)%mapdrslen
           map(1:nummap)=templates(index)%mapdrs(1:nummap)

           if ( number.eq.1 ) then
              N=list(11)+list(13)
              do i=1,N
                map(nummap+i)=4
              enddo
              nummap=nummap+N
           endif

         end subroutine

      end module