Procedure

     IDW2AT ( Get file architecture and type from ID word )

     SUBROUTINE IDW2AT ( IDWORD, ARCH, TYPE )

Abstract

     Extract the architecture and type of a SPICE binary kernel file
     from a file ID word.

Required_Reading

     None.

Keywords

     KERNEL
     UTILITY

Declarations

     IMPLICIT NONE

     CHARACTER*(*)         IDWORD
     CHARACTER*(*)         ARCH
     CHARACTER*(*)         TYPE

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     IDWORD     I   The IDWORD to be examined.
     ARCH       O   The file architecture DAS or DAF.
     TYPE       O   The type of the file.

Detailed_Input

     IDWORD   is the ID word from a SPICE binary kernel file or a
              text version of a binary kernel file whose
              architecture and type are to be extracted.

Detailed_Output

     ARCH     is the file architecture used to store the data in
              a SPICE binary kernel file. If the architecture cannot
              be extracted or is not recognized the value '?' is
              returned.

              The possible architectures are:

                 ASC -- An ASCII text file.
                 DAF -- A DAF based file.
                 DAS -- A DAS based file.
                 KPL -- Kernel Pool File (i.e., a text kernel)
                 TXT -- An ASCII text file.
                 TE1 -- Text E-Kernel type 1.


     TYPE     is the type of the SPICE file. If the type can not be
              extracted or if it is blank, the value '?' is
              returned.

              The type can only be extracted by this routine if
              the ID word follows the convention

                 <architecture>/<type>

              where <architecture> is one of the file architectures
              specified above, and

                 <type> = 'xxxx'

              where 'xxxx' represents a four character mnemonic or
              code for the file type.

              This subroutine does not do any checking of the file
              types. If a valid architecture is found and the type
              is non-blank, that is what will be returned. It is up
              to a higher level authority to determine whether a type
              is valid.

Parameters

     None.

Exceptions

     1)  If the variable ID word is blank, both the architecture and
         type will be unknown, specified by '?'.

Files

     None.

Particulars

     This subroutine is a support utility routine that attempts
     to extract the architecture and type of a file from its ID word.
     It may not be possible to determine the type of the file from the
     ID word alone. Older files which contain the ID words 'NAIF/NIP',
     or 'NAIF/DAF' do not have sufficient information in the ID word to
     determine the type of the file. A type for the ID word 'NAIF/DAS'
     is always 'PRE ', since files with this ID word were pre-release
     DAS files.

     A file architecture can always be extracted from a valid SPICE
     ID word.

     This subroutine and the subroutine GETFAT (get file architecture
     and type) are intimately related. Whenever one of them is modified
     the other should be checked to see if the modifications affect it.
     Whenever a new architecture is added, both of the subroutines are
     affected.

Examples

     Suppose you wish to write a single routine for converting files
     between text and binary formats. You can use this routine to
     determine the architecture and type of the file and then pass the
     file to the appropriate low level file conversion routine to
     handle the actual conversion.

        CALL IDW2AT ( IDWORD, ARCH, TYPE )

        IF ( ARCH .EQ. 'DAF' ) THEN

           convert a DAF file

        ELSE IF ( ARCH .EQ. 'DAS' ) THEN

           convert a DAS file

        ELSE

           WRITE(*,*) 'File architecture not supported.'

        END IF

Restrictions

     None.

Literature_References

     None.

Author_and_Institution

     J. Diaz del Rio    (ODC Space)
     K.R. Gehringer     (JPL)

Version

    SPICELIB Version 2.1.0, 20-AUG-2021 (JDR)

        Added IMPLICIT NONE statement.

        Edited the header to comply with NAIF standard.

    SPICELIB Version 2.0.0, 26-OCT-1995 (KRG)

        Changed the Version line from "Beta" to "SPICELIB" for the
        current revisions. The subroutine was already in SPICELIB,
        but the Version line said "Beta."

        Added several new architectures:

           KPL -- Kernel Pool File (i.e., a text kernel)
           TXT -- An ASCII text file.
           ASC -- An ASCII text file.
           TE1 -- Text E-Kernel type 1.

        Changed the response foe the ID word 'NAIF/DAS' to be
        consistent with GETFAT. It now sets the architecture to 'DAS'
        and the type to 'PRE', for pre-release version.

    SPICELIB Version 1.0.0, 30-SEP-1993 (KRG)