SUBROUTINE MESGBC(LUNIN,MESGTYP,ICOMP)
C$$$ SUBPROGRAM DOCUMENTATION BLOCK
C
C SUBPROGRAM: MESGBC
C PRGMMR: KEYSER ORG: NP22 DATE: 2003-11-04
C
C ABSTRACT: THIS SUBROUTINE EXAMINES A BUFR MESSAGE AND RETURNS BOTH
C THE MESSAGE TYPE FROM SECTION 1 AND A MESSAGE COMPRESSION INDICATOR
C UNPACKED FROM SECTION 3. IT OBTAINS THE BUFR MESSAGE VIA TWO
C DIFFERENT METHODS, BASED UPON THE SIGN OF LUNIN.
C IF LUNIN IS GREATER THAN ZERO, THIS SUBROUTINE READS AND EXAMINES
C SECTION 1 OF MESSAGES IN A BUFR FILE IN SEQUENCE UNTIL IT FINDS THE
C FIRST MESSAGE THAT ACTUALLY CONTAINS REPORT DATA {I.E., BEYOND THE
C BUFR TABLE (DICTIONARY) MESSAGES AT THE TOP AND, FOR DUMP FILES,
C BEYOND THE TWO DUMMY MESSAGES CONTAINING THE CENTER TIME AND THE
C DUMP TIME}. IT THEN RETURNS THE MESSAGE TYPE AND COMPRESSION
C INDICATOR FOR THIS FIRST DATA MESSAGE. IN THIS CASE, THE BUFR FILE
C SHOULD NOT BE OPENED VIA BUFR ARCHIVE LIBRARY SUBROUTINE OPENBF
C PRIOR TO CALLING THIS SUBROUTINE. HOWEVER, THE BUFR FILE MUST BE
C CONNECTED TO UNIT ABS(LUNIN). WHEN USED THIS WAY, THIS SUBROUTINE
C IS IDENTICAL TO BUFR ARCHIVE LIBRARY SUBROUTINE MESGBF EXCEPT MESGBF
C DOES NOT RETURN ANY INFORMATION ABOUT COMPRESSION AND MESGBF READS
C UNTIL IT FINDS THE FIRST NON-DICTIONARY MESSAGE REGARDLESS OF
C WHETHER OR NOT IT CONTAINS ANY REPORTS (I.E., IT WOULD STOP AT THE
C DUMMY MESSAGE CONTAINING THE CENTER TIME FOR DUMP FILES).
C THE SECOND METHOD IN WHICH THIS SUBROUTINE CAN BE USED OCCURS
C WHEN LUNIN IS PASSED IN WITH A VALUE LESS THAN ZERO. IN THIS CASE,
C IT SIMPLY RETURNS THE MESSAGE TYPE AND COMPRESSION INDICATOR FOR THE
C BUFR MESSAGE CURRENTLY STORED IN THE INTERNAL MESSAGE BUFFER (ARRAY
C MBAY IN COMMON BLOCK /BITBUF/). IN THIS CASE, THE BUFR FILE
C CONNECTED TO ABS(LUNIN) MUST HAVE BEEN PREVIOUSLY OPENED FOR INPUT
C OPERATIONS BY BUFR ARCHIVE LIBRARY SUBROUTINE OPENBF, AND THE BUFR
C MESSAGE MUST HAVE BEEN READ INTO MEMORY BY BUFR ARCHIVE LIBRARY
C ROUTINE READMG OR EQUIVALENT.
C
C PROGRAM HISTORY LOG:
C 2003-11-04 D. KEYSER -- ORIGINAL AUTHOR
C 2004-06-29 D. KEYSER -- ADDED NEW OPTION TO RETURN MESSAGE TYPE AND
C COMPRESSION INDICATOR FOR BUFR MESSAGE
C CURRENTLY STORED IN MEMORY (TRIGGERED BY
C INPUT ARGUMENT LUNIN LESS THAN ZERO)
C 2004-08-09 J. ATOR -- MAXIMUM MESSAGE LENGTH INCREASED FROM
C 20,000 TO 50,000 BYTES
C 2005-11-29 J. ATOR -- USE IUPBS01, GETLENS AND RDMSGW
C 2009-03-23 J. ATOR -- USE IUPBS3 AND IDXMSG
C 2012-09-15 J. WOOLLEN -- CONVERT TO C LANGUAGE I/O INTERFACE
C ADD OPENBF AND CLOSBF FOR THE CASE
C WHEN LUNIN GT 0
C
C USAGE: CALL MESGBC (LUNIN, MESGTYP, ICOMP)
C INPUT ARGUMENT LIST:
C LUNIN - INTEGER: ABSOLUTE VALUE IS FORTRAN LOGICAL UNIT NUMBER
C FOR BUFR FILE
C - IF LUNIN IS GREATER THAN ZERO, THIS SUBROUTINE
C READS THROUGH ALL BUFR MESSAGES FROM BEGINNING OF
C FILE UNTIL IT FINDS THE FIRST MESSAGE CONTAINING
C REPORT DATA
C - IF LUNIN IS LESS THAN ZERO, THIS SUBROUTINE
C OPERATES ON THE BUFR MESSAGE CURRENTLY STORED IN
C MEMORY
C
C OUTPUT ARGUMENT LIST:
C MESGTYP - INTEGER: BUFR MESSAGE TYPE FOR EITHER THE FIRST
C MESSAGE IN FILE CONTAINING REPORT DATA (IF LUNIN > 0),
C OR FOR THE MESSAGE CURRENTLY IN MEMORY (IF LUNIN < 0)
C -256 = for LUNIN > 0 case only: no messages read
C or error reading file
C < 0 = for LUNIN > 0 case only: none of the
C messages read contain reports; this is the
C negative of the message type the last
C message read (i.e., -11 indicates the BUFR
C file contains only BUFR table messages)
C ICOMP - INTEGER: BUFR MESSAGE COMPRESSION SWITCH:
C -3 = for LUNIN > 0 case only: BUFR file does not
C exist
C -2 = for LUNIN > 0 case only: BUFR file does not
C contain any report messages
C -1 = for LUNIN > 0 case only: cannot determine
C if first BUFR message containing report
C data is compressed due to error reading
C file
C 0 = BUFR message (either first containing
C report data if LUNIN > 0, or that currently
C in memory if LUNIN < 0) is NOT compressed
C 1 = BUFR message (either first containing
C report data if LUNIN > 0, or that currently
C in memory if LUNIN < 0) IS compressed
C
C INPUT FILES:
C UNIT ABS(LUNIN) - BUFR FILE
C
C REMARKS:
C THIS ROUTINE CALLS: CLOSBF IDXMSG IUPBS01 IUPBS3
C OPENBF RDMSGW STATUS
C THIS ROUTINE IS CALLED BY: COPYSB UFBTAB
C Also called by application programs.
C
C ATTRIBUTES:
C LANGUAGE: FORTRAN 77
C MACHINE: PORTABLE TO ALL PLATFORMS
C
C$$$
INCLUDE 'bufrlib.prm'
COMMON /BITBUF/ MAXBYT,IBIT,IBAY(MXMSGLD4),MBYT(NFILES),
. MBAY(MXMSGLD4,NFILES)
DIMENSION MSGS(MXMSGLD4)
C-----------------------------------------------------------------------
C-----------------------------------------------------------------------
LUNIT = ABS(LUNIN)
C DETERMINE METHOD OF OPERATION BASED ON SIGN OF LUNIN
C LUNIN > 0 - REWIND AND LOOK FOR FIRST DATA MESSAGE (ITYPE = 0)
C LUNIN < 0 - LOOK AT MESSAGE CURRENLY IN MEMORY (ITYPE = 1)
C ---------------------------------------------------------------
ITYPE = 0
IF(LUNIT.NE.LUNIN) ITYPE = 1
ICOMP = -1
MESGTYP = -256
IF(ITYPE.EQ.0) THEN
IREC = 0
C CALL OPENBF SINCE FILE IS NOT OPEN TO THE C INTERFACE YET
C ---------------------------------------------------------
CALL OPENBF(LUNIT,'INX',LUNIT)
C READ PAST ANY BUFR TABLES AND RETURN THE FIRST MESSAGE TYPE FOUND
C -----------------------------------------------------------------
1 CALL RDMSGW(LUNIT,MSGS,IER)
IF(IER.EQ.-1) GOTO 900
IF(IER.EQ.-2) GOTO 901
IREC = IREC + 1
MESGTYP = IUPBS01(MSGS,'MTYP')
IF((IDXMSG(MSGS).EQ.1).OR.(IUPBS3(MSGS,'NSUB').EQ.0)) GOTO 1
ELSE
C RETURN MESSAGE TYPE FOR MESSAGE CURRENTLY STORED IN MEMORY
C ----------------------------------------------------------
CALL STATUS(LUNIT,LUN,IL,IM)
DO I=1,12
MSGS(I) = MBAY(I,LUN)
ENDDO
MESGTYP = IUPBS01(MSGS,'MTYP')
END IF
C SET THE COMPRESSION SWITCH
C --------------------------
ICOMP = IUPBS3(MSGS,'ICMP')
GOTO 100
C CAN ONLY GET TO STATEMENTS 900 OR 901 WHEN ITYPE = 0
C ----------------------------------------------------
900 IF(IREC.EQ.0) THEN
MESGTYP = -256
ICOMP = -3
ELSE
IF(MESGTYP.GE.0) MESGTYP = -MESGTYP
ICOMP = -2
ENDIF
GOTO 100
901 MESGTYP = -256
ICOMP = -1
C EXIT
C ----
100 IF(ITYPE.EQ.0) CALL CLOSBF(LUNIT)
RETURN
END