getgbp.f

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C> @file
C> @brief Finds a grib message.
C> @author Mark Iredell @date 1994-04-01
 
C> Read a grib index file (or optionally the grib file itself)
C> to get the index buffer (i.e. table of contents) for the grib file.
C> (The index buffer is saved for use by future prospective calls.)
C> Find in the index buffer a reference to the grib message requested.
C> The grib message request specifies the number of messages to skip
C> and the unpacked pds and gds parameters. (A requested parameter
C> of -1 means to allow any value of this parameter to be found.)
C> If the requested grib message is found, then it is read from the
C> grib file. Its message number is returned along with the unpacked
C> pds and gds parameters and the packed grib message. If the grib
C> message is not found, then the return code will be nonzero.
C>
C> Program history log:
C> - Mark Iredell 1994-04-01
C> - Mark Iredell 1995-10-31 Modularized portions of code into subprograms
C> and allowed for unspecified index file.
C>
C> @param[in] lugb integer unit of the unblocked grib data file.
C> @param[in] lugi integer unit of the unblocked grib index file
C> (=0 to get index buffer from the grib file).
C> @param[in] jg integer maximum number of bytes in the grib message.
C> @param[in] j integer number of messages to skip
C> (=0 to search from beginning)
C> (<0 to read index buffer and skip -1-j messages).
C> @param[in] jpds integer (200) pds parameters for which to search.
C> (=-1 for wildcard).
C> - 1): id of center.
C> - 2): generating process id number.
C> - 3): grid definition.
C> - 4): gds/bms flag (right adj copy of octet 8).
C> - 5): indicator of parameter.
C> - 6): type of level.
C> - 7): height/pressure , etc of level.
C> - 8): year including (century-1).
C> - 9): month of year.
C> - 10: day of month.
C> - 11: hour of day.
C> - 12: minute of hour.
C> - 13: indicator of forecast time unit.
C> - 14: time range 1.
C> - 15: time range 2.
C> - 16: time range flag.
C> - 17: number included in average.
C> - 18: version nr of grib specification.
C> - 19: version nr of parameter table.
C> - 20: nr missing from average/accumulation.
C> - 21: century of reference time of data.
C> - 22: units decimal scale factor.
C> - 23: subcenter number.
C> - 24: pds byte 29, for nmc ensemble products.
C>  - 128 if forecast field error.
C>  - 64 if bias corrected fcst field.
C>  - 32 if smoothed field.
C>  - warning: can be combination of more than 1.
C> - 25: pds byte 30, not used.
C> @param[in] jgds integer (200) gds parameters for which to search
C> (only searched if jpds(3)=255)
C> (=-1 for wildcard).
C> - 1): data representation type.
C> - 19: number of vertical coordinate parameters.
C> - 20: octet number of the list of vertical coordinate parameters or
C> octet number of the list of numbers of points in each row or
C> 255 if neither are present.
C> - 21: for grids with pl, number of points in grid.
C> - 22: number of words in each row.
C> - Latitude/longitude grids.
C>  - 2: n(i) nr points on latitude circle.
C>  - 3: n(j) nr points on longitude meridian.
C>  - 4: la(1) latitude of origin.
C>  - 5: lo(1) longitude of origin.
C>  - 6: resolution flag (right adj copy of octet 17).
C>  - 7: la(2) latitude of extreme point.
C>  - 8: lo(2) longitude of extreme point.
C>  - 9: di longitudinal direction of increment.
C>  - 10: dj latitudinal direction increment.
C>  - 11: scanning mode flag (right adj copy of octet 28).
C> - Gaussian  grids.
C>  - 2: n(i) nr points on latitude circle.
C>  - 3: n(j) nr points on longitude meridian.
C>  - 4: la(1) latitude of origin.
C>  - 5: lo(1) longitude of origin.
C>  - 6: resolution flag  (right adj copy of octet 17).
C>  - 7: la(2) latitude of extreme point.
C>  - 8: lo(2) longitude of extreme point.
C>  - 9: di longitudinal direction of increment.
C>  - 10: n - nr of circles pole to equator.
C>  - 11: scanning mode flag (right adj copy of octet 28).
C>  - 12: nv - nr of vert coord parameters.
C>  - 13: pv - octet nr of list of vert coord parameters or
C> pl - location of the list of numbers of points in each row
C> (if no vert coord parameters are present) or
C> 255 if neither are present
C> - Polar stereographic grids.
C>  - 2: n(i) nr points along lat circle.
C>  - 3: n(j) nr points along lon circle.
C>  - 4: la(1) latitude of origin.
C>  - 5: lo(1) longitude of origin.
C>  - 6: resolution flag  (right adj copy of octet 17).
C>  - 7: lov grid orientation.
C>  - 8: dx - x direction increment.
C>  - 9: dy - y direction increment.
C>  - 10: projection center flag.
C>  - 11: scanning mode (right adj copy of octet 28).
C> - Spherical harmonic coefficients.
C>  - 2: j pentagonal resolution parameter.
C>  - 3: k pentagonal resolution parameter.
C>  - 4: m pentagonal resolution parameter.
C>  - 5: representation type.
C>  - 6: coefficient storage mode.
C> - Mercator grids.
C>  - 2: n(i) nr points on latitude circle.
C>  - 3: n(j) nr points on longitude meridian.
C>  - 4: la(1) latitude of origin.
C>  - 5: lo(1) longitude of origin.
C>  - 6: resolution flag (right adj copy of octet 17).
C>  - 7: la(2) latitude of last grid point.
C>  - 8: lo(2) longitude of last grid point.
C>  - 9: latit - latitude of projection intersection.
C>  - 10: reserved.
C>  - 11: scanning mode flag (right adj copy of octet 28).
C>  - 12: longitudinal dir grid length.
C>  - 13: latitudinal dir grid length.
C> - Lambert conformal grids.
C>  - 2): nx nr points along x-axis.
C>  - 3): ny nr points along y-axis.
C>  - 4): la1 lat of origin (lower left).
C>  - 5): lo1 lon of origin (lower left).
C>  - 6): resolution (right adj copy of octet 17).
C>  - 7): lov - orientation of grid.
C>  - 8): dx - x-dir increment.
C>  - 9): dy - y-dir increment.
C>  - 10: projection center flag.
C>  - 11: scanning mode flag (right adj copy of octet 28).
C>  - 12: latin 1 - first lat from pole of secant cone inter.
C>  - 13: latin 2 - second lat from pole of secant cone inter.
C> @param[out] kg integer number of bytes in the grib message.
C> @param[out] k integer message number unpacked
C> (can be same as j in calling program in order to facilitate multiple searches).
C> @param[out] kpds integer (200) unpacked pds parameters.
C> @param[out] kgds integer (200) unpacked gds parameters.
C> @param[out] g character*1 (kg) grib message.
C> @param[out] iret integer return code.
C> - 0: all ok.
C> - 96: error reading index file.
C> - 97: error reading grib file.
C> - 98: number of bytes greater than jg.
C> - 99: request not found.
C>
C> @note In order to unpack grib from a multiprocessing environment
C> where each processor is attempting to read from its own pair of
C> logical units, one must directly call subprogram getgbmp as below,
C> allocating a private copy of cbuf, nlen and nnum to each processor.
C> Do not engage the same logical unit from more than one processor.
C>
C> @author Mark Iredell @date 1994-04-01
C-----------------------------------------------------------------------
      SUBROUTINE getgbp(LUGB,LUGI,JG,J,JPDS,JGDS,
     &                  KG,K,KPDS,KGDS,G,IRET)
      INTEGER JPDS(200),JGDS(200),KPDS(200),KGDS(200)
      CHARACTER G(JG)
      parameter(mbuf=256*1024)
      CHARACTER CBUF(MBUF)
      SAVE cbuf,nlen,nnum,mnum
      DATA lux/0/
C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
C  DETERMINE WHETHER INDEX BUFFER NEEDS TO BE INITIALIZED
      IF(lugi.GT.0.AND.(j.LT.0.OR.lugi.NE.lux)) THEN
        lux=lugi
        jj=min(j,-1-j)
      ELSEIF(lugi.LE.0.AND.(j.LT.0.OR.lugb.NE.lux)) THEN
        lux=lugb
        jj=min(j,-1-j)
      ELSE
        jj=j
      ENDIF
C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
C  FIND AND UNPACK GRIB MESSAGE
      CALL getgbmp(lugb,lugi,jg,jj,jpds,jgds,
     &             mbuf,cbuf,nlen,nnum,mnum,
     &             kg,k,kpds,kgds,g,iret)
      IF(iret.EQ.96) lux=0
C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      RETURN
      END