getgbeh.f

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C> @file
C> @brief Find a grib message.
C> @author Mark Iredell @date 1995-10-31
 
C> Read a grib index file (or optionally the grib file itself) to get
C> the index buffer (i.e. table of contents) for the grib file. (The
C> index buffer is saved for use by future prospective calls.) Find
C> 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 of
C> -1 means to allow any value of this parameter to be found.) If the
C> requested grib message is found, then its message number is
C> returned along with the unpacked pds and gds parameters. If the
C> grib message is not found, then the return code will be nonzero.
C>
C> Program History:
C> - 1995-10-31  Mark Iredell 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> (only used if lugi=0)
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] 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 (can
C> be combination of more than 1).
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> - 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.
C> or octet number of the list of numbers of points in each row
C> or 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 pl location
C>  of the list of numbers of points in each row (if no vert coord
C>  parameters are present or 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[in] JENS Integer (200) ensemble pds parms for which to
C> search (only searched if jpds(23)=2).
C> - -1 for wildcard.
C> - 1 application identifier.
C> - 2 ensemble type.
C> - 3 ensemble identifier.
C> - 4 product identifier.
C> - 5 smoothing flag.
C> @param[out] KG Integer number of bytes in the grib message.
C> @param[out] KF Integer number of data points in the message.
C> @param[out] K Integer message number unpacked (can be same as j in
C> 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] KENS Integer (200) unpacked ensemble pds parms.
C> @param[out] IRET Integer return code.
C> - 0 all ok.
C> - 96 error reading index file.
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 getgbemh as
C> below, allocating a private copy of cbuf, nlen and nnum to each
C> processor. Do not engage the same logical unit from more than one
C> processor.
C>
C> @author Mark Iredell @date 94-04-01
      SUBROUTINE getgbeh(LUGB,LUGI,J,JPDS,JGDS,JENS,
     &                   KG,KF,K,KPDS,KGDS,KENS,IRET)
      INTEGER JPDS(200),JGDS(200),JENS(200)
      INTEGER KPDS(200),KGDS(200),KENS(200)
      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 getgbemh(lugb,lugi,jj,jpds,jgds,jens,
     &              mbuf,cbuf,nlen,nnum,mnum,
     &              kg,kf,k,kpds,kgds,kens,iret)
      IF(iret.EQ.96) lux=0
C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      RETURN
      END