Implement GFS weatherdata plugin

refs #556

src/plugins/weatherdata/gfs/g2clib/g2_create.c

@@ -0,0 +1,127 @@
+#include <stdio.h>
+#include "grib2.h"
+
+#define MAPSEC1LEN 13
+
+g2int g2_create(unsigned char *cgrib,g2int *listsec0,g2int *listsec1)
+//$$$  SUBPROGRAM DOCUMENTATION BLOCK
+//                .      .    .                                       .
+// SUBPROGRAM:    g2_create 
+//   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2002-10-31
+//
+// ABSTRACT: This routine initializes a new GRIB2 message and packs
+//   GRIB2 sections 0 (Indicator Section) and 1 (Identification Section).
+//   This routine is used with routines "g2_addlocal", "g2_addgrid", 
+//   "g2_addfield", and "g2_gribend" to create a complete GRIB2 message.  
+//   g2_create must be called first to initialize a new GRIB2 message.
+//   Also, a call to g2_gribend is required to complete GRIB2 message
+//   after all fields have been added.
+//
+// PROGRAM HISTORY LOG:
+// 2002-10-31  Gilbert
+//
+// USAGE:    int g2_create(unsigned char *cgrib,g2int *listsec0,g2int *listsec1)
+//   INPUT ARGUMENTS:
+//     cgrib    - Character array to contain the GRIB2 message
+//     listsec0 - Contains information needed for GRIB Indicator Section 0.
+//                Must be dimensioned >= 2.
+//                listsec0[0]=Discipline-GRIB Master Table Number
+//                            (see Code Table 0.0)
+//                listsec0[1]=GRIB Edition Number (currently 2)
+//     listsec1 - Contains information needed for GRIB Identification Section 1.
+//                Must be dimensioned >= 13.
+//                listsec1[0]=Id of orginating centre (Common Code Table C-1)
+//                listsec1[1]=Id of orginating sub-centre (local table)
+//                listsec1[2]=GRIB Master Tables Version Number (Code Table 1.0)
+//                listsec1[3]=GRIB Local Tables Version Number (Code Table 1.1)
+//                listsec1[4]=Significance of Reference Time (Code Table 1.2)
+//                listsec1[5]=Reference Time - Year (4 digits)
+//                listsec1[6]=Reference Time - Month
+//                listsec1[7]=Reference Time - Day
+//                listsec1[8]=Reference Time - Hour
+//                listsec1[9]=Reference Time - Minute
+//                listsec1[10]=Reference Time - Second
+//                listsec1[11]=Production status of data (Code Table 1.3)
+//                listsec1[12]=Type of processed data (Code Table 1.4)
+//
+//   OUTPUT ARGUMENTS:      
+//     cgrib    - Char array to contain the new GRIB2 message.
+//                Must be allocated large enough to store the entire
+//                GRIB2 message.
+//
+//   RETURN VALUES:
+//     ierr     - return code.
+//              > 0 = Current size of new GRIB2 message
+//               -1 = Tried to use for version other than GRIB Edition 2
+//
+// REMARKS: This routine is intended for use with routines "g2_addlocal", 
+//          "g2_addgrid", "g2_addfield", and "g2_gribend" to create a complete 
+//          GRIB2 message.
+//
+// ATTRIBUTES:
+//   LANGUAGE: C
+//   MACHINE:  
+//
+//$$$
+{
+
+      g2int  ierr;
+      g2int   zero=0,one=1;
+      g2int   mapsec1len=MAPSEC1LEN;
+      g2int   mapsec1[MAPSEC1LEN]={ 2,2,1,1,1,2,1,1,1,1,1,1,1 };
+      g2int   i,lensec0,lensec1,iofst,ibeg,nbits,len;
+
+      ierr=0;
+//
+//  Currently handles only GRIB Edition 2.
+//  
+      if (listsec0[1] != 2) {
+        printf("g2_create: can only code GRIB edition 2.");
+        ierr=-1;
+        return (ierr);
+      }
+//
+//  Pack Section 0 - Indicator Section 
+//  ( except for total length of GRIB message )
+//
+      cgrib[0]=0x47;   // 'G'            // Beginning of GRIB message
+      cgrib[1]=0x52;   // 'R'
+      cgrib[2]=0x49;   // 'I'
+      cgrib[3]=0x42;   // 'B'
+      sbit(cgrib,&zero,32,16);           // reserved for future use
+      sbit(cgrib,listsec0+0,48,8);       // Discipline
+      sbit(cgrib,listsec0+1,56,8);       // GRIB edition number
+      lensec0=16;      // bytes (octets)
+//
+//  Pack Section 1 - Identification Section
+//
+      ibeg=lensec0*8;        //   Calculate offset for beginning of section 1
+      iofst=ibeg+32;         //   leave space for length of section
+      sbit(cgrib,&one,iofst,8);     // Store section number ( 1 )
+      iofst=iofst+8;
+      //
+      //   Pack up each input value in array listsec1 into the
+      //   the appropriate number of octets, which are specified in
+      //   corresponding entries in array mapsec1.
+      //
+      for (i=0;i<mapsec1len;i++) {
+        nbits=mapsec1[i]*8;
+        sbit(cgrib,listsec1+i,iofst,nbits);
+        iofst=iofst+nbits;
+      }
+      //
+      //   Calculate length of section 1 and store it in octets
+      //   1-4 of section 1.
+      //
+      lensec1=(iofst-ibeg)/8;
+      sbit(cgrib,&lensec1,ibeg,32);
+//
+//  Put current byte total of message into Section 0
+//
+      sbit(cgrib,&zero,64,32);
+      len=lensec0+lensec1;
+      sbit(cgrib,&len,96,32);
+
+      return (len);
+
+}