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#include <stdio.h>
#include "grib2.h"
g2int g2_gribend(unsigned char *cgrib)
//$$$ SUBPROGRAM DOCUMENTATION BLOCK
// . . . .
// SUBPROGRAM: g2_gribend
// PRGMMR: Gilbert ORG: W/NP11 DATE: 2002-10-31
//
// ABSTRACT: This routine finalizes a GRIB2 message after all grids
// and fields have been added. It adds the End Section ( "7777" )
// to the end of the GRIB message and calculates the length and stores
// it in the appropriate place in Section 0.
// This routine is used with routines "g2_create", "g2_addlocal",
// "g2_addgrid", and "g2_addfield" to create a complete GRIB2 message.
// g2_create must be called first to initialize a new GRIB2 message.
//
// PROGRAM HISTORY LOG:
// 2002-10-31 Gilbert
//
// USAGE: int g2_gribend(unsigned char *cgrib)
// INPUT ARGUMENT:
// cgrib - Char array containing all the data sections added
// be previous calls to g2_create, g2_addlocal, g2_addgrid,
// and g2_addfield.
//
// OUTPUT ARGUMENTS:
// cgrib - Char array containing the finalized GRIB2 message
//
// RETURN VALUES:
// ierr - Return code.
// > 0 = Length of the final GRIB2 message in bytes.
// -1 = GRIB message was not initialized. Need to call
// routine g2_create first.
// -2 = GRIB message already complete.
// -3 = Sum of Section byte counts doesn't add to total byte count
// -4 = Previous Section was not 7.
//
// REMARKS: This routine is intended for use with routines "g2_create",
// "g2_addlocal", "g2_addgrid", and "g2_addfield" to create a complete
// GRIB2 message.
//
// ATTRIBUTES:
// LANGUAGE: C
// MACHINE:
//
//$$$
{
g2int iofst,lencurr,len,ilen,isecnum;
g2int ierr,lengrib;
static unsigned char G=0x47; // 'G'
static unsigned char R=0x52; // 'R'
static unsigned char I=0x49; // 'I'
static unsigned char B=0x42; // 'B'
static unsigned char seven=0x37; // '7'
ierr=0;
//
// Check to see if beginning of GRIB message exists
//
if ( cgrib[0]!=G || cgrib[1]!=R || cgrib[2]!=I || cgrib[3]!=B ) {
printf("g2_gribend: GRIB not found in given message.\n");
ierr=-1;
return (ierr);
}
//
// Get current length of GRIB message
//
gbit(cgrib,&lencurr,96,32);
//
// Loop through all current sections of the GRIB message to
// find the last section number.
//
len=16; // Length of Section 0
for (;;) {
// Get number and length of next section
iofst=len*8;
gbit(cgrib,&ilen,iofst,32);
iofst=iofst+32;
gbit(cgrib,&isecnum,iofst,8);
len=len+ilen;
// Exit loop if last section reached
if ( len == lencurr ) break;
// If byte count for each section doesn't match current
// total length, then there is a problem.
if ( len > lencurr ) {
printf("g2_gribend: Section byte counts don''t add to total.\n");
printf("g2_gribend: Sum of section byte counts = %d\n",(int)len);
printf("g2_gribend: Total byte count in Section 0 = %d\n",(int)lencurr);
ierr=-3;
return (ierr);
}
}
//
// Can only add End Section (Section 8) after Section 7.
//
if ( isecnum != 7 ) {
printf("g2_gribend: Section 8 can only be added after Section 7.\n");
printf("g2_gribend: Section %ld was the last found in given GRIB message.\n",isecnum);
ierr=-4;
return (ierr);
}
//
// Add Section 8 - End Section
//
//cgrib(lencurr+1:lencurr+4)=c7777
cgrib[lencurr]=seven;
cgrib[lencurr+1]=seven;
cgrib[lencurr+2]=seven;
cgrib[lencurr+3]=seven;
//
// Update current byte total of message in Section 0
//
lengrib=lencurr+4;
sbit(cgrib,&lengrib,96,32);
return (lengrib);
}
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