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#include <stdio.h>
#include <stdlib.h>
#include "grib2.h"
g2int g2_unpack6(unsigned char *cgrib,g2int *iofst,g2int ngpts,g2int *ibmap,
g2int **bmap)
//$$$ SUBPROGRAM DOCUMENTATION BLOCK
// . . . .
// SUBPROGRAM: g2_unpack6
// PRGMMR: Gilbert ORG: W/NP11 DATE: 2002-10-31
//
// ABSTRACT: This subroutine unpacks Section 6 (Bit-Map Section)
// as defined in GRIB Edition 2.
//
// PROGRAM HISTORY LOG:
// 2002-10-31 Gilbert
//
// USAGE: int g2_unpack6(unsigned char *cgrib,g2int *iofst,g2int ngpts,
// g2int *ibmap,g2int **bmap)
// INPUT ARGUMENTS:
// cgrib - char array containing Section 6 of the GRIB2 message
// iofst - Bit offset of the beginning of Section 6 in cgrib.
// ngpts - Number of grid points specified in the bit-map
//
// OUTPUT ARGUMENTS:
// iofst - Bit offset at the end of Section 6, returned.
// ibmap - Bitmap indicator ( see Code Table 6.0 )
// 0 = bitmap applies and is included in Section 6.
// 1-253 = Predefined bitmap applies
// 254 = Previously defined bitmap applies to this field
// 255 = Bit map does not apply to this product.
// bmap - Pointer to an integer array containing decoded bitmap.
// ( if ibmap=0 )
//
// RETURN VALUES:
// ierr - Error return code.
// 0 = no error
// 2 = Not Section 6
// 4 = Unrecognized pre-defined bit-map.
// 6 = memory allocation error
//
// REMARKS: None
//
// ATTRIBUTES:
// LANGUAGE: C
// MACHINE:
//
//$$$//
{
g2int j,ierr,isecnum;
g2int *lbmap=0;
g2int *intbmap;
ierr=0;
*bmap=0; //NULL
*iofst=*iofst+32; // skip Length of Section
gbit(cgrib,&isecnum,*iofst,8); // Get Section Number
*iofst=*iofst+8;
if ( isecnum != 6 ) {
ierr=2;
fprintf(stderr,"g2_unpack6: Not Section 6 data.\n");
return(ierr);
}
gbit(cgrib,ibmap,*iofst,8); // Get bit-map indicator
*iofst=*iofst+8;
if (*ibmap == 0) { // Unpack bitmap
if (ngpts > 0) lbmap=(g2int *)calloc(ngpts,sizeof(g2int));
if (lbmap == 0) {
ierr=6;
return(ierr);
}
else {
*bmap=lbmap;
}
intbmap=(g2int *)calloc(ngpts,sizeof(g2int));
gbits(cgrib,intbmap,*iofst,1,0,ngpts);
*iofst=*iofst+ngpts;
for (j=0;j<ngpts;j++) {
lbmap[j]=(g2int)intbmap[j];
}
free(intbmap);
// else if (*ibmap.eq.254) ! Use previous bitmap
// return(ierr);
// else if (*ibmap.eq.255) ! No bitmap in message
// bmap(1:ngpts)=.true.
// else {
// print *,'gf_unpack6: Predefined bitmap ',*ibmap,' not recognized.'
// ierr=4;
}
return(ierr); // End of Section 6 processing
}
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