1                 : #include <stdio.h>
       2                 : #include <stdlib.h>
       3                 : #include "grib2.h"
       4                 : 
       5               2 : g2int g2_unpack6(unsigned char *cgrib,g2int *iofst,g2int ngpts,g2int *ibmap,
       6                 :                g2int **bmap)
       7                 : //$$$  SUBPROGRAM DOCUMENTATION BLOCK
       8                 : //                .      .    .                                       .
       9                 : // SUBPROGRAM:    g2_unpack6 
      10                 : //   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2002-10-31
      11                 : //
      12                 : // ABSTRACT: This subroutine unpacks Section 6 (Bit-Map Section)
      13                 : //           as defined in GRIB Edition 2.
      14                 : //
      15                 : // PROGRAM HISTORY LOG:
      16                 : // 2002-10-31  Gilbert
      17                 : //
      18                 : // USAGE:    int g2_unpack6(unsigned char *cgrib,g2int *iofst,g2int ngpts,
      19                 : //                          g2int *ibmap,g2int **bmap)
      20                 : //   INPUT ARGUMENTS:
      21                 : //     cgrib    - char array containing Section 6 of the GRIB2 message
      22                 : //     iofst    - Bit offset of the beginning of Section 6 in cgrib.
      23                 : //     ngpts    - Number of grid points specified in the bit-map
      24                 : //
      25                 : //   OUTPUT ARGUMENTS:      
      26                 : //     iofst    - Bit offset at the end of Section 6, returned.
      27                 : //     ibmap    - Bitmap indicator ( see Code Table 6.0 )
      28                 : //                0 = bitmap applies and is included in Section 6.
      29                 : //                1-253 = Predefined bitmap applies
      30                 : //                254 = Previously defined bitmap applies to this field
      31                 : //                255 = Bit map does not apply to this product.
      32                 : //     bmap     - Pointer to an integer array containing decoded bitmap. 
      33                 : //                ( if ibmap=0 )
      34                 : //
      35                 : //   RETURN VALUES:
      36                 : //     ierr     - Error return code.
      37                 : //                0 = no error
      38                 : //                2 = Not Section 6
      39                 : //                4 = Unrecognized pre-defined bit-map.
      40                 : //                6 = memory allocation error
      41                 : //
      42                 : // REMARKS: None
      43                 : //
      44                 : // ATTRIBUTES:
      45                 : //   LANGUAGE: C
      46                 : //   MACHINE:
      47                 : //
      48                 : //$$$//
      49                 : {
      50                 :       g2int j,ierr,isecnum;
      51               2 :       g2int *lbmap=0;
      52                 :       g2int *intbmap;
      53                 : 
      54               2 :       ierr=0;
      55               2 :       *bmap=0;    //NULL
      56                 : 
      57               2 :       *iofst=*iofst+32;    // skip Length of Section
      58               2 :       gbit(cgrib,&isecnum,*iofst,8);         // Get Section Number
      59               2 :       *iofst=*iofst+8; 
      60                 : 
      61               2 :       if ( isecnum != 6 ) {
      62               0 :          ierr=2;
      63               0 :          fprintf(stderr,"g2_unpack6: Not Section 6 data.\n");
      64               0 :          return(ierr);
      65                 :       }
      66                 : 
      67               2 :       gbit(cgrib,ibmap,*iofst,8);    // Get bit-map indicator
      68               2 :       *iofst=*iofst+8;
      69                 : 
      70               2 :       if (*ibmap == 0) {               // Unpack bitmap
      71               0 :          if (ngpts > 0) lbmap=(g2int *)calloc(ngpts,sizeof(g2int));
      72               0 :          if (lbmap == 0) {
      73               0 :             ierr=6;
      74               0 :             return(ierr);
      75                 :          }
      76                 :          else {
      77               0 :             *bmap=lbmap;
      78                 :          }
      79               0 :          intbmap=(g2int *)calloc(ngpts,sizeof(g2int));  
      80               0 :          gbits(cgrib,intbmap,*iofst,1,0,ngpts);
      81               0 :          *iofst=*iofst+ngpts;
      82               0 :          for (j=0;j<ngpts;j++) {
      83               0 :            lbmap[j]=(g2int)intbmap[j];
      84                 :          }
      85               0 :          free(intbmap);
      86                 : //      else if (*ibmap.eq.254)               ! Use previous bitmap
      87                 : //        return(ierr);
      88                 : //      else if (*ibmap.eq.255)               ! No bitmap in message
      89                 : //        bmap(1:ngpts)=.true.
      90                 : //      else {
      91                 : //        print *,'gf_unpack6: Predefined bitmap ',*ibmap,' not recognized.'
      92                 : //        ierr=4;
      93                 :       }
      94                 :       
      95               2 :       return(ierr);    // End of Section 6 processing
      96                 : 
      97                 : }