Line data    Source code

       1             : #include <stdio.h>
       2             : #include <stdlib.h>
       3             : #include "grib2.h"
       4             : 
       5         460 : g2int g2_unpack1(unsigned char *cgrib,g2int *iofst,g2int **ids,g2int *idslen)
       6             : /*//$$$  SUBPROGRAM DOCUMENTATION BLOCK
       7             : //                .      .    .                                       .
       8             : // SUBPROGRAM:    g2_unpack1
       9             : //   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2002-10-29
      10             : //
      11             : // ABSTRACT: This subroutine unpacks Section 1 (Identification Section)
      12             : //           as defined in GRIB Edition 2.
      13             : //
      14             : // PROGRAM HISTORY LOG:
      15             : // 2002-10-29  Gilbert
      16             : //
      17             : // USAGE:    int g2_unpack1(unsigned char *cgrib,g2int *iofst,g2int **ids,
      18             : //                          g2int *idslen)
      19             : //   INPUT ARGUMENTS:
      20             : //     cgrib    - char array containing Section 1 of the GRIB2 message
      21             : //     iofst    - Bit offset for the beginning of Section 1 in cgrib.
      22             : //
      23             : //   OUTPUT ARGUMENTS:
      24             : //     iofst    - Bit offset at the end of Section 1, returned.
      25             : //     ids      - address of pointer to integer array containing information
      26             : //                read from Section 1, the Identification section.
      27             : //            ids[0]  = Identification of originating Centre
      28             : //                                 ( see Common Code Table C-1 )
      29             : //            ids[1]  = Identification of originating Sub-centre
      30             : //            ids[2]  = GRIB Master Tables Version Number
      31             : //                                 ( see Code Table 1.0 )
      32             : //            ids[3]  = GRIB Local Tables Version Number
      33             : //                                 ( see Code Table 1.1 )
      34             : //            ids[4]  = Significance of Reference Time (Code Table 1.2)
      35             : //            ids[5]  = Year ( 4 digits )
      36             : //            ids[6]  = Month
      37             : //            ids[7]  = Day
      38             : //            ids[8]  = Hour
      39             : //            ids[9]  = Minute
      40             : //            ids[10]  = Second
      41             : //            ids[11]  = Production status of processed data
      42             : //                                 ( see Code Table 1.3 )
      43             : //            ids[12]  = Type of processed data ( see Code Table 1.4 )
      44             : //     idslen   - Number of elements in ids[].
      45             : //
      46             : //   RETURN VALUES:
      47             : //     ierr     - Error return code.
      48             : //                0 = no error
      49             : //                2 = Array passed is not section 1
      50             : //                6 = memory allocation error
      51             : //
      52             : // REMARKS:
      53             : //
      54             : // ATTRIBUTES:
      55             : //   LANGUAGE: C
      56             : //   MACHINE:
      57             : //
      58             : //$$$
      59             : */
      60             : {
      61             : 
      62         460 :       g2int i,lensec,nbits,ierr,isecnum = 0;
      63         460 :       g2int mapid[13]={2,2,1,1,1,2,1,1,1,1,1,1,1};
      64             : 
      65         460 :       ierr=0;
      66         460 :       *idslen=13;
      67         460 :       *ids=0;
      68             : 
      69         460 :       gbit(cgrib,&lensec,*iofst,32);        // Get Length of Section
      70         460 :       *iofst=*iofst+32;
      71         460 :       gbit(cgrib,&isecnum,*iofst,8);         // Get Section Number
      72         460 :       *iofst=*iofst+8;
      73             : 
      74         460 :       if ( isecnum != 1 ) {
      75           0 :          ierr=2;
      76           0 :          *idslen=13;
      77           0 :          fprintf(stderr,"g2_unpack1: Not Section 1 data.\n");
      78           0 :          return(ierr);
      79             :       }
      80             : 
      81             :       //
      82             :       //   Unpack each value into array ids from the
      83             :       //   the appropriate number of octets, which are specified in
      84             :       //   corresponding entries in array mapid.
      85             :       //
      86         460 :       *ids=(g2int *)calloc(*idslen,sizeof(g2int));
      87         460 :       if (*ids == 0) {
      88           0 :          ierr=6;
      89           0 :          return(ierr);
      90             :       }
      91             : 
      92        6440 :       for (i=0;i<*idslen;i++) {
      93        5980 :         nbits=mapid[i]*8;
      94        5980 :         gbit(cgrib,*ids+i,*iofst,nbits);
      95        5980 :         *iofst=*iofst+nbits;
      96             :       }
      97             : 
      98         460 :       return(ierr);    // End of Section 1 processing
      99             : }