#include <stdio.h>

#include <stdlib.h>

#include <limits.h>

#include "grib2.h"

g2int g2_unpack4(unsigned char *cgrib,g2int cgrib_length,g2int *iofst,g2int *ipdsnum,g2int **ipdstmpl,

               g2int *mappdslen,g2float **coordlist,g2int *numcoord)

////$$$  SUBPROGRAM DOCUMENTATION BLOCK

//                .      .    .                                       .

// SUBPROGRAM:    g2_unpack4

//   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2002-10-31

//

// ABSTRACT: This subroutine unpacks Section 4 (Product Definition Section)

//           as defined in GRIB Edition 2.

//

// PROGRAM HISTORY LOG:

// 2002-10-31  Gilbert

// 2009-01-14  Vuong     Changed structure name template to gtemplate

//

// USAGE:    int g2_unpack4(unsigned char *cgrib,g2int *iofst,g2int *ipdsnum,

//                          g2int **ipdstmpl,g2int *mappdslen,

//                          g2float **coordlist,g2int *numcoord)

//   INPUT ARGUMENTS:

//     cgrib    - Char array containing Section 4 of the GRIB2 message

//     iofst    - Bit offset of the beginning of Section 4 in cgrib.

//

//   OUTPUT ARGUMENTS:

//     iofst    - Bit offset of the end of Section 4, returned.

//     ipdsnum  - Product Definition Template Number ( see Code Table 4.0)

//     ipdstmpl - Pointer to integer array containing the data values for

//                the specified Product Definition

//                Template ( N=ipdsnum ).  Each element of this integer

//                array contains an entry (in the order specified) of Product

//                Definition Template 4.N

//     mappdslen- Number of elements in ipdstmpl[].  i.e. number of entries

//                in Product Definition Template 4.N  ( N=ipdsnum ).

//     coordlist- Pointer to real array containing floating point values

//                intended to document

//                the vertical discretisation associated to model data

//                on hybrid coordinate vertical levels.  (part of Section 4)

//     numcoord - number of values in array coordlist.

//

//   RETURN VALUES:

//     ierr     - Error return code.

//                0 = no error

//                2 = Not section 4

//                5 = "GRIB" message contains an undefined Product Definition

//                    Template.

//                6 = memory allocation error

//

// REMARKS:

//

// ATTRIBUTES:

//   LANGUAGE: C

//   MACHINE:

//

//$$$//

{

      g2int ierr,needext,i,j,nbits,isecnum = 0;

      g2int lensec,isign = 0,newlen;

      g2int *coordieee;

      g2int *lipdstmpl=0;

      g2float *lcoordlist;

      gtemplate *mappds;

      ierr=0;

      *ipdstmpl=0;    // NULL

      *coordlist=0;    // NULL

      gbit2(cgrib,cgrib_length,&lensec,*iofst,32);        // Get Length of Section

      *iofst=*iofst+32;

      gbit2(cgrib,cgrib_length,&isecnum,*iofst,8);         // Get Section Number

      *iofst=*iofst+8;

      if ( isecnum != 4 ) {

         ierr=2;

         *numcoord=0;

         *mappdslen=0;

        // fprintf(stderr,"g2_unpack4: Not Section 4 data.\n");

         return(ierr);

      }

      gbit2(cgrib,cgrib_length,numcoord,*iofst,16);    // Get num of coordinate values

      *iofst=*iofst+16;

      gbit2(cgrib,cgrib_length,ipdsnum,*iofst,16);    // Get Prod. Def Template num.

      *iofst=*iofst+16;

      //   Get Product Definition Template

      mappds=getpdstemplate(*ipdsnum);

      if (mappds == 0) {       // undefine template

        ierr=5;

        *mappdslen=0;

        return(ierr);

      }

      *mappdslen=mappds->maplen;

      needext=mappds->needext;

      //

      //   Unpack each value into array ipdstmpl from the

      //   the appropriate number of octets, which are specified in

      //   corresponding entries in array mappds.

      //

      if (*mappdslen > 0) lipdstmpl=(g2int *)calloc(*mappdslen,sizeof(g2int));

      if (lipdstmpl == 0) {

         ierr=6;

         *mappdslen=0;

         *ipdstmpl=0;     //NULL

         free(mappds);

         return(ierr);

      }

      else {

         *ipdstmpl=lipdstmpl;

      }

      for (i=0;i<mappds->maplen;i++) {

        nbits=abs(mappds->map[i])*8;

        if ( mappds->map[i] >= 0 ) {

          gbit2(cgrib,cgrib_length,lipdstmpl+i,*iofst,nbits);

        }

        else {

          gbit2(cgrib,cgrib_length,&isign,*iofst,1);

          gbit2(cgrib,cgrib_length,lipdstmpl+i,*iofst+1,nbits-1);

          if (isign == 1) lipdstmpl[i]=-1*lipdstmpl[i];

        }

        *iofst=*iofst+nbits;

      }

      //

      //   Check to see if the Product Definition Template needs to be

      //   extended.

      //   The number of values in a specific template may vary

      //   depending on data specified in the "static" part of the

      //   template.

      //

      if ( needext ==1 ) {

        free(mappds);

        mappds=extpdstemplate(*ipdsnum,lipdstmpl);

        newlen=mappds->maplen+mappds->extlen;

        lipdstmpl=(g2int *)realloc(lipdstmpl,newlen*sizeof(g2int));

        *ipdstmpl=lipdstmpl;

        //   Unpack the rest of the Product Definition Template

        j=0;

        for (i=*mappdslen;i<newlen;i++) {

#ifdef notneeded

          if( mappds->ext[j] < INT_MIN / 8 || mappds->ext[j] > INT_MAX / 8 )

          {

              ierr=6;

              *numcoord=0;

              *mappdslen=0;

              *coordlist=0;    // NULL

              *ipdstmpl=0;

              free(mappds->ext);

              free(mappds);

              free(lipdstmpl);

              return(ierr);

          }

#endif

          nbits=abs(mappds->ext[j])*8;

          lipdstmpl[i] = 0;

          if ( mappds->ext[j] >= 0 ) {

            gbit2(cgrib,cgrib_length,lipdstmpl+i,*iofst,nbits);

          }

          else {

            gbit2(cgrib,cgrib_length,&isign,*iofst,1);

            gbit2(cgrib,cgrib_length,lipdstmpl+i,*iofst+1,nbits-1);

            if (isign == 1) lipdstmpl[i]=-1*lipdstmpl[i];

          }

          *iofst=*iofst+nbits;

          j++;

        }

        *mappdslen=newlen;

      }

      free(mappds->ext);

      free(mappds);

      //

      //   Get Optional list of vertical coordinate values

      //   after the Product Definition Template, if necessary.

      //

      *coordlist=0;    // NULL

      if ( *numcoord != 0 ) {

         coordieee=(g2int *)calloc(*numcoord,sizeof(g2int));

         lcoordlist=(g2float *)calloc(*numcoord,sizeof(g2float));

         if (coordieee == 0 || lcoordlist == 0) {

            ierr=6;

            *numcoord=0;

            *coordlist=0;    // NULL

            if( coordieee != 0 ) free(coordieee);

            if( lcoordlist != 0 ) free(lcoordlist);

            return(ierr);

         }

         else {

            *coordlist=lcoordlist;

         }

        gbits(cgrib,cgrib_length,coordieee,*iofst,32,0,*numcoord);

        rdieee(coordieee,*coordlist,*numcoord);

        free(coordieee);

        *iofst=*iofst+(32*(*numcoord));

      }

      return(ierr);    // End of Section 4 processing

}