Line data    Source code

       1             : #include <stdio.h>
       2             : #include <stdlib.h>
       3             : #include <limits.h>
       4             : #include "grib2.h"
       5             : 
       6          16 : g2int pngunpack(unsigned char *cpack,g2int len,g2int *idrstmpl,g2int ndpts,
       7             :                 g2float *fld)
       8             : //$$$  SUBPROGRAM DOCUMENTATION BLOCK
       9             : //                .      .    .                                       .
      10             : // SUBPROGRAM:    pngunpack
      11             : //   PRGMMR: Gilbert          ORG: W/NP11    DATE: 2003-08-27
      12             : //
      13             : // ABSTRACT: This subroutine unpacks a data field that was packed into a
      14             : //   PNG image format
      15             : //   using info from the GRIB2 Data Representation Template 5.41 or 5.40010.
      16             : //
      17             : // PROGRAM HISTORY LOG:
      18             : // 2003-08-27  Gilbert
      19             : //
      20             : // USAGE:    pngunpack(unsigned char *cpack,g2int len,g2int *idrstmpl,g2int ndpts,
      21             : //                     g2float *fld)
      22             : //   INPUT ARGUMENT LIST:
      23             : //     cpack    - The packed data field (character*1 array)
      24             : //     len      - length of packed field cpack().
      25             : //     idrstmpl - Pointer to array of values for Data Representation
      26             : //                Template 5.41 or 5.40010
      27             : //     ndpts    - The number of data values to unpack
      28             : //
      29             : //   OUTPUT ARGUMENT LIST:
      30             : //     fld[]    - Contains the unpacked data values
      31             : //
      32             : // REMARKS: None
      33             : //
      34             : // ATTRIBUTES:
      35             : //   LANGUAGE: C
      36             : //   MACHINE:  IBM SP
      37             : //
      38             : //$$$
      39             : {
      40             : 
      41             :       g2int  *ifld;
      42          16 :       g2int  j,nbits,iret = 0,width,height;
      43             :       g2float  refD, refV,bscale,dscale, bdscale;
      44             :       unsigned char *ctemp;
      45             : 
      46          16 :       rdieee(idrstmpl+0,&refV,1);
      47          16 :       bscale = (g2float)int_power(2.0,idrstmpl[1]);
      48          16 :       dscale = (g2float)int_power(10.0,-idrstmpl[2]);
      49          16 :       bdscale = bscale * dscale;
      50          16 :       refD = refV * dscale;
      51             : 
      52          16 :       nbits = idrstmpl[3];
      53             : //
      54             : //  if nbits equals 0, we have a constant field where the reference value
      55             : //  is the data value at each gridpoint
      56             : //
      57          16 :       if (nbits != 0) {
      58          14 :          int nbytes = nbits/8;
      59          14 :          if( ndpts != 0 && nbytes > INT_MAX / ndpts )
      60             :          {
      61           0 :              return 1;
      62             :          }
      63          14 :          ifld=(g2int *)calloc(ndpts,sizeof(g2int));
      64             :          // Was checked just before
      65             :          // coverity[integer_overflow,overflow_sink]
      66          14 :          ctemp=(unsigned char *)calloc((size_t)(ndpts)*nbytes,1);
      67          14 :          if ( ifld == NULL || ctemp == NULL) {
      68           0 :             fprintf(stderr, "Could not allocate space in jpcunpack.\n"
      69             :                     "Data field NOT unpacked.\n");
      70           0 :             free(ifld);
      71           0 :             free(ctemp);
      72           0 :             return(1);
      73             :          }
      74          14 :          iret=(g2int)dec_png(cpack,len,&width,&height,ctemp, ndpts, nbits);
      75          14 :          gbits(ctemp,ndpts*nbytes,ifld,0,nbits,0,ndpts);
      76     4504420 :          for (j=0;j<ndpts;j++) {
      77     4504410 :             fld[j] = refD + bdscale*(g2float)(ifld[j]);
      78             :          }
      79          14 :          free(ctemp);
      80          14 :          free(ifld);
      81             :       }
      82             :       else {
      83           4 :          for (j=0;j<ndpts;j++) fld[j]=refD;
      84             :       }
      85             : 
      86          16 :       return(iret);
      87             : }