Coverage Report

Created: 2025-06-09 08:44

/src/gdal/frmts/grib/degrib/g2clib/jpcunpack.c
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#include <float.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "grib2.h"
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static float DoubleToFloatClamp(double val) {
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   if (val >= FLT_MAX) return FLT_MAX;
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   if (val <= -FLT_MAX) return -FLT_MAX;
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   return (float)val;
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}
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g2int jpcunpack(unsigned char *cpack,g2int len,g2int *idrstmpl,g2int ndpts,
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                g2float **fld)
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//$$$  SUBPROGRAM DOCUMENTATION BLOCK
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//                .      .    .                                       .
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// SUBPROGRAM:    jpcunpack
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//   PRGMMR: Gilbert          ORG: W/NP11    DATE: 2003-08-27
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//
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// ABSTRACT: This subroutine unpacks a data field that was packed into a
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//   JPEG2000 code stream
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//   using info from the GRIB2 Data Representation Template 5.40 or 5.40000.
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//
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// PROGRAM HISTORY LOG:
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// 2003-08-27  Gilbert
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//
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// USAGE:    jpcunpack(unsigned char *cpack,g2int len,g2int *idrstmpl,g2int ndpts,
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//                     g2float *fld)
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//   INPUT ARGUMENT LIST:
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//     cpack    - The packed data field (character*1 array)
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//     len      - length of packed field cpack().
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//     idrstmpl - Pointer to array of values for Data Representation
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//                Template 5.40 or 5.40000
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//     ndpts    - The number of data values to unpack
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//
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//   OUTPUT ARGUMENT LIST:
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//     fld[]    - Contains the unpacked data values
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//
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// REMARKS: None
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//
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// ATTRIBUTES:
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//   LANGUAGE: C
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//   MACHINE:  IBM SP
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//
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//$$$
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{
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      g2int  *ifld;
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      g2int  j,nbits, iret;
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      g2float  ref,bscale,dscale;
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      rdieee(idrstmpl+0,&ref,1);
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      bscale = DoubleToFloatClamp(int_power(2.0,idrstmpl[1]));
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      dscale = DoubleToFloatClamp(int_power(10.0,-idrstmpl[2]));
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      nbits = idrstmpl[3];
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//
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//  if nbits equals 0, we have a constant field where the reference value
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//  is the data value at each gridpoint
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//
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      *fld = 0;
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      if (nbits != 0) {
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         ifld = NULL;
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         iret= (g2int) dec_jpeg2000(cpack,len,&ifld,ndpts);
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         if( iret != 0 )
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         {
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             free(ifld);
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             return -1;
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         }
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         *fld =(g2float *)calloc(ndpts,sizeof(g2float));
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         if( *fld == 0 )
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         {
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             free(ifld);
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             return -1;
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         }
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         for (j=0;j<ndpts;j++) {
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           (*fld)[j]=(((g2float)ifld[j]*bscale)+ref)*dscale;
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         }
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         free(ifld);
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      }
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      else {
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         // Limit to 2 GB
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         if( ndpts > 500 * 1024 * 1024 )
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         {
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             fprintf(stderr, "jpcunpack: ndpts = %d > 500 * 1024 * 1024", ndpts );
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             return -1;
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         }
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         *fld =(g2float *)calloc(ndpts,sizeof(g2float));
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         if( *fld == 0 )
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         {
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             return -1;
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         }
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         for (j=0;j<ndpts;j++) (*fld)[j]=ref * dscale;
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      }
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      return(0);
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}