jpcunpack.c

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#include "grib2_int.h"
#include <stdio.h>
#include <stdlib.h>
 
static int
jpcunpack_int(unsigned char *cpack, g2int len, g2int *idrstmpl, g2int ndpts,
              void *fld, int fld_is_double, int verbose)
{
    g2int *ifld;
    g2int j, nbits;
    float ref, bscale, dscale;
    float *ffld = fld;
    double *dfld = fld;
 
    LOG((2, "jpcunpack_int len %ld ndpts %ld fld_is_double %d", len, ndpts, fld_is_double));
 
    rdieee(idrstmpl, &ref, 1);
    bscale = int_power(2.0, idrstmpl[1]);
    dscale = int_power(10.0, -idrstmpl[2]);
    nbits = idrstmpl[3];
 
    /* If nbits equals 0, we have a constant field where the reference
     * value is the data value at each gridpoint. */
    if (nbits != 0)
    {
        if (!(ifld = calloc(ndpts, sizeof(g2int))))
        {
            if (verbose)
                fprintf(stderr, "Could not allocate space in jpcunpack.\n  Data field NOT upacked.\n");
            return G2C_ENOMEM;
        }
        dec_jpeg2000((char *)cpack, len, ifld);
        if (fld_is_double)
        {
            for (j = 0; j < ndpts; j++)
                dfld[j] = (((float)ifld[j] * bscale) + ref) * dscale;
        }
        else
        {
            for (j = 0; j < ndpts; j++)
                ffld[j] = (((float)ifld[j] * bscale) + ref) * dscale;
        }
        free(ifld);
    }
    else
    {
        if (fld_is_double)
        {
            for (j = 0; j < ndpts; j++)
                dfld[j] = ref;
        }
        else
        {
            for (j = 0; j < ndpts; j++)
                ffld[j] = ref;
        }
    }
 
    return G2C_NOERROR;
}
 
g2int
jpcunpack(unsigned char *cpack, g2int len, g2int *idrstmpl, g2int ndpts,
          float *fld)
{
    int ret;
 
    LOG((2, "g2c_jpcunpack len %lld ndpts %lld", len, ndpts));
 
    if ((ret = jpcunpack_int(cpack, len, idrstmpl, ndpts, fld, 0, 1)) == G2_JPCUNPACK_MEM)
        return G2_JPCUNPACK_MEM;
 
    return ret;
}
 
int
g2c_jpcunpackf(unsigned char *cpack, size_t len, int *idrstmpl, size_t ndpts,
               float *fld)
{
    g2int idrstmpl8[G2C_JPEG_DRS_TEMPLATE_LEN];
    g2int len8 = len, ndpts8 = ndpts;
    int i;
 
    LOG((2, "g2c_jpcunpackf len %d ndpts %lld", len, ndpts));
 
    for (i = 0; i < G2C_JPEG_DRS_TEMPLATE_LEN; i++)
        idrstmpl8[i] = idrstmpl[i];
 
    return jpcunpack_int(cpack, len8, idrstmpl8, ndpts8, fld, 0, 0);
}
 
int
g2c_jpcunpackd(unsigned char *cpack, size_t len, int *idrstmpl, size_t ndpts,
               double *fld)
{
    g2int idrstmpl8[G2C_JPEG_DRS_TEMPLATE_LEN];
    g2int len8 = len, ndpts8 = ndpts;
    int i;
 
    LOG((2, "g2c_jpcunpackd len %lld ndpts %lld", len, ndpts));
 
    for (i = 0; i < G2C_JPEG_DRS_TEMPLATE_LEN; i++)
        idrstmpl8[i] = idrstmpl[i];
 
    return jpcunpack_int(cpack, len8, idrstmpl8, ndpts8, fld, 1, 0);
}