g2_unpack2.c

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#include "grib2_int.h"
#include <stdio.h>
#include <stdlib.h>
 
g2int
g2_unpack2(unsigned char *cgrib, g2int *iofst, g2int *lencsec2,
           unsigned char **csec2)
{
    g2int isecnum;
    g2int lensec, ipos, j;
 
    *lencsec2 = 0;
    *csec2 = NULL;
 
    /* Get Length of Section. */
    gbit(cgrib, &lensec, *iofst, 32);
    *iofst = *iofst + 32;
    *lencsec2 = lensec - 5;
 
    /* Get Section Number. */
    gbit(cgrib, &isecnum, *iofst, 8);
    *iofst = *iofst + 8;
    ipos = *iofst / 8;
 
    if (isecnum != 2)
    {
        *lencsec2 = 0;
        fprintf(stderr, "g2_unpack2: Not Section 2 data.\n");
        return G2_UNPACK_BAD_SEC;
    }
 
    /* If the length is 0, we are done. */
    if (*lencsec2 == 0)
        return G2_NO_ERROR;
 
    if (!(*csec2 = malloc(*lencsec2)))
    {
        *lencsec2 = 0;
        return G2_UNPACK_NO_MEM;
    }
 
    for (j = 0; j < *lencsec2; j++)
        (*csec2)[j] = cgrib[ipos + j];
 
    *iofst = *iofst + (*lencsec2 * 8);
 
    return G2_NO_ERROR;
}