#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "grb2.h"
#include "wgrib2.h"
#include "fnlist.h"

/*
 * Fix_undef.c
 *
 * 2/2020: Public Domain: Wesley Ebisuzaki
 *
 * Some sections have fields that have unused fields, the
 * contents of these fields can be anything.  This causes
 * problems with section to section comparisons.
 */

extern int fix_undef_flag;

/*
 * HEADER:100:fix_undef:setup:0:set unused values to undef
 */

int f_fix_undef(ARG0) {
    fix_undef_flag = 1;
    return 0;
}


int fix_undef(unsigned char **sec) {

    int center, gdt;
    unsigned char *p;
 
    gdt = code_table_3_1(sec);
    center = GB2_Center(sec);
    p = NULL;

    /* get basic angle for grids with subangle */
    switch (gdt) {
	case 0:
	case 1:
	case 2:
	case 3:
	case 4:
	case 40:
	case 41:
	case 42:
	case 43:
	    p = &(sec[3][38]);
	    break;
	case 32768:
	case 32769:
	    if (center == NCEP) p = &(sec[3][38]);
	    break;
    }

    if (p) {
        /* if basic angle is zero, subangle is undefined */
        if (p[0] == 0 && p[1] == 0 && p[2] == 0 && p[3] == 0) {
            p[4] = p[5] = p[6] = p[7] = 255;
        }
    }
    return 0;
}