#define _GDSTOOL_

/*
 * 3/29/2001 fix in new_polar_GDS by Gerry Wiener
 * 6/3/2001 change roundoff, suggested by Steven Danz
 */

/* round vs trunctation */

#include <math.h>
#ifndef RINT
#define RINT(a)	((int) floor((a)+0.5))
#endif

unsigned char *GDStool(unsigned char *pds, unsigned char *gds, ...);

enum g_tool {g_end, g_init, g_byte, g_2bytes, g_s2bytes,
   g_3bytes, g_s3bytes, g_bit, g_and, g_or};           

/* choose one set */

/*
   for fortran grid: real data(nlon,nlat)

   nlat/nlon = number of lat/lon rows/columns
   lat1/lon1 = lat/lon of data(1,1)
   lat2/lon2 = lat/lon of data(nlon,nlat)

   for S or W, use negative value

   dlon, dlat = degrees of lon/lat of grid interval

 */

#define new_LatLon_GDS(pds,nlon,nlat,lon1,lat1,lon2,lat2,dlon,dlat) \
	GDStool(pds,NULL,g_init,32,0,g_2bytes,6,nlon,g_2bytes,8,nlat, \
	g_s3bytes,10,RINT(1000.0*(lat1)),g_s3bytes,13,RINT(1000.0*(lon1)), \
	g_s3bytes,17,RINT(1000.0*(lat2)),g_s3bytes,20,RINT(1000.0*(lon2)), \
	g_s2bytes,23,RINT(1000.0*(dlon)),g_s2bytes,25,RINT(1000.0*(dlat)), \
	g_or, 27, ((lat1) < (lat2)) * 64, \
	g_byte,16,128,g_byte,4,255,g_end)

/*
   For gaussian grid(nlon,nlat)

   nlon/nlat = number of lon/lat points
   lon1,lat1 = coordinates of grid(1,1)

  */

#define new_Gaussian_GDS(pds,nlon,nlat,lon1,lat1) \
	GDStool(pds,NULL,g_init,32,0,g_2bytes,6,nlon,g_2bytes,8,nlat, \
	g_s3bytes,10,RINT(1000.0*(lat1)), \
	g_s3bytes,13,RINT(1000.0*(lon1)), \
	g_s3bytes,17,RINT(-1000.0*(lat1)), \
        g_s3bytes,20,RINT(1000.0*((lon1)+360.0-360.0/(nlon))), \
	g_s2bytes,23,RINT(1000.0*360.0 / nlon),g_s2bytes,25, nlat / 2, \
	g_or, 27, ((lat1) < 0.0) * 64, \
	g_byte,16,128,g_byte,4,255,g_byte,5,4,g_end)
	
/*
 * make a polar stereographic GDS
 *
 * (nx,ny) = grid dimensions
 * (lon1,lat1) = lon/lat of first grid point (deg)
 * lov = the orientation of the grids
 * (dx,dy) = grid length (km) at 60N or 60S
 * south_pole = 1 for south polar stereographics, 0 for nps
 * scan_s2n = 1 if grid is written from south to north else 0
 */

#define new_polar_GDS(pds,nx,ny,lon1,lat1,lov,dx,dy,south_pole,scan_s2n) \
        GDStool(pds,NULL,g_init,32,0,g_byte,5,5,g_byte,4,255,\
	g_2bytes,6,nx,g_2bytes,8,ny,g_s3bytes,10,(int) (1000.0*(lat1)),\
	g_s3bytes,13,RINT(1000.0*(lon1)),g_byte,16,128,\
	g_s3bytes,17,RINT(1000.0*(lov)),g_s3bytes,20,(int) (1000.0*(dx)),\
	g_s3bytes,23,RINT(1000.0*(dy)),g_byte,26,south_pole*128,\
	g_byte,27,scan_s2n*64,g_end)