// host_os.cpp	host operating system classes

//		dave mccaldon (d.mccalden@staffordshire.ac.uk)



#include "host_os.h"

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <dos.h>



char *msdos_info (void)

{

	return ("MS-DOS version %d.%d");

};



char *dosemu_info (void)

{

	return ("Linux dosemu version %d.%d");

};



char *mswindows_info (void)

{

	return ("MS-Windows version %d.%d");

};



char *desqview_info (void)

{

	return ("Desq-View version %d.%d");

};



host_os::host_os (void)

{

	status = NOT_OK;

	if (mswindows_detect () == true) format = mswindows_info;

//	else if (dosemu_detect () == true) format = dosemu_info;

	else if (desqview_detect () == true) format = desqview_info;

	else

	{

		status = OK;

		msdos_version ();

		format = msdos_info;

	}

}





char *host_os::information( char *p )

{

	if( p == NULL )

		p = (char *) malloc( strlen( format() ) + 12 );

	sprintf( p, format(), ver_major, ver_minor );



	return p;

}



void host_os::msdos_version()

{

	ver_major = _osmajor;			// borlandc constants

	ver_minor = _osminor;

}



boolean host_os::mswindows_detect()

{

	union   REGS r;



	r.x.ax = 0x1600;

	int86( 0x2F, &r, &r );

	if( r.h.al & 0x7F )

	{

		ver_major = r.h.al;

		ver_minor = r.h.ah;

		return (true);

	}



	return (false);

}



boolean host_os::dosemu_detect()

{

	union   REGS r;



	// this is slightly more difficult than just calling the dosemu

	// interrupt (0xE5), we need to check if the interrupt has a

	// handler, as DOS and BIOS don't establish a default handler



	if( getvect( 0xE5 ) == NULL )

		return (false);

	r.x.ax = 0;

	int86( 0xE5, &r, &r );

	if( r.x.ax == 0xAA55 )			// check signature

	{

		ver_major = r.h.bh;

		ver_minor = r.h.bl;

		return (true);

	}



	return (false);

}



boolean host_os::desqview_detect()

{

	union   REGS r;



	r.x.ax = 0x2B01;                // AL=01 => get desqview version

	r.x.cx = 0x4445;		// CX = 'DE'

	r.x.dx = 0x5351;		// DX = 'SQ'

	int86( 0x21, &r, &r );

	if( r.h.al != 0xFF )

	{

		ver_major = r.h.bh;

		ver_minor = r.h.bl;

		return (true);

	}



	return (false);

}