// 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); 
}