/*++


Module Name:

    uptime.c

Abstract:

    Program to print UPTIME.

Author:

    Ahdrey Shedel


   You may distribute under the terms of the GNU General Public License
   You can contact author at andreys@cr.cyco.com or http://www.chat.ru/~ashedel

--*/


#define WIN32_LEAN_AND_MEAN
#define _DLL


#include <stdio.h>
#include <windows.h>

#pragma warning(push, 4)


#pragma comment(exestr, "\n\nUPTIME: Copyright (C) 1999 Andrey Shedel (andreys@cr.cyco.com)\n\n")
#pragma comment(lib,"kernel32.lib")
#pragma comment(lib,"ntdll.lib")
#pragma comment(linker, "-entry:raw_main")
#pragma comment(linker, "-opt:nowin98")
#pragma comment(linker, "-subsystem:console")
#pragma comment(linker, "-merge:.rdata=.text")


typedef ULONG NTSTATUS;
typedef short CSHORT;


typedef enum _SYSTEM_INFORMATION_CLASS {
	SystemTimeInformation      = 3,        // 0x20
}SYSTEM_INFORMATION_CLASS; //46 members.


typedef struct _TIME_INFORMATION {
	LARGE_INTEGER BootTime;            // 0x00
	LARGE_INTEGER CurrentTime;         // 0x08
	LARGE_INTEGER TimeZoneBias;        // 0x10
	ULONG CurrentTimeZoneId;           // 0x18
	ULONG Zero;
}TIME_INFORMATION, *PTIME_INFORMATION; // 0x20



NTSYSAPI
NTSTATUS
NTAPI
NtQuerySystemInformation(
    IN SYSTEM_INFORMATION_CLASS InformationClass,
    IN PVOID InfoBuffer,
    IN ULONG BufferSize,
    OUT PULONG LengthReturned
   );





typedef struct _TIME_FIELDS {
    CSHORT Year;        // range [1601...]
    CSHORT Month;       // range [1..12]
    CSHORT Day;         // range [1..31]
    CSHORT Hour;        // range [0..23]
    CSHORT Minute;      // range [0..59]
    CSHORT Second;      // range [0..59]
    CSHORT Milliseconds;// range [0..999]
    CSHORT Weekday;     // range [0..6] == [Sunday..Saturday]
} TIME_FIELDS;
typedef TIME_FIELDS *PTIME_FIELDS;




NTSYSAPI
VOID
NTAPI
RtlTimeToElapsedTimeFields (
    PLARGE_INTEGER Time,
    PTIME_FIELDS TimeFields
   );





__inline
void
__fastcall
_puts(IN const char* msg)
{
	ULONG Written;
	WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), msg,
			  strlen(msg), &Written, NULL);
}




void
__fastcall
uptime_print(
    IN __int64 time
   )
{
	TIME_FIELDS tf;
	char sz[100];

#define format_year_part "%5hu"
#define format_time_part "%hu:%02hu:%02hu.%03hu"

	static const char format[] = format_year_part " " format_time_part;

	RtlTimeToElapsedTimeFields((PLARGE_INTEGER)&time, &tf);

	if(0 != tf.Day)
	{
		sprintf(sz,
				format,
				tf.Day,
				tf.Hour,
				tf.Minute,
				tf.Second,
				tf.Milliseconds);
	}
	else
	{
		sprintf(sz,
				format + sizeof(format_year_part),
				tf.Hour,
				tf.Minute,
				tf.Second,
				tf.Milliseconds);
	}

	_puts(sz);
}


__inline
__int64
uptime_get(void)
{
	TIME_INFORMATION info;
	ULONG length;

	if(NtQuerySystemInformation(
								SystemTimeInformation,
								&info,
								sizeof(info),
								&length
							   ))
	{
		return 0;
	}

	return info.CurrentTime.QuadPart - info.BootTime.QuadPart;
}




void __cdecl raw_main(void)
{
	uptime_print(uptime_get());
	ExitProcess(0);
}