i_system.h

// SONIC ROBO BLAST 2
//-----------------------------------------------------------------------------
// Copyright (C) 1993-1996 by id Software, Inc.
// Copyright (C) 1998-2000 by DooM Legacy Team.
// Copyright (C) 1999-2023 by Sonic Team Junior.
//
// This program is free software distributed under the
// terms of the GNU General Public License, version 2.
// See the 'LICENSE' file for more details.
//-----------------------------------------------------------------------------
/// \file  i_system.h
/// \brief System specific interface stuff.

#ifndef __I_SYSTEM__
#define __I_SYSTEM__

#include "d_ticcmd.h"
#include "d_event.h"

#ifdef __GNUG__
#pragma interface
#endif

/**	\brief max quit functions
*/
#define MAX_QUIT_FUNCS     16


/**	\brief Graphic system had started up
*/
extern UINT8 graphics_started;

/**	\brief Keyboard system is up and run
*/
extern UINT8 keyboard_started;

/**	\brief	The I_GetFreeMem function

	\param	total	total memory in the system

	\return	free memory in the system
*/
size_t I_GetFreeMem(size_t *total);

/**	\brief	Returns precise time value for performance measurement. The precise
            time should be a monotonically increasing counter, and will wrap.
			precise_t is internally represented as an unsigned integer and
			integer arithmetic may be used directly between values of precise_t.
  */
precise_t I_GetPreciseTime(void);

/**	\brief	Fills a buffer with random data, returns amount of data obtained.
  */
size_t I_GetRandomBytes(char *destination, size_t count);

/** \brief  Get the precision of precise_t in units per second. Invocations of
            this function for the program's duration MUST return the same value.
  */
UINT64 I_GetPrecisePrecision(void);

/** \brief  Get the current time in rendering tics, including fractions.
*/
double I_GetFrameTime(void);

/**	\brief	Sleeps for the given duration in milliseconds. Depending on the
            operating system's scheduler, the calling thread may give up its
			time slice for a longer duration. The implementation should give a
			best effort to sleep for the given duration, without spin-locking.
			Calling code should check the current precise time after sleeping
			and not assume the thread has slept for the expected duration.