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Diffstat (limited to 'dependencies/SDL/SDL_timer.h')
-rw-r--r-- | dependencies/SDL/SDL_timer.h | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/dependencies/SDL/SDL_timer.h b/dependencies/SDL/SDL_timer.h new file mode 100644 index 0000000..62f81d4 --- /dev/null +++ b/dependencies/SDL/SDL_timer.h @@ -0,0 +1,222 @@ +/* + Simple DirectMedia Layer + Copyright (C) 1997-2022 Sam Lantinga <slouken@libsdl.org> + + This software is provided 'as-is', without any express or implied + warranty. In no event will the authors be held liable for any damages + arising from the use of this software. + + Permission is granted to anyone to use this software for any purpose, + including commercial applications, and to alter it and redistribute it + freely, subject to the following restrictions: + + 1. The origin of this software must not be misrepresented; you must not + claim that you wrote the original software. If you use this software + in a product, an acknowledgment in the product documentation would be + appreciated but is not required. + 2. Altered source versions must be plainly marked as such, and must not be + misrepresented as being the original software. + 3. This notice may not be removed or altered from any source distribution. +*/ + +#ifndef SDL_timer_h_ +#define SDL_timer_h_ + +/** + * \file SDL_timer.h + * + * Header for the SDL time management routines. + */ + +#include "SDL_stdinc.h" +#include "SDL_error.h" + +#include "begin_code.h" +/* Set up for C function definitions, even when using C++ */ +#ifdef __cplusplus +extern "C" { +#endif + +/** + * Get the number of milliseconds since SDL library initialization. + * + * This value wraps if the program runs for more than ~49 days. + * + * This function is not recommended as of SDL 2.0.18; use SDL_GetTicks64() + * instead, where the value doesn't wrap every ~49 days. There are places in + * SDL where we provide a 32-bit timestamp that can not change without + * breaking binary compatibility, though, so this function isn't officially + * deprecated. + * + * \returns an unsigned 32-bit value representing the number of milliseconds + * since the SDL library initialized. + * + * \since This function is available since SDL 2.0.0. + * + * \sa SDL_TICKS_PASSED + */ +extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void); + +/** + * Get the number of milliseconds since SDL library initialization. + * + * Note that you should not use the SDL_TICKS_PASSED macro with values + * returned by this function, as that macro does clever math to compensate for + * the 32-bit overflow every ~49 days that SDL_GetTicks() suffers from. 64-bit + * values from this function can be safely compared directly. + * + * For example, if you want to wait 100 ms, you could do this: + * + * ```c + * const Uint64 timeout = SDL_GetTicks64() + 100; + * while (SDL_GetTicks64() < timeout) { + * // ... do work until timeout has elapsed + * } + * ``` + * + * \returns an unsigned 64-bit value representing the number of milliseconds + * since the SDL library initialized. + * + * \since This function is available since SDL 2.0.18. + */ +extern DECLSPEC Uint64 SDLCALL SDL_GetTicks64(void); + +/** + * Compare 32-bit SDL ticks values, and return true if `A` has passed `B`. + * + * This should be used with results from SDL_GetTicks(), as this macro + * attempts to deal with the 32-bit counter wrapping back to zero every ~49 + * days, but should _not_ be used with SDL_GetTicks64(), which does not have + * that problem. + * + * For example, with SDL_GetTicks(), if you want to wait 100 ms, you could + * do this: + * + * ```c + * const Uint32 timeout = SDL_GetTicks() + 100; + * while (!SDL_TICKS_PASSED(SDL_GetTicks(), timeout)) { + * // ... do work until timeout has elapsed + * } + * ``` + * + * Note that this does not handle tick differences greater + * than 2^31 so take care when using the above kind of code + * with large timeout delays (tens of days). + */ +#define SDL_TICKS_PASSED(A, B) ((Sint32)((B) - (A)) <= 0) + +/** + * Get the current value of the high resolution counter. + * + * This function is typically used for profiling. + * + * The counter values are only meaningful relative to each other. Differences + * between values can be converted to times by using + * SDL_GetPerformanceFrequency(). + * + * \returns the current counter value. + * + * \since This function is available since SDL 2.0.0. + * + * \sa SDL_GetPerformanceFrequency + */ +extern DECLSPEC Uint64 SDLCALL SDL_GetPerformanceCounter(void); + +/** + * Get the count per second of the high resolution counter. + * + * \returns a platform-specific count per second. + * + * \since This function is available since SDL 2.0.0. + * + * \sa SDL_GetPerformanceCounter + */ +extern DECLSPEC Uint64 SDLCALL SDL_GetPerformanceFrequency(void); + +/** + * Wait a specified number of milliseconds before returning. + * + * This function waits a specified number of milliseconds before returning. It + * waits at least the specified time, but possibly longer due to OS + * scheduling. + * + * \param ms the number of milliseconds to delay + * + * \since This function is available since SDL 2.0.0. + */ +extern DECLSPEC void SDLCALL SDL_Delay(Uint32 ms); + +/** + * Function prototype for the timer callback function. + * + * The callback function is passed the current timer interval and returns + * the next timer interval. If the returned value is the same as the one + * passed in, the periodic alarm continues, otherwise a new alarm is + * scheduled. If the callback returns 0, the periodic alarm is cancelled. + */ +typedef Uint32 (SDLCALL * SDL_TimerCallback) (Uint32 interval, void *param); + +/** + * Definition of the timer ID type. + */ +typedef int SDL_TimerID; + +/** + * Call a callback function at a future time. + * + * If you use this function, you must pass `SDL_INIT_TIMER` to SDL_Init(). + * + * The callback function is passed the current timer interval and the user + * supplied parameter from the SDL_AddTimer() call and should return the next + * timer interval. If the value returned from the callback is 0, the timer is + * canceled. + * + * The callback is run on a separate thread. + * + * Timers take into account the amount of time it took to execute the + * callback. For example, if the callback took 250 ms to execute and returned + * 1000 (ms), the timer would only wait another 750 ms before its next + * iteration. + * + * Timing may be inexact due to OS scheduling. Be sure to note the current + * time with SDL_GetTicks() or SDL_GetPerformanceCounter() in case your + * callback needs to adjust for variances. + * + * \param interval the timer delay, in milliseconds, passed to `callback` + * \param callback the SDL_TimerCallback function to call when the specified + * `interval` elapses + * \param param a pointer that is passed to `callback` + * \returns a timer ID or 0 if an error occurs; call SDL_GetError() for more + * information. + * + * \since This function is available since SDL 2.0.0. + * + * \sa SDL_RemoveTimer + */ +extern DECLSPEC SDL_TimerID SDLCALL SDL_AddTimer(Uint32 interval, + SDL_TimerCallback callback, + void *param); + +/** + * Remove a timer created with SDL_AddTimer(). + * + * \param id the ID of the timer to remove + * \returns SDL_TRUE if the timer is removed or SDL_FALSE if the timer wasn't + * found. + * + * \since This function is available since SDL 2.0.0. + * + * \sa SDL_AddTimer + */ +extern DECLSPEC SDL_bool SDLCALL SDL_RemoveTimer(SDL_TimerID id); + + +/* Ends C function definitions when using C++ */ +#ifdef __cplusplus +} +#endif +#include "close_code.h" + +#endif /* SDL_timer_h_ */ + +/* vi: set ts=4 sw=4 expandtab: */ |