src/SDL.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2016 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.
*/
#include "./SDL_internal.h"

#if defined(__WIN32__)
#include "core/windows/SDL_windows.h"
#endif

/* Initialization code for SDL */

#include "SDL.h"
#include "SDL_bits.h"
#include "SDL_revision.h"
#include "SDL_assert_c.h"
#include "events/SDL_events_c.h"
#include "haptic/SDL_haptic_c.h"
#include "joystick/SDL_joystick_c.h"

/* Initialization/Cleanup routines */
#if !SDL_TIMERS_DISABLED
extern int SDL_TimerInit(void);
extern void SDL_TimerQuit(void);
extern void SDL_TicksInit(void);
extern void SDL_TicksQuit(void);
#endif
#if SDL_VIDEO_DRIVER_WINDOWS
extern int SDL_HelperWindowCreate(void);
extern int SDL_HelperWindowDestroy(void);
#endif


/* The initialized subsystems */
#ifdef SDL_MAIN_NEEDED
static SDL_bool SDL_MainIsReady = SDL_FALSE;
#else
static SDL_bool SDL_MainIsReady = SDL_TRUE;
#endif
static SDL_bool SDL_bInMainQuit = SDL_FALSE;
static Uint8 SDL_SubsystemRefCount[ 32 ];

/* Private helper to increment a subsystem's ref counter. */
static void
SDL_PrivateSubsystemRefCountIncr(Uint32 subsystem)
{
    int subsystem_index = SDL_MostSignificantBitIndex32(subsystem);
    SDL_assert(SDL_SubsystemRefCount[subsystem_index] < 255);
    ++SDL_SubsystemRefCount[subsystem_index];
}

/* Private helper to decrement a subsystem's ref counter. */
static void
SDL_PrivateSubsystemRefCountDecr(Uint32 subsystem)
{
    int subsystem_index = SDL_MostSignificantBitIndex32(subsystem);
    if (SDL_SubsystemRefCount[subsystem_index] > 0) {
        --SDL_SubsystemRefCount[subsystem_index];
    }
}

/* Private helper to check if a system needs init. */
static SDL_bool
SDL_PrivateShouldInitSubsystem(Uint32 subsystem)
{
    int subsystem_index = SDL_MostSignificantBitIndex32(subsystem);
    SDL_assert(SDL_SubsystemRefCount[subsystem_index] < 255);
    return (SDL_SubsystemRefCount[subsystem_index] == 0);
}

/* Private helper to check if a system needs to be quit. */
static SDL_bool
SDL_PrivateShouldQuitSubsystem(Uint32 subsystem) {
    int subsystem_index = SDL_MostSignificantBitIndex32(subsystem);
    if (SDL_SubsystemRefCount[subsystem_index] == 0) {
      return SDL_FALSE;
    }

    /* If we're in SDL_Quit, we shut down every subsystem, even if refcount
     * isn't zero.
     */
    return SDL_SubsystemRefCount[subsystem_index] == 1 || SDL_bInMainQuit;
}

void
SDL_SetMainReady(void)
{
    SDL_MainIsReady = SDL_TRUE;
}

int
SDL_InitSubSystem(Uint32 flags)
{
    if (!SDL_MainIsReady) {
        SDL_SetError("Application didn't initialize properly, did you include SDL_main.h in the file containing your main() function?");
        return -1;
    }

    /* Clear the error message */
    SDL_ClearError();

#if SDL_VIDEO_DRIVER_WINDOWS
	if ((flags & (SDL_INIT_HAPTIC|SDL_INIT_JOYSTICK))) {
		if (SDL_HelperWindowCreate() < 0) {
			return -1;
		}
	}
#endif

#if !SDL_TIMERS_DISABLED
    SDL_TicksInit();
#endif

    if ((flags & SDL_INIT_GAMECONTROLLER)) {
        /* game controller implies joystick */
        flags |= SDL_INIT_JOYSTICK;
    }

    if ((flags & (SDL_INIT_VIDEO|SDL_INIT_JOYSTICK))) {
        /* video or joystick implies events */
        flags |= SDL_INIT_EVENTS;
    }

    /* Initialize the event subsystem */
    if ((flags & SDL_INIT_EVENTS)) {
#if !SDL_EVENTS_DISABLED
        if (SDL_PrivateShouldInitSubsystem(SDL_INIT_EVENTS)) {
            if (SDL_StartEventLoop() < 0) {
                return (-1);
            }
            SDL_QuitInit();
        }
        SDL_PrivateSubsystemRefCountIncr(SDL_INIT_EVENTS);
#else
        return SDL_SetError("SDL not built with events support");
#endif
    }

    /* Initialize the timer subsystem */
    if ((flags & SDL_INIT_TIMER)){
#if !SDL_TIMERS_DISABLED
        if (SDL_PrivateShouldInitSubsystem(SDL_INIT_TIMER)) {
            if (SDL_TimerInit() < 0) {
                return (-1);
            }
        }
        SDL_PrivateSubsystemRefCountIncr(SDL_INIT_TIMER);
#else
        return SDL_SetError("SDL not built with timer support");
#endif
    }

    /* Initialize the video subsystem */
    if ((flags & SDL_INIT_VIDEO)){
#if !SDL_VIDEO_DISABLED
        if (SDL_PrivateShouldInitSubsystem(SDL_INIT_VIDEO)) {
            if (SDL_VideoInit(NULL) < 0) {
                return (-1);
            }
        }
        SDL_PrivateSubsystemRefCountIncr(SDL_INIT_VIDEO);
#else
        return SDL_SetError("SDL not built with video support");
#endif
    }

    /* Initialize the audio subsystem */
    if ((flags & SDL_INIT_AUDIO)){
#if !SDL_AUDIO_DISABLED
        if (SDL_PrivateShouldInitSubsystem(SDL_INIT_AUDIO)) {
            if (SDL_AudioInit(NULL) < 0) {
                return (-1);
            }
        }
        SDL_PrivateSubsystemRefCountIncr(SDL_INIT_AUDIO);
#else
        return SDL_SetError("SDL not built with audio support");
#endif
    }

    /* Initialize the joystick subsystem */
    if ((flags & SDL_INIT_JOYSTICK)){
#if !SDL_JOYSTICK_DISABLED
        if (SDL_PrivateShouldInitSubsystem(SDL_INIT_JOYSTICK)) {
           if (SDL_JoystickInit() < 0) {
               return (-1);
           }
        }
        SDL_PrivateSubsystemRefCountIncr(SDL_INIT_JOYSTICK);
#else
        return SDL_SetError("SDL not built with joystick support");
#endif
    }

    if ((flags & SDL_INIT_GAMECONTROLLER)){
#if !SDL_JOYSTICK_DISABLED
        if (SDL_PrivateShouldInitSubsystem(SDL_INIT_GAMECONTROLLER)) {
            if (SDL_GameControllerInit() < 0) {
                return (-1);
            }
        }
        SDL_PrivateSubsystemRefCountIncr(SDL_INIT_GAMECONTROLLER);
#else
        return SDL_SetError("SDL not built with joystick support");
#endif
    }

    /* Initialize the haptic subsystem */
    if ((flags & SDL_INIT_HAPTIC)){
#if !SDL_HAPTIC_DISABLED
        if (SDL_PrivateShouldInitSubsystem(SDL_INIT_HAPTIC)) {
            if (SDL_HapticInit() < 0) {
                return (-1);
            }
        }
        SDL_PrivateSubsystemRefCountIncr(SDL_INIT_HAPTIC);
#else
        return SDL_SetError("SDL not built with haptic (force feedback) support");
#endif
    }

    return (0);
}

int
SDL_Init(Uint32 flags)
{
    return SDL_InitSubSystem(flags);
}

void
SDL_QuitSubSystem(Uint32 flags)
{
    /* Shut down requested initialized subsystems */
#if !SDL_JOYSTICK_DISABLED
    if ((flags & SDL_INIT_GAMECONTROLLER)) {
        /* game controller implies joystick */
        flags |= SDL_INIT_JOYSTICK;

        if (SDL_PrivateShouldQuitSubsystem(SDL_INIT_GAMECONTROLLER)) {
            SDL_GameControllerQuit();
        }
        SDL_PrivateSubsystemRefCountDecr(SDL_INIT_GAMECONTROLLER);
    }

    if ((flags & SDL_INIT_JOYSTICK)) {
        /* joystick implies events */
        flags |= SDL_INIT_EVENTS;

        if (SDL_PrivateShouldQuitSubsystem(SDL_INIT_JOYSTICK)) {
            SDL_JoystickQuit();
        }
        SDL_PrivateSubsystemRefCountDecr(SDL_INIT_JOYSTICK);
    }
#endif

#if !SDL_HAPTIC_DISABLED
    if ((flags & SDL_INIT_HAPTIC)) {
        if (SDL_PrivateShouldQuitSubsystem(SDL_INIT_HAPTIC)) {
            SDL_HapticQuit();
        }
        SDL_PrivateSubsystemRefCountDecr(SDL_INIT_HAPTIC);
    }
#endif

#if !SDL_AUDIO_DISABLED
    if ((flags & SDL_INIT_AUDIO)) {
        if (SDL_PrivateShouldQuitSubsystem(SDL_INIT_AUDIO)) {
            SDL_AudioQuit();
        }
        SDL_PrivateSubsystemRefCountDecr(SDL_INIT_AUDIO);
    }
#endif

#if !SDL_VIDEO_DISABLED
    if ((flags & SDL_INIT_VIDEO)) {
        /* video implies events */
        flags |= SDL_INIT_EVENTS;

        if (SDL_PrivateShouldQuitSubsystem(SDL_INIT_VIDEO)) {
            SDL_VideoQuit();
        }
        SDL_PrivateSubsystemRefCountDecr(SDL_INIT_VIDEO);
    }
#endif

#if !SDL_TIMERS_DISABLED
    if ((flags & SDL_INIT_TIMER)) {
        if (SDL_PrivateShouldQuitSubsystem(SDL_INIT_TIMER)) {
            SDL_TimerQuit();
        }
        SDL_PrivateSubsystemRefCountDecr(SDL_INIT_TIMER);
    }
#endif

#if !SDL_EVENTS_DISABLED
    if ((flags & SDL_INIT_EVENTS)) {
        if (SDL_PrivateShouldQuitSubsystem(SDL_INIT_EVENTS)) {
            SDL_QuitQuit();
            SDL_StopEventLoop();
        }
        SDL_PrivateSubsystemRefCountDecr(SDL_INIT_EVENTS);
    }
#endif
}

Uint32
SDL_WasInit(Uint32 flags)
{
    int i;
    int num_subsystems = SDL_arraysize(SDL_SubsystemRefCount);
    Uint32 initialized = 0;

    if (!flags) {
        flags = SDL_INIT_EVERYTHING;
    }

    num_subsystems = SDL_min(num_subsystems, SDL_MostSignificantBitIndex32(flags) + 1);

    /* Iterate over each bit in flags, and check the matching subsystem. */
    for (i = 0; i < num_subsystems; ++i) {
        if ((flags & 1) && SDL_SubsystemRefCount[i] > 0) {
            initialized |= (1 << i);
        }

        flags >>= 1;
    }

    return initialized;
}

void
SDL_Quit(void)
{
    SDL_bInMainQuit = SDL_TRUE;

    /* Quit all subsystems */
#if SDL_VIDEO_DRIVER_WINDOWS
    SDL_HelperWindowDestroy();
#endif
    SDL_QuitSubSystem(SDL_INIT_EVERYTHING);

#if !SDL_TIMERS_DISABLED
    SDL_TicksQuit();
#endif

    SDL_ClearHints();
    SDL_AssertionsQuit();
    SDL_LogResetPriorities();

    /* Now that every subsystem has been quit, we reset the subsystem refcount
     * and the list of initialized subsystems.
     */
    SDL_memset( SDL_SubsystemRefCount, 0x0, sizeof(SDL_SubsystemRefCount) );

    SDL_bInMainQuit = SDL_FALSE;
}

/* Get the library version number */
void
SDL_GetVersion(SDL_version * ver)
{
    SDL_VERSION(ver);
}

/* Get the library source revision */
const char *
SDL_GetRevision(void)
{
    return SDL_REVISION;
}

/* Get the library source revision number */
int
SDL_GetRevisionNumber(void)
{
    return SDL_REVISION_NUMBER;
}

/* Get the name of the platform */
const char *
SDL_GetPlatform()
{
#if __AIX__
    return "AIX";
#elif __ANDROID__
    return "Android";
#elif __BSDI__
    return "BSDI";
#elif __DREAMCAST__
    return "Dreamcast";
#elif __EMSCRIPTEN__
    return "Emscripten";
#elif __FREEBSD__
    return "FreeBSD";
#elif __HAIKU__
    return "Haiku";
#elif __HPUX__
    return "HP-UX";
#elif __IRIX__
    return "Irix";
#elif __LINUX__
    return "Linux";
#elif __MINT__
    return "Atari MiNT";
#elif __MACOS__
    return "MacOS Classic";
#elif __MACOSX__
    return "Mac OS X";
#elif __NACL__
    return "NaCl";
#elif __NETBSD__
    return "NetBSD";
#elif __OPENBSD__
    return "OpenBSD";
#elif __OS2__
    return "OS/2";
#elif __OSF__
    return "OSF/1";
#elif __QNXNTO__
    return "QNX Neutrino";
#elif __RISCOS__
    return "RISC OS";
#elif __SOLARIS__
    return "Solaris";
#elif __WIN32__
    return "Windows";
#elif __WINRT__
    return "WinRT";
#elif __TVOS__
    return "tvOS";
#elif __IPHONEOS__
    return "iOS";
#elif __PSP__
    return "PlayStation Portable";
#else
    return "Unknown (see SDL_platform.h)";
#endif
}

#if defined(__WIN32__)

#if !defined(HAVE_LIBC) || (defined(__WATCOMC__) && defined(BUILD_DLL))
/* Need to include DllMain() on Watcom C for some reason.. */

BOOL APIENTRY
_DllMainCRTStartup(HANDLE hModule,
                   DWORD ul_reason_for_call, LPVOID lpReserved)
{
    switch (ul_reason_for_call) {
    case DLL_PROCESS_ATTACH:
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
    }
    return TRUE;
}
#endif /* building DLL with Watcom C */

#endif /* __WIN32__ */

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