diff options
Diffstat (limited to '3rdparty/SDL2/src/thread/generic/SDL_syssem.c')
-rw-r--r-- | 3rdparty/SDL2/src/thread/generic/SDL_syssem.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/3rdparty/SDL2/src/thread/generic/SDL_syssem.c b/3rdparty/SDL2/src/thread/generic/SDL_syssem.c new file mode 100644 index 00000000000..92afcb0c07f --- /dev/null +++ b/3rdparty/SDL2/src/thread/generic/SDL_syssem.c @@ -0,0 +1,217 @@ +/* + 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" + +/* An implementation of semaphores using mutexes and condition variables */ + +#include "SDL_timer.h" +#include "SDL_thread.h" +#include "SDL_systhread_c.h" + + +#if SDL_THREADS_DISABLED + +SDL_sem * +SDL_CreateSemaphore(Uint32 initial_value) +{ + SDL_SetError("SDL not built with thread support"); + return (SDL_sem *) 0; +} + +void +SDL_DestroySemaphore(SDL_sem * sem) +{ +} + +int +SDL_SemTryWait(SDL_sem * sem) +{ + return SDL_SetError("SDL not built with thread support"); +} + +int +SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout) +{ + return SDL_SetError("SDL not built with thread support"); +} + +int +SDL_SemWait(SDL_sem * sem) +{ + return SDL_SetError("SDL not built with thread support"); +} + +Uint32 +SDL_SemValue(SDL_sem * sem) +{ + return 0; +} + +int +SDL_SemPost(SDL_sem * sem) +{ + return SDL_SetError("SDL not built with thread support"); +} + +#else + +struct SDL_semaphore +{ + Uint32 count; + Uint32 waiters_count; + SDL_mutex *count_lock; + SDL_cond *count_nonzero; +}; + +SDL_sem * +SDL_CreateSemaphore(Uint32 initial_value) +{ + SDL_sem *sem; + + sem = (SDL_sem *) SDL_malloc(sizeof(*sem)); + if (!sem) { + SDL_OutOfMemory(); + return NULL; + } + sem->count = initial_value; + sem->waiters_count = 0; + + sem->count_lock = SDL_CreateMutex(); + sem->count_nonzero = SDL_CreateCond(); + if (!sem->count_lock || !sem->count_nonzero) { + SDL_DestroySemaphore(sem); + return NULL; + } + + return sem; +} + +/* WARNING: + You cannot call this function when another thread is using the semaphore. +*/ +void +SDL_DestroySemaphore(SDL_sem * sem) +{ + if (sem) { + sem->count = 0xFFFFFFFF; + while (sem->waiters_count > 0) { + SDL_CondSignal(sem->count_nonzero); + SDL_Delay(10); + } + SDL_DestroyCond(sem->count_nonzero); + if (sem->count_lock) { + SDL_LockMutex(sem->count_lock); + SDL_UnlockMutex(sem->count_lock); + SDL_DestroyMutex(sem->count_lock); + } + SDL_free(sem); + } +} + +int +SDL_SemTryWait(SDL_sem * sem) +{ + int retval; + + if (!sem) { + return SDL_SetError("Passed a NULL semaphore"); + } + + retval = SDL_MUTEX_TIMEDOUT; + SDL_LockMutex(sem->count_lock); + if (sem->count > 0) { + --sem->count; + retval = 0; + } + SDL_UnlockMutex(sem->count_lock); + + return retval; +} + +int +SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout) +{ + int retval; + + if (!sem) { + return SDL_SetError("Passed a NULL semaphore"); + } + + /* A timeout of 0 is an easy case */ + if (timeout == 0) { + return SDL_SemTryWait(sem); + } + + SDL_LockMutex(sem->count_lock); + ++sem->waiters_count; + retval = 0; + while ((sem->count == 0) && (retval != SDL_MUTEX_TIMEDOUT)) { + retval = SDL_CondWaitTimeout(sem->count_nonzero, + sem->count_lock, timeout); + } + --sem->waiters_count; + if (retval == 0) { + --sem->count; + } + SDL_UnlockMutex(sem->count_lock); + + return retval; +} + +int +SDL_SemWait(SDL_sem * sem) +{ + return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); +} + +Uint32 +SDL_SemValue(SDL_sem * sem) +{ + Uint32 value; + + value = 0; + if (sem) { + SDL_LockMutex(sem->count_lock); + value = sem->count; + SDL_UnlockMutex(sem->count_lock); + } + return value; +} + +int +SDL_SemPost(SDL_sem * sem) +{ + if (!sem) { + return SDL_SetError("Passed a NULL semaphore"); + } + + SDL_LockMutex(sem->count_lock); + if (sem->waiters_count > 0) { + SDL_CondSignal(sem->count_nonzero); + } + ++sem->count; + SDL_UnlockMutex(sem->count_lock); + + return 0; +} + +#endif /* SDL_THREADS_DISABLED */ +/* vi: set ts=4 sw=4 expandtab: */ |