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author | Hendrik Leppkes <h.leppkes@gmail.com> | 2015-10-10 10:45:16 +0300 |
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committer | Hendrik Leppkes <h.leppkes@gmail.com> | 2015-10-10 10:45:16 +0300 |
commit | 89da893c880d872c6615308d3223e755c3fc8dd2 (patch) | |
tree | 2f59c6fd0b93e20bfa69f4b5dcf290687c81808e /compat/w32pthreads.h | |
parent | 3e3779cd517e4d2d1f21d5eb6afdb428cd3c1aa0 (diff) | |
parent | b22693b06d1e5d73454a65c203b4d31c1ca5b69a (diff) |
Merge commit 'b22693b06d1e5d73454a65c203b4d31c1ca5b69a'
* commit 'b22693b06d1e5d73454a65c203b4d31c1ca5b69a':
w32pthreads: Add pthread_once emulation
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>
Diffstat (limited to 'compat/w32pthreads.h')
-rw-r--r-- | compat/w32pthreads.h | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/compat/w32pthreads.h b/compat/w32pthreads.h index deb1c536af..700a726e87 100644 --- a/compat/w32pthreads.h +++ b/compat/w32pthreads.h @@ -124,6 +124,19 @@ static inline int pthread_mutex_unlock(pthread_mutex_t *m) } #if _WIN32_WINNT >= 0x0600 +typedef INIT_ONCE pthread_once_t; +#define PTHREAD_ONCE_INIT INIT_ONCE_STATIC_INIT + +static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void)) +{ + BOOL pending = FALSE; + InitOnceBeginInitialize(once_control, 0, &pending, NULL); + if (pending) + init_routine(); + InitOnceComplete(once_control, 0, NULL); + return 0; +} + static inline int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr) { InitializeConditionVariable(cond); @@ -155,8 +168,63 @@ static inline int pthread_cond_signal(pthread_cond_t *cond) } #else // _WIN32_WINNT < 0x0600 +/* for pre-Windows 6.0 platforms, define INIT_ONCE struct, + * compatible to the one used in the native API */ + +typedef union pthread_once_t { + void * Ptr; ///< For the Windows 6.0+ native functions + LONG state; ///< For the pre-Windows 6.0 compat code +} pthread_once_t; + +#define PTHREAD_ONCE_INIT {0} + +/* function pointers to init once API on windows 6.0+ kernels */ +static BOOL (WINAPI *initonce_begin)(pthread_once_t *lpInitOnce, DWORD dwFlags, BOOL *fPending, void **lpContext); +static BOOL (WINAPI *initonce_complete)(pthread_once_t *lpInitOnce, DWORD dwFlags, void *lpContext); + +/* pre-Windows 6.0 compat using a spin-lock */ +static inline void w32thread_once_fallback(LONG volatile *state, void (*init_routine)(void)) +{ + switch (InterlockedCompareExchange(state, 1, 0)) { + /* Initial run */ + case 0: + init_routine(); + InterlockedExchange(state, 2); + break; + /* Another thread is running init */ + case 1: + while (1) { + MemoryBarrier(); + if (*state == 2) + break; + Sleep(0); + } + break; + /* Initialization complete */ + case 2: + break; + } +} + +static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void)) +{ + /* Use native functions on Windows 6.0+ */ + if (initonce_begin && initonce_complete) { + BOOL pending = FALSE; + initonce_begin(once_control, 0, &pending, NULL); + if (pending) + init_routine(); + initonce_complete(once_control, 0, NULL); + return 0; + } + + w32thread_once_fallback(&once_control->state, init_routine); + return 0; +} + /* for pre-Windows 6.0 platforms we need to define and use our own condition * variable and api */ + typedef struct win32_cond_t { pthread_mutex_t mtx_broadcast; pthread_mutex_t mtx_waiter_count; @@ -319,6 +387,10 @@ static av_unused void w32thread_init(void) (void*)GetProcAddress(kernel_dll, "WakeConditionVariable"); cond_wait = (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS"); + initonce_begin = + (void*)GetProcAddress(kernel_dll, "InitOnceBeginInitialize"); + initonce_complete = + (void*)GetProcAddress(kernel_dll, "InitOnceComplete"); #endif } |