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vpx_thread: use native windows cond var if available

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BUG=b/29583578

original webp change:

commit 110ad5835ecd66995d0e7f66dca1b90dea595f5a
Author: James Zern <jzern@google.com>
Date:   Mon Nov 23 19:49:58 2015 -0800

    thread: use native windows cond var if available

    Vista / Server 2008 and up. no speed difference observed.

    Change-Id: Ice19704777cb679b290dc107a751a0f36dd0c0a9

100644 blob 4fc372b7bc6980a9ed3618c8cce5b67ed7b0f412 src/utils/thread.c
100644 blob 840831185502d42a3246e4b7ff870121c8064791 src/utils/thread.h

Change-Id: Iede7ae8a7184e4b17a4050b33956918fc84e15b5
This commit is contained in:
James Zern 2016-07-01 14:29:04 -07:00
parent d4d6c58e37
commit 8cc525e82b
1 changed files with 22 additions and 0 deletions
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22
vpx_util/vpx_thread.h
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@ -33,11 +33,17 @@ extern "C" {
#include <windows.h> // NOLINT
typedef HANDLE pthread_t;
typedef CRITICAL_SECTION pthread_mutex_t;
#if _WIN32_WINNT >= 0x0600 // Windows Vista / Server 2008 or greater
#define USE_WINDOWS_CONDITION_VARIABLE
typedef CONDITION_VARIABLE pthread_cond_t;
#else
typedef struct {
HANDLE waiting_sem_;
HANDLE received_sem_;
HANDLE signal_event_;
} pthread_cond_t;
#endif // _WIN32_WINNT >= 0x600
//------------------------------------------------------------------------------
// simplistic pthread emulation layer
@ -97,15 +103,22 @@ static INLINE int pthread_mutex_destroy(pthread_mutex_t *const mutex) {
// Condition
static INLINE int pthread_cond_destroy(pthread_cond_t *const condition) {
int ok = 1;
#ifdef USE_WINDOWS_CONDITION_VARIABLE
(void)condition;
#else
ok &= (CloseHandle(condition->waiting_sem_) != 0);
ok &= (CloseHandle(condition->received_sem_) != 0);
ok &= (CloseHandle(condition->signal_event_) != 0);
#endif
return !ok;
}
static INLINE int pthread_cond_init(pthread_cond_t *const condition,
void* cond_attr) {
(void)cond_attr;
#ifdef USE_WINDOWS_CONDITION_VARIABLE
InitializeConditionVariable(condition);
#else
condition->waiting_sem_ = CreateSemaphore(NULL, 0, MAX_DECODE_THREADS, NULL);
condition->received_sem_ = CreateSemaphore(NULL, 0, MAX_DECODE_THREADS, NULL);
condition->signal_event_ = CreateEvent(NULL, FALSE, FALSE, NULL);
@ -115,11 +128,15 @@ static INLINE int pthread_cond_init(pthread_cond_t *const condition,
pthread_cond_destroy(condition);
return 1;
}
#endif
return 0;
}
static INLINE int pthread_cond_signal(pthread_cond_t *const condition) {
int ok = 1;
#ifdef USE_WINDOWS_CONDITION_VARIABLE
WakeConditionVariable(condition);
#else
if (WaitForSingleObject(condition->waiting_sem_, 0) == WAIT_OBJECT_0) {
// a thread is waiting in pthread_cond_wait: allow it to be notified
ok = SetEvent(condition->signal_event_);
@ -128,12 +145,16 @@ static INLINE int pthread_cond_signal(pthread_cond_t *const condition) {
ok &= (WaitForSingleObject(condition->received_sem_, INFINITE) !=
WAIT_OBJECT_0);
}
#endif
return !ok;
}
static INLINE int pthread_cond_wait(pthread_cond_t *const condition,
pthread_mutex_t *const mutex) {
int ok;
#ifdef USE_WINDOWS_CONDITION_VARIABLE
ok = SleepConditionVariableCS(condition, mutex, INFINITE);
#else
// note that there is a consumer available so the signal isn't dropped in
// pthread_cond_signal
if (!ReleaseSemaphore(condition->waiting_sem_, 1, NULL))
@ -144,6 +165,7 @@ static INLINE int pthread_cond_wait(pthread_cond_t *const condition,
WAIT_OBJECT_0);
ok &= ReleaseSemaphore(condition->received_sem_, 1, NULL);
pthread_mutex_lock(mutex);
#endif
return !ok;
}
#elif defined(__OS2__)