Commit e17bb9e3 authored by John Koleszar's avatar John Koleszar Committed by Gerrit Code Review
Browse files

Merge "rtcd: merge rtcd.c from master" into experimental

parents cdd0ed13 47dcdf11
......@@ -11,20 +11,95 @@
#define RTCD_C
#include "vpx_rtcd.h"
#if CONFIG_MULTITHREAD && defined(_WIN32)
#include <windows.h>
#include <stdlib.h>
static void once(void (*func)(void))
{
static CRITICAL_SECTION *lock;
static LONG waiters;
static int done;
void *lock_ptr = &lock;
/* If the initialization is complete, return early. This isn't just an
* optimization, it prevents races on the destruction of the global
* lock.
*/
if(done)
return;
InterlockedIncrement(&waiters);
/* Get a lock. We create one and try to make it the one-true-lock,
* throwing it away if we lost the race.
*/
{
/* Scope to protect access to new_lock */
CRITICAL_SECTION *new_lock = malloc(sizeof(CRITICAL_SECTION));
InitializeCriticalSection(new_lock);
if (InterlockedCompareExchangePointer(lock_ptr, new_lock, NULL) != NULL)
{
DeleteCriticalSection(new_lock);
free(new_lock);
}
}
/* At this point, we have a lock that can be synchronized on. We don't
* care which thread actually performed the allocation.
*/
EnterCriticalSection(lock);
if (!done)
{
func();
done = 1;
}
LeaveCriticalSection(lock);
/* Last one out should free resources. The destructed objects are
* protected by checking if(done) above.
*/
if(!InterlockedDecrement(&waiters))
{
DeleteCriticalSection(lock);
free(lock);
lock = NULL;
}
}
#elif CONFIG_MULTITHREAD && HAVE_PTHREAD_H
#include <pthread.h>
static void once(void (*func)(void))
{
static pthread_once_t lock = PTHREAD_ONCE_INIT;
pthread_once(&lock, func);
}
#else
/* No-op version that performs no synchronization. vpx_rtcd() is idempotent,
* so as long as your platform provides atomic loads/stores of pointers
* no synchronization is strictly necessary.
*/
static void once(void (*func)(void)) {
static int done;
static void once(void (*func)(void))
{
static int done;
if(!done) {
func();
done = 1;
}
if(!done)
{
func();
done = 1;
}
}
#endif
void vpx_rtcd() {
once(setup_rtcd_internal);
void vpx_rtcd()
{
once(setup_rtcd_internal);
}
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