SDL_syssem.cpp
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2006 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Sam Lantinga
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slouken@libsdl.org
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*/
/*
SDL_syssem.cpp
Epoc version by Markus Mertama (w@iki.fi)
*/
/* Semaphore functions using the Win32 API */
#include <e32std.h>
#include "SDL_error.h"
#include "SDL_thread.h"
#define SDL_MUTEX_TIMEOUT -2
struct SDL_semaphore
{
TInt handle;
TInt count;
};
extern TInt CreateUnique(TInt (*aFunc)(const TDesC& aName, TAny*, TAny*), TAny*, TAny*);
extern TInt NewThread(const TDesC& aName, TAny* aPtr1, TAny* aPtr2);
TInt NewSema(const TDesC& aName, TAny* aPtr1, TAny* aPtr2)
{
TInt value = *((TInt*) aPtr2);
return ((RSemaphore*)aPtr1)->CreateGlobal(aName, value);
}
/* Create a semaphore */
SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
{
RSemaphore s;
TInt status = CreateUnique(NewSema, &s, &initial_value);
if(status != KErrNone)
{
SDL_SetError("Couldn't create semaphore");
}
SDL_semaphore* sem = new /*(ELeave)*/ SDL_semaphore;
sem->handle = s.Handle();
sem->count = initial_value;
return(sem);
}
/* Free the semaphore */
void SDL_DestroySemaphore(SDL_sem *sem)
{
if ( sem )
{
RSemaphore sema;
sema.SetHandle(sem->handle);
sema.Signal(sema.Count());
sema.Close();
delete sem;
sem = NULL;
}
}
struct TInfo
{
TInfo(TInt aTime, TInt aHandle) :
iTime(aTime), iHandle(aHandle), iVal(0) {}
TInt iTime;
TInt iHandle;
TInt iVal;
};
TBool ThreadRun(TAny* aInfo)
{
TInfo* info = STATIC_CAST(TInfo*, aInfo);
User::After(info->iTime);
RSemaphore sema;
sema.SetHandle(info->iHandle);
sema.Signal();
info->iVal = SDL_MUTEX_TIMEOUT;
return 0;
}
void _WaitAll(SDL_sem *sem)
{
//since SemTryWait may changed the counter.
//this may not be atomic, but hopes it works.
RSemaphore sema;
sema.SetHandle(sem->handle);
sema.Wait();
while(sem->count < 0)
{
sema.Wait();
}
}
int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
{
if ( ! sem ) {
SDL_SetError("Passed a NULL sem");
return -1;
}
if ( timeout == SDL_MUTEX_MAXWAIT )
{
_WaitAll(sem);
return SDL_MUTEX_MAXWAIT;
}
RThread thread;
TInfo* info = new (ELeave)TInfo(timeout, sem->handle);
TInt status = CreateUnique(NewThread, &thread, info);
if(status != KErrNone)
return status;
thread.Resume();
_WaitAll(sem);
if(thread.ExitType() == EExitPending)
{
thread.Kill(SDL_MUTEX_TIMEOUT);
}
thread.Close();
return info->iVal;
}
int SDL_SemTryWait(SDL_sem *sem)
{
if(sem->count > 0)
{
sem->count--;
}
return SDL_MUTEX_TIMEOUT;
}
int SDL_SemWait(SDL_sem *sem)
{
return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
}
/* Returns the current count of the semaphore */
Uint32 SDL_SemValue(SDL_sem *sem)
{
if ( ! sem ) {
SDL_SetError("Passed a NULL sem");
return 0;
}
return sem->count;
}
int SDL_SemPost(SDL_sem *sem)
{
if ( ! sem ) {
SDL_SetError("Passed a NULL sem");
return -1;
}
sem->count++;
RSemaphore sema;
sema.SetHandle(sem->handle);
sema.Signal();
return 0;
}