src/thread/symbian/SDL_syssem.cpp

   1 /*
   2    SDL - Simple DirectMedia Layer
   3    Copyright (C) 1997, 1998, 1999, 2000  Sam Lantinga
   4
   5    This library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public
   7    License as published by the Free Software Foundation; either
   8    version 2 of the License, or (at your option) any later version.
   9
  10    This library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with this library; if not, write to the Free
  17    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18
  19    Sam Lantinga
  20    slouken@devolution.com
  21    */
  22
  23 #include <e32std.h>
  24 #include "SDL_error.h"
  25 #include "SDL_thread.h"
  26
  27 #define SDL_MUTEX_TIMEOUT -2
  28
  29 struct SDL_semaphore
  30 {
  31         int handle;
  32         int count;
  33 };
  34
  35 extern int CreateUnique(int (*aFunc)(const TDesC& aName, void*, void*), void*, void*);
  36
  37 int NewSema(const TDesC& aName, void* aPtr1, void* aPtr2)
  38 {
  39         int value = *((int*) aPtr2);
  40         return ((RSemaphore*)aPtr1)->CreateGlobal(aName, value);
  41 }
  42
  43 /* Create a semaphore */
  44 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
  45 {
  46         RSemaphore s;
  47         int status = CreateUnique(NewSema, &s, &initial_value);
  48         if(status != KErrNone)
  49         {
  50                 SDL_SetError("Couldn't create semaphore");
  51         }
  52         SDL_semaphore* sem = new SDL_semaphore;
  53         sem->handle = s.Handle();
  54         sem->count = initial_value;
  55         return(sem);
  56 }
  57
  58 /* Free the semaphore */
  59 void SDL_DestroySemaphore(SDL_sem *sem)
  60 {
  61         if ( sem )
  62         {
  63                 RSemaphore sema;
  64                 sema.SetHandle(sem->handle);
  65                 sema.Signal(sem->count);
  66                 sema.Close();
  67                 delete sem;
  68                 sem = NULL;
  69         }
  70 }
  71
  72 void _WaitAll(SDL_sem *sem)
  73 {
  74         //since SemTryWait may changed the counter.
  75         //this may not be atomic, but hopes it works.
  76         RSemaphore sema;
  77         sema.SetHandle(sem->handle);
  78         sema.Wait();
  79         while(sem->count < 0)
  80         {
  81                 sema.Wait();
  82         }
  83 }
  84
  85 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
  86 {
  87         if ( ! sem ) {
  88                 SDL_SetError("Passed a NULL sem");
  89                 return -1;
  90         }
  91
  92         if ( timeout == SDL_MUTEX_MAXWAIT )
  93         {
  94                 _WaitAll(sem);
  95                 return SDL_MUTEX_MAXWAIT;
  96         }
  97
  98         RSemaphore sema;
  99         sema.SetHandle(sem->handle);
 100         if(KErrNone == sema.Wait(timeout))
 101                 return 0;
 102         return -1;
 103 }
 104
 105 int SDL_SemTryWait(SDL_sem *sem)
 106 {
 107         if(sem->count > 0)
 108         {
 109                 sem->count--;
 110         }
 111         return SDL_MUTEX_TIMEOUT;
 112 }
 113
 114 int SDL_SemWait(SDL_sem *sem)
 115 {
 116         return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
 117 }
 118
 119 /* Returns the current count of the semaphore */
 120 Uint32 SDL_SemValue(SDL_sem *sem)
 121 {
 122         if ( ! sem ) {
 123                 SDL_SetError("Passed a NULL sem");
 124                 return 0;
 125         }
 126         return sem->count;
 127 }
 128
 129 int SDL_SemPost(SDL_sem *sem)
 130 {
 131         if ( ! sem ) {
 132                 SDL_SetError("Passed a NULL sem");
 133                 return -1;
 134         }
 135         sem->count++;
 136         RSemaphore sema;
 137         sema.SetHandle(sem->handle);
 138         sema.Signal();
 139         return 0;
 140 }