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 /* Semaphore functions using the Win32 API */
  24
  25 //#include <stdio.h>
  26 //#include <stdlib.h>
  27 #include <e32std.h>
  28
  29 #include "SDL_error.h"
  30 #include "SDL_thread.h"
  31
  32 #define SDL_MUTEX_TIMEOUT -2
  33
  34 struct SDL_semaphore
  35 {
  36         TInt handle;
  37         TInt count;
  38 };
  39
  40
  41 extern TInt CreateUnique(TInt (*aFunc)(const TDesC& aName, TAny*, TAny*), TAny*, TAny*);
  42
  43 TInt NewSema(const TDesC& aName, TAny* aPtr1, TAny* aPtr2)
  44 {
  45         TInt value = *((TInt*) aPtr2);
  46         return ((RSemaphore*)aPtr1)->CreateGlobal(aName, value);
  47 }
  48
  49 /* Create a semaphore */
  50 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
  51 {
  52         RSemaphore s;
  53         TInt status = CreateUnique(NewSema, &s, &initial_value);
  54         if(status != KErrNone)
  55         {
  56                 SDL_SetError("Couldn't create semaphore");
  57         }
  58         SDL_semaphore* sem = new /*(ELeave)*/ SDL_semaphore;
  59         sem->handle = s.Handle();
  60         sem->count = initial_value;
  61         return(sem);
  62 }
  63
  64 /* Free the semaphore */
  65 void SDL_DestroySemaphore(SDL_sem *sem)
  66 {
  67         if ( sem )
  68         {
  69                 RSemaphore sema;
  70                 sema.SetHandle(sem->handle);
  71                 while(--sem->count)
  72                         sema.Signal();
  73                 sema.Close();
  74                 delete sem;
  75                 sem = NULL;
  76         }
  77 }
  78
  79 void _WaitAll(SDL_sem *sem)
  80 {
  81         //since SemTryWait may changed the counter.
  82         //this may not be atomic, but hopes it works.
  83         RSemaphore sema;
  84         sema.SetHandle(sem->handle);
  85         sema.Wait();
  86         while(sem->count < 0)
  87         {
  88                 sema.Wait();
  89         }
  90 }
  91
  92 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
  93 {
  94         if ( ! sem ) {
  95                 SDL_SetError("Passed a NULL sem");
  96                 return -1;
  97         }
  98
  99         if ( timeout == SDL_MUTEX_MAXWAIT )
 100         {
 101                 _WaitAll(sem);
 102                 return SDL_MUTEX_MAXWAIT;
 103         }
 104
 105         RSemaphore sema;
 106         sema.SetHandle(sem->handle);
 107         if(KErrNone == sema.Wait(timeout))
 108                 return 0;
 109         return -1;
 110 }
 111
 112 int SDL_SemTryWait(SDL_sem *sem)
 113 {
 114         if(sem->count > 0)
 115         {
 116                 sem->count--;
 117         }
 118         return SDL_MUTEX_TIMEOUT;
 119 }
 120
 121 int SDL_SemWait(SDL_sem *sem)
 122 {
 123         return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
 124 }
 125
 126 /* Returns the current count of the semaphore */
 127 Uint32 SDL_SemValue(SDL_sem *sem)
 128 {
 129         if ( ! sem ) {
 130                 SDL_SetError("Passed a NULL sem");
 131                 return 0;
 132         }
 133         return sem->count;
 134 }
 135
 136 int SDL_SemPost(SDL_sem *sem)
 137 {
 138         if ( ! sem ) {
 139                 SDL_SetError("Passed a NULL sem");
 140                 return -1;
 141         }
 142         sem->count++;
 143         RSemaphore sema;
 144         sema.SetHandle(sem->handle);
 145         sema.Signal();
 146         return 0;
 147 }