src/thread/SDL_thread.c - third_party/sdl - Git at Google

 /*
   Simple DirectMedia Layer
   Copyright (C) 1997-2011 Sam Lantinga <slouken@libsdl.org>

   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
   arising from the use of this software.

   Permission is granted to anyone to use this software for any purpose,
   including commercial applications, and to alter it and redistribute it
   freely, subject to the following restrictions:

   1. The origin of this software must not be misrepresented; you must not
      claim that you wrote the original software. If you use this software
      in a product, an acknowledgment in the product documentation would be
      appreciated but is not required.
   2. Altered source versions must be plainly marked as such, and must not be
      misrepresented as being the original software.
   3. This notice may not be removed or altered from any source distribution.
 */
 #include "SDL_config.h"

 /* System independent thread management routines for SDL */

 #include "SDL_mutex.h"
 #include "SDL_thread.h"
 #include "SDL_thread_c.h"
 #include "SDL_systhread.h"

 #define ARRAY_CHUNKSIZE	32
 /* The array of threads currently active in the application
    (except the main thread)
    The manipulation of an array here is safer than using a linked list.
 */
 static int SDL_maxthreads = 0;
 static int SDL_numthreads = 0;
 static SDL_Thread **SDL_Threads = NULL;
 static SDL_mutex *thread_lock = NULL;

 static int
 SDL_ThreadsInit(void)
 {
     int retval;

     retval = 0;
     thread_lock = SDL_CreateMutex();
     if (thread_lock == NULL) {
         retval = -1;
     }
     return (retval);
 }

 /* This should never be called...
    If this is called by SDL_Quit(), we don't know whether or not we should
    clean up threads here.  If any threads are still running after this call,
    they will no longer have access to any per-thread data.
  */
 #if 0
 static void
 SDL_ThreadsQuit(void)
 {
     SDL_mutex *mutex;

     mutex = thread_lock;
     thread_lock = NULL;
     if (mutex != NULL) {
         SDL_DestroyMutex(mutex);
     }
 }
 #endif

 /* Routines for manipulating the thread list */
 static void
 SDL_AddThread(SDL_Thread * thread)
 {
     /* WARNING:
        If the very first threads are created simultaneously, then
        there could be a race condition causing memory corruption.
        In practice, this isn't a problem because by definition there
        is only one thread running the first time this is called.
      */
     if (!thread_lock) {
         if (SDL_ThreadsInit() < 0) {
             return;
         }
     }
     SDL_mutexP(thread_lock);

     /* Expand the list of threads, if necessary */
 #ifdef DEBUG_THREADS
     printf("Adding thread (%d already - %d max)\n",
            SDL_numthreads, SDL_maxthreads);
 #endif
     if (SDL_numthreads == SDL_maxthreads) {
         SDL_Thread **threads;
         threads = (SDL_Thread **) SDL_realloc(SDL_Threads,
                                               (SDL_maxthreads +
                                                ARRAY_CHUNKSIZE) *
                                               (sizeof *threads));
         if (threads == NULL) {
             SDL_OutOfMemory();
             goto done;
         }
         SDL_maxthreads += ARRAY_CHUNKSIZE;
         SDL_Threads = threads;
     }
     SDL_Threads[SDL_numthreads++] = thread;
   done:
     SDL_mutexV(thread_lock);
 }

 static void
 SDL_DelThread(SDL_Thread * thread)
 {
     int i;

     if (!thread_lock) {
         return;
     }
     SDL_mutexP(thread_lock);
     for (i = 0; i < SDL_numthreads; ++i) {
         if (thread == SDL_Threads[i]) {
             break;
         }
     }
     if (i < SDL_numthreads) {
         if (--SDL_numthreads > 0) {
             while (i < SDL_numthreads) {
                 SDL_Threads[i] = SDL_Threads[i + 1];
                 ++i;
             }
         } else {
             SDL_maxthreads = 0;
             SDL_free(SDL_Threads);
             SDL_Threads = NULL;
         }
 #ifdef DEBUG_THREADS
         printf("Deleting thread (%d left - %d max)\n",
                SDL_numthreads, SDL_maxthreads);
 #endif
     }
     SDL_mutexV(thread_lock);

 #if 0   /* There could be memory corruption if another thread is starting */
     if (SDL_Threads == NULL) {
         SDL_ThreadsQuit();
     }
 #endif
 }

 /* The default (non-thread-safe) global error variable */
 static SDL_error SDL_global_error;

 /* Routine to get the thread-specific error variable */
 SDL_error *
 SDL_GetErrBuf(void)
 {
     SDL_error *errbuf;

     errbuf = &SDL_global_error;
     if (SDL_Threads) {
         int i;
         SDL_threadID this_thread;

         this_thread = SDL_ThreadID();
         SDL_mutexP(thread_lock);
         for (i = 0; i < SDL_numthreads; ++i) {
             if (this_thread == SDL_Threads[i]->threadid) {
                 errbuf = &SDL_Threads[i]->errbuf;
                 break;
             }
         }
         SDL_mutexV(thread_lock);
     }
     return (errbuf);
 }


 /* Arguments and callback to setup and run the user thread function */
 typedef struct
 {
     int (SDLCALL * func) (void *);
     void *data;
     SDL_Thread *info;
     SDL_sem *wait;
 } thread_args;

 void
 SDL_RunThread(void *data)
 {
     thread_args *args;
     int (SDLCALL * userfunc) (void *);
     void *userdata;
     int *statusloc;

     /* Perform any system-dependent setup
        - this function cannot fail, and cannot use SDL_SetError()
      */
     SDL_SYS_SetupThread();

     /* Get the thread id */
     args = (thread_args *) data;
     args->info->threadid = SDL_ThreadID();

     /* Figure out what function to run */
     userfunc = args->func;
     userdata = args->data;
     statusloc = &args->info->status;

     /* Wake up the parent thread */
     SDL_SemPost(args->wait);

     /* Run the function */
     *statusloc = userfunc(userdata);
 }

 #ifdef SDL_PASSED_BEGINTHREAD_ENDTHREAD
 #undef SDL_CreateThread
 DECLSPEC SDL_Thread *SDLCALL
 SDL_CreateThread(int (SDLCALL * fn) (void *), void *data,
                  pfnSDL_CurrentBeginThread pfnBeginThread,
                  pfnSDL_CurrentEndThread pfnEndThread)
 #else
 DECLSPEC SDL_Thread *SDLCALL
 SDL_CreateThread(int (SDLCALL * fn) (void *), void *data)
 #endif
 {
     SDL_Thread *thread;
     thread_args *args;
     int ret;

     /* Allocate memory for the thread info structure */
     thread = (SDL_Thread *) SDL_malloc(sizeof(*thread));
     if (thread == NULL) {
         SDL_OutOfMemory();
         return (NULL);
     }
     SDL_memset(thread, 0, (sizeof *thread));
     thread->status = -1;

     /* Set up the arguments for the thread */
     args = (thread_args *) SDL_malloc(sizeof(*args));
     if (args == NULL) {
         SDL_OutOfMemory();
         SDL_free(thread);
         return (NULL);
     }
     args->func = fn;
     args->data = data;
     args->info = thread;
     args->wait = SDL_CreateSemaphore(0);
     if (args->wait == NULL) {
         SDL_free(thread);
         SDL_free(args);
         return (NULL);
     }

     /* Add the thread to the list of available threads */
     SDL_AddThread(thread);

     /* Create the thread and go! */
 #ifdef SDL_PASSED_BEGINTHREAD_ENDTHREAD
     ret = SDL_SYS_CreateThread(thread, args, pfnBeginThread, pfnEndThread);
 #else
     ret = SDL_SYS_CreateThread(thread, args);
 #endif
     if (ret >= 0) {
         /* Wait for the thread function to use arguments */
         SDL_SemWait(args->wait);
     } else {
         /* Oops, failed.  Gotta free everything */
         SDL_DelThread(thread);
         SDL_free(thread);
         thread = NULL;
     }
     SDL_DestroySemaphore(args->wait);
     SDL_free(args);

     /* Everything is running now */
     return (thread);
 }

 SDL_threadID
 SDL_GetThreadID(SDL_Thread * thread)
 {
     SDL_threadID id;

     if (thread) {
         id = thread->threadid;
     } else {
         id = SDL_ThreadID();
     }
     return id;
 }

 int
 SDL_SetThreadPriority(SDL_ThreadPriority priority)
 {
     return SDL_SYS_SetThreadPriority(priority);
 }

 void
 SDL_WaitThread(SDL_Thread * thread, int *status)
 {
     if (thread) {
         SDL_SYS_WaitThread(thread);
         if (status) {
             *status = thread->status;
         }
         SDL_DelThread(thread);
         SDL_free(thread);
     }
 }

 /* vi: set ts=4 sw=4 expandtab: */
	/*
	Simple DirectMedia Layer
	Copyright (C) 1997-2011 Sam Lantinga <slouken@libsdl.org>

	This software is provided 'as-is', without any express or implied
	warranty. In no event will the authors be held liable for any damages
	arising from the use of this software.

	Permission is granted to anyone to use this software for any purpose,
	including commercial applications, and to alter it and redistribute it
	freely, subject to the following restrictions:

	1. The origin of this software must not be misrepresented; you must not
	claim that you wrote the original software. If you use this software
	in a product, an acknowledgment in the product documentation would be
	appreciated but is not required.
	2. Altered source versions must be plainly marked as such, and must not be
	misrepresented as being the original software.
	3. This notice may not be removed or altered from any source distribution.
	*/
	#include "SDL_config.h"

	/* System independent thread management routines for SDL */

	#include "SDL_mutex.h"
	#include "SDL_thread.h"
	#include "SDL_thread_c.h"
	#include "SDL_systhread.h"

	#define ARRAY_CHUNKSIZE 32
	/* The array of threads currently active in the application
	(except the main thread)
	The manipulation of an array here is safer than using a linked list.
	*/
	static int SDL_maxthreads = 0;
	static int SDL_numthreads = 0;
	static SDL_Thread **SDL_Threads = NULL;
	static SDL_mutex *thread_lock = NULL;

	static int
	SDL_ThreadsInit(void)
	{
	int retval;

	retval = 0;
	thread_lock = SDL_CreateMutex();
	if (thread_lock == NULL) {
	retval = -1;
	}
	return (retval);
	}

	/* This should never be called...
	If this is called by SDL_Quit(), we don't know whether or not we should
	clean up threads here. If any threads are still running after this call,
	they will no longer have access to any per-thread data.
	*/
	#if 0
	static void
	SDL_ThreadsQuit(void)
	{
	SDL_mutex *mutex;

	mutex = thread_lock;
	thread_lock = NULL;
	if (mutex != NULL) {
	SDL_DestroyMutex(mutex);
	}
	}
	#endif

	/* Routines for manipulating the thread list */
	static void
	SDL_AddThread(SDL_Thread * thread)
	{
	/* WARNING:
	If the very first threads are created simultaneously, then
	there could be a race condition causing memory corruption.
	In practice, this isn't a problem because by definition there
	is only one thread running the first time this is called.
	*/
	if (!thread_lock) {
	if (SDL_ThreadsInit() < 0) {
	return;
	}
	}
	SDL_mutexP(thread_lock);

	/* Expand the list of threads, if necessary */
	#ifdef DEBUG_THREADS
	printf("Adding thread (%d already - %d max)\n",
	SDL_numthreads, SDL_maxthreads);
	#endif
	if (SDL_numthreads == SDL_maxthreads) {
	SDL_Thread **threads;
	threads = (SDL_Thread **) SDL_realloc(SDL_Threads,
	(SDL_maxthreads +
	ARRAY_CHUNKSIZE) *
	(sizeof *threads));
	if (threads == NULL) {
	SDL_OutOfMemory();
	goto done;
	}
	SDL_maxthreads += ARRAY_CHUNKSIZE;
	SDL_Threads = threads;
	}
	SDL_Threads[SDL_numthreads++] = thread;
	done:
	SDL_mutexV(thread_lock);
	}

	static void
	SDL_DelThread(SDL_Thread * thread)
	{
	int i;

	if (!thread_lock) {
	return;
	}
	SDL_mutexP(thread_lock);
	for (i = 0; i < SDL_numthreads; ++i) {
	if (thread == SDL_Threads[i]) {
	break;
	}
	}
	if (i < SDL_numthreads) {
	if (--SDL_numthreads > 0) {
	while (i < SDL_numthreads) {
	SDL_Threads[i] = SDL_Threads[i + 1];
	++i;
	}
	} else {
	SDL_maxthreads = 0;
	SDL_free(SDL_Threads);
	SDL_Threads = NULL;
	}
	#ifdef DEBUG_THREADS
	printf("Deleting thread (%d left - %d max)\n",
	SDL_numthreads, SDL_maxthreads);
	#endif
	}
	SDL_mutexV(thread_lock);

	#if 0 /* There could be memory corruption if another thread is starting */
	if (SDL_Threads == NULL) {
	SDL_ThreadsQuit();
	}
	#endif
	}

	/* The default (non-thread-safe) global error variable */
	static SDL_error SDL_global_error;

	/* Routine to get the thread-specific error variable */
	SDL_error *
	SDL_GetErrBuf(void)
	{
	SDL_error *errbuf;

	errbuf = &SDL_global_error;
	if (SDL_Threads) {
	int i;
	SDL_threadID this_thread;

	this_thread = SDL_ThreadID();
	SDL_mutexP(thread_lock);
	for (i = 0; i < SDL_numthreads; ++i) {
	if (this_thread == SDL_Threads[i]->threadid) {
	errbuf = &SDL_Threads[i]->errbuf;
	break;
	}
	}
	SDL_mutexV(thread_lock);
	}
	return (errbuf);
	}


	/* Arguments and callback to setup and run the user thread function */
	typedef struct
	{
	int (SDLCALL * func) (void *);
	void *data;
	SDL_Thread *info;
	SDL_sem *wait;
	} thread_args;

	void
	SDL_RunThread(void *data)
	{
	thread_args *args;
	int (SDLCALL * userfunc) (void *);
	void *userdata;
	int *statusloc;

	/* Perform any system-dependent setup
	- this function cannot fail, and cannot use SDL_SetError()
	*/
	SDL_SYS_SetupThread();

	/* Get the thread id */
	args = (thread_args *) data;
	args->info->threadid = SDL_ThreadID();

	/* Figure out what function to run */
	userfunc = args->func;
	userdata = args->data;
	statusloc = &args->info->status;

	/* Wake up the parent thread */
	SDL_SemPost(args->wait);

	/* Run the function */
	*statusloc = userfunc(userdata);
	}

	#ifdef SDL_PASSED_BEGINTHREAD_ENDTHREAD
	#undef SDL_CreateThread
	DECLSPEC SDL_Thread *SDLCALL
	SDL_CreateThread(int (SDLCALL * fn) (void ), void data,
	pfnSDL_CurrentBeginThread pfnBeginThread,
	pfnSDL_CurrentEndThread pfnEndThread)
	#else
	DECLSPEC SDL_Thread *SDLCALL
	SDL_CreateThread(int (SDLCALL * fn) (void ), void data)
	#endif
	{
	SDL_Thread *thread;
	thread_args *args;
	int ret;

	/* Allocate memory for the thread info structure */
	thread = (SDL_Thread ) SDL_malloc(sizeof(thread));
	if (thread == NULL) {
	SDL_OutOfMemory();
	return (NULL);
	}
	SDL_memset(thread, 0, (sizeof *thread));
	thread->status = -1;

	/* Set up the arguments for the thread */
	args = (thread_args ) SDL_malloc(sizeof(args));
	if (args == NULL) {
	SDL_OutOfMemory();
	SDL_free(thread);
	return (NULL);
	}
	args->func = fn;
	args->data = data;
	args->info = thread;
	args->wait = SDL_CreateSemaphore(0);
	if (args->wait == NULL) {
	SDL_free(thread);
	SDL_free(args);
	return (NULL);
	}

	/* Add the thread to the list of available threads */
	SDL_AddThread(thread);

	/* Create the thread and go! */
	#ifdef SDL_PASSED_BEGINTHREAD_ENDTHREAD
	ret = SDL_SYS_CreateThread(thread, args, pfnBeginThread, pfnEndThread);
	#else
	ret = SDL_SYS_CreateThread(thread, args);
	#endif
	if (ret >= 0) {
	/* Wait for the thread function to use arguments */
	SDL_SemWait(args->wait);
	} else {
	/* Oops, failed. Gotta free everything */
	SDL_DelThread(thread);
	SDL_free(thread);
	thread = NULL;
	}
	SDL_DestroySemaphore(args->wait);
	SDL_free(args);

	/* Everything is running now */
	return (thread);
	}

	SDL_threadID
	SDL_GetThreadID(SDL_Thread * thread)
	{
	SDL_threadID id;

	if (thread) {
	id = thread->threadid;
	} else {
	id = SDL_ThreadID();
	}
	return id;
	}

	int
	SDL_SetThreadPriority(SDL_ThreadPriority priority)
	{
	return SDL_SYS_SetThreadPriority(priority);
	}

	void
	SDL_WaitThread(SDL_Thread * thread, int *status)
	{
	if (thread) {
	SDL_SYS_WaitThread(thread);
	if (status) {
	*status = thread->status;
	}
	SDL_DelThread(thread);
	SDL_free(thread);
	}
	}

	/* vi: set ts=4 sw=4 expandtab: */