Merge commit 'dec0d4ec4153bf9fc2b78ae6c2df45b6ea8dde7a' as 'external/sdl/SDL'

2023-07-25 22:27:55 +02:00
parent b38ea75e56 dec0d4ec41
commit b8e444eaa8
1663 changed files with 627495 additions and 0 deletions
--- a/external/sdl/SDL/src/thread/generic/SDL_syscond.c
+++ b/external/sdl/SDL/src/thread/generic/SDL_syscond.c
@ -0,0 +1,218 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2023 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_internal.h"
+
+/* An implementation of condition variables using semaphores and mutexes */
+/*
+   This implementation borrows heavily from the BeOS condition variable
+   implementation, written by Christopher Tate and Owen Smith.  Thanks!
+ */
+
+#include "../generic/SDL_syscond_c.h"
+
+/* If two implementations are to be compiled into SDL (the active one
+ * will be chosen at runtime), the function names need to be
+ * suffixed
+ */
+#ifndef SDL_THREAD_GENERIC_COND_SUFFIX
+#define SDL_CreateCondition_generic      SDL_CreateCondition
+#define SDL_DestroyCondition_generic     SDL_DestroyCondition
+#define SDL_SignalCondition_generic      SDL_SignalCondition
+#define SDL_BroadcastCondition_generic   SDL_BroadcastCondition
+#define SDL_WaitConditionTimeoutNS_generic SDL_WaitConditionTimeoutNS
+#endif
+
+typedef struct SDL_cond_generic
+{
+    SDL_Mutex *lock;
+    int waiting;
+    int signals;
+    SDL_Semaphore *wait_sem;
+    SDL_Semaphore *wait_done;
+} SDL_cond_generic;
+
+/* Create a condition variable */
+SDL_Condition *SDL_CreateCondition_generic(void)
+{
+    SDL_cond_generic *cond;
+
+    cond = (SDL_cond_generic *)SDL_malloc(sizeof(SDL_cond_generic));
+    if (cond) {
+        cond->lock = SDL_CreateMutex();
+        cond->wait_sem = SDL_CreateSemaphore(0);
+        cond->wait_done = SDL_CreateSemaphore(0);
+        cond->waiting = cond->signals = 0;
+        if (!cond->lock || !cond->wait_sem || !cond->wait_done) {
+            SDL_DestroyCondition_generic((SDL_Condition *)cond);
+            cond = NULL;
+        }
+    } else {
+        SDL_OutOfMemory();
+    }
+    return (SDL_Condition *)cond;
+}
+
+/* Destroy a condition variable */
+void SDL_DestroyCondition_generic(SDL_Condition *_cond)
+{
+    SDL_cond_generic *cond = (SDL_cond_generic *)_cond;
+    if (cond) {
+        if (cond->wait_sem) {
+            SDL_DestroySemaphore(cond->wait_sem);
+        }
+        if (cond->wait_done) {
+            SDL_DestroySemaphore(cond->wait_done);
+        }
+        if (cond->lock) {
+            SDL_DestroyMutex(cond->lock);
+        }
+        SDL_free(cond);
+    }
+}
+
+/* Restart one of the threads that are waiting on the condition variable */
+int SDL_SignalCondition_generic(SDL_Condition *_cond)
+{
+    SDL_cond_generic *cond = (SDL_cond_generic *)_cond;
+    if (cond == NULL) {
+        return SDL_InvalidParamError("cond");
+    }
+
+    /* If there are waiting threads not already signalled, then
+       signal the condition and wait for the thread to respond.
+     */
+    SDL_LockMutex(cond->lock);
+    if (cond->waiting > cond->signals) {
+        ++cond->signals;
+        SDL_PostSemaphore(cond->wait_sem);
+        SDL_UnlockMutex(cond->lock);
+        SDL_WaitSemaphore(cond->wait_done);
+    } else {
+        SDL_UnlockMutex(cond->lock);
+    }
+
+    return 0;
+}
+
+/* Restart all threads that are waiting on the condition variable */
+int SDL_BroadcastCondition_generic(SDL_Condition *_cond)
+{
+    SDL_cond_generic *cond = (SDL_cond_generic *)_cond;
+    if (cond == NULL) {
+        return SDL_InvalidParamError("cond");
+    }
+
+    /* If there are waiting threads not already signalled, then
+       signal the condition and wait for the thread to respond.
+     */
+    SDL_LockMutex(cond->lock);
+    if (cond->waiting > cond->signals) {
+        int i, num_waiting;
+
+        num_waiting = (cond->waiting - cond->signals);
+        cond->signals = cond->waiting;
+        for (i = 0; i < num_waiting; ++i) {
+            SDL_PostSemaphore(cond->wait_sem);
+        }
+        /* Now all released threads are blocked here, waiting for us.
+           Collect them all (and win fabulous prizes!) :-)
+         */
+        SDL_UnlockMutex(cond->lock);
+        for (i = 0; i < num_waiting; ++i) {
+            SDL_WaitSemaphore(cond->wait_done);
+        }
+    } else {
+        SDL_UnlockMutex(cond->lock);
+    }
+
+    return 0;
+}
+
+/* Wait on the condition variable for at most 'timeoutNS' nanoseconds.
+   The mutex must be locked before entering this function!
+   The mutex is unlocked during the wait, and locked again after the wait.
+
+Typical use:
+
+Thread A:
+    SDL_LockMutex(lock);
+    while ( ! condition ) {
+        SDL_WaitCondition(cond, lock);
+    }
+    SDL_UnlockMutex(lock);
+
+Thread B:
+    SDL_LockMutex(lock);
+    ...
+    condition = true;
+    ...
+    SDL_SignalCondition(cond);
+    SDL_UnlockMutex(lock);
+ */
+int SDL_WaitConditionTimeoutNS_generic(SDL_Condition *_cond, SDL_Mutex *mutex, Sint64 timeoutNS)
+{
+    SDL_cond_generic *cond = (SDL_cond_generic *)_cond;
+    int retval;
+
+    if (cond == NULL) {
+        return SDL_InvalidParamError("cond");
+    }
+
+    /* Obtain the protection mutex, and increment the number of waiters.
+       This allows the signal mechanism to only perform a signal if there
+       are waiting threads.
+     */
+    SDL_LockMutex(cond->lock);
+    ++cond->waiting;
+    SDL_UnlockMutex(cond->lock);
+
+    /* Unlock the mutex, as is required by condition variable semantics */
+    SDL_UnlockMutex(mutex);
+
+    /* Wait for a signal */
+    retval = SDL_WaitSemaphoreTimeoutNS(cond->wait_sem, timeoutNS);
+
+    /* Let the signaler know we have completed the wait, otherwise
+       the signaler can race ahead and get the condition semaphore
+       if we are stopped between the mutex unlock and semaphore wait,
+       giving a deadlock.  See the following URL for details:
+       http://web.archive.org/web/20010914175514/http://www-classic.be.com/aboutbe/benewsletter/volume_III/Issue40.html#Workshop
+     */
+    SDL_LockMutex(cond->lock);
+    if (cond->signals > 0) {
+        /* If we timed out, we need to eat a condition signal */
+        if (retval > 0) {
+            SDL_WaitSemaphore(cond->wait_sem);
+        }
+        /* We always notify the signal thread that we are done */
+        SDL_PostSemaphore(cond->wait_done);
+
+        /* Signal handshake complete */
+        --cond->signals;
+    }
+    --cond->waiting;
+    SDL_UnlockMutex(cond->lock);
+
+    /* Lock the mutex, as is required by condition variable semantics */
+    SDL_LockMutex(mutex);
+
+    return retval;
+}