1 files changed, 333 insertions, 0 deletions

diff --git a/contrib/SDL-3.2.8/test/testsem.c b/contrib/SDL-3.2.8/test/testsem.c
new file mode 100644
index 0000000..78de533
--- /dev/null
+++ b/contrib/SDL-3.2.8/test/testsem.c
@@ -0,0 +1,333 @@
+/*
+  Copyright (C) 1997-2025 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.
+*/
+
+/* Simple test of the SDL semaphore code */
+
+#include <signal.h>
+
+#include <SDL3/SDL.h>
+#include <SDL3/SDL_main.h>
+#include <SDL3/SDL_test.h>
+
+#define NUM_THREADS 10
+/* This value should be smaller than the maximum count of the */
+/* semaphore implementation: */
+#define NUM_OVERHEAD_OPS      10000
+#define NUM_OVERHEAD_OPS_MULT 10
+
+static SDL_Semaphore *sem;
+static int alive;
+
+typedef struct Thread_State
+{
+    SDL_Thread *thread;
+    int number;
+    bool flag;
+    int loop_count;
+    int content_count;
+} Thread_State;
+
+static void log_usage(char *progname, SDLTest_CommonState *state) {
+    static const char *options[] = { "[--no-threads]", "init_value", NULL };
+    SDLTest_CommonLogUsage(state, progname, options);
+}
+
+static void
+killed(int sig)
+{
+    alive = 0;
+}
+
+static int SDLCALL
+ThreadFuncRealWorld(void *data)
+{
+    Thread_State *state = (Thread_State *)data;
+    while (alive) {
+        SDL_WaitSemaphore(sem);
+        SDL_Log("Thread number %d has got the semaphore (value = %" SDL_PRIu32 ")!",
+                state->number, SDL_GetSemaphoreValue(sem));
+        SDL_Delay(200);
+        SDL_SignalSemaphore(sem);
+        SDL_Log("Thread number %d has released the semaphore (value = %" SDL_PRIu32 ")!",
+                state->number, SDL_GetSemaphoreValue(sem));
+        ++state->loop_count;
+        SDL_Delay(1); /* For the scheduler */
+    }
+    SDL_Log("Thread number %d exiting.", state->number);
+    return 0;
+}
+
+static void
+TestRealWorld(int init_sem)
+{
+    Thread_State thread_states[NUM_THREADS] = { { 0 } };
+    int i;
+    int loop_count;
+
+    sem = SDL_CreateSemaphore(init_sem);
+
+    SDL_Log("Running %d threads, semaphore value = %d", NUM_THREADS,
+            init_sem);
+    alive = 1;
+    /* Create all the threads */
+    for (i = 0; i < NUM_THREADS; ++i) {
+        char name[64];
+        (void)SDL_snprintf(name, sizeof(name), "Thread%u", (unsigned int)i);
+        thread_states[i].number = i;
+        thread_states[i].thread = SDL_CreateThread(ThreadFuncRealWorld, name, (void *)&thread_states[i]);
+    }
+
+    /* Wait 10 seconds */
+    SDL_Delay(10 * 1000);
+
+    /* Wait for all threads to finish */
+    SDL_Log("Waiting for threads to finish");
+    alive = 0;
+    loop_count = 0;
+    for (i = 0; i < NUM_THREADS; ++i) {
+        SDL_WaitThread(thread_states[i].thread, NULL);
+        loop_count += thread_states[i].loop_count;
+    }
+    SDL_Log("Finished waiting for threads, ran %d loops in total", loop_count);
+    SDL_Log("%s", "");
+
+    SDL_DestroySemaphore(sem);
+}
+
+static void
+TestWaitTimeout(void)
+{
+    Uint64 start_ticks;
+    Uint64 end_ticks;
+    Uint64 duration;
+    bool result;
+
+    sem = SDL_CreateSemaphore(0);
+    SDL_Log("Waiting 2 seconds on semaphore");
+
+    start_ticks = SDL_GetTicks();
+    result = SDL_WaitSemaphoreTimeout(sem, 2000);
+    end_ticks = SDL_GetTicks();
+
+    duration = end_ticks - start_ticks;
+
+    /* Accept a little offset in the effective wait */
+    SDL_Log("Wait took %" SDL_PRIu64 " milliseconds", duration);
+    SDL_Log("%s", "");
+    SDL_assert(duration > 1900 && duration < 2050);
+
+    /* Check to make sure the return value indicates timed out */
+    if (result) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "SDL_WaitSemaphoreTimeout returned: %d; expected: false", result);
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "%s", "");
+    }
+
+    SDL_DestroySemaphore(sem);
+}
+
+static void
+TestOverheadUncontended(void)
+{
+    Uint64 start_ticks;
+    Uint64 end_ticks;
+    Uint64 duration;
+    int i, j;
+
+    sem = SDL_CreateSemaphore(0);
+    SDL_Log("Doing %d uncontended Post/Wait operations on semaphore", NUM_OVERHEAD_OPS * NUM_OVERHEAD_OPS_MULT);
+
+    start_ticks = SDL_GetTicks();
+    for (i = 0; i < NUM_OVERHEAD_OPS_MULT; i++) {
+        for (j = 0; j < NUM_OVERHEAD_OPS; j++) {
+            SDL_SignalSemaphore(sem);
+        }
+        for (j = 0; j < NUM_OVERHEAD_OPS; j++) {
+            SDL_WaitSemaphore(sem);
+        }
+    }
+    end_ticks = SDL_GetTicks();
+
+    duration = end_ticks - start_ticks;
+    SDL_Log("Took %" SDL_PRIu64 " milliseconds", duration);
+    SDL_Log("%s", "");
+
+    SDL_DestroySemaphore(sem);
+}
+
+static int SDLCALL
+ThreadFuncOverheadContended(void *data)
+{
+    Thread_State *state = (Thread_State *)data;
+
+    if (state->flag) {
+        while (alive) {
+            if (!SDL_TryWaitSemaphore(sem)) {
+                ++state->content_count;
+            }
+            ++state->loop_count;
+        }
+    } else {
+        while (alive) {
+            /* Timeout needed to allow check on alive flag */
+            if (!SDL_WaitSemaphoreTimeout(sem, 50)) {
+                ++state->content_count;
+            }
+            ++state->loop_count;
+        }
+    }
+    return 0;
+}
+
+static void
+TestOverheadContended(bool try_wait)
+{
+    Uint64 start_ticks;
+    Uint64 end_ticks;
+    Uint64 duration;
+    Thread_State thread_states[NUM_THREADS] = { { 0 } };
+    char textBuffer[1024];
+    int loop_count;
+    int content_count;
+    int i, j;
+    size_t len;
+
+    sem = SDL_CreateSemaphore(0);
+    SDL_Log("Doing %d contended %s operations on semaphore using %d threads",
+            NUM_OVERHEAD_OPS * NUM_OVERHEAD_OPS_MULT, try_wait ? "Post/TryWait" : "Post/WaitTimeout", NUM_THREADS);
+    alive = 1;
+    /* Create multiple threads to starve the semaphore and cause contention */
+    for (i = 0; i < NUM_THREADS; ++i) {
+        char name[64];
+        (void)SDL_snprintf(name, sizeof(name), "Thread%u", (unsigned int)i);
+        thread_states[i].flag = try_wait;
+        thread_states[i].thread = SDL_CreateThread(ThreadFuncOverheadContended, name, (void *)&thread_states[i]);
+    }
+
+    start_ticks = SDL_GetTicks();
+    for (i = 0; i < NUM_OVERHEAD_OPS_MULT; i++) {
+        for (j = 0; j < NUM_OVERHEAD_OPS; j++) {
+            SDL_SignalSemaphore(sem);
+        }
+        /* Make sure threads consumed everything */
+        while (SDL_GetSemaphoreValue(sem)) {
+            /* Friendlier with cooperative threading models */
+            SDL_DelayNS(1);
+        }
+    }
+    end_ticks = SDL_GetTicks();
+
+    alive = 0;
+    loop_count = 0;
+    content_count = 0;
+    for (i = 0; i < NUM_THREADS; ++i) {
+        SDL_WaitThread(thread_states[i].thread, NULL);
+        loop_count += thread_states[i].loop_count;
+        content_count += thread_states[i].content_count;
+    }
+    SDL_assert_release((loop_count - content_count) == NUM_OVERHEAD_OPS * NUM_OVERHEAD_OPS_MULT);
+
+    duration = end_ticks - start_ticks;
+    SDL_Log("Took %" SDL_PRIu64 " milliseconds, threads %s %d out of %d times in total (%.2f%%)",
+            duration, try_wait ? "where contended" : "timed out", content_count,
+            loop_count, ((float)content_count * 100) / loop_count);
+    /* Print how many semaphores where consumed per thread */
+    (void)SDL_snprintf(textBuffer, sizeof(textBuffer), "{ ");
+    for (i = 0; i < NUM_THREADS; ++i) {
+        if (i > 0) {
+            len = SDL_strlen(textBuffer);
+            (void)SDL_snprintf(textBuffer + len, sizeof(textBuffer) - len, ", ");
+        }
+        len = SDL_strlen(textBuffer);
+        (void)SDL_snprintf(textBuffer + len, sizeof(textBuffer) - len, "%d", thread_states[i].loop_count - thread_states[i].content_count);
+    }
+    len = SDL_strlen(textBuffer);
+    (void)SDL_snprintf(textBuffer + len, sizeof(textBuffer) - len, " }");
+    SDL_Log("%s", textBuffer);
+
+    SDL_DestroySemaphore(sem);
+}
+
+int main(int argc, char **argv)
+{
+    int arg_count = 0;
+    int i;
+    int init_sem = 0;
+    bool enable_threads = true;
+    SDLTest_CommonState *state;
+
+    /* Initialize test framework */
+    state = SDLTest_CommonCreateState(argv, 0);
+    if (!state) {
+        return 1;
+    }
+
+    /* Parse commandline */
+    for (i = 1; i < argc;) {
+        int consumed;
+
+        consumed = SDLTest_CommonArg(state, i);
+        if (consumed == 0) {
+            consumed = -1;
+            if (SDL_strcasecmp(argv[i], "--no-threads") == 0) {
+                enable_threads = false;
+                consumed = 1;
+            } else if (arg_count == 0) {
+                char *endptr;
+                init_sem = SDL_strtol(argv[i], &endptr, 0);
+                if (endptr != argv[i] && *endptr == '\0') {
+                    arg_count++;
+                    consumed = 1;
+                }
+            }
+        }
+        if (consumed <= 0) {
+            log_usage(argv[0], state);
+            return 1;
+        }
+
+        i += consumed;
+    }
+
+    if (arg_count != 1) {
+        log_usage(argv[0], state);
+        return 1;
+    }
+
+    /* Load the SDL library */
+    if (!SDL_Init(0)) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s", SDL_GetError());
+        return 1;
+    }
+    (void)signal(SIGTERM, killed);
+    (void)signal(SIGINT, killed);
+
+    if (enable_threads) {
+        if (init_sem > 0) {
+            TestRealWorld(init_sem);
+        }
+
+        TestWaitTimeout();
+    }
+
+    TestOverheadUncontended();
+
+    if (enable_threads) {
+        TestOverheadContended(false);
+
+        TestOverheadContended(true);
+    }
+
+    SDL_Quit();
+    SDLTest_CommonDestroyState(state);
+
+    return 0;
+}