SDL

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/*
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  Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>
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  This software is provided 'as-is', without any express or implied
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  warranty.  In no event will the authors be held liable for any damages
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  arising from the use of this software.
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  Permission is granted to anyone to use this software for any purpose,
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  including commercial applications, and to alter it and redistribute it
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  freely.
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*/
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/* Test the thread and rwlock locking functions
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   Also exercises the system's signal/thread interaction
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*/
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#include <SDL3/SDL.h>
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#include <SDL3/SDL_main.h>
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#include <SDL3/SDL_test.h>
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static SDL_RWLock *rwlock = NULL;
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static SDL_ThreadID mainthread;
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static SDL_AtomicInt doterminate;
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static int nb_threads = 6;
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static SDL_Thread **threads;
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static int worktime = 1000;
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static int writerworktime = 100;
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static int timeout = 10000;
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static SDLTest_CommonState *state;
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static void DoWork(const int workticks)  /* "Work" */
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{
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    const SDL_ThreadID tid = SDL_GetCurrentThreadID();
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    const SDL_bool is_reader = tid != mainthread;
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    const char *typestr = is_reader ? "Reader" : "Writer";
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    SDL_Log("%s Thread %" SDL_PRIu64 ": ready to work\n", typestr, tid);
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    if (is_reader) {
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        SDL_LockRWLockForReading(rwlock);
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    } else {
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        SDL_LockRWLockForWriting(rwlock);
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    }
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    SDL_Log("%s Thread %" SDL_PRIu64 ": start work!\n", typestr, tid);
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    SDL_Delay(workticks);
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    SDL_Log("%s Thread %" SDL_PRIu64 ": work done!\n", typestr, tid);
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    SDL_UnlockRWLock(rwlock);
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    /* If this sleep isn't done, then threads may starve */
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    SDL_Delay(10);
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}
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static int SDLCALL
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ReaderRun(void *data)
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{
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    SDL_Log("Reader Thread %" SDL_PRIu64 ": starting up", SDL_GetCurrentThreadID());
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    while (!SDL_AtomicGet(&doterminate)) {
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        DoWork(worktime);
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    }
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    SDL_Log("Reader Thread %" SDL_PRIu64 ": exiting!\n", SDL_GetCurrentThreadID());
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    return 0;
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}
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int main(int argc, char *argv[])
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{
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    int i;
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    /* Initialize test framework */
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    state = SDLTest_CommonCreateState(argv, 0);
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    if (!state) {
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        return 1;
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    }
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    SDL_AtomicSet(&doterminate, 0);
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    /* Enable standard application logging */
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    SDL_SetLogPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
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    /* Parse commandline */
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    for (i = 1; i < argc;) {
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        int consumed;
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        consumed = SDLTest_CommonArg(state, i);
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        if (!consumed) {
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            if (SDL_strcmp(argv[i], "--nbthreads") == 0) {
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                if (argv[i + 1]) {
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                    char *endptr;
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                    nb_threads = SDL_strtol(argv[i + 1], &endptr, 0);
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                    if (endptr != argv[i + 1] && *endptr == '\0' && nb_threads > 0) {
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                        consumed = 2;
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                    }
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                }
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            } else if (SDL_strcmp(argv[i], "--worktime") == 0) {
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                if (argv[i + 1]) {
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                    char *endptr;
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                    worktime = SDL_strtol(argv[i + 1], &endptr, 0);
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                    if (endptr != argv[i + 1] && *endptr == '\0' && worktime > 0) {
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                        consumed = 2;
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                    }
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                }
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            } else if (SDL_strcmp(argv[i], "--writerworktime") == 0) {
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                if (argv[i + 1]) {
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                    char *endptr;
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                    writerworktime = SDL_strtol(argv[i + 1], &endptr, 0);
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                    if (endptr != argv[i + 1] && *endptr == '\0' && writerworktime > 0) {
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                        consumed = 2;
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                    }
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                }
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            } else if (SDL_strcmp(argv[i], "--timeout") == 0) {
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                if (argv[i + 1]) {
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                    char *endptr;
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                    timeout = (Uint64) SDL_strtol(argv[i + 1], &endptr, 0);
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                    if (endptr != argv[i + 1] && *endptr == '\0' && timeout > 0) {
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                        consumed = 2;
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                    }
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                }
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            }
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        }
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        if (consumed <= 0) {
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            static const char *options[] = {
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                "[--nbthreads NB]",
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                "[--worktime ms]",
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                "[--writerworktime ms]",
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                "[--timeout ms]",
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                NULL,
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            };
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            SDLTest_CommonLogUsage(state, argv[0], options);
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            return 1;
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        }
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        i += consumed;
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    }
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    threads = SDL_malloc(nb_threads * sizeof(SDL_Thread*));
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    /* Load the SDL library */
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    if (SDL_Init(0) < 0) {
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        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "%s\n", SDL_GetError());
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        return 1;
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    }
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    SDL_AtomicSet(&doterminate, 0);
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    rwlock = SDL_CreateRWLock();
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    if (!rwlock) {
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        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create rwlock: %s\n", SDL_GetError());
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        SDL_Quit();
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        SDLTest_CommonDestroyState(state);
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        return 1;
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    }
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    mainthread = SDL_GetCurrentThreadID();
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    SDL_Log("Writer thread: %" SDL_PRIu64 "\n", mainthread);
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    for (i = 0; i < nb_threads; ++i) {
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        char name[64];
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        (void)SDL_snprintf(name, sizeof(name), "Reader%d", i);
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        threads[i] = SDL_CreateThread(ReaderRun, name, NULL);
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        if (threads[i] == NULL) {
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            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create reader thread! %s\n", SDL_GetError());
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        }
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    }
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    while (!SDL_AtomicGet(&doterminate) && (SDL_GetTicks() < ((Uint64) timeout))) {
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        DoWork(writerworktime);
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    }
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    SDL_AtomicSet(&doterminate, 1);
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    SDL_Log("Waiting on reader threads to terminate...");
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    for (i = 0; i < nb_threads; ++i) {
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        SDL_WaitThread(threads[i], NULL);
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    }
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    SDL_Log("Reader threads have terminated, quitting!");
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    SDL_DestroyRWLock(rwlock);
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    SDL_Quit();
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    SDLTest_CommonDestroyState(state);
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    return 0;
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}
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