From cb50087482cf5a4239ad9c96b7157c45eac12876 Mon Sep 17 00:00:00 2001
From: Nikias Bassen
Date: Sun, 20 Jun 2021 01:56:35 +0200
Subject: thread: Add condition variable support

---
 src/thread.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/thread.h | 11 +++++++++
 2 files changed, 86 insertions(+)

diff --git a/src/thread.c b/src/thread.c
index eb535ab..796ea0b 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -67,6 +67,8 @@ int thread_join(THREAD_T thread)
 
 int thread_alive(THREAD_T thread)
 {
+	if (!thread)
+		return 0;
 #ifdef WIN32
 	return WaitForSingleObject(thread, 0) == WAIT_TIMEOUT;
 #else
@@ -138,3 +140,76 @@ void thread_once(thread_once_t *once_control, void (*init_routine)(void))
 	pthread_once(once_control, init_routine);
 #endif
 }
+
+void cond_init(cond_t* cond)
+{
+#ifdef WIN32
+	cond->sem = CreateSemaphore(NULL, 0, 32767, NULL);
+#else
+	pthread_cond_init(cond, NULL);
+#endif
+}
+
+void cond_destroy(cond_t* cond)
+{
+#ifdef WIN32
+	CloseHandle(cond->sem);
+#else
+	pthread_cond_destroy(cond);
+#endif
+}
+
+int cond_signal(cond_t* cond)
+{
+#ifdef WIN32
+	int result = 0;
+	if (!ReleaseSemaphore(cond->sem, 1, NULL)) {
+		result = -1;
+	}
+	return result;
+#else
+	return pthread_cond_signal(cond);
+#endif
+}
+
+int cond_wait(cond_t* cond, mutex_t* mutex)
+{
+#ifdef WIN32
+	mutex_unlock(mutex);
+	DWORD res = WaitForSingleObject(cond->sem, INFINITE);
+	switch (res) {
+		case WAIT_OBJECT_0:
+			return 0;
+		default:
+			return -1;
+	}
+#else
+	return pthread_cond_wait(cond, mutex);
+#endif
+}
+
+int cond_wait_timeout(cond_t* cond, mutex_t* mutex, unsigned int timeout_ms)
+{
+#ifdef WIN32
+	mutex_unlock(mutex);
+	DWORD res = WaitForSingleObject(cond->sem, timeout_ms);
+	switch (res) {
+		case WAIT_OBJECT_0:
+		case WAIT_TIMEOUT:
+			return 0;
+		default:
+			return -1;
+	}
+#else
+	struct timespec ts;
+	struct timeval now;
+	gettimeofday(&now, NULL);
+
+	ts.tv_sec = now.tv_sec + timeout_ms / 1000;
+	ts.tv_nsec = now.tv_usec * 1000 + 1000 * 1000 * (timeout_ms % 1000);
+	ts.tv_sec += ts.tv_nsec / (1000 * 1000 * 1000);
+	ts.tv_nsec %= (1000 * 1000 * 1000);
+
+	return pthread_cond_timedwait(cond, mutex, &ts);
+#endif
+}
diff --git a/src/thread.h b/src/thread.h
index 23e4510..2aadc6e 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -28,6 +28,9 @@
 #include <windows.h>
 typedef HANDLE THREAD_T;
 typedef CRITICAL_SECTION mutex_t;
+typedef struct {
+	HANDLE sem;
+} cond_t;
 typedef volatile struct {
 	LONG lock;
 	int state;
@@ -38,8 +41,10 @@ typedef volatile struct {
 #else
 #include <pthread.h>
 #include <signal.h>
+#include <sys/time.h>
 typedef pthread_t THREAD_T;
 typedef pthread_mutex_t mutex_t;
+typedef pthread_cond_t cond_t;
 typedef pthread_once_t thread_once_t;
 #define THREAD_ONCE_INIT PTHREAD_ONCE_INIT
 #define THREAD_ID pthread_self()
@@ -73,4 +78,10 @@ void mutex_unlock(mutex_t* mutex);
 
 void thread_once(thread_once_t *once_control, void (*init_routine)(void));
 
+void cond_init(cond_t* cond);
+void cond_destroy(cond_t* cond);
+int cond_signal(cond_t* cond);
+int cond_wait(cond_t* cond, mutex_t* mutex);
+int cond_wait_timeout(cond_t* cond, mutex_t* mutex, unsigned int timeout_ms);
+
 #endif
-- 
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