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#import win32 "sys/windows.odin" when ODIN_OS == "windows";
#import "atomics.odin";
Semaphore :: struct {
_handle: win32.Handle,
}
Mutex :: struct {
_semaphore: Semaphore,
_counter: i32,
_owner: i32,
_recursion: i32,
}
current_thread_id :: proc() -> i32 {
return i32(win32.GetCurrentThreadId());
}
semaphore_init :: proc(s: ^Semaphore) {
s._handle = win32.CreateSemaphoreA(nil, 0, 1<<31-1, nil);
}
semaphore_destroy :: proc(s: ^Semaphore) {
win32.CloseHandle(s._handle);
}
semaphore_post :: proc(s: ^Semaphore, count: int) {
win32.ReleaseSemaphore(s._handle, i32(count), nil);
}
semaphore_release :: proc(s: ^Semaphore) #inline { semaphore_post(s, 1); }
semaphore_wait :: proc(s: ^Semaphore) {
win32.WaitForSingleObject(s._handle, win32.INFINITE);
}
mutex_init :: proc(m: ^Mutex) {
atomics.store(&m._counter, 0);
atomics.store(&m._owner, current_thread_id());
semaphore_init(&m._semaphore);
m._recursion = 0;
}
mutex_destroy :: proc(m: ^Mutex) {
semaphore_destroy(&m._semaphore);
}
mutex_lock :: proc(m: ^Mutex) {
thread_id := current_thread_id();
if atomics.fetch_add(&m._counter, 1) > 0 {
if thread_id != atomics.load(&m._owner) {
semaphore_wait(&m._semaphore);
}
}
atomics.store(&m._owner, thread_id);
m._recursion++;
}
mutex_try_lock :: proc(m: ^Mutex) -> bool {
thread_id := current_thread_id();
if atomics.load(&m._owner) == thread_id {
atomics.fetch_add(&m._counter, 1);
} else {
expected: i32 = 0;
if atomics.load(&m._counter) != 0 {
return false;
}
if atomics.compare_exchange(&m._counter, expected, 1) == 0 {
return false;
}
atomics.store(&m._owner, thread_id);
}
m._recursion++;
return true;
}
mutex_unlock :: proc(m: ^Mutex) {
recursion: i32;
thread_id := current_thread_id();
assert(thread_id == atomics.load(&m._owner));
m._recursion--;
recursion = m._recursion;
if recursion == 0 {
atomics.store(&m._owner, thread_id);
}
if atomics.fetch_add(&m._counter, -1) > 1 {
if recursion == 0 {
semaphore_release(&m._semaphore);
}
}
}
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