1 files changed, 119 insertions, 0 deletions
diff --git a/src/windows7.rs b/src/windows7.rs
new file mode 100755
index 0000000..2007d05
--- /dev/null
+++ b/src/windows7.rs
@@ -0,0 +1,119 @@
+use core::cell::UnsafeCell;
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct SrwLock {
+	ptr: *mut core::ffi::c_void,
+}
+
+const SRWLOCK_INIT: SrwLock = SrwLock {
+	ptr: core::ptr::null_mut(),
+};
+
+type Boolean = u8;
+
+#[link(name = "kernel32")]
+extern "system" {
+	pub fn AcquireSRWLockShared(srwlock: *mut SrwLock);
+	pub fn AcquireSRWLockExclusive(srwlock: *mut SrwLock);
+	pub fn TryAcquireSRWLockShared(srwlock: *mut SrwLock) -> Boolean;
+	pub fn TryAcquireSRWLockExclusive(srwlock: *mut SrwLock) -> Boolean;
+	pub fn ReleaseSRWLockShared(srwlock: *mut SrwLock);
+	pub fn ReleaseSRWLockExclusive(srwlock: *mut SrwLock);
+}
+
+pub struct Mutex(UnsafeCell<SrwLock>);
+
+unsafe impl Send for Mutex {}
+unsafe impl Sync for Mutex {}
+
+impl Mutex {
+	#[inline]
+	pub const fn new() -> Self {
+		Self(UnsafeCell::new(SRWLOCK_INIT))
+	}
+
+	/// Locks the mutex
+	///
+	/// # Safety
+	///
+	/// UB occurs if the mutex is already locked by the current thread and the
+	/// `unsafe_lock` feature is enabled.
+	#[inline]
+	pub unsafe fn lock(&self) {
+		unsafe {
+			AcquireSRWLockExclusive(self.0.get());
+		}
+	}
+
+	/// If the mutex is unlocked, it is locked, and this function returns
+	/// `true'. Otherwise, `false` is returned.
+	#[inline]
+	pub unsafe fn try_lock(&self) -> bool {
+		unsafe { TryAcquireSRWLockExclusive(self.0.get()) != 0 }
+	}
+
+	/// Unlocks the mutex
+	///
+	/// # Safety
+	///
+	/// UB occurs if the mutex is already unlocked or if it has been locked on
+	/// a different thread.
+	#[inline]
+	pub unsafe fn unlock(&self) {
+		unsafe {
+			ReleaseSRWLockExclusive(self.0.get());
+		}
+	}
+
+	pub unsafe fn is_locked(&self) -> bool {
+		if self.try_lock() {
+			unsafe {
+				self.unlock();
+			}
+			false
+		} else {
+			true
+		}
+	}
+}
+
+pub struct RwLock {
+	inner: UnsafeCell<c::SRWLOCK>,
+}
+
+unsafe impl Send for RwLock {}
+unsafe impl Sync for RwLock {}
+
+impl RwLock {
+	#[inline]
+	pub const fn new() -> RwLock {
+		RwLock {
+			inner: UnsafeCell::new(c::SRWLOCK_INIT),
+		}
+	}
+	#[inline]
+	pub fn read(&self) {
+		unsafe { c::AcquireSRWLockShared(self.inner.get()) }
+	}
+	#[inline]
+	pub fn try_read(&self) -> bool {
+		unsafe { c::TryAcquireSRWLockShared(self.inner.get()) != 0 }
+	}
+	#[inline]
+	pub fn write(&self) {
+		unsafe { c::AcquireSRWLockExclusive(self.inner.get()) }
+	}
+	#[inline]
+	pub fn try_write(&self) -> bool {
+		unsafe { c::TryAcquireSRWLockExclusive(self.inner.get()) != 0 }
+	}
+	#[inline]
+	pub unsafe fn read_unlock(&self) {
+		c::ReleaseSRWLockShared(self.inner.get())
+	}
+	#[inline]
+	pub unsafe fn write_unlock(&self) {
+		c::ReleaseSRWLockExclusive(self.inner.get())
+	}
+}