Don't expose NonZero through libstd.

1 files changed, 98 insertions, 0 deletions

diff --git a/src/libcore/nonzero.rs b/src/libcore/nonzero.rs
new file mode 100644
index 00000000000..f976f08bf84
--- /dev/null
+++ b/src/libcore/nonzero.rs
@@ -0,0 +1,98 @@
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Exposes the NonZero lang item which provides optimization hints.
+
+use cmp::Eq;
+use intrinsics;
+use kinds::Copy;
+use ops::Deref;
+use option::Option;
+use option::Option::Some;
+use ptr::{null, null_mut, RawPtr, RawMutPtr};
+
+/// A wrapper type for raw pointers and integers that will never be
+/// NULL or 0 that might allow certain optimizations.
+#[lang="non_zero"]
+#[deriving(Clone, PartialEq, Eq, PartialOrd)]
+#[experimental]
+pub struct NonZero<T>(T);
+
+impl<T> NonZero<T> {
+    /// Create an instance of NonZero with the provided value.
+    /// You must indeed ensure that the value is actually "non-zero".
+    #[inline(always)]
+    pub unsafe fn new(inner: T) -> NonZero<T> {
+        NonZero(inner)
+    }
+}
+
+impl<T: Copy> Copy for NonZero<T> {}
+
+impl<T> Deref<T> for NonZero<T> {
+    #[inline]
+    fn deref<'a>(&'a self) -> &'a T {
+        let NonZero(ref inner) = *self;
+        inner
+    }
+}
+
+impl<T> RawPtr<T> for NonZero<*const T> {
+    #[inline]
+    fn null() -> NonZero<*const T> { NonZero(null()) }
+
+    #[inline]
+    fn is_null(&self) -> bool { false }
+
+    #[inline]
+    fn to_uint(&self) -> uint {
+        **self as uint
+    }
+
+    #[inline]
+    unsafe fn offset(self, count: int) -> NonZero<*const T> {
+        NonZero(intrinsics::offset(*self, count))
+    }
+
+    #[inline]
+    unsafe fn as_ref<'a>(&self) -> Option<&'a T> {
+        Some(&***self)
+    }
+}
+
+impl<T> RawPtr<T> for NonZero<*mut T> {
+    #[inline]
+    fn null() -> NonZero<*mut T> { NonZero(null_mut()) }
+
+    #[inline]
+    fn is_null(&self) -> bool { false }
+
+    #[inline]
+    fn to_uint(&self) -> uint {
+        **self as uint
+    }
+
+    #[inline]
+    unsafe fn offset(self, count: int) -> NonZero<*mut T> {
+        NonZero(intrinsics::offset(*self as *const T, count) as *mut T)
+    }
+
+    #[inline]
+    unsafe fn as_ref<'a>(&self) -> Option<&'a T> {
+        Some(&***self)
+    }
+}
+
+impl<T> RawMutPtr<T> for NonZero<*mut T> {
+    #[inline]
+    unsafe fn as_mut<'a>(&self) -> Option<&'a mut T> {
+        Some(&mut ***self)
+    }
+}