Add {IoSlice, IoSliceMut}::advance

1 files changed, 24 insertions, 0 deletions

diff --git a/src/libstd/sys/windows/io.rs b/src/libstd/sys/windows/io.rs
index f0da2323f4f..e44dcbe164d 100644
--- a/src/libstd/sys/windows/io.rs
+++ b/src/libstd/sys/windows/io.rs
@@ -22,6 +22,18 @@ impl<'a> IoSlice<'a> {
     }
 
     #[inline]
+    pub fn advance(&mut self, n: usize) {
+        if (self.vec.len as usize) < n {
+            panic!("advancing IoSlice beyond its length");
+        }
+
+        unsafe {
+            self.vec.len -= n as c::ULONG;
+            self.vec.buf = self.vec.buf.add(n);
+        }
+    }
+
+    #[inline]
     pub fn as_slice(&self) -> &[u8] {
         unsafe {
             slice::from_raw_parts(self.vec.buf as *mut u8, self.vec.len as usize)
@@ -49,6 +61,18 @@ impl<'a> IoSliceMut<'a> {
     }
 
     #[inline]
+    pub fn advance(&mut self, n: usize) {
+        if (self.vec.len as usize) < n {
+            panic!("advancing IoSliceMut beyond its length");
+        }
+
+        unsafe {
+            self.vec.len -= n as c::ULONG;
+            self.vec.buf = self.vec.buf.add(n);
+        }
+    }
+
+    #[inline]
     pub fn as_slice(&self) -> &[u8] {
         unsafe {
             slice::from_raw_parts(self.vec.buf as *mut u8, self.vec.len as usize)