1 files changed, 43 insertions, 0 deletions
diff --git a/vendor/png/src/traits.rs b/vendor/png/src/traits.rs
new file mode 100644
index 0000000..ffc10e7
--- /dev/null
+++ b/vendor/png/src/traits.rs
@@ -0,0 +1,43 @@
+use std::io;
+
+macro_rules! read_bytes_ext {
+    ($output_type:ty) => {
+        impl<W: io::Read + ?Sized> ReadBytesExt<$output_type> for W {
+            #[inline]
+            fn read_be(&mut self) -> io::Result<$output_type> {
+                let mut bytes = [0u8; std::mem::size_of::<$output_type>()];
+                self.read_exact(&mut bytes)?;
+                Ok(<$output_type>::from_be_bytes(bytes))
+            }
+        }
+    };
+}
+
+macro_rules! write_bytes_ext {
+    ($input_type:ty) => {
+        impl<W: io::Write + ?Sized> WriteBytesExt<$input_type> for W {
+            #[inline]
+            fn write_be(&mut self, n: $input_type) -> io::Result<()> {
+                self.write_all(&n.to_be_bytes())
+            }
+        }
+    };
+}
+
+/// Read extension to read big endian data
+pub trait ReadBytesExt<T>: io::Read {
+    /// Read `T` from a bytes stream. Most significant byte first.
+    fn read_be(&mut self) -> io::Result<T>;
+}
+
+/// Write extension to write big endian data
+pub trait WriteBytesExt<T>: io::Write {
+    /// Writes `T` to a bytes stream. Most significant byte first.
+    fn write_be(&mut self, _: T) -> io::Result<()>;
+}
+
+read_bytes_ext!(u8);
+read_bytes_ext!(u16);
+read_bytes_ext!(u32);
+
+write_bytes_ext!(u32);