od: add byteorder_io

copied from: https://github.com/netvl/immeta/blob/4460ee/src/utils.rs
workaround for: https://github.com/BurntSushi/byteorder/issues/41

src/od/byteorder_io.rs

@@ -0,0 +1,46 @@
+// from: https://github.com/netvl/immeta/blob/4460ee/src/utils.rs#L76
+
+use std::io::{self, Read, BufRead, ErrorKind};
+
+use byteorder::{self, ReadBytesExt, LittleEndian, BigEndian};
+use byteorder::ByteOrder as ByteOrderTrait;
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum ByteOrder {
+    Little,
+    Big,
+}
+
+macro_rules! gen_byte_order_ops {
+    ($($read_name:ident, $write_name:ident -> $tpe:ty),+) => {
+        impl ByteOrder {
+            $(
+            #[inline]
+            pub fn $read_name(self, source: &[u8]) -> $tpe {
+                match self {
+                    ByteOrder::Little => LittleEndian::$read_name(source),
+                    ByteOrder::Big => BigEndian::$read_name(source),
+                }
+            }
+
+            pub fn $write_name(self, target: &mut [u8], n: $tpe) {
+                match self {
+                    ByteOrder::Little => LittleEndian::$write_name(target, n),
+                    ByteOrder::Big => BigEndian::$write_name(target, n),
+                }
+            }
+            )+
+        }
+    }
+}
+
+gen_byte_order_ops! {
+    read_u16, write_u16 -> u16,
+    read_u32, write_u32 -> u32,
+    read_u64, write_u64 -> u64,
+    read_i16, write_i16 -> i16,
+    read_i32, write_i32 -> i32,
+    read_i64, write_i64 -> i64,
+    read_f32, write_f32 -> f32,
+    read_f64, write_f64 -> f64
+}