Add common impls for Error type

nicholasbishop · GabrielMajeri · commit ad816f41690c · 2022-05-16T12:55:55.000+03:00
Derive `Eq`, `PartialEq`, `Ord`, `PartialOrd`, and `Hash`. Also add a
`Display` impl.
diff --git a/src/lib.rs b/src/lib.rs
@@ -5,16 +5,28 @@
 #![deny(clippy::all)]
 
 use bit_field::BitField;
+use core::fmt::{self, Display, Formatter};
 
 /// Possible errors returned by the API.
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
 pub enum Error {
     /// Not enough space left in the output buffer.
     BufferOverflow,
     /// Input contained a character which cannot be represented in UCS-2.
     MultiByte,
 }
 
+impl Display for Error {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::BufferOverflow => f.write_str("output buffer is too small"),
+            Self::MultiByte => {
+                f.write_str("input contains a character which cannot be represented in UCS-2")
+            }
+        }
+    }
+}
+
 type Result<T> = core::result::Result<T, Error>;
 
 /// Encodes an input UTF-8 string into a UCS-2 string.
