default Decoder::decode() impl

1 files changed, 10 insertions, 5 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 1ae01fb..c5b0610 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -165,16 +165,21 @@ pub trait DecodeError {
     fn bad_operand(&self) -> bool;
 }
 
-pub trait Decoder<Inst> where Inst: Sized {
+pub trait Decoder<Inst> where Inst: Sized + Default {
     type Error: DecodeError + Debug + Display;
-    fn decode<T: IntoIterator<Item=u8>>(&self, bytes: T) -> Result<Inst, Self::Error>;
-    fn decode_into<T: IntoIterator<Item=u8>>(&self, &mut Inst, bytes: T) -> Result<(), Self::Error>;
+
+    fn decode<T: IntoIterator<Item=u8>>(&self, bytes: T) -> Result<Inst, Self::Error> {
+        let mut inst = Inst::default();
+        self.decode_into(&mut inst, bytes).map(|_: ()| inst)
+    }
+
+    fn decode_into<T: IntoIterator<Item=u8>>(&self, inst: &mut Inst, bytes: T) -> Result<(), Self::Error>;
 }
 
 #[cfg(feature="use-serde")]
 pub trait Arch {
     type Address: Address + Debug + Hash + PartialEq + Eq + Serialize + for<'de> Deserialize<'de>;
-    type Instruction: Instruction + LengthedInstruction<Unit=Self::Address> + Debug;
+    type Instruction: Instruction + LengthedInstruction<Unit=Self::Address> + Debug + Default;
     type DecodeError: DecodeError + Debug + Display;
     type Decoder: Decoder<Self::Instruction, Error=Self::DecodeError> + Default;
     type Operand;
@@ -183,7 +188,7 @@ pub trait Arch {
 #[cfg(not(feature="use-serde"))]
 pub trait Arch {
     type Address: Address + Debug + Hash + PartialEq + Eq;
-    type Instruction: Instruction + LengthedInstruction<Unit=Self::Address> + Debug;
+    type Instruction: Instruction + LengthedInstruction<Unit=Self::Address> + Debug + Default;
     type DecodeError: DecodeError + Debug + Display;
     type Decoder: Decoder<Self::Instruction, Error=Self::DecodeError> + Default;
     type Operand;