Trivial types for encoding and decoding

sway-lib-std/src/lib.sw

@@ -57,3 +57,4 @@ pub mod low_level_call;
 pub mod array_conversions;
 pub mod bytes_conversions;
 pub mod clone;
+pub mod trivial;

sway-lib-std/src/trivial.sw

@@ -0,0 +1,86 @@
+library;
+
+use ::codec::{AbiDecode, AbiEncode, Buffer, BufferReader};
+use ::marker::Enum;
+
+pub struct TrivialBool {
+    value: u8,
+}
+
+impl TrivialBool {
+    pub fn unwrap(self) -> bool {
+        match self.value {
+            0 => false,
+            1 => true,
+            _ => __revert(0),
+        }
+    }
+}
+
+impl AbiEncode for TrivialBool {
+    // fn is_encode_trivial() -> bool {
+    //    true
+    // }
+
+    fn abi_encode(self, buffer: Buffer) -> Buffer {
+        self.value.abi_encode(buffer)
+    }
+}
+
+impl AbiDecode for TrivialBool {
+    // fn is_decode_trivial() -> bool {
+    //    true
+    // }
+
+    fn abi_decode(ref mut buffer: BufferReader) -> TrivialBool {
+        let value: u8 = buffer.read::<u8>();
+        TrivialBool { value }
+    }
+}
+
+pub struct TrivialEnum<T>
+where
+    T: Enum + AbiEncode + AbiDecode,
+{
+    value: T,
+}
+
+impl<T> TrivialEnum<T>
+where
+    T: Enum + AbiEncode + AbiDecode,
+{
+    pub fn unwrap(self) -> T {
+        // this is not useless, as an invalid
+        // discriminant will revert
+        match self.value {
+            v => v,
+        }
+    }
+}
+
+impl<T> AbiEncode for TrivialEnum<T>
+where
+    T: Enum + AbiEncode + AbiDecode,
+{
+    // fn is_encode_trivial() -> bool {
+    //    true
+    // }
+
+    fn abi_encode(self, buffer: Buffer) -> Buffer {
+        self.value.abi_encode(buffer)
+    }
+}
+
+impl<T> AbiDecode for TrivialEnum<T>
+where
+    T: Enum + AbiEncode + AbiDecode,
+{
+    // fn is_decode_trivial() -> bool {
+    //    true
+    // }
+
+    fn abi_decode(ref mut buffer: BufferReader) -> TrivialEnum<T> {
+        let value: T = buffer.decode::<T>();
+        TrivialEnum { value }
+    }
+}