f The K stands for complicated

Author: tnull

lightning/src/ln/channel.rs

@@ -5988,9 +5988,7 @@ impl<Signer: Sign> Writeable for Channel<Signer> {
 		// `user_id` used to be a single u64 value. In order to remain backwards compatible with
 		// versions prior to 0.0.113, the u128 is serialized as two separate u64 values. We write
 		// the low bytes now and the optional high bytes later.
-		let mut low_bytes = [0u8; 8];
-		low_bytes.copy_from_slice(&self.user_id.to_be_bytes()[8..16]);
-		let user_id_low = u64::from_be_bytes(low_bytes);
+		let user_id_low = self.user_id as u64;
 		user_id_low.write(writer)?;
 
 		// Version 1 deserializers expected to read parts of the config object here. Version 2
@@ -6239,9 +6237,7 @@ impl<Signer: Sign> Writeable for Channel<Signer> {
 		// `user_id` used to be a single u64 value. In order to remain backwards compatible with
 		// versions prior to 0.0.113, the u128 is serialized as two separate u64 values. Therefore,
 		// we write the high bytes as an option here.
-		let mut high_bytes = [0u8; 8];
-		high_bytes.copy_from_slice(&self.user_id.to_be_bytes()[0..8]);
-		let user_id_high_opt = Some(u64::from_be_bytes(high_bytes));
+		let user_id_high_opt = Some((self.user_id >> 64) as u64);
 
 		write_tlv_fields!(writer, {
 			(0, self.announcement_sigs, option),
@@ -6585,12 +6581,11 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<(&'a K, u32)> for Channel<Signer>
 		// `user_id` used to be a single u64 value. In order to remain backwards
 		// compatible with versions prior to 0.0.113, the u128 is serialized as two
 		// separate u64 values.
-		let mut user_id_bytes = [0u8; 16];
-		user_id_bytes[8..16].copy_from_slice(&user_id_low.to_be_bytes());
-		if let Some(high_bytes) = user_id_high_opt {
-			user_id_bytes[0..8].copy_from_slice(&high_bytes.to_be_bytes());
-		}
-		let user_id = u128::from_be_bytes(user_id_bytes);
+		let user_id = if let Some(user_id_high) = user_id_high_opt {
+			user_id_low as u128 + ((user_id_high as u128) << 64)
+		} else {
+			user_id_low as u128
+		};
 
 		Ok(Channel {
 			user_id,

lightning/src/util/events.rs

@@ -787,12 +787,8 @@ impl Writeable for Event {
 				// `user_channel_id` used to be a single u64 value. In order to remain backwards
 				// compatible with versions prior to 0.0.113, the u128 is serialized as two
 				// separate u64 values.
-				let mut low_bytes = [0u8; 8];
-				low_bytes.copy_from_slice(&user_channel_id.to_be_bytes()[8..16]);
-				let user_channel_id_low = u64::from_be_bytes(low_bytes);
-				let mut high_bytes = [0u8; 8];
-				high_bytes.copy_from_slice(&user_channel_id.to_be_bytes()[0..8]);
-				let user_channel_id_high = u64::from_be_bytes(high_bytes);
+				let user_channel_id_low = *user_channel_id as u64;
+				let user_channel_id_high = (*user_channel_id >> 64) as u64;
 				write_tlv_fields!(writer, {
 					(0, channel_id, required),
 					(1, user_channel_id_low, required),
@@ -1021,13 +1017,11 @@ impl MaybeReadable for Event {
 					// backwards compatible with versions prior to 0.0.113, the u128 is serialized
 					// as two separate u64 values.
 					let user_channel_id = if let Some(user_channel_id_low) = user_channel_id_low_opt {
-						let mut user_channel_id_bytes = [0u8; 16];
 						if let Some(user_channel_id_high) = user_channel_id_high_opt {
-							user_channel_id_bytes[0..8].copy_from_slice(&user_channel_id_high.to_be_bytes());
+							user_channel_id_low as u128 + ((user_channel_id_high as u128) << 64)
+						} else {
+							user_channel_id_low as u128
 						}
-
-						user_channel_id_bytes[8..16].copy_from_slice(&user_channel_id_low.to_be_bytes());
-						u128::from_be_bytes(user_channel_id_bytes)
 					} else { 0u128 };
 					Ok(Some(Event::ChannelClosed { channel_id, user_channel_id, reason: reason.unwrap() }))
 				};