diff --git a/gradle.properties b/gradle.properties
index 24212a0..8e48d10 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,7 +4,7 @@ kotlin.code.style=official
 specifyKotlinAsDependency=false
 
 projectGroup=ru.dbotthepony.kommons
-projectVersion=2.9.23
+projectVersion=2.9.24
 
 guavaDepVersion=33.0.0
 gsonDepVersion=2.8.9
diff --git a/src/main/kotlin/ru/dbotthepony/kommons/io/StreamCodec.kt b/src/main/kotlin/ru/dbotthepony/kommons/io/StreamCodec.kt
index 1dd6558..609851d 100644
--- a/src/main/kotlin/ru/dbotthepony/kommons/io/StreamCodec.kt
+++ b/src/main/kotlin/ru/dbotthepony/kommons/io/StreamCodec.kt
@@ -179,8 +179,33 @@ interface StreamCodec<V> {
 			return value.map(codec::copy)
 		}
 	}
+
+	class Mapping<T, R>(private val codec: StreamCodec<T>, private val from: T.() -> R, private val to: R.() -> T, private val copy: R.() -> R = { this }) : StreamCodec<R> {
+		override fun read(stream: DataInputStream): R {
+			return from(codec.read(stream))
+		}
+
+		override fun write(stream: DataOutputStream, value: R) {
+			codec.write(stream, to(value))
+		}
+
+		override fun copy(value: R): R {
+			return copy(value)
+		}
+	}
 }
 
+fun <T, R> StreamCodec<T>.map(from: T.() -> R, to: R.() -> T): StreamCodec<R> {
+	return StreamCodec.Mapping(this, from, to)
+}
+
+fun <T, R> StreamCodec<T>.map(from: T.() -> R, to: R.() -> T, copy: R.() -> R): StreamCodec<R> {
+	return StreamCodec.Mapping(this, from, to, copy)
+}
+
+fun <T : Any> StreamCodec<T>.optional() = StreamCodec.Optional(this)
+fun <T> StreamCodec<T>.koptional() = StreamCodec.KOptional(this)
+
 val NullValueCodec = StreamCodec.Impl({ _ -> null }, { _, _ -> })
 val BooleanValueCodec = StreamCodec.Impl(DataInputStream::readBoolean, 1L, DataOutputStream::writeBoolean)
 val ByteValueCodec = StreamCodec.Impl(DataInputStream::readByte, 1L, { s, v -> s.writeByte(v.toInt()) })
@@ -196,6 +221,11 @@ val VarIntValueCodec = StreamCodec.Impl(DataInputStream::readSignedVarInt, DataO
 val VarLongValueCodec = StreamCodec.Impl(DataInputStream::readSignedVarLong, DataOutputStream::writeSignedVarLong)
 val BinaryStringCodec = StreamCodec.Impl(DataInputStream::readBinaryString, DataOutputStream::writeBinaryString)
 
+val UnsignedVarLongCodec = StreamCodec.Impl(DataInputStream::readVarLong, DataOutputStream::writeVarLong)
+val UnsignedVarIntCodec = StreamCodec.Impl(DataInputStream::readVarInt, DataOutputStream::writeVarInt)
+
+val ByteArrayCodec = StreamCodec.Impl(DataInputStream::readByteArray, DataOutputStream::writeByteArray)
+
 val RGBCodec = StreamCodec.Impl(
 	{ s -> RGBAColor(s.readFloat(), s.readFloat(), s.readFloat()) },
 	{ s, v -> s.writeFloat(v.red); s.writeFloat(v.green); s.writeFloat(v.blue) })