scodec.codecs.ConditionalCodec.scala Maven / Gradle / Ivy
package scodec
package codecs
import scodec.bits.BitVector
private[codecs] final class ConditionalCodec[A](included: Boolean, codec: => Codec[A]) extends Codec[Option[A]] {
private lazy val evaluatedCodec = codec
override def sizeBound = if (included) evaluatedCodec.sizeBound else SizeBound.exact(0)
override def encode(a: Option[A]) = {
a.filter { _ => included } match {
case None => Attempt.successful(BitVector.empty)
case Some(a) => evaluatedCodec.encode(a)
}
}
override def decode(buffer: BitVector) = {
if (included)
evaluatedCodec.decode(buffer).map { _ map { result => Some(result) } }
else
Attempt.successful(DecodeResult(None, buffer))
}
override def toString = if(included) s"conditional(true, $evaluatedCodec)" else "conditional(false, ?)"
}