scodec.codecs.ZlibCodec.scala Maven / Gradle / Ivy
package scodec
package codecs
import java.util.zip.{DataFormatException, Inflater}
import scodec.bits.{BitVector, ByteVector}
private[scodec] class ZlibCodec[A](codec: Codec[A], level: Int, strategy: Int, nowrap: Boolean, chunkSize: Int) extends Codec[A] {
def sizeBound = SizeBound.unknown
def encode(a: A) =
codec.encode(a).map { b =>
b.deflate(level, strategy, nowrap, chunkSize)
}
def decode(b: BitVector) =
inflate(b, chunkSize).fold(
e => Attempt.failure(Err(e.getMessage)),
bb => codec.decode(bb.value.bits).map(_.mapRemainder(_ => bb.remainder))
)
private def inflate(b: BitVector, chunkSize: Int): Either[DataFormatException, DecodeResult[ByteVector]] = {
if (b.isEmpty) Right(DecodeResult(b.bytes, b))
else {
val arr = b.bytes.toArray
val inflater = new Inflater(false)
try {
inflater.setInput(arr)
try {
val buffer = new Array[Byte](chunkSize min arr.length)
def loop(acc: ByteVector): ByteVector = {
if (inflater.finished || inflater.needsInput) acc
else {
val count = inflater inflate buffer
loop(acc ++ ByteVector(buffer, 0, count))
}
}
val inflated = loop(ByteVector.empty)
if (inflater.finished) Right(DecodeResult(inflated, b.drop(inflater.getBytesRead * 8)))
else Left(new DataFormatException("Insufficient data -- inflation reached end of input without completing inflation - " + inflated))
} catch {
case e: DataFormatException => Left(e)
}
} finally {
inflater.end()
}
}
}
}