fs2.protocols.pcapng.ByteOrderMagic.scala Maven / Gradle / Ivy
/*
* Copyright (c) 2013 Functional Streams for Scala
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package fs2.protocols
package pcapng
import scodec._
import scodec.bits._
import scodec.codecs._
object ByteOrderMagic extends Codec[ByteOrdering] {
private val BigEndian = hex"1a2b3c4d"
private val LittleEndian = hex"4d3c2b1a"
def sizeBound = SizeBound.exact(32)
def encode(bo: ByteOrdering) = bo match {
case ByteOrdering.BigEndian => Attempt.successful(BigEndian.bits)
case ByteOrdering.LittleEndian => Attempt.successful(LittleEndian.bits)
}
def decode(buf: BitVector) =
bytes(4).decode(buf).flatMap {
case DecodeResult(BigEndian, rest) =>
Attempt.successful(DecodeResult(ByteOrdering.BigEndian, rest))
case DecodeResult(LittleEndian, rest) =>
Attempt.successful(DecodeResult(ByteOrdering.LittleEndian, rest))
case DecodeResult(other, _) =>
Attempt.failure(
Err(s"unable to detect byte ordering due to unrecognized magic number $other")
)
}
}