scodec.protocols.mpeg.transport.psi.ConditionalAccessTable.scala Maven / Gradle / Ivy
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package scodec.protocols.mpeg
package transport
package psi
import scodec.Codec
import scodec.bits._
import scodec.codecs._
case class ConditionalAccessTable(
version: Int,
current: Boolean,
descriptors: List[ConditionalAccessDescriptor]
) extends Table {
def tableId = ConditionalAccessSection.TableId
def toSections: GroupedSections[ConditionalAccessSection] = ConditionalAccessTable.toSections(this)
}
object ConditionalAccessTable {
def toSections(cat: ConditionalAccessTable): GroupedSections[ConditionalAccessSection] = {
val grouped = groupBasedOnSize(cat.descriptors.toVector)
val lastSection = grouped.size - 1
val sections = grouped.zipWithIndex.map { case (ds, idx) =>
ConditionalAccessSection(SectionExtension(65535, cat.version, cat.current, idx, lastSection), ds.toList)
}
if (sections.isEmpty)
GroupedSections(ConditionalAccessSection(SectionExtension(65535, cat.version, cat.current, 0, 0), Nil))
else
GroupedSections(sections.head, sections.tail.toList)
}
private def groupBasedOnSize(sections: Vector[ConditionalAccessDescriptor]): Vector[Vector[ConditionalAccessDescriptor]] = {
val MaxBitsLeft = (1024 - 12) * 8L
def sizeOf(c: ConditionalAccessDescriptor): Long = (6 * 8) + c.privateData.size
@annotation.tailrec
def go(remaining: Vector[ConditionalAccessDescriptor], cur: Vector[ConditionalAccessDescriptor], bitsLeft: Long, acc: Vector[Vector[ConditionalAccessDescriptor]]): Vector[Vector[ConditionalAccessDescriptor]] = {
if (remaining.isEmpty) acc :+ cur
else {
val next = remaining.head
val bitsNeeded = (6 * 8) + sizeOf(next)
val newBitsLeft = bitsLeft - bitsNeeded
if (newBitsLeft >= 0) go(remaining.tail, cur :+ next, newBitsLeft, acc)
else {
go(remaining, Vector.empty, MaxBitsLeft, acc :+ cur)
}
}
}
go(sections, Vector.empty, MaxBitsLeft, Vector.empty)
}
def fromSections(sections: GroupedSections[ConditionalAccessSection]): Either[String, ConditionalAccessTable] = {
def extract[A](name: String, f: ConditionalAccessSection => A): Either[String, A] = {
val extracted = sections.list.map(f).distinct
if (extracted.size == 1) Right(extracted.head)
else Left(s"sections have diferring $name: " + extracted.mkString(", "))
}
for {
version <- extract("versions", _.extension.version).right
} yield {
val current = sections.list.foldLeft(false) { (acc, s) => acc || s.extension.current }
ConditionalAccessTable(
version,
current,
(for {
section <- sections.list
descriptor <- section.descriptors
} yield descriptor)
)
}
}
implicit val tableSupport: TableSupport[ConditionalAccessTable] = new TableSupport[ConditionalAccessTable] {
def tableId = ConditionalAccessSection.TableId
def toTable(gs: GroupedSections[Section]) =
gs.narrow[ConditionalAccessSection].toRight(s"Not CAT sections").right.flatMap { sections => fromSections(sections) }
def toSections(cat: ConditionalAccessTable) = ConditionalAccessTable.toSections(cat)
}
}
case class ConditionalAccessSection(
extension: SectionExtension,
descriptors: List[ConditionalAccessDescriptor]
) extends ExtendedSection {
def tableId = ConditionalAccessSection.TableId
}
object ConditionalAccessSection {
val TableId = 1
type Fragment = List[ConditionalAccessDescriptor]
private val fragmentCodec: Codec[Fragment] =
list(Codec[ConditionalAccessDescriptor])
implicit val sectionFragmentCodec: SectionFragmentCodec[ConditionalAccessSection] =
SectionFragmentCodec.psi[ConditionalAccessSection, Fragment](
TableId,
(ext, descriptors) => ConditionalAccessSection(ext, descriptors),
cat => (cat.extension, cat.descriptors)
)(fragmentCodec)
}
case class ConditionalAccessDescriptor(systemId: Int, pid: Pid, privateData: BitVector)
object ConditionalAccessDescriptor {
val Tag = 9
implicit val codec: Codec[ConditionalAccessDescriptor] = {
constant(Tag) ~>
variableSizeBytes(uint8,
("ca_system_id" | uint16) ::
(reserved(3) ~>
("ca_pid" | Codec[Pid])) ::
bits
)
}.as[ConditionalAccessDescriptor]
}