ujson.ByteBufferParser.scala Maven / Gradle / Ivy

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package ujson
import upickle.core.{ObjArrVisitor, Visitor}

import scala.annotation.{switch, tailrec}
import java.nio.ByteBuffer
import java.nio.charset.StandardCharsets

/**
 * Basic ByteBuffer parser.
 *
 * This assumes that the provided ByteBuffer is ready to be read. The
 * user is responsible for any necessary flipping/resetting of the
 * ByteBuffer before parsing.
 *
 * The parser makes absolute calls to the ByteBuffer, which will not
 * update its own mutable position fields.
 */
final class ByteBufferParser[J](src: ByteBuffer) extends ByteParser[J]{
  private[this] final val start = src.position()
  private[this] final val limit = src.limit() - start


  protected[this] final def close() = { src.position(start) }
  override def growBuffer(until: Int): Unit = ()
  def readDataIntoBuffer(buffer: Array[Byte], bufferOffset: Int) = {

    if(buffer == null) (java.util.Arrays.copyOfRange(src.array(), start, src.limit()), limit == 0, limit)
    else (src.array(), true, -1)
  }
}

object ByteBufferParser extends Transformer[ByteBuffer]{
  def transform[T](j: ByteBuffer, f: Visitor[_, T]) = new ByteBufferParser(j).parse(f)
}