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/*
 * Copyright (c) 2013, Scodec
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package scodec
package codecs

import scodec.bits.BitVector

private[codecs] final class ByteCodec(bits: Int, signed: Boolean) extends Codec[Byte]:

  require(
    bits > 0 && bits <= (if signed then 8 else 7),
    "bits must be in range [1, 8] for signed and [1, 7] for unsigned"
  )

  private val MaxValue = ((1 << (if signed then bits - 1 else bits)) - 1).toByte
  private val MinValue = (if signed then -(1 << (bits - 1)) else 0).toByte

  private def description = s"$bits-bit ${if signed then "signed" else "unsigned"} byte"

  override def sizeBound = SizeBound.exact(bits.toLong)

  override def encode(b: Byte) =
    if b > MaxValue then
      Attempt.failure(Err(s"$b is greater than maximum value $MaxValue for $description"))
    else if b < MinValue then
      Attempt.failure(Err(s"$b is less than minimum value $MinValue for $description"))
    else Attempt.successful(BitVector.fromByte(b, bits))

  override def decode(buffer: BitVector) =
    buffer.acquire(bits.toLong) match
      case Left(_)  => Attempt.failure(Err.insufficientBits(bits.toLong, buffer.size))
      case Right(b) => Attempt.successful(DecodeResult(b.toByte(signed), buffer.drop(bits.toLong)))

  override def toString = description