tcpipSocket/Chat/Core/RoomListResponsePacket.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace Core
{
	public class RoomListResponsePacket : IPacket
	{
		public List<string> RoomNames { get; }

		public RoomListResponsePacket(ICollection<string> roomNames)
		{
			RoomNames = new List<string>(roomNames);
		}

		public RoomListResponsePacket(byte[] buffer)
		{
			RoomNames = new List<string>();
			for (int cursor = 2; cursor < buffer.Length;)
			{
				short roomNameSize = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(buffer, cursor));
				cursor += sizeof(short);

				RoomNames.Add(Encoding.UTF8.GetString(buffer, cursor, roomNameSize));
				cursor += roomNameSize;
			}
		}

		public byte[] Serialize()
		{
			byte[] packetType = BitConverter.GetBytes(IPAddress.HostToNetworkOrder((short)PacketType.RoomListResponse));

			short dataSize = (short)(packetType.Length);

			List<byte[]> temp = new List<byte[]>();
			foreach (string item in RoomNames)
			{
				byte[] nameBuffer = Encoding.UTF8.GetBytes(item);
				byte[] nameSize = BitConverter.GetBytes(IPAddress.HostToNetworkOrder((short)nameBuffer.Length));
				dataSize += (short)(nameBuffer.Length + nameSize.Length);
				temp.Add(nameSize);
				temp.Add(nameBuffer);
			}

			byte[] header = BitConverter.GetBytes(IPAddress.HostToNetworkOrder(dataSize));

			byte[] buffer = new byte[2 + dataSize];

			int cursor = 0;
			Array.Copy(header, 0, buffer, cursor, header.Length);
			cursor += header.Length;

			Array.Copy(packetType, 0, buffer, cursor, packetType.Length);
			cursor += packetType.Length;

			foreach (byte[] item in temp)
			{
				Array.Copy(item, 0, buffer, cursor, item.Length);
				cursor += item.Length;
			}

			return buffer;
		}
	}
}