using?System;
using?System.Collections.Generic;
using?System.Linq;
using?System.Text;
using?System.Threading;

namespace?RUDPSLib.XModem1
{
????//Version?1.3

????//This?class?is?tested?to?be?100%?compatibel?to?Microsoft（r）?Hyperterminal?5.1

????//XmodemTransmit:?supports?both?CRC?and?checksum
????//XModemReceive:?only?supports?checksum

????//Feel?free?to?use/modify/copy/distribute?this?file
????public?class?XModem
????{
????????#region?Events

????????private?System.EventHandler?PacketReceivedEvent;
????????public?event?System.EventHandler?PacketReceived
????????{
????????????add
????????????{
????????????????PacketReceivedEvent?=?（System.EventHandler）System.Delegate.Combine（PacketReceivedEvent?value）;
????????????}
????????????remove
????????????{
????????????????PacketReceivedEvent?=?（System.EventHandler）System.Delegate.Remove（PacketReceivedEvent?value）;
????????????}
????????}

????????public?delegate?void?PacketSentEventHandler（int?TXStringSize）;
????????private?PacketSentEventHandler?PacketSentEvent;

????????public?event?PacketSentEventHandler?PacketSent
????????{
????????????add
????????????{
????????????????PacketSentEvent?=?（PacketSentEventHandler）System.Delegate.Combine（PacketSentEvent?value）;
????????????}
????????????remove
????????????{
????????????????PacketSentEvent?=?（PacketSentEventHandler）System.Delegate.Remove（PacketSentEvent?value）;
????????????}
????????}


????????#endregion

????????#region?Members

????????private?System.IO.Ports.SerialPort?port?=?null;

????????private?byte?SOH?=?（byte）（0x01）;
????????//header?for?128byte-packets
????????private?byte?STX?=?（byte）（0x02）;
????????//header?for?1024byte-packets
????????private?byte?EOT?=?（byte）（0x04）;
????????//end?of?transmission
????????private?byte?ACK?=?（byte）（0x06）;
????????//acknowledge
????????private?byte?NAK?=?（byte）（0x15）;
????????//negativ?acknowledge
????????private?byte?CAN?=?（byte）（0x18）;
????????///?

????????///?cancel?transfer
????????///?

????????private?byte?CTRLZ?=?（byte）（0x1A）;
????????//padding?char?to?fill?data?blocks?????????private?byte?C_pad?=?（byte）（0x43）;

????????//start?of?a?CRC?request
????????private?ushort?MAXRETRANS?=?System.Convert.ToUInt16（25）;

????????//1024?for?XModem?1k?+?3?head?chars?+?2?crc?+?nul
????????private?byte[]?xbuff?=?new?byte[1029];

????????private?int?bufsz;
????????private?int?crc?=?1;
????????private?byte?packetno?=?（byte）1;
????????private?int?i;
????????private?int?c;
????????private?int?len?=?0;
????????private?int?retry;

????????#endregion

????????#region?Constructor

????????public?XModem（System.IO.Ports.SerialPort?port）
????????{
????????????if?（!port.IsOpen）
????????????????port.Open（）;
????????????this.port?=?port;
????????}

????????#endregion

????????#region?Implementation

????????#region?XModemReceive

????????//
????????//receive?byte?Array?via?XModem?using?either