Imports System
Imports System.Runtime.InteropServices

Namespace JustinIO
Class CommPort
Public PortNum As String
Public BaudRate As Integer
Public ByteSize As Byte
Public Parity As Byte '// 0-4=no,odd,even,mark,space
Public StopBits As Byte '// 0,1,2 = 1, 1.5, 2
Public ReadTimeout As Integer '//comm port win32 file handle
Private hComm As Integer = -1
Public Opened As Boolean = False
'//win32 api constants
Private Const GENERIC_READ As Int64 = &H80000000
Private Const GENERIC_WRITE As Int64 = &H40000000
Private Const OPEN_EXISTING As Integer = 3
Private Const INVALID_HANDLE_VALUE As Integer = -1

#Region "struct"

<StructLayout(LayoutKind.Sequential)> _
Public Structure DCB
'//taken from c struct in platform sdk
Public DCBlength As Integer '// sizeof(DCB)
Public BaudRate As Integer '// 指定当前波特率 current baud rate
'// these are the c struct bit fields, bit twiddle flag to set
Public fBinary As Integer '// 指定是否允许二进制模式,在windows95中必须主TRUE binary mode, no EOF check
Public fParity As Integer '// 指定是否允许奇偶校验 enable parity checking
Public fOutxCtsFlow As Integer '// 指定CTS是否用于检测发送控制，当为TRUE是CTS为OFF，发送将被挂起。 CTS output flow control
Public fOutxDsrFlow As Integer '// 指定CTS是否用于检测发送控制 DSR output flow control
Public fDtrControl As Integer '// DTR_CONTROL_DISABLE值将DTR置为OFF, DTR_CONTROL_ENABLE值将DTR置为ON, DTR_CONTROL_HANDSHAKE允许DTR"握手" DTR flow control type
Public fDsrSensitivity As Integer '// 当该值为TRUE时DSR为OFF时接收的字节被忽略 DSR sensitivity
Public fTXContinueOnXoff As Integer '// 指定当接收缓冲区已满,并且驱动程序已经发送出XoffChar字符时发送是否停止。TRUE时，在接收缓冲区接收到缓冲区已满的字节XoffLim且驱动程序已经发送出XoffChar字符中止接收字节之后，发送继续进行。　FALSE时，在接收缓冲区接收到代表缓冲区已空的字节XonChar且驱动程序已经发送出恢复发送的XonChar之后，发送继续进行。XOFF continues Tx
Public fOutX As Integer '// TRUE时，接收到XoffChar之后便停止发送接收到XonChar之后将重新开始 XON/XOFF out flow control
Public fInX As Integer '// TRUE时，接收缓冲区接收到代表缓冲区满的XoffLim之后，XoffChar发送出去接收缓冲区接收到代表缓冲区空的XonLim之后，XonChar发送出去 XON/XOFF in flow control
Public fErrorChar As Integer '// 该值为TRUE且fParity为TRUE时，用ErrorChar 成员指定的字符代替奇偶校验错误的接收字符 enable error replacement
Public fNull As Integer '// eTRUE时，接收时去掉空（0值）字节 enable null stripping
Public fRtsControl As Integer '// RTS flow control
'/*RTS_CONTROL_DISABLE时,RTS置为OFF
' * 　 RTS_CONTROL_ENABLE时, RTS置为ON
' * 　　 RTS_CONTROL_HANDSHAKE时,
' * 　　 当接收缓冲区小于半满时RTS为ON
' * 　 　 当接收缓冲区超过四分之三满时RTS为OFF
' * 　　 RTS_CONTROL_TOGGLE时,
' * 　　 当接收缓冲区仍有剩余字节时RTS为ON ,否则缺省为OFF*/
Public fAbortOnError As Integer '// TRUE时,有错误发生时中止读和写操作 abort on error
Public fDummy2 As Integer '// 未使用 reserved
Public flags As Int64
Public wReserved As UInt16 '// 未使用,必须为0 not currently used
Public XonLim As UInt16 '// 指定在XON字符发送这前接收缓冲区中可允许的最小字节数 transmit XON threshold
Public XoffLim As UInt16 '// 指定在XOFF字符发送这前接收缓冲区中可允许的最小字节数 transmit XOFF threshold
Public ByteSize As Byte '// 指定端口当前使用的数据位 number of bits/byte, 4-8
Public Parity As Byte '// 指定端口当前使用的奇偶校验方法,可能为:EVENPARITY,MARKPARITY,NOPARITY,ODDPARITY 0-4=no,odd,even,mark,space
Public StopBits As Byte '// 指定端口当前使用的停止位数,可能为:ONESTOPBIT,ONE5STOPBITS,TWOSTOPBIT