'**************************************************************************************
'
'modSocketMaster module 1.1
'Copyright (c) 2004 by Emiliano Scavuzzo <anshoku@yahoo.com>
'
'Rosario, Argentina
'
'**************************************************************************************
'This module contains API declarations and helper functions for the CSocketMaster class
'**************************************************************************************

Option Explicit

'==============================================================================
'API FUNCTIONS
'==============================================================================

Public Declare Sub api_CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Public Declare Function api_WSAGetLastError Lib "ws2_32.dll" Alias "WSAGetLastError" () As Long
Public Declare Function api_GlobalAlloc Lib "kernel32" Alias "GlobalAlloc" (ByVal wFlags As Long, ByVal dwBytes As Long) As Long
Public Declare Function api_GlobalFree Lib "kernel32" Alias "GlobalFree" (ByVal hMem As Long) As Long
Private Declare Function api_WSAStartup Lib "ws2_32.dll" Alias "WSAStartup" (ByVal wVersionRequired As Long, lpWSADATA As WSAData) As Long
Private Declare Function api_WSACleanup Lib "ws2_32.dll" Alias "WSACleanup" () As Long
Private Declare Function api_WSAAsyncGetHostByName Lib "ws2_32.dll" Alias "WSAAsyncGetHostByName" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal strHostName As String, buf As Any, ByVal buflen As Long) As Long
Private Declare Function api_WSAAsyncSelect Lib "wsock32.dll" Alias "WSAAsyncSelect" (ByVal s As Long, ByVal hwnd As Long, ByVal wMsg As Long, ByVal lEvent As Long) As Long
Private Declare Function api_CreateWindowEx Lib "user32" Alias "CreateWindowExA" (ByVal dwExStyle As Long, ByVal lpClassName As String, ByVal lpWindowName As String, ByVal dwStyle As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hWndParent As Long, ByVal hMenu As Long, ByVal hInstance As Long, lpParam As Any) As Long
Private Declare Function api_DestroyWindow Lib "user32" Alias "DestroyWindow" (ByVal hwnd As Long) As Long
Private Declare Function api_lstrlen Lib "kernel32" Alias "lstrlenA" (ByVal lpString As Any) As Long
Private Declare Function api_lstrcpy Lib "kernel32" Alias "lstrcpyA" (ByVal lpString1 As String, ByVal lpString2 As Long) As Long


'==============================================================================
'CONSTANTS
'==============================================================================

Public Const SOCKET_ERROR   As Integer = -1
Public Const INVALID_SOCKET As Integer = -1
Public Const INADDR_NONE As Long = &HFFFF

Private Const WSADESCRIPTION_LEN As Integer = 257
Private Const WSASYS_STATUS_LEN  As Integer = 129

Private Enum WinsockVersion
    SOCKET_VERSION_11 = &H101
    SOCKET_VERSION_22 = &H202
End Enum

Public Const MAXGETHOSTSTRUCT = 1024

Public Const AF_INET        As Long = 2
Public Const SOCK_STREAM    As Long = 1
Public Const SOCK_DGRAM     As Long = 2
Public Const IPPROTO_TCP    As Long = 6
Public Const IPPROTO_UDP    As Long = 17

Public Const FD_READ = &H1&
Public Const FD_WRITE = &H2&
Public Const FD_ACCEPT = &H8&
Public Const FD_CONNECT = &H10&
Public Const FD_CLOSE = &H20&

Private Const OFFSET_2 = 65536
Private Const MAXINT_2 = 32767

Public Const GMEM_FIXED = &H0
Public Const LOCAL_HOST_BUFF As Integer = 256

Public Const SOL_SOCKET         As Long = 65535
Public Const SO_SNDBUF          As Long = &H1001&
Public Const SO_RCVBUF          As Long = &H1002&
Public Const SO_MAX_MSG_SIZE    As Long = &H2003
Public Const SO_BROADCAST       As Long = &H20
Public Const FIONREAD           As Long = &H4004667F

'==============================================================================
'ERROR CODES
'==============================================================================

Public Const WSABASEERR         As Long = 10000
Public Const WSAEINTR           As Long = (WSABASEERR + 4)
Public Const WSAEACCES          As Long = (WSABASEERR + 13)
Public Const WSAEFAULT          As Long = (WSABASEERR + 14)
Public Const WSAEINVAL          As Long = (WSABASEERR + 22)
Public Const WSAEMFILE          As Long = (WSABASEERR + 24)
Public Const WSAEWOULDBLOCK     As Long = (WSABASEERR + 35)
Public Const WSAEINPROGRESS     As Long = (WSABASEERR + 36)
Public Const WSAEALREADY        As Long = (WSABASEERR + 37)
Public Const WSAENOTSOCK        As Long = (WSABASEERR + 38)
Public Const WSAEDESTADDRREQ    As Long = (WSABASEERR + 39)
Public Const WSAEMSGSIZE        As Long = (WSABASEERR + 40)
Public Const WSAEPROTOTYPE      As Long = (WSABASEERR + 41)
Public Const WSAENOPROTOOPT     As Long = (WSABASEERR + 42)
Public Const WSAEPROTONOSUPPORT As Long = (WSABASEERR + 43)
Public Const WSAESOCKTNOSUPPORT As Long = (WSABASEERR + 44)
Public Const WSAEOPNOTSUPP      As Long = (WSABASEERR + 45)
Public Const WSAEPFNOSUPPORT    As Long = (WSABASEERR + 46)
Public Const WSAEAFNOSUPPORT    As Long = (WSABASEERR + 47)
Public Const WSAEADDRINUSE      As Long = (WSABASEERR + 48)
Public Const WSAEADDRNOTAVAIL   As Long = (WSABASEERR + 49)
Public Const WSAENETDOWN        As Long = (WSABASEERR + 50)
Public Const WSAENETUNREACH     As Long = (WSABASEERR + 51)
Public Const WSAENETRESET       As Long = (WSABASEERR + 52)
Public Const WSAECONNABORTED    As Long = (WSABASEERR + 53)
Public Const WSAECONNRESET      As Long = (WSABASEERR + 54)
Public Const WSAENOBUFS         As Long = (WSABASEERR + 55)
Public Const WSAEISCONN         As Long = (WSABASEERR + 56)
Public Const WSAENOTCONN        As Long = (WSABASEERR + 57)
Public Const WSAESHUTDOWN       As Long = (WSABASEERR + 58)
Public Const WSAETIMEDOUT       As Long = (WSABASEERR + 60)
Public Const WSAEHOSTUNREACH    As Long = (WSABASEERR + 65)
Public Const WSAECONNREFUSED    As Long = (WSABASEERR + 61)
Public Const WSAEPROCLIM        As Long = (WSABASEERR + 67)
Public Const WSASYSNOTREADY     As Long = (WSABASEERR + 91)
Public Const WSAVERNOTSUPPORTED As Long = (WSABASEERR + 92)
Public Const WSANOTINITIALISED  As Long = (WSABASEERR + 93)
Public Const WSAHOST_NOT_FOUND  As Long = (WSABASEERR + 1001)
Public Const WSATRY_AGAIN       As Long = (WSABASEERR + 1002)
Public Const WSANO_RECOVERY     As Long = (WSABASEERR + 1003)
Public Const WSANO_DATA         As Long = (WSABASEERR + 1004)

'==============================================================================
'WINSOCK CONTROL ERROR CODES
'==============================================================================

Public Const sckOutOfMemory = 7
Public Const sckBadState = 40006
Public Const sckInvalidArg = 40014
Public Const sckUnsupported = 40018
Public Const sckInvalidOp = 40020

'==============================================================================
'STRUCTURES
'==============================================================================

Private Type WSAData
   wVersion       As Integer
   wHighVersion   As Integer
   szDescription  As String * WSADESCRIPTION_LEN
   szSystemStatus As String * WSASYS_STATUS_LEN
   iMaxSockets    As Integer
   iMaxUdpDg      As Integer
   lpVendorInfo   As Long
End Type

Public Type HOSTENT
    hName     As Long
    hAliases  As Long
    hAddrType As Integer
    hLength   As Integer
    hAddrList As Long
End Type

Public Type sockaddr_in
    sin_family       As Integer
    sin_port         As Integer
    sin_addr         As Long
    sin_zero(1 To 8) As Byte
End Type

'==============================================================================
'MEMBER VARIABLES
'==============================================================================

Private m_blnInitiated          As Boolean      'specify if winsock service was initiated
Private m_lngSocksQuantity      As Long         'number of instances created
Private m_colSocketsInst        As Collection   'sockets list and instance owner
Private m_colAcceptList         As Collection   'sockets in queue that need to be accepted
Private m_lngWindowHandle       As Long         'message window handle

'==============================================================================
'SUBCLASSING DECLARATIONS
'by Paul Caton
'==============================================================================
Private Declare Function api_IsWindow Lib "user32" Alias "IsWindow" (ByVal hwnd As Long) As Long
Private Declare Function api_GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Private Declare Function api_SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function api_GetModuleHandle Lib "kernel32" Alias "GetModuleHandleA" (ByVal lpModuleName As String) As Long
Private Declare Function api_GetProcAddress Lib "kernel32" Alias "GetProcAddress" (ByVal hModule As Long, ByVal lpProcName As String) As Long

Private Const PATCH_06 As Long = 106
Private Const PATCH_09 As Long = 137

Private Const GWL_WNDPROC = (-4)

Private Const WM_USER = &H400

Public Const RESOLVE_MESSAGE As Long = WM_USER + &H400
Public Const SOCKET_MESSAGE  As Long = WM_USER + &H401

Private lngMsgCntA      As Long     'TableA entry count
Private lngMsgCntB      As Long     'TableB entry count
Private lngTableA1()    As Long     'TableA1: list of async handles
Private lngTableA2()    As Long     'TableA2: list of async handles owners
Private lngTableB1()    As Long     'TableB1: list of sockets
Private lngTableB2()    As Long     'TableB2: list of sockets owners
Private hWndSub         As Long     'window handle subclassed
Private nAddrSubclass   As Long     'address of our WndProc
Private nAddrOriginal   As Long     'address of original WndProc


'This function initiates the processes needed to keep
'control of sockets. Returns 0 if it has success.
Public Function InitiateProcesses() As Long

InitiateProcesses = 0
m_lngSocksQuantity = m_lngSocksQuantity + 1

'if the service wasn't initiated yet we do it now
If Not m_blnInitiated Then
     
    Subclass_Initialize
   
    m_blnInitiated = True
    
    Dim lngResult As Long
    lngResult = InitiateService
    
    If lngResult = 0 Then
        Debug.Print "OK Winsock service initiated"
    Else
        Debug.Print "ERROR trying to initiate winsock service"
        Err.Raise lngResult, "modSocketMaster.InitiateProcesses", GetErrorDescription(lngResult)
        InitiateProcesses = lngResult
    End If
    
End If
End Function

'This function initiate the winsock service calling
'the api_WSAStartup funtion and returns resulting value.
Private Function InitiateService() As Long
Dim udtWSAData As WSAData
Dim lngResult As Long

lngResult = api_WSAStartup(SOCKET_VERSION_11, udtWSAData)
InitiateService = lngResult
End Function

'Once we are done with the class instance we call this
'function to discount it and finish winsock service if
'it was the last one.
'Returns 0 if it has success.
Public Function FinalizeProcesses() As Long
FinalizeProcesses = 0
m_lngSocksQuantity = m_lngSocksQuantity - 1

'if the service was initiated and there's no more instances
'of the class then we finish the service
If m_blnInitiated And m_lngSocksQuantity = 0 Then
    If FinalizeService = SOCKET_ERROR Then
        Dim lngErrorCode As Long
        lngErrorCode = Err.LastDllError
        FinalizeProcesses = lngErrorCode
        Err.Raise lngErrorCode, "modSocketMaster.FinalizeProcesses", GetErrorDescription(lngErrorCode)
    Else
        Debug.Print "OK Winsock service finalized"
    End If
    
    Subclass_Terminate
    m_blnInitiated = False
End If

End Function

'Finish winsock service calling the function
'api_WSACleanup and returns the result.
Private Function FinalizeService() As Long
Dim lngResultado As Long
lngResultado = api_WSACleanup
FinalizeService = lngResultado
End Function

'This function receives a number that represents an error
'and returns the corresponding description string.
Public Function GetErrorDescription(ByVal lngErrorCode As Long) As String
Select Case lngErrorCode
    Case WSAEACCES
        GetErrorDescription = "Permission denied."
    Case WSAEADDRINUSE
        GetErrorDescription = "Address already in use."
    Case WSAEADDRNOTAVAIL
        GetErrorDescription = "Cannot assign requested address."
    Case WSAEAFNOSUPPORT
        GetErrorDescription = "Address family not supported by protocol family."
    Case WSAEALREADY
        GetErrorDescription = "Operation already in progress."
    Case WSAECONNABORTED
        GetErrorDescription = "Software caused connection abort."
    Case WSAECONNREFUSED
        GetErrorDescription = "Connection refused."
    Case WSAECONNRESET
        GetErrorDescription = "Connection reset by peer."
    Case WSAEDESTADDRREQ
        GetErrorDescription = "Destination address required."
    Case WSAEFAULT
        GetErrorDescription = "Bad address."
    Case WSAEHOSTUNREACH
        GetErrorDescription = "No route to host."
    Case WSAEINPROGRESS
        GetErrorDescription = "Operation now in progress."
    Case WSAEINTR
        GetErrorDescription = "Interrupted function call."
    Case WSAEINVAL
        GetErrorDescription = "Invalid argument."
    Case WSAEISCONN
        GetErrorDescription = "Socket is already connected."
    Case WSAEMFILE
        GetErrorDescription = "Too many open files."
    Case WSAEMSGSIZE
        GetErrorDescription = "Message too long."
    Case WSAENETDOWN
        GetErrorDescription = "Network is down."
    Case WSAENETRESET
        GetErrorDescription = "Network dropped connection on reset."
    Case WSAENETUNREACH
        GetErrorDescription = "Network is unreachable."
    Case WSAENOBUFS
        GetErrorDescription = "No buffer space available."
    Case WSAENOPROTOOPT
        GetErrorDescription = "Bad protocol option."
    Case WSAENOTCONN
        GetErrorDescription = "Socket is not connected."
    Case WSAENOTSOCK
        GetErrorDescription = "Socket operation on nonsocket."
    Case WSAEOPNOTSUPP
        GetErrorDescription = "Operation not supported."
    Case WSAEPFNOSUPPORT
        GetErrorDescription = "Protocol family not supported."
    Case WSAEPROCLIM
        GetErrorDescription = "Too many processes."
    Case WSAEPROTONOSUPPORT
        GetErrorDescription = "Protocol not supported."
    Case WSAEPROTOTYPE
        GetErrorDescription = "Protocol wrong type for socket."
    Case WSAESHUTDOWN
        GetErrorDescription = "Cannot send after socket shutdown."
    Case WSAESOCKTNOSUPPORT
        GetErrorDescription = "Socket type not supported."
    Case WSAETIMEDOUT
        GetErrorDescription = "Connection timed out."
    Case WSAEWOULDBLOCK
        GetErrorDescription = "Resource temporarily unavailable."
    Case WSAHOST_NOT_FOUND
        GetErrorDescription = "Host not found."
    Case WSANOTINITIALISED
        GetErrorDescription = "Successful WSAStartup not yet performed."
    Case WSANO_DATA
        GetErrorDescription = "Valid name, no data record of requested type."
    Case WSANO_RECOVERY
        GetErrorDescription = "This is a nonrecoverable error."
    Case WSASYSNOTREADY
        GetErrorDescription = "Network subsystem is unavailable."
    Case WSATRY_AGAIN
        GetErrorDescription = "Nonauthoritative host not found."
    Case WSAVERNOTSUPPORTED
        GetErrorDescription = "Winsock.dll version out of range."
    Case Else
        GetErrorDescription = "Unknown error."
End Select

End Function

'Create a window that is used to capture sockets messages.
'Returns 0 if it has success.
Private Function CreateWinsockMessageWindow() As Long
m_lngWindowHandle = api_CreateWindowEx(0&, "STATIC", "SOCKET_WINDOW", 0&, 0&, 0&, 0&, 0&, 0&, 0&, App.hInstance, ByVal 0&)

If m_lngWindowHandle = 0 Then
    CreateWinsockMessageWindow = sckOutOfMemory
    Exit Function
Else
    CreateWinsockMessageWindow = 0
    Debug.Print "OK Created winsock message window " & m_lngWindowHandle
End If
End Function

'Destroy the window that is used to capture sockets messages.
'Returns 0 if it has success.
Private Function DestroyWinsockMessageWindow() As Long
DestroyWinsockMessageWindow = 0

If m_lngWindowHandle = 0 Then
    Debug.Print "WARNING lngWindowHandle is ZERO"
    Exit Function
End If
    
Dim lngResult As Long

lngResult = api_DestroyWindow(m_lngWindowHandle)
    
If lngResult = 0 Then
    DestroyWinsockMessageWindow = sckOutOfMemory
    Err.Raise sckOutOfMemory, "modSocketMaster.DestroyWinsockMessageWindow", "Out of memory"
Else
    Debug.Print "OK Destroyed winsock message window " & m_lngWindowHandle
    m_lngWindowHandle = 0
End If
    
End Function

'When a socket needs to resolve a hostname in asynchronous way
'it calls this function. If it has success it returns a nonzero
'number that represents the async task handle and register this
'number in the TableA list.
'Returns 0 if it fails.
Public Function ResolveHost(ByVal strHost As String, ByVal lngHOSTENBuf As Long, ByVal lngObjectPointer As Long) As Long
Dim lngAsynHandle As Long
lngAsynHandle = api_WSAAsyncGetHostByName(m_lngWindowHandle, RESOLVE_MESSAGE, strHost, ByVal lngHOSTENBuf, MAXGETHOSTSTRUCT)
If lngAsynHandle <> 0 Then Subclass_AddResolveMessage lngAsynHandle, lngObjectPointer
ResolveHost = lngAsynHandle
End Function

'Returns the hi word from a double word.
Public Function HiWord(lngValue As Long) As Long
If (lngValue And &H80000000) = &H80000000 Then
    HiWord = ((lngValue And &H7FFF0000) \ &H10000) Or &H8000&
Else
    HiWord = (lngValue And &HFFFF0000) \ &H10000
End If
End Function

'Returns the low word from a double word.
Public Function LoWord(lngValue As Long) As Long
LoWord = (lngValue And &HFFFF&)
End Function

'Receives a string pointer and it turns it into a regular string.
Public Function StringFromPointer(ByVal lPointer As Long) As String
Dim strTemp As String
Dim lRetVal As Long

strTemp = String$(api_lstrlen(ByVal lPointer), 0)
lRetVal = api_lstrcpy(ByVal strTemp, ByVal lPointer)
If lRetVal Then StringFromPointer = strTemp
End Function

'The function takes an unsigned Integer from and API and 
'converts it to a Long for display or arithmetic purposes
Public Function UnsignedToInteger(Value As Long) As Integer
If Value < 0 Or Value >= OFFSET_2 Then Error 6 ' Overflow
If Value <= MAXINT_2 Then
    UnsignedToInteger = Value
Else
    UnsignedToInteger = Value - OFFSET_2
End If
End Function

'The function takes a Long containing a value in the range 
'of an unsigned Integer and returns an Integer that you 
'can pass to an API that requires an unsigned Integer
Public Function IntegerToUnsigned(Value As Integer) As Long
If Value < 0 Then
    IntegerToUnsigned = Value + OFFSET_2
Else
    IntegerToUnsigned = Value
End If
End Function

'Adds the socket to the m_colSocketsInst collection, and
'registers that socket with WSAAsyncSelect Winsock API
'function to receive network events for the socket.
'If this socket is the first one to be registered, the
'window and collection will be created in this function as well.
Public Function RegisterSocket(ByVal lngSocket As Long, ByVal lngObjectPointer As Long, ByVal blnEvents As Boolean) As Boolean

If m_colSocketsInst Is Nothing Then
    Set m_colSocketsInst = New Collection
    Debug.Print "OK Created socket collection"
    
    If CreateWinsockMessageWindow <> 0 Then
        Err.Raise sckOutOfMemory, "modSocketMaster.RegisterSocket", "Out of memory"
    End If
    
    Subclass_Subclass (m_lngWindowHandle)
    
End If

Subclass_AddSocketMessage lngSocket, lngObjectPointer

'Do we need to register socket events?
If blnEvents Then
    Dim lngEvents As Long
    Dim lngResult As Long
    Dim lngErrorCode As Long

    lngEvents = FD_READ Or FD_WRITE Or FD_ACCEPT Or FD_CONNECT Or FD_CLOSE
    lngResult = api_WSAAsyncSelect(lngSocket, m_lngWindowHandle, SOCKET_MESSAGE, lngEvents)
        
    If lngResult = SOCKET_ERROR Then
        Debug.Print "ERROR trying to register events from socket " & lngSocket
        lngErrorCode = Err.LastDllError
        Err.Raise lngErrorCode, "modSocketMaster.RegisterSocket", GetErrorDescription(lngErrorCode)
    Else
        Debug.Print "OK Registered events from socket " & lngSocket
    End If
End If

m_colSocketsInst.Add lngObjectPointer, "S" & lngSocket
RegisterSocket = True
End Function

'Removes the socket from the m_colSocketsInst collection
'If it is the last socket in that collection, the window
'and colection will be destroyed as well.
Public Sub UnregisterSocket(ByVal lngSocket As Long)
Subclass_DelSocketMessage lngSocket
On Error Resume Next
m_colSocketsInst.Remove "S" & lngSocket

If m_colSocketsInst.Count = 0 Then
    Set m_colSocketsInst = Nothing
    Subclass_UnSubclass
    DestroyWinsockMessageWindow
    Debug.Print "OK Destroyed socket collection"
End If
End Sub

'Returns TRUE si the socket that is passed is registered
'in the colSocketsInst collection.
Public Function IsSocketRegistered(ByVal lngSocket As Long) As Boolean
On Error GoTo Error_Handler

m_colSocketsInst.Item ("S" & lngSocket)
IsSocketRegistered = True

Exit Function

Error_Handler:
    IsSocketRegistered = False
End Function

'When ResolveHost is called an async task handle is added
'to TableA list. Use this function to remove that record.
Public Sub UnregisterResolution(ByVal lngAsynHandle As Long)
Subclass_DelResolveMessage lngAsynHandle
End Sub

'It turns a CSocketMaster instance pointer into an actual instance.
Private Function SocketObjectFromPointer(ByVal lngPointer As Long) As CSocketMaster

Dim objSocket As CSocketMaster

api_CopyMemory objSocket, lngPointer, 4&
Set SocketObjectFromPointer = objSocket
api_CopyMemory objSocket, 0&, 4&

End Function

'Assing a temporal instance of CSocketMaster to a
'socket and register this socket to the accept list.
Public Sub RegisterAccept(ByVal lngSocket As Long)
If m_colAcceptList Is Nothing Then
    Set m_colAcceptList = New Collection
    Debug.Print "OK Created accept collection"
End If
Dim Socket As CSocketMaster
Set Socket = New CSocketMaster
Socket.Accept lngSocket
m_colAcceptList.Add Socket, "S" & lngSocket
End Sub

'Returns True is lngSocket is registered on the
'accept list.
Public Function IsAcceptRegistered(ByVal lngSocket As Long) As Boolean
On Error GoTo Error_Handler

m_colAcceptList.Item ("S" & lngSocket)
IsAcceptRegistered = True

Exit Function

Error_Handler:
    IsAcceptRegistered = False
End Function

'Unregister lngSocket from the accept list.
Public Sub UnregisterAccept(ByVal lngSocket As Long)
m_colAcceptList.Remove "S" & lngSocket

If m_colAcceptList.Count = 0 Then
    Set m_colAcceptList = Nothing
    Debug.Print "OK Destroyed accept collection"
End If
End Sub

'Return the accept instance class from a socket.
Public Function GetAcceptClass(ByVal lngSocket As Long) As CSocketMaster
Set GetAcceptClass = m_colAcceptList("S" & lngSocket)
End Function


'==============================================================================
'SUBCLASSING CODE
'based on code by Paul Caton
'==============================================================================

Private Sub Subclass_Initialize()
Const PATCH_01 As Long = 15                                 'Code buffer offset to the location of the relative address to EbMode
Const PATCH_03 As Long = 76                                 'Relative address of SetWindowsLong
Const PATCH_05 As Long = 100                                 'Relative address of CallWindowProc
Const FUNC_EBM As String = "EbMode"                         'VBA's EbMode function allows the machine code thunk to know if the IDE has stopped or is on a breakpoint
Const FUNC_SWL As String = "SetWindowLongA"                 'SetWindowLong allows the cSubclasser machine code thunk to unsubclass the subclasser itself if it detects via the EbMode function that the IDE has stopped
Const FUNC_CWP As String = "CallWindowProcA"                'We use CallWindowProc to call the original WndProc
Const MOD_VBA5 As String = "vba5"                           'Location of the EbMode function if running VB5
Const MOD_VBA6 As String = "vba6"                           'Location of the EbMode function if running VB6
Const MOD_USER As String = "user32"                         'Location of the SetWindowLong & CallWindowProc functions
  Dim i        As Long                                      'Loop index
  Dim nLen     As Long                                      'String lengths
  Dim sHex     As String                                    'Hex code string
  Dim sCode    As String                                    'Binary code string
  
  'Store the hex pair machine code representation in sHex
  sHex = "5850505589E55753515231C0EB0EE8xxxxx01x83F802742285C074258B45103D0008000074433D01080000745BE8200000005A595B5FC9C21400E813000000EBF168xxxxx02x6AFCFF750CE8xxxxx03xEBE0FF7518FF7514FF7510FF750C68xxxxx04xE8xxxxx05xC3BBxxxxx06x8B4514BFxxxxx07x89D9F2AF75B629CB4B8B1C9Dxxxxx08xEB1DBBxxxxx09x8B4514BFxxxxx0Ax89D9F2AF759729CB4B8B1C9Dxxxxx0Bx895D088B1B8B5B1C89D85A595B5FC9FFE0"
  nLen = Len(sHex)                                          'Length of hex pair string
  
  'Convert the string from hex pairs to bytes and store in the ASCII string opcode buffer
  For i = 1 To nLen Step 2                                  'For each pair of hex characters
    sCode = sCode & ChrB$(Val("&H" & Mid$(sHex, i, 2)))     'Convert a pair of hex characters to a byte and append to the ASCII string
  Next i                                                    'Next pair
  
  nLen = LenB(sCode)                                        'Get the machine code length
  nAddrSubclass = api_GlobalAlloc(0, nLen)                  'Allocate fixed memory for machine code buffer
  Debug.Print "OK Subclass memory allocated at: " & nAddrSubclass

  'Copy the code to allocated memory
  Call api_CopyMemory(ByVal nAddrSubclass, ByVal StrPtr(sCode), nLen)

  If Subclass_InIDE Then
    'Patch the jmp (EB0E) with two nop's (90) enabling the IDE breakpoint/stop checking code
    Call api_CopyMemory(ByVal nAddrSubclass + 12, &H9090, 2)
    
    i = Subclass_AddrFunc(MOD_VBA6, FUNC_EBM)               'Get the address of EbMode in vba6.dll
    If i = 0 Then                                           'Found?
      i = Subclass_AddrFunc(MOD_VBA5, FUNC_EBM)             'VB5 perhaps, try vba5.dll
    End If

    Debug.Assert i                                          'Ensure the EbMode function was found
    Call Subclass_PatchRel(PATCH_01, i)                     'Patch the relative address to the EbMode api function
  End If
  
  Call Subclass_PatchRel(PATCH_03, Subclass_AddrFunc(MOD_USER, FUNC_SWL))     'Address of the SetWindowLong api function
  Call Subclass_PatchRel(PATCH_05, Subclass_AddrFunc(MOD_USER, FUNC_CWP))     'Address of the CallWindowProc api function
End Sub

'UnSubclass and release the allocated memory
Private Sub Subclass_Terminate()
  Call Subclass_UnSubclass                                      'UnSubclass if the Subclass thunk is active
  Call api_GlobalFree(nAddrSubclass)                            'Release the allocated memory
  Debug.Print "OK Freed subclass memory at: " & nAddrSubclass
  nAddrSubclass = 0
  ReDim lngTableA1(1 To 1)
  ReDim lngTableA2(1 To 1)
  ReDim lngTableB1(1 To 1)
  ReDim lngTableB2(1 To 1)
End Sub

'Return whether we're running in the IDE. Public for general utility purposes
Private Function Subclass_InIDE() As Boolean
  Debug.Assert Subclass_SetTrue(Subclass_InIDE)
End Function

'Set the window subclass
Private Function Subclass_Subclass(ByVal hwnd As Long) As Boolean
Const PATCH_02 As Long = 66                                'Address of the previous WndProc
Const PATCH_04 As Long = 95                                'Address of the previous WndProc
  
  If hWndSub = 0 Then
    Debug.Assert api_IsWindow(hwnd)                         'Invalid window handle
    hWndSub = hwnd                                          'Store the window handle
    
    'Get the original window proc
    nAddrOriginal = api_GetWindowLong(hwnd, GWL_WNDPROC)
    Call Subclass_PatchVal(PATCH_02, nAddrOriginal)                  'Original WndProc address for CallWindowProc, call the original WndProc
    Call Subclass_PatchVal(PATCH_04, nAddrOriginal)                  'Original WndProc address for SetWindowLong, unsubclass on IDE stop
    
    'Set our WndProc in place of the original
    nAddrOriginal = api_SetWindowLong(hwnd, GWL_WNDPROC, nAddrSubclass)
    If nAddrOriginal <> 0 Then
      nAddrOriginal = 0
      Subclass_Subclass = True                                       'Success
    End If
  End If
  
  Debug.Assert Subclass_Subclass
End Function

'Stop subclassing the window
Private Function Subclass_UnSubclass() As Boolean
  If hWndSub <> 0 Then
    lngMsgCntA = 0
    lngMsgCntB = 0
    Call Subclass_PatchVal(PATCH_06, lngMsgCntA)                              'Patch the TableA entry count to ensure no further Proc callbacks
    Call Subclass_PatchVal(PATCH_09, lngMsgCntB)                              'Patch the TableB entry count to ensure no further Proc callbacks
    
    'Restore the original WndProc
    Call api_SetWindowLong(hWndSub, GWL_WNDPROC, nAddrOriginal)
    
    hWndSub = 0                                             'Indicate the subclasser is inactive

    Subclass_UnSubclass = True                              'Success
  End If
  
End Function

'Return the address of the passed function in the passed dll
Private Function Subclass_AddrFunc(ByVal sDLL As String, _
                          ByVal sProc As String) As Long
  Subclass_AddrFunc = api_GetProcAddress(api_GetModuleHandle(sDLL), sProc)
  
End Function

'Return the address of the low bound of the passed table array
Private Function Subclass_AddrMsgTbl(ByRef aMsgTbl() As Long) As Long
  On Error Resume Next                                    'The table may not be dimensioned yet so we need protection
    Subclass_AddrMsgTbl = VarPtr(aMsgTbl(1))              'Get the address of the first element of the passed message table
  On Error GoTo 0                                         'Switch off error protection
End Function

'Patch the machine code buffer offset with the relative address to the target address
Private Sub Subclass_PatchRel(ByVal nOffset As Long, _
                     ByVal nTargetAddr As Long)
  Call api_CopyMemory(ByVal (nAddrSubclass + nOffset), nTargetAddr - nAddrSubclass - nOffset - 4, 4)
End Sub

'Patch the machine code buffer offset with the passed value
Private Sub Subclass_PatchVal(ByVal nOffset As Long, _
                     ByVal nValue As Long)
  Call api_CopyMemory(ByVal (nAddrSubclass + nOffset), nValue, 4)
End Sub

'Worker function for InIDE - will only be called whilst running in the IDE
Private Function Subclass_SetTrue(bValue As Boolean) As Boolean
  Subclass_SetTrue = True
  bValue = True
End Function

Private Sub Subclass_AddResolveMessage(ByVal lngAsync As Long, ByVal lngObjectPointer As Long)
Dim Count As Long
For Count = 1 To lngMsgCntA
    Select Case lngTableA1(Count)
    
    Case -1
        lngTableA1(Count) = lngAsync
        lngTableA2(Count) = lngObjectPointer
        Exit Sub
    Case lngAsync
        Debug.Print "WARNING: Async already registered!"
        Exit Sub
    End Select
Next Count

lngMsgCntA = lngMsgCntA + 1
ReDim Preserve lngTableA1(1 To lngMsgCntA)
ReDim Preserve lngTableA2(1 To lngMsgCntA)
 
lngTableA1(lngMsgCntA) = lngAsync
lngTableA2(lngMsgCntA) = lngObjectPointer
Subclass_PatchTableA

End Sub

Private Sub Subclass_AddSocketMessage(ByVal lngSocket As Long, ByVal lngObjectPointer As Long)
Dim Count As Long
For Count = 1 To lngMsgCntB
    Select Case lngTableB1(Count)
    
    Case -1
        lngTableB1(Count) = lngSocket
        lngTableB2(Count) = lngObjectPointer
        Exit Sub
    Case lngSocket
        Debug.Print "WARNING: Socket already registered!"
        Exit Sub
    End Select
Next Count

lngMsgCntB = lngMsgCntB + 1
ReDim Preserve lngTableB1(1 To lngMsgCntB)
ReDim Preserve lngTableB2(1 To lngMsgCntB)
 
lngTableB1(lngMsgCntB) = lngSocket
lngTableB2(lngMsgCntB) = lngObjectPointer
Subclass_PatchTableB

End Sub

Private Sub Subclass_DelResolveMessage(ByVal lngAsync As Long)
Dim Count As Long
For Count = 1 To lngMsgCntA
    If lngTableA1(Count) = lngAsync Then
        lngTableA1(Count) = -1
        lngTableA2(Count) = -1
        Exit Sub
    End If
Next Count
End Sub

Private Sub Subclass_DelSocketMessage(ByVal lngSocket As Long)
Dim Count As Long
For Count = 1 To lngMsgCntB
    If lngTableB1(Count) = lngSocket Then
        lngTableB1(Count) = -1
        lngTableB2(Count) = -1
        Exit Sub
    End If
Next Count
End Sub

Private Sub Subclass_PatchTableA()
Const PATCH_07 As Long = 114
Const PATCH_08 As Long = 130

Call Subclass_PatchVal(PATCH_06, lngMsgCntA)
Call Subclass_PatchVal(PATCH_07, Subclass_AddrMsgTbl(lngTableA1))
Call Subclass_PatchVal(PATCH_08, Subclass_AddrMsgTbl(lngTableA2))
End Sub

Private Sub Subclass_PatchTableB()
Const PATCH_0A As Long = 145
Const PATCH_0B As Long = 161

Call Subclass_PatchVal(PATCH_09, lngMsgCntB)
Call Subclass_PatchVal(PATCH_0A, Subclass_AddrMsgTbl(lngTableB1))
Call Subclass_PatchVal(PATCH_0B, Subclass_AddrMsgTbl(lngTableB2))
End Sub

Public Sub Subclass_ChangeOwner(ByVal lngSocket As Long, ByVal lngObjectPointer As Long)
Dim Count As Long
For Count = 1 To lngMsgCntB
    If lngTableB1(Count) = lngSocket Then
        lngTableB2(Count) = lngObjectPointer
        Exit Sub
    End If
Next Count
End Sub

Dim strLocalHost As String
Dim arrIpAddress(1 To 4) As Byte
Dim Count As Integer
Dim udtHostent As HOSTENT
Dim strIpAddress As String

strLocalHost = GetLocalHostName

lngResult = api_gethostbyname(strLocalHost)

If lngResult = 0 Then
    GetLocalIP = vbNullString
    Dim lngErrorCode As Long
    lngErrorCode = Err.LastDllError
    Err.Raise lngErrorCode, "CSocketMaster.GetLocalIP", GetErrorDescription(lngErrorCode)
Else
    api_CopyMemory udtHostent, ByVal lngResult, LenB(udtHostent)
    api_CopyMemory lngPtrToIP, ByVal udtHostent.hAddrList, 4
    api_CopyMemory arrIpAddress(1), ByVal lngPtrToIP, 4
   
    For Count = 1 To 4
        strIpAddress = strIpAddress & arrIpAddress(Count) & "."
    Next
   
    strIpAddress = Left$(strIpAddress, Len(strIpAddress) - 1)
    GetLocalIP = strIpAddress
End If
End Function

'If Host is an IP doesn't resolve anything and returns a
'a 32 bits long IP.
'If Host isn't an IP then returns vbNull, tries to resolve it
'in asynchronous way and acts according to enmDestination.
Private Function ResolveIfHostname(ByVal Host As String, ByVal enmDestination As DestResolucion) As Long
Dim lngAddress As Long
lngAddress = api_inet_addr(Host)

If lngAddress = INADDR_NONE Then 'if Host isn't an IP
    
    ResolveIfHostname = vbNull
    m_enmState = sckResolvingHost: Debug.Print "STATE: sckResolvingHost"
    
    If AllocateMemory Then
        
        Dim lngAsynHandle As Long
        lngAsynHandle = modSocketMaster.ResolveHost(Host, m_lngMemoryPointer, ObjPtr(Me))
        
        If lngAsynHandle = 0 Then
            FreeMemory
            m_enmState = sckError: Debug.Print "STATE: sckError"
            Dim lngErrorCode As Long
            lngErrorCode = Err.LastDllError
            Dim blnCancelDisplay As Boolean
            blnCancelDisplay = True
            RaiseEvent Error(lngErrorCode, GetErrorDescription(lngErrorCode), 0, "CSocketMaster.ResolveIfHostname", "", 0, blnCancelDisplay)
            If blnCancelDisplay = False Then MsgBox GetErrorDescription(lngErrorCode), vbOKOnly, "CSocketMaster.ResolveIfHostname"
        Else
            m_colWaitingResolutions.Add enmDestination, "R" & lngAsynHandle
            Debug.Print "Resolving host " & Host; " with handle " & lngAsynHandle
        End If
        
    Else
        
        m_enmState = sckError: Debug.Print "STATE: sckError"
        Debug.Print "Error trying to allocate memory"
        Err.Raise sckOutOfMemory, "CSocketMaster.ResolveIfHostname", "Out of memory"
        
    End If
    
Else 'if Host is an IP doen't need to resolve anything
    ResolveIfHostname = lngAddress
End If
End Function

'Resolves a hots (if necessary) in synchronous way
'If succeeds returns a 32 bits long IP,
'strHostIP = readable IP string and lngErrorCode = 0
'If fails returns vbNull,
'strHostIP = vbNullString and lngErrorCode <> 0
Private Function ResolveIfHostnameSync(ByVal Host As String, ByRef strHostIP As String, ByRef lngErrorCode As Long) As Long
Dim lngPtrToHOSTENT As Long
Dim udtHostent As HOSTENT
Dim lngAddress As Long
Dim lngPtrToIP As Long
Dim arrIpAddress(1 To 4) As Byte
Dim Count As Integer

If Host = vbNullString Then
    strHostIP = vbNullString
    lngErrorCode = WSAEAFNOSUPPORT
    ResolveIfHostnameSync = vbNull
    Exit Function
End If

lngAddress = api_inet_addr(Host)

If lngAddress = INADDR_NONE Then 'if Host isn't an IP
    
    lngPtrToHOSTENT = api_gethostbyname(Host)
    
    If lngPtrToHOSTENT = 0 Then
        lngErrorCode = Err.LastDllError
        strHostIP = vbNullString
        ResolveIfHostnameSync = vbNull
    Else
        api_CopyMemory udtHostent, ByVal lngPtrToHOSTENT, LenB(udtHostent)
        api_CopyMemory lngPtrToIP, ByVal udtHostent.hAddrList, 4
        api_CopyMemory arrIpAddress(1), ByVal lngPtrToIP, 4
        api_CopyMemory lngAddress, ByVal lngPtrToIP, 4
        
        For Count = 1 To 4
            strHostIP = strHostIP & arrIpAddress(Count) & "."
        Next
        
        strHostIP = Left$(strHostIP, Len(strHostIP) - 1)
        
        lngErrorCode = 0
        ResolveIfHostnameSync = lngAddress
    End If
    
Else 'if Host is an IP doen't need to resolve anything
    
    lngErrorCode = 0
    strHostIP = Host
    ResolveIfHostnameSync = lngAddress
    
End If
End Function

'Returns local port from a connected or bound socket.
'Returns SOCKET_ERROR if fails.
Private Function GetLocalPort(ByVal lngSocket As Long) As Long
Dim udtSockAddr As sockaddr_in
Dim lngResult As Long

lngResult = api_getsockname(lngSocket, udtSockAddr, LenB(udtSockAddr))

If lngResult = SOCKET_ERROR Then
    GetLocalPort = SOCKET_ERROR
Else
    GetLocalPort = modSocketMaster.IntegerToUnsigned(api_ntohs(udtSockAddr.sin_port))
End If
End Function

Public Sub SendData(data As Variant)

Dim arrData() As Byte 'We store the data here before send it

If m_enmProtocol = sckTCPProtocol Then
    If m_enmState <> sckConnected Then
        Err.Raise sckBadState, "CSocketMaster.SendData", "Wrong protocol or connection state for the requested transaction or request"
        Exit Sub
    End If
Else 'If we use UDP we create a socket if there isn't one yet
    If Not SocketExists Then Exit Sub
    If Not BindInternal Then Exit Sub
    m_enmState = sckOpen: Debug.Print "STATE: sckOpen"
End If

'We need to convert data variant into a byte array
Select Case varType(data)
        Case vbString
            Dim strdata As String
            strdata = CStr(data)
            If Len(strdata) = 0 Then Exit Sub
            ReDim arrData(Len(strdata) - 1)
            arrData() = StrConv(strdata, vbFromUnicode)
        Case vbArray + vbByte
            Dim strArray As String
            strArray = StrConv(data, vbUnicode)
            If Len(strArray) = 0 Then Exit Sub
            arrData() = StrConv(strArray, vbFromUnicode)
        Case vbBoolean
            Dim blnData As Boolean
            blnData = CBool(data)
            ReDim arrData(LenB(blnData) - 1)
            api_CopyMemory arrData(0), blnData, LenB(blnData)
        Case vbByte
            Dim bytData As Byte
            bytData = CByte(data)
            ReDim arrData(LenB(bytData) - 1)
            api_CopyMemory arrData(0), bytData, LenB(bytData)
        Case vbCurrency
            Dim curData As Currency
            curData = CCur(data)
            ReDim arrData(LenB(curData) - 1)
            api_CopyMemory arrData(0), curData, LenB(curData)
        Case vbDate
            Dim datData As Date
            datData = CDate(data)
            ReDim arrData(LenB(datData) - 1)
            api_CopyMemory arrData(0), datData, LenB(datData)
        Case vbDouble
            Dim dblData As Double
            dblData = CDbl(data)
            ReDim arrData(LenB(dblData) - 1)
            api_CopyMemory arrData(0), dblData, LenB(dblData)
        Case vbInteger
            Dim intData As Integer
            intData = CInt(data)
            ReDim arrData(LenB(intData) - 1)
            api_CopyMemory arrData(0), intData, LenB(intData)
        Case vbLong
            Dim lngData As Long
            lngData = CLng(data)
            ReDim arrData(LenB(lngData) - 1)
            api_CopyMemory arrData(0), lngData, LenB(lngData)
        Case vbSingle
            Dim sngData As Single
            sngData = CSng(data)
            ReDim arrData(LenB(sngData) - 1)
            api_CopyMemory arrData(0), sngData, LenB(sngData)
        Case Else
            Err.Raise sckUnsupported, "CSocketMaster.SendData", "Unsupported variant type."
    End Select

'if there's already something in the buffer that means we are
'already sending data, so we put the new data in the buffer
'and exit silently
If Len(m_strSendBuffer) > 0 Then
    m_strSendBuffer = m_strSendBuffer + StrConv(arrData(), vbUnicode)
    Exit Sub
Else
    m_strSendBuffer = m_strSendBuffer + StrConv(arrData(), vbUnicode)
End If

'send the data
SendBufferedData

End Sub

'Check which protocol we are using to decide which
'function should handle the data sending.
Private Sub SendBufferedData()
If m_enmProtocol = sckTCPProtocol Then
    SendBufferedDataTCP
Else
    SendBufferedDataUDP
End If
End Sub

'Send buffered data if we are using UDP protocol.
Private Sub SendBufferedDataUDP()
Dim lngAddress As Long
Dim udtSockAddr As sockaddr_in
Dim arrData() As Byte
Dim lngBufferLength As Long
Dim lngResult As Long
Dim lngErrorCode As Long

   
Dim strTemp As String
lngAddress = ResolveIfHostnameSync(m_strRemoteHost, strTemp, lngErrorCode)
    
If lngErrorCode <> 0 Then
    m_strSendBuffer = ""
    
    If lngErrorCode = WSAEAFNOSUPPORT Then
        Err.Raise lngErrorCode, "CSocketMaster.SendBufferedDataUDP", GetErrorDescription(lngErrorCode)
    Else
        Err.Raise sckInvalidArg, "CSocketMaster.SendBufferedDataUDP", "Invalid argument"
    End If
End If

With udtSockAddr
    .sin_addr = lngAddress
    .sin_family = AF_INET
    .sin_port = api_htons(modSocketMaster.UnsignedToInteger(m_lngRemotePort))
End With
    
lngBufferLength = Len(m_strSendBuffer)
    
arrData() = StrConv(m_strSendBuffer, vbFromUnicode)
    
m_strSendBuffer = ""

lngResult = api_sendto(m_lngSocketHandle, arrData(0), lngBufferLength, 0&, udtSockAddr, LenB(udtSockAddr))
    
If lngResult = SOCKET_ERROR Then
    lngErrorCode = Err.LastDllError
    m_enmState = sckError: Debug.Print "STATE: sckError"
    Dim blnCancelDisplay As Boolean
    blnCancelDisplay = True
    RaiseEvent Error(lngErrorCode, GetErrorDescription(lngErrorCode), 0, "CSocketMaster.SendBufferedDataUDP", "", 0, blnCancelDisplay)
    If blnCancelDisplay = False Then MsgBox GetErrorDescription(lngErrorCode), vbOKOnly, "CSocketMaster.SendBufferedDataUDP"
End If
    
End Sub

'Send buffered data if we are using TCP protocol.
Private Sub SendBufferedDataTCP()

Dim arrData()       As Byte
Dim lngBufferLength As Long
Dim lngResult    As Long
Dim lngTotalSent As Long

Do Until lngResult = SOCKET_ERROR Or Len(m_strSendBuffer) = 0

    lngBufferLength = Len(m_strSendBuffer)

    If lngBufferLength > m_lngSendBufferLen Then
        lngBufferLength = m_lngSendBufferLen
        arrData() = StrConv(Left$(m_strSendBuffer, m_lngSendBufferLen), vbFromUnicode)
    Else
        arrData() = StrConv(m_strSendBuffer, vbFromUnicode)
    End If

    lngResult = api_send(m_lngSocketHandle, arrData(0), lngBufferLength, 0&)

    If lngResult = SOCKET_ERROR Then
        Dim lngErrorCode As Long
        lngErrorCode = Err.LastDllError
    
        If lngErrorCode = WSAEWOULDBLOCK Then
            Debug.Print "WARNING: Send buffer full, waiting..."
            If lngTotalSent > 0 Then RaiseEvent SendProgress(lngTotalSent, Len(m_strSendBuffer))
        Else
            m_enmState = sckError: Debug.Print "STATE: sckError"
            Dim blnCancelDisplay As Boolean
            blnCancelDisplay = True
            RaiseEvent Error(lngErrorCode, GetErrorDescription(lngErrorCode), 0, "CSocketMaster.SendBufferedData", "", 0, blnCancelDisplay)
            If blnCancelDisplay = False Then MsgBox GetErrorDescription(lngErrorCode), vbOKOnly, "CSocketMaster.SendBufferedData"
        End If

    Else
        Debug.Print "OK Bytes sent: " & lngResult
        lngTotalSent = lngTotalSent + lngResult
        If Len(m_strSendBuffer) > lngResult Then
            m_strSendBuffer = Mid$(m_strSendBuffer, lngResult + 1)
        Else
            Debug.Print "OK Finished SENDING"
            m_strSendBuffer = ""
            Dim lngTemp As Long
            lngTemp = lngTotalSent
            lngTotalSent = 0
            RaiseEvent SendProgress(lngTemp, 0)
            RaiseEvent SendComplete
        End If
    End If

Loop

End Sub

'This function retrieves data from the Winsock buffer
'into the class local buffer. The function returns number
'of bytes retrieved (received).
Private Function RecvDataToBuffer() As Long
Dim arrBuffer() As Byte
Dim lngBytesReceived As Long
Dim strBuffTemporal As String

ReDim arrBuffer(m_lngRecvBufferLen - 1)

lngBytesReceived = api_recv(m_lngSocketHandle, arrBuffer(0), m_lngRecvBufferLen, 0&)

If lngBytesReceived = SOCKET_ERROR Then
    
    m_enmState = sckError: Debug.Print "STATE: sckError"
    Dim lngErrorCode As Long
    lngErrorCode = Err.LastDllError
    Err.Raise lngErrorCode, "CSocketMaster.RecvDataToBuffer", GetErrorDescription(lngErrorCode)
    
ElseIf lngBytesReceived > 0 Then
    
    strBuffTemporal = StrConv(arrBuffer(), vbUnicode)
    m_strRecvBuffer = m_strRecvBuffer & Left$(strBuffTemporal, lngBytesReceived)
    RecvDataToBuffer = lngBytesReceived
    
End If

End Function

'Retrieves some socket options.
'If it is an UDP socket also sets SO_BROADCAST option.
Private Sub ProcessOptions()
Dim lngResult As Long
Dim lngBuffer As Long
Dim lngErrorCode As Long

If m_enmProtocol = sckTCPProtocol Then
    lngResult = api_getsockopt(m_lngSocketHandle, SOL_SOCKET, SO_RCVBUF, lngBuffer, LenB(lngBuffer))
    
    If lngResult = SOCKET_ERROR Then
        lngErrorCode = Err.LastDllError
        Err.Raise lngErrorCode, "CSocketMaster.ProcessOptions", GetErrorDescription(lngErrorCode)
    Else
        m_lngRecvBufferLen = lngBuffer
    End If

    lngResult = api_getsockopt(m_lngSocketHandle, SOL_SOCKET, SO_SNDBUF, lngBuffer, LenB(lngBuffer))

    If lngResult = SOCKET_ERROR Then
        lngErrorCode = Err.LastDllError
        Err.Raise lngErrorCode, "CSocketMaster.ProcessOptions", GetErrorDescription(lngErrorCode)
    Else
        m_lngSendBufferLen = lngBuffer
    End If

Else
    lngBuffer = 1
    lngResult = api_setsockopt(m_lngSocketHandle, SOL_SOCKET, SO_BROADCAST, lngBuffer, LenB(lngBuffer))
    
    lngResult = api_getsockopt(m_lngSocketHandle, SOL_SOCKET, SO_MAX_MSG_SIZE, lngBuffer, LenB(lngBuffer))

    If lngResult = SOCKET_ERROR Then
        lngErrorCode = Err.LastDllError
        Err.Raise lngErrorCode, "CSocketMaster.ProcessOptions", GetErrorDescription(lngErrorCode)
    Else
        m_lngRecvBufferLen = lngBuffer
        m_lngSendBufferLen = lngBuffer
    End If
End If


Debug.Print "Winsock buffer size for sends: " & m_lngRecvBufferLen
Debug.Print "Winsock buffer size for receives: " & m_lngSendBufferLen
End Sub

Public Sub GetData(ByRef data As Variant, Optional varType As Variant, Optional maxLen As Variant)

If m_enmProtocol = sckTCPProtocol Then
    If m_enmState <> sckConnected And Not m_blnAcceptClass Then
        Err.Raise sckBadState, "CSocketMaster.GetData", "Wrong protocol or connection state for the requested transaction or request"
        Exit Sub
    End If
Else
    If m_enmState <> sckOpen Then
        Err.Raise sckBadState, "CSocketMaster.GetData", "Wrong protocol or connection state for the requested transaction or request"
        Exit Sub
    End If
    If GetBufferLenUDP = 0 Then Exit Sub
End If

If Not IsMissing(maxLen) Then
    If IsNumeric(maxLen) Then
        If CLng(maxLen) < 0 Then
            Err.Raise sckInvalidArg, "CSocketMaster.GetData", "The argument passed to a function was not in the correct format or in the specified range."
        End If
    Else
        If m_enmProtocol = sckTCPProtocol Then
            maxLen = Len(m_strRecvBuffer)
        Else
            maxLen = GetBufferLenUDP
        End If
    End If
End If

Dim lngBytesRecibidos  As Long

lngBytesRecibidos = RecvData(data, False, varType, maxLen)
Debug.Print "OK Bytes obtained from buffer: " & lngBytesRecibidos

End Sub

Public Sub PeekData(ByRef data As Variant, Optional varType As Variant, Optional maxLen As Variant)

If m_enmProtocol = sckTCPProtocol Then
    If m_enmState <> sckConnected Then
        Err.Raise sckBadState, "CSocketMaster.PeekData", "Wrong protocol or connection state for the requested transaction or request"
        Exit Sub
    End If
Else
    If m_enmState <> sckOpen Then
        Err.Raise sckBadState, "CSocketMaster.PeekData", "Wrong protocol or connection state for the requested transaction or request"
        Exit Sub
    End If
    If GetBufferLenUDP = 0 Then Exit Sub
End If

If Not IsMissing(maxLen) Then
    If IsNumeric(maxLen) Then
        If CLng(maxLen) < 0 Then
            Err.Raise sckInvalidArg, "CSocketMaster.PeekData", "The argument passed to a function was not in the correct format or in the specified range."
        End If
    Else
        If m_enmProtocol = sckTCPProtocol Then
            maxLen = Len(m_strRecvBuffer)
        Else
            maxLen = GetBufferLenUDP
        End If
    End If
End If

Dim lngBytesRecibidos  As Long

lngBytesRecibidos = RecvData(data, True, varType, maxLen)
Debug.Print "OK Bytes obtained from buffer: " & lngBytesRecibidos
End Sub


'This function is to retrieve data from the buffer. If we are using TCP
'then the data is retrieved from a local buffer (m_strRecvBuffer). If we
'are using UDP the data is retrieved from winsock buffer.
'It can be called by two public methods of the class - GetData and PeekData.
'Behavior of the function is defined by the blnPeek argument. If a value of
'that argument is TRUE, the function returns number of bytes in the
'buffer, and copy data from that buffer into the data argument.
'If a value of the blnPeek is FALSE, then this function returns number of
'bytes received, and move data from the buffer into the data
'argument. MOVE means that data will be removed from the buffer.
Private Function RecvData(ByRef data As Variant, ByVal blnPeek As Boolean, Optional varClass As Variant, Optional maxLen As Variant) As Long

Dim blnMaxLenMiss   As Boolean
Dim blnClassMiss As Boolean
Dim strRecvData     As String
Dim lngBufferLen    As Long
Dim arrBuffer()     As Byte
Dim lngErrorCode    As Long

If m_enmProtocol = sckTCPProtocol Then
    lngBufferLen = Len(m_strRecvBuffer)
Else
    lngBufferLen = GetBufferLenUDP
End If

blnMaxLenMiss = IsMissing(maxLen)
blnClassMiss = IsMissing(varClass)

'Select type of data
If varType(data) = vbEmpty Then
    If blnClassMiss Then varClass = vbArray + vbByte
Else
    varClass = varType(data)
End If

'As stated on Winsock control documentation if the
'data type passed is string or byte array type then
'we must take into account maxLen argument.
'If it is another type maxLen is ignored.
If varClass = vbString Or varClass = vbArray + vbByte Then

    If blnMaxLenMiss Then 'if maxLen argument is missing
    
        If lngBufferLen = 0 Then
        
            RecvData = 0
        
            arrBuffer = StrConv("", vbFromUnicode)
            data = arrBuffer

            Exit Function
    
        Else
            
            RecvData = lngBufferLen
            arrBuffer = BuildArray(lngBufferLen, blnPeek, lngErrorCode)

        End If

    Else 'if maxLen argument is not missing

        If maxLen = 0 Or lngBufferLen = 0 Then

            RecvData = 0
        
            arrBuffer = StrConv("", vbFromUnicode)
            data = arrBuffer
            
            If m_enmProtocol = sckUDPProtocol Then
                EmptyBuffer
                Err.Raise WSAEMSGSIZE, "CSocketMaster.RecvData", GetErrorDescription(WSAEMSGSIZE)
            End If
            
            Exit Function
        
        ElseIf maxLen > lngBufferLen Then
            
            RecvData = lngBufferLen
            arrBuffer = BuildArray(lngBufferLen, blnPeek, lngErrorCode)

        Else
            
            RecvData = CLng(maxLen)
            arrBuffer() = BuildArray(CLng(maxLen), blnPeek, lngErrorCode)

        End If
    
    End If
        
End If

    Select Case varClass
    
    Case vbString
        Dim strdata As String
        strdata = StrConv(arrBuffer(), vbUnicode)
        data = strdata
    Case vbArray + vbByte
        data = arrBuffer
    Case vbBoolean
        Dim blnData As Boolean
        If LenB(blnData) > lngBufferLen Then Exit Function
        arrBuffer = BuildArray(LenB(blnData), blnPeek, lngErrorCode)
        RecvData = LenB(blnData)
        api_CopyMemory blnData, arrBuffer(0), LenB(blnData)
        data = blnData
    Case vbByte
        Dim bytData As Byte
        If LenB(bytData) > lngBufferLen Then Exit Function
        arrBuffer = BuildArray(LenB(bytData), blnPeek, lngErrorCode)
        RecvData = LenB(bytData)
        api_CopyMemory bytData, arrBuffer(0), LenB(bytData)
        data = bytData
    Case vbCurrency
        Dim curData As Currency
        If LenB(curData) > lngBufferLen Then Exit Function
        arrBuffer = BuildArray(LenB(curData), blnPeek, lngErrorCode)
        RecvData = LenB(curData)
        api_CopyMemory curData, arrBuffer(0), LenB(curData)
        data = curData
    Case vbDate
        Dim datData As Date
        If LenB(datData) > lngBufferLen Then Exit Function
        arrBuffer = BuildArray(LenB(datData), blnPeek, lngErrorCode)
        RecvData = LenB(datData)
        api_CopyMemory datData, arrBuffer(0), LenB(datData)
        data = datData
    Case vbDouble
        Dim dblData As Double
        If LenB(dblData) > lngBufferLen Then Exit Function
        arrBuffer = BuildArray(LenB(dblData), blnPeek, lngErrorCode)
        RecvData = LenB(dblData)
        api_CopyMemory dblData, arrBuffer(0), LenB(dblData)
        data = dblData
    Case vbInteger
        Dim intData As Integer
        If LenB(intData) > lngBufferLen Then Exit Function
        arrBuffer = BuildArray(LenB(intData), blnPeek, lngErrorCode)
        RecvData = LenB(intData)
        api_CopyMemory intData, arrBuffer(0), LenB(intData)
        data = intData
    Case vbLong
        Dim lngData As Long
        If LenB(lngData) > lngBufferLen Then Exit Function
        arrBuffer = BuildArray(LenB(lngData), blnPeek, lngErrorCode)
        RecvData = LenB(lngData)
        api_CopyMemory lngData, arrBuffer(0), LenB(lngData)
        data = lngData
    Case vbSingle
        Dim sngData As Single
        If LenB(sngData) > lngBufferLen Then Exit Function
        arrBuffer = BuildArray(LenB(sngData), blnPeek, lngErrorCode)
        RecvData = LenB(sngData)
        api_CopyMemory sngData, arrBuffer(0), LenB(sngData)
        data = sngData
    Case Else
        Err.Raise sckUnsupported, "CSocketMaster.RecvData", "Unsupported variant type."
       
    End Select

'if BuildArray returns an error is handled here
If lngErrorCode <> 0 Then
    Err.Raise lngErrorCode, "CSocketMaster.RecvData", GetErrorDescription(lngErrorCode)
End If

End Function

'Returns a byte array of Size bytes filled with incoming buffer data.
Private Function BuildArray(ByVal Size As Long, ByVal blnPeek As Boolean, ByRef lngErrorCode As Long) As Byte()
Dim strdata As String

If m_enmProtocol = sckTCPProtocol Then
        
    strdata = Left$(m_strRecvBuffer, CLng(Size))
    BuildArray = StrConv(strdata, vbFromUnicode)
                
    If Not blnPeek Then
        m_strRecvBuffer = Mid$(m_strRecvBuffer, Size + 1)
    End If

Else 'UDP protocol
    Dim arrBuffer() As Byte
    Dim lngResult As Long
    Dim udtSockAddr As sockaddr_in
    Dim lngFlags As Long
    
    If blnPeek Then lngFlags = MSG_PEEK
    
    ReDim arrBuffer(Size - 1)
    
    lngResult = api_recvfrom(m_lngSocketHandle, arrBuffer(0), Size, lngFlags, udtSockAddr, LenB(udtSockAddr))
    
    If lngResult = SOCKET_ERROR Then
        lngErrorCode = Err.LastDllError
    End If
    
    BuildArray = arrBuffer
    GetRemoteInfoFromSI udtSockAddr, m_lngRemotePort, m_strRemoteHostIP, m_strRemoteHost
    
End If
End Function

'Clean resolution system that is in charge of
'asynchronous hostname resolutions.
Private Sub CleanResolutionSystem()
Dim varAsynHandle As Variant

'cancel async resolutions if they're still running
For Each varAsynHandle In m_colWaitingResolutions
    api_WSACancelAsyncRequest varAsynHandle
    modSocketMaster.UnregisterResolution varAsynHandle
Next

'free memory buffer where resolution results are stored
FreeMemory
End Sub

Public Sub Listen()
If m_enmState <> sckClosed And m_enmState <> sckOpen Then
    Err.Raise sckInvalidOp, "CSocketMaster.Listen", "Invalid operation at current state"
End If

If Not SocketExists Then Exit Sub
If Not BindInternal Then Exit Sub

Dim lngResult As Long

lngResult = api_listen(m_lngSocketHandle, SOMAXCONN)

If lngResult = SOCKET_ERROR Then
    Dim lngErrorCode As Long
    lngErrorCode = Err.LastDllError
    Err.Raise lngErrorCode, "CSocketMaster.Listen", GetErrorDescription(lngErrorCode)
Else
    m_enmState = sckListening: Debug.Print "STATE: sckListening"
End If

End Sub

Public Sub Accept(requestID As Long)
If m_enmState <> sckClosed Then
    Err.Raise sckInvalidOp, "CSocketMaster.Accept", "Invalid operation at current state"
End If

Dim lngResult As Long
Dim udtSockAddr As sockaddr_in
Dim lngErrorCode As Long

m_lngSocketHandle = requestID
m_enmProtocol = sckTCPProtocol
ProcessOptions

If Not modSocketMaster.IsAcceptRegistered(requestID) Then
    If IsSocketRegistered(requestID) Then
        Err.Raise sckBadState, "CSocketMaster.Accept", "Wrong protocol or connection state for the requested transaction or request"
    Else
        m_blnAcceptClass = True
        m_enmState = sckConnected: Debug.Print "STATE: sckConnected"
        modSocketMaster.RegisterSocket m_lngSocketHandle, ObjPtr(Me), False
        Exit Sub
    End If
End If

Dim clsSocket As CSocketMaster
Set clsSocket = GetAcceptClass(requestID)
modSocketMaster.UnregisterAccept requestID

lngResult = api_getsockname(m_lngSocketHandle, udtSockAddr, LenB(udtSockAddr))

If lngResult = SOCKET_ERROR Then
    
    lngErrorCode = Err.LastDllError
    Err.Raise lngErrorCode, "CSocketMaster.Accept", GetErrorDescription(lngErrorCode)
    
Else

    m_lngLocalPortBind = IntegerToUnsigned(api_ntohs(udtSockAddr.sin_port))
    m_strLocalIP = StringFromPointer(api_inet_ntoa(udtSockAddr.sin_addr))
    
End If

GetRemoteInfo m_lngSocketHandle, m_lngRemotePort, m_strRemoteHostIP, m_strRemoteHost
m_enmState = sckConnected: Debug.Print "STATE: sckConnected"

If clsSocket.BytesReceived > 0 Then
    clsSocket.GetData m_strRecvBuffer
End If

modSocketMaster.Subclass_ChangeOwner requestID, ObjPtr(Me)

If Len(m_strRecvBuffer) > 0 Then RaiseEvent DataArrival(Len(m_strRecvBuffer))

If clsSocket.State = sckClosing Then
    m_enmState = sckClosing: Debug.Print "STATE: sckClosing"
    RaiseEvent CloseSck
End If

Set clsSocket = Nothing
End Sub

'Retrieves remote info from a connected socket.
'If succeeds returns TRUE and loads the arguments.
'If fails returns FALSE and arguments are not loaded.
Private Function GetRemoteInfo(ByVal lngSocket As Long, ByRef lngRemotePort As Long, ByRef strRemoteHostIP As String, ByRef strRemoteHost As String) As Boolean
GetRemoteInfo = False
Dim lngResult As Long
Dim udtSockAddr As sockaddr_in

lngResult = api_getpeername(lngSocket, udtSockAddr, LenB(udtSockAddr))

If lngResult = 0 Then
    GetRemoteInfo = True
    GetRemoteInfoFromSI udtSockAddr, lngRemotePort, strRemoteHostIP, strRemoteHost
Else
   lngRemotePort = 0
   strRemoteHostIP = ""
   strRemoteHost = ""
End If
End Function

'Gets remote info from a sockaddr_in structure.
Private Sub GetRemoteInfoFromSI(ByRef udtSockAddr As sockaddr_in, ByRef lngRemotePort As Long, ByRef strRemoteHostIP As String, ByRef strRemoteHost As String)

'Dim lngResult As Long
'Dim udtHostent As HOSTENT

lngRemotePort = IntegerToUnsigned(api_ntohs(udtSockAddr.sin_port))
strRemoteHostIP = StringFromPointer(api_inet_ntoa(udtSockAddr.sin_addr))
'lngResult = api_gethostbyaddr(udtSockAddr.sin_addr, 4&, AF_INET)

'If lngResult <> 0 Then
'    api_CopyMemory udtHostent, ByVal lngResult, LenB(udtHostent)
'    strRemoteHost = StringFromPointer(udtHostent.hName)
'Else
    m_strRemoteHost = ""
'End If

End Sub

'Returns winsock incoming buffer length from an UDP socket.
Private Function GetBufferLenUDP() As Long
Dim lngResult As Long
Dim lngBuffer As Long
lngResult = api_ioctlsocket(m_lngSocketHandle, FIONREAD, lngBuffer)

If lngResult = SOCKET_ERROR Then
    GetBufferLenUDP = 0
Else
    GetBufferLenUDP = lngBuffer
End If
End Function

'Empty winsock incoming buffer from an UDP socket.
Private Sub EmptyBuffer()
Dim B As Byte
api_recv m_lngSocketHandle, B, Len(B), 0&
End Sub