Detailed Description

The FGfdmSocket class enables JSBSim to communicate via sockets.

This class provides functionality for sending and receiving data over a socket connection. It can behave as both a client and/or a server, depending on the constructor used. The socket can use either UDP or TCP protocol for communication.

Definition at line 75 of file FGfdmSocket.h.

#include <FGfdmSocket.h>

Inheritance diagram for FGfdmSocket:

Collaboration diagram for FGfdmSocket:

Public Types
enum	ProtocolType { ptUDP , ptTCP }

Public Types inherited from FGJSBBase
enum	{ eL = 1 , eM , eN }
	Moments L, M, N. More...

enum	{ eP = 1 , eQ , eR }
	Rates P, Q, R. More...

enum	{ eU = 1 , eV , eW }
	Velocities U, V, W. More...

enum	{ eX = 1 , eY , eZ }
	Positions X, Y, Z. More...

enum	{ ePhi = 1 , eTht , ePsi }
	Euler angles Phi, Theta, Psi. More...

enum	{ eDrag = 1 , eSide , eLift }
	Stability axis forces, Drag, Side force, Lift. More...

enum	{ eRoll = 1 , ePitch , eYaw }
	Local frame orientation Roll, Pitch, Yaw. More...

enum	{ eNorth = 1 , eEast , eDown }
	Local frame position North, East, Down. More...

enum	{ eLat = 1 , eLong , eRad }
	Locations Radius, Latitude, Longitude. More...

enum	{ inNone = 0 , inDegrees , inRadians , inMeters , inFeet }
	Conversion specifiers. More...

Public Member Functions
	FGfdmSocket (const std::string &address, int port, int protocol, int precision=7)
	Construct a client socket.

	FGfdmSocket (int port, int protocol, int precision=7)
	Construct a server socket.

void	Append (const char *)
	Append the specified C-style string to the internal buffer.

void	Append (const std::string &s)
	Append the specified string to the internal buffer.

void	Append (double value)
	Append the specified double value to the internal buffer.

void	Append (long value)
	Append the specified long value to the internal buffer.

void	Clear (const std::string &s)
	Clear the internal buffer and appends the specified string.

void	Clear (void)
	Clear the internal buffer.

void	Close (void)
	Close the socket connection if the protocol is TCP.

bool	GetConnectStatus (void)
	Return the connection status of the socket.

std::string	Receive (void)
	Receive data from the socket connection.

int	Reply (const std::string &text)
	Send a reply to the client ending by a prompt "JSBSim>".

void	Send (const char *data, int length)
	Send the specified data over the socket connection.

void	Send (const std::string &data)

void	Send (void)
	Send the internal buffer over the socket connection.

void	WaitUntilReadable (void)
	Wait until the TCP socket is readable.

Public Member Functions inherited from FGJSBBase
	FGJSBBase ()
	Constructor for FGJSBBase.

virtual	~FGJSBBase ()
	Destructor for FGJSBBase.

void	disableHighLighting (void)
	Disables highlighting in the console output.

Additional Inherited Members
Static Public Member Functions inherited from FGJSBBase
static const std::string &	GetVersion (void)
	Returns the version number of JSBSim.

static constexpr double	KelvinToFahrenheit (double kelvin)
	Converts from degrees Kelvin to degrees Fahrenheit.

static constexpr double	CelsiusToRankine (double celsius)
	Converts from degrees Celsius to degrees Rankine.

static constexpr double	RankineToCelsius (double rankine)
	Converts from degrees Rankine to degrees Celsius.

static constexpr double	KelvinToRankine (double kelvin)
	Converts from degrees Kelvin to degrees Rankine.

static constexpr double	RankineToKelvin (double rankine)
	Converts from degrees Rankine to degrees Kelvin.

static constexpr double	FahrenheitToCelsius (double fahrenheit)
	Converts from degrees Fahrenheit to degrees Celsius.

static constexpr double	CelsiusToFahrenheit (double celsius)
	Converts from degrees Celsius to degrees Fahrenheit.

static constexpr double	CelsiusToKelvin (double celsius)
	Converts from degrees Celsius to degrees Kelvin.

static constexpr double	KelvinToCelsius (double kelvin)
	Converts from degrees Kelvin to degrees Celsius.

static constexpr double	FeetToMeters (double measure)
	Converts from feet to meters.

static bool	EqualToRoundoff (double a, double b)
	Finite precision comparison.

static bool	EqualToRoundoff (float a, float b)
	Finite precision comparison.

static bool	EqualToRoundoff (float a, double b)
	Finite precision comparison.

static bool	EqualToRoundoff (double a, float b)
	Finite precision comparison.

static constexpr double	Constrain (double min, double value, double max)
	Constrain a value between a minimum and a maximum value.

static constexpr double	sign (double num)

Static Public Attributes inherited from FGJSBBase
static char	highint [5] = {27, '[', '1', 'm', '\0' }
	highlights text

static char	halfint [5] = {27, '[', '2', 'm', '\0' }
	low intensity text

static char	normint [6] = {27, '[', '2', '2', 'm', '\0' }
	normal intensity text

static char	reset [5] = {27, '[', '0', 'm', '\0' }
	resets text properties

static char	underon [5] = {27, '[', '4', 'm', '\0' }
	underlines text

static char	underoff [6] = {27, '[', '2', '4', 'm', '\0' }
	underline off

static char	fgblue [6] = {27, '[', '3', '4', 'm', '\0' }
	blue text

static char	fgcyan [6] = {27, '[', '3', '6', 'm', '\0' }
	cyan text

static char	fgred [6] = {27, '[', '3', '1', 'm', '\0' }
	red text

static char	fggreen [6] = {27, '[', '3', '2', 'm', '\0' }
	green text

static char	fgdef [6] = {27, '[', '3', '9', 'm', '\0' }
	default text

static short	debug_lvl = 1

Static Protected Member Functions inherited from FGJSBBase
static std::string	CreateIndexedPropertyName (const std::string &Property, int index)

Static Protected Attributes inherited from FGJSBBase
static constexpr double	radtodeg = 180. / M_PI

static constexpr double	degtorad = M_PI / 180.

static constexpr double	hptoftlbssec = 550.0

static constexpr double	psftoinhg = 0.014138

static constexpr double	psftopa = 47.88

static constexpr double	fttom = 0.3048

static constexpr double	ktstofps = 1852./(3600*fttom)

static constexpr double	fpstokts = 1.0 / ktstofps

static constexpr double	inchtoft = 1.0/12.0

static constexpr double	m3toft3 = 1.0/(fttomfttomfttom)

static constexpr double	in3tom3 = inchtoftinchtoftinchtoft/m3toft3

static constexpr double	inhgtopa = 3386.38

static constexpr double	slugtolb = 32.174049
	Note that definition of lbtoslug by the inverse of slugtolb and not to a different constant you can also get from some tables will make lbtoslug*slugtolb == 1 up to the magnitude of roundoff.

static constexpr double	lbtoslug = 1.0/slugtolb

static constexpr double	kgtolb = 2.20462

static constexpr double	kgtoslug = 0.06852168

static const std::string	needed_cfg_version = "2.0"

static const std::string	JSBSim_version = JSBSIM_VERSION " " __DATE__ " " __TIME__

Member Enumeration Documentation

◆ ProtocolType

enum ProtocolType

Definition at line 177 of file FGfdmSocket.h.

177{ptUDP, ptTCP};

Constructor & Destructor Documentation

◆ FGfdmSocket() [1/2]

FGfdmSocket	(	const std::string &	address,
		int	port,
		int	protocol,
		int	precision = `7`
	)

Construct a client socket.

Parameters

address	The IP address or hostname of the server to connect to.
port	The port number to connect to.
protocol	The protocol to use for communication (ptUDP or ptTCP).
precision	The precision to use for floating-point numbers (default is 7).

Definition at line 98 of file FGfdmSocket.cpp.

{
  sckt = sckt_in = INVALID_SOCKET;
  Protocol = (ProtocolType)protocol;
  connected = false;
  struct addrinfo *addr = nullptr;
  this->precision = precision;
 
#ifdef _WIN32
  if (!LoadWinSockDLL(debug_lvl)) return;
#endif
 
  struct addrinfo hints;
  memset(&hints, 0, sizeof(struct addrinfo));
  hints.ai_family = AF_INET;
  if (protocol == ptUDP)
    hints.ai_socktype = SOCK_DGRAM;
  else
    hints.ai_socktype = SOCK_STREAM;
  hints.ai_protocol = 0;
  if (!is_number(address))
    hints.ai_flags = AI_ADDRCONFIG;
  else
    hints.ai_flags = AI_NUMERICHOST;
 
  int failure = getaddrinfo(address.c_str(), NULL, &hints, &addr);
  if (failure || !addr) {
    FGLogging log(LogLevel::ERROR);
    log << "Could not get host net address " << address;
 
    if (hints.ai_flags == AI_NUMERICHOST)
      log << " by number...\n";
    else
      log << " by name...\n";
 
    log  << gai_strerror(failure) << "\n";
 
    freeaddrinfo(addr);
    return;
  }
 
  sckt = socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
 
  if (debug_lvl > 0) {
    FGLogging log(LogLevel::DEBUG);
    if (protocol == ptUDP)  //use udp protocol
      log << "Creating UDP socket on port " << port << "\n";
    else //use tcp protocol
      log << "Creating TCP socket on port " << port << "\n";
  }
 
  if (sckt != INVALID_SOCKET) {  // successful
    int len = sizeof(struct sockaddr_in);
    memcpy(&scktName, addr->ai_addr, len);
    scktName.sin_port = htons(port);
 
    if (connect(sckt, (struct sockaddr*)&scktName, len) == 0) {   // successful
      if (debug_lvl > 0) {
        FGLogging log(LogLevel::DEBUG);
        log << "Successfully connected to socket for output ...\n";
      }
      connected = true;
    } else {         // unsuccessful
      FGLogging log(LogLevel::ERROR);
      log << "Could not connect to socket for output ...\n";
    }
  } else {          // unsuccessful
    FGLogging log(LogLevel::ERROR);
    log << "Could not create socket for FDM output, error = " << errno << "\n";
  }
 
  freeaddrinfo(addr);
 
  Debug(0);
}

◆ FGfdmSocket() [2/2]

FGfdmSocket	(	int	port,
		int	protocol,
		int	precision = `7`
	)

Construct a server socket.

Parameters

port	The port number to listen on.
protocol	The protocol to use for communication (ptUDP or ptTCP).
precision	The precision to use for floating-point numbers (default is 7).

Definition at line 176 of file FGfdmSocket.cpp.

{
  sckt = INVALID_SOCKET;
  connected = false;
  Protocol = (ProtocolType)protocol;
  string ProtocolName;
  this->precision = precision;
 
#ifdef _WIN32
  if (!LoadWinSockDLL(debug_lvl)) return;
#endif
 
  if (Protocol == ptUDP) {  //use udp protocol
    ProtocolName = "UDP";
    sckt = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
#ifdef _WIN32
    u_long NonBlock = 1; // True
    ioctlsocket(sckt, FIONBIO, &NonBlock);
#else
    int flags = fcntl(sckt, F_GETFL, 0);
    fcntl(sckt, F_SETFL, flags | O_NONBLOCK);
#endif
  }
  else {
    ProtocolName = "TCP";
    sckt = socket(AF_INET, SOCK_STREAM, 0);
  }
 
  if (debug_lvl > 0) {
    FGLogging log(LogLevel::DEBUG);
    log << "Creating input " << ProtocolName << " socket on port " << port
        << "\n";
  }
 
  if (sckt != INVALID_SOCKET) {
    memset(&scktName, 0, sizeof(struct sockaddr_in));
    scktName.sin_family = AF_INET;
    scktName.sin_port = htons(port);
 
    if (Protocol == ptUDP)
      scktName.sin_addr.s_addr = htonl(INADDR_ANY);
 
    socklen_t len = sizeof(struct sockaddr_in);
    if (bind(sckt, (struct sockaddr*)&scktName, len) != SOCKET_ERROR) {
      if (debug_lvl > 0) {
        FGLogging log(LogLevel::DEBUG);
        log << "Successfully bound to " << ProtocolName
            << " input socket on port " << port << "\n\n";
      }
 
      if (Protocol == ptTCP) {
        if (listen(sckt, 5) != SOCKET_ERROR) { // successful listen()
          connected = true;
#ifdef _WIN32
          u_long NoBlock = 1;
          ioctlsocket(sckt, FIONBIO, &NoBlock);
#else
          int flags = fcntl(sckt, F_GETFL, 0);
          fcntl(sckt, F_SETFL, flags | O_NONBLOCK);
#endif
          sckt_in = accept(sckt, (struct sockaddr*)&scktName, &len);
        } else {
          closesocket(sckt);
          sckt = INVALID_SOCKET;
          FGLogging log(LogLevel::ERROR);
          log << "Could not listen ...\n";
        }
      } else
        connected = true;
    } else {         // unsuccessful
      closesocket(sckt);
      sckt = INVALID_SOCKET;
      FGLogging log(LogLevel::ERROR);
      log << "Could not bind to " << ProtocolName << " input socket, error = "
          << errno << "\n";
    }
  } else {          // unsuccessful
      FGLogging log(LogLevel::ERROR);
      log << "Could not create " << ProtocolName << " socket for input, error = "
          << errno << "\n";
  }
 
  Debug(0);
}

◆ ~FGfdmSocket()

~FGfdmSocket ( )

Definition at line 263 of file FGfdmSocket.cpp.

{
  // Release the file descriptors to the OS.
  if (sckt_in != INVALID_SOCKET) shutdown(sckt_in, SD_BOTH);
  if (sckt != INVALID_SOCKET) closesocket(sckt);
  Debug(1);
}

Member Function Documentation

◆ Append() [1/4]

void Append ( const char * item )

Append the specified C-style string to the internal buffer.

Parameters

s	The C-style string to append.

Definition at line 385 of file FGfdmSocket.cpp.

{
  if (buffer.tellp() > 0) buffer << ',';
  buffer << item;
}

◆ Append() [2/4]

void Append ( const std::string & s )

inline

Append the specified string to the internal buffer.

Parameters

s	The string to append.

Definition at line 131 of file FGfdmSocket.h.

131{Append(s.c_str());}

JSBSim::FGfdmSocket::Append

void Append(const std::string &s)

Append the specified string to the internal buffer.

Definition FGfdmSocket.h:131

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◆ Append() [3/4]

void Append ( double value )

Append the specified double value to the internal buffer.

Parameters

value The double value to append.

Definition at line 393 of file FGfdmSocket.cpp.

{
  if (buffer.tellp() > 0) buffer << ',';
  buffer << std::setw(12) << std::setprecision(precision) << item;
}

◆ Append() [4/4]

void Append ( long value )

Append the specified long value to the internal buffer.

Parameters

value The long value to append.

Definition at line 401 of file FGfdmSocket.cpp.

{
  if (buffer.tellp() > 0) buffer << ',';
  buffer << std::setw(12) << item;
}

◆ Clear() [1/2]

void Clear ( const std::string & s )

Clear the internal buffer and appends the specified string.

Parameters

s	The string to append after clearing the buffer.

Definition at line 377 of file FGfdmSocket.cpp.

{
  Clear();
  buffer << s << ' ';
}

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◆ Clear() [2/2]

void Clear ( void )

Clear the internal buffer.

Definition at line 370 of file FGfdmSocket.cpp.

{
  buffer.str("");
}

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◆ Close()

void Close ( void )

Close the socket connection if the protocol is TCP.

Definition at line 361 of file FGfdmSocket.cpp.

{
  assert(Protocol == ptTCP);
  closesocket(sckt_in);
  sckt_in = INVALID_SOCKET;
}

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◆ GetConnectStatus()

bool GetConnectStatus ( void )

inline

Return the connection status of the socket.

Returns: True if the socket is connected, false otherwise.

Definition at line 172 of file FGfdmSocket.h.

172{return connected;}

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◆ Receive()

string Receive ( void )

Receive data from the socket connection.

Returns: The received data as a string.

Definition at line 273 of file FGfdmSocket.cpp.

{
  char buf[1024];
  string data;      // TODO should allocate this with a standard size as a
                    // class attribute and pass as a reference?
 
  if (Protocol == ptTCP){
    if (sckt_in == INVALID_SOCKET) {
      socklen_t len = sizeof(struct sockaddr_in);
      sckt_in = accept(sckt, (struct sockaddr*)&scktName, &len);
      if (sckt_in != INVALID_SOCKET) {
#ifdef _WIN32
        u_long NoBlock = 1;
        ioctlsocket(sckt_in, FIONBIO, &NoBlock);
#else
        int flags = fcntl(sckt_in, F_GETFL, 0);
        fcntl(sckt_in, F_SETFL, flags | O_NONBLOCK);
#endif
        if (send(sckt_in, "Connected to JSBSim server\r\nJSBSim> ", 36, 0) == SOCKET_ERROR)
          LogSocketError("Receive - TCP connection acknowledgement");
      }
    }
 
    if (sckt_in != INVALID_SOCKET) {
      int num_chars;
 
      while ((num_chars = recv(sckt_in, buf, sizeof buf, 0)) > 0)
        data.append(buf, num_chars);
 
      if (num_chars == SOCKET_ERROR || num_chars == 0) {
#ifdef _WIN32
        if (WSAGetLastError() != WSAEWOULDBLOCK)
#else
        if (errno != EWOULDBLOCK)
#endif
        {
          LogSocketError("Receive - TCP data reception");
          // when nothing received and the error isn't "would block"
          // then assume that the client has closed the socket.
          FGLogging log(LogLevel::INFO);
          log << "Socket Closed. Back to listening\n";
          closesocket(sckt_in);
          sckt_in = INVALID_SOCKET;
        }
      }
    }
  }
 
  // this is for FGUDPInputSocket
  if (sckt != INVALID_SOCKET && Protocol == ptUDP) {
    struct sockaddr addr;
    socklen_t fromlen = sizeof addr;
    int num_chars = recvfrom(sckt, buf, sizeof buf, 0, (struct sockaddr*)&addr, &fromlen);
    if (num_chars > 0) data.append(buf, num_chars);
    if (num_chars == SOCKET_ERROR) {
#ifdef _WIN32
      if (WSAGetLastError() != WSAEWOULDBLOCK)
#else
      if (errno != EWOULDBLOCK)
#endif
        LogSocketError("Receive - UDP data reception");
    }
  }
 
  return data;
}

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◆ Reply()

int Reply ( const std::string & text )

Send a reply to the client ending by a prompt "JSBSim>".

Parameters

text	The reply text to send.

Returns: The number of bytes sent.

Definition at line 342 of file FGfdmSocket.cpp.

{
  int num_chars_sent=0;
  assert(Protocol == ptTCP);
 
  if (sckt_in != INVALID_SOCKET) {
    num_chars_sent = send(sckt_in, text.c_str(), text.size(), 0);
    if (num_chars_sent == SOCKET_ERROR) LogSocketError("Reply - Send data");
    if (send(sckt_in, "JSBSim> ", 8, 0) == SOCKET_ERROR) LogSocketError("Reply - Prompt");
  } else {
    FGLogging log(LogLevel::ERROR);
    log << "Socket reply must be to a valid socket\n";
    return -1;
  }
  return num_chars_sent;
}

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◆ Send() [1/3]

void Send	(	const char *	data,
		int	length
	)

Send the specified data over the socket connection.

Parameters

data	The data to send.
length	The length of the data.

Definition at line 418 of file FGfdmSocket.cpp.

{
  if (Protocol == ptTCP && sckt_in != INVALID_SOCKET) {
    if ((send(sckt_in, data, length, 0)) == SOCKET_ERROR) LogSocketError("Send - TCP data sending");
    return;
  }
 
  if (Protocol == ptUDP && sckt != INVALID_SOCKET) {
    if ((send(sckt, data, length, 0)) == SOCKET_ERROR) LogSocketError("Send - UDP data sending");
    return;
  }
 
  FGLogging log(LogLevel::ERROR);
  log << "Data sending must be to a valid socket\n";
}

◆ Send() [2/3]

void Send ( const std::string & data )

inline

Definition at line 109 of file FGfdmSocket.h.

109{ Send(data.c_str(), data.length()); }

JSBSim::FGfdmSocket::Send

void Send(void)

Send the internal buffer over the socket connection.

Definition FGfdmSocket.cpp:409

◆ Send() [3/3]

void Send ( void )

Send the internal buffer over the socket connection.

Definition at line 409 of file FGfdmSocket.cpp.

{
  buffer << '\n';
  string str = buffer.str();
  Send(str.c_str(), str.size());
}

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◆ WaitUntilReadable()

void WaitUntilReadable ( void )

Wait until the TCP socket is readable.

Definition at line 436 of file FGfdmSocket.cpp.

{
  assert(Protocol == ptTCP);
  if (sckt_in == INVALID_SOCKET) return;
 
  fd_set fds;
  FD_ZERO(&fds);
  FD_SET(sckt_in, &fds);
 
  int result = select(FD_SETSIZE, &fds, nullptr, nullptr, nullptr);
 
  if (result == 0) {
    FGLogging log(LogLevel::ERROR);
    log << "Socket timeout.\n";
    return;
  } else if (result != SOCKET_ERROR)
    return;
 
  LogSocketError("WaitUntilReadable");
}

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The documentation for this class was generated from the following files:

Detailed Description

Public Types

Public Member Functions

Additional Inherited Members

Member Enumeration Documentation

◆ ProtocolType

Constructor & Destructor Documentation

◆ FGfdmSocket() [1/2]

◆ FGfdmSocket() [2/2]

◆ ~FGfdmSocket()

Member Function Documentation

◆ Append() [1/4]

◆ Append() [2/4]

◆ Append() [3/4]

◆ Append() [4/4]

◆ Clear() [1/2]

◆ Clear() [2/2]

◆ Close()

◆ GetConnectStatus()

◆ Receive()

◆ Reply()

◆ Send() [1/3]

◆ Send() [2/3]

◆ Send() [3/3]

◆ WaitUntilReadable()