// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package net

import (
	
	
	
	
	
)

// BUG(mikio): On JS and Windows, the File method of TCPConn and
// TCPListener is not implemented.

// TCPAddr represents the address of a TCP end point.
type TCPAddr struct {
	IP   IP
	Port int
	Zone string // IPv6 scoped addressing zone
}

// Network returns the address's network name, "tcp".
func ( *TCPAddr) () string { return "tcp" }

func ( *TCPAddr) () string {
	if  == nil {
		return "<nil>"
	}
	 := ipEmptyString(.IP)
	if .Zone != "" {
		return JoinHostPort(+"%"+.Zone, itoa(.Port))
	}
	return JoinHostPort(, itoa(.Port))
}

func ( *TCPAddr) () bool {
	if  == nil || .IP == nil {
		return true
	}
	return .IP.IsUnspecified()
}

func ( *TCPAddr) () Addr {
	if  == nil {
		return nil
	}
	return 
}

// ResolveTCPAddr returns an address of TCP end point.
//
// The network must be a TCP network name.
//
// If the host in the address parameter is not a literal IP address or
// the port is not a literal port number, ResolveTCPAddr resolves the
// address to an address of TCP end point.
// Otherwise, it parses the address as a pair of literal IP address
// and port number.
// The address parameter can use a host name, but this is not
// recommended, because it will return at most one of the host name's
// IP addresses.
//
// See func Dial for a description of the network and address
// parameters.
func (,  string) (*TCPAddr, error) {
	switch  {
	case "tcp", "tcp4", "tcp6":
	case "": // a hint wildcard for Go 1.0 undocumented behavior
		 = "tcp"
	default:
		return nil, UnknownNetworkError()
	}
	,  := DefaultResolver.internetAddrList(context.Background(), , )
	if  != nil {
		return nil, 
	}
	return .forResolve(, ).(*TCPAddr), nil
}

// TCPConn is an implementation of the Conn interface for TCP network
// connections.
type TCPConn struct {
	conn
}

// SyscallConn returns a raw network connection.
// This implements the syscall.Conn interface.
func ( *TCPConn) () (syscall.RawConn, error) {
	if !.ok() {
		return nil, syscall.EINVAL
	}
	return newRawConn(.fd)
}

// ReadFrom implements the io.ReaderFrom ReadFrom method.
func ( *TCPConn) ( io.Reader) (int64, error) {
	if !.ok() {
		return 0, syscall.EINVAL
	}
	,  := .readFrom()
	if  != nil &&  != io.EOF {
		 = &OpError{Op: "readfrom", Net: .fd.net, Source: .fd.laddr, Addr: .fd.raddr, Err: }
	}
	return , 
}

// CloseRead shuts down the reading side of the TCP connection.
// Most callers should just use Close.
func ( *TCPConn) () error {
	if !.ok() {
		return syscall.EINVAL
	}
	if  := .fd.closeRead();  != nil {
		return &OpError{Op: "close", Net: .fd.net, Source: .fd.laddr, Addr: .fd.raddr, Err: }
	}
	return nil
}

// CloseWrite shuts down the writing side of the TCP connection.
// Most callers should just use Close.
func ( *TCPConn) () error {
	if !.ok() {
		return syscall.EINVAL
	}
	if  := .fd.closeWrite();  != nil {
		return &OpError{Op: "close", Net: .fd.net, Source: .fd.laddr, Addr: .fd.raddr, Err: }
	}
	return nil
}

// SetLinger sets the behavior of Close on a connection which still
// has data waiting to be sent or to be acknowledged.
//
// If sec < 0 (the default), the operating system finishes sending the
// data in the background.
//
// If sec == 0, the operating system discards any unsent or
// unacknowledged data.
//
// If sec > 0, the data is sent in the background as with sec < 0. On
// some operating systems after sec seconds have elapsed any remaining
// unsent data may be discarded.
func ( *TCPConn) ( int) error {
	if !.ok() {
		return syscall.EINVAL
	}
	if  := setLinger(.fd, );  != nil {
		return &OpError{Op: "set", Net: .fd.net, Source: .fd.laddr, Addr: .fd.raddr, Err: }
	}
	return nil
}

// SetKeepAlive sets whether the operating system should send
// keep-alive messages on the connection.
func ( *TCPConn) ( bool) error {
	if !.ok() {
		return syscall.EINVAL
	}
	if  := setKeepAlive(.fd, );  != nil {
		return &OpError{Op: "set", Net: .fd.net, Source: .fd.laddr, Addr: .fd.raddr, Err: }
	}
	return nil
}

// SetKeepAlivePeriod sets period between keep-alives.
func ( *TCPConn) ( time.Duration) error {
	if !.ok() {
		return syscall.EINVAL
	}
	if  := setKeepAlivePeriod(.fd, );  != nil {
		return &OpError{Op: "set", Net: .fd.net, Source: .fd.laddr, Addr: .fd.raddr, Err: }
	}
	return nil
}

// SetNoDelay controls whether the operating system should delay
// packet transmission in hopes of sending fewer packets (Nagle's
// algorithm).  The default is true (no delay), meaning that data is
// sent as soon as possible after a Write.
func ( *TCPConn) ( bool) error {
	if !.ok() {
		return syscall.EINVAL
	}
	if  := setNoDelay(.fd, );  != nil {
		return &OpError{Op: "set", Net: .fd.net, Source: .fd.laddr, Addr: .fd.raddr, Err: }
	}
	return nil
}

func newTCPConn( *netFD) *TCPConn {
	 := &TCPConn{conn{}}
	setNoDelay(.fd, true)
	return 
}

// DialTCP acts like Dial for TCP networks.
//
// The network must be a TCP network name; see func Dial for details.
//
// If laddr is nil, a local address is automatically chosen.
// If the IP field of raddr is nil or an unspecified IP address, the
// local system is assumed.
func ( string, ,  *TCPAddr) (*TCPConn, error) {
	switch  {
	case "tcp", "tcp4", "tcp6":
	default:
		return nil, &OpError{Op: "dial", Net: , Source: .opAddr(), Addr: .opAddr(), Err: UnknownNetworkError()}
	}
	if  == nil {
		return nil, &OpError{Op: "dial", Net: , Source: .opAddr(), Addr: nil, Err: errMissingAddress}
	}
	 := &sysDialer{network: , address: .String()}
	,  := .dialTCP(context.Background(), , )
	if  != nil {
		return nil, &OpError{Op: "dial", Net: , Source: .opAddr(), Addr: .opAddr(), Err: }
	}
	return , nil
}

// TCPListener is a TCP network listener. Clients should typically
// use variables of type Listener instead of assuming TCP.
type TCPListener struct {
	fd *netFD
	lc ListenConfig
}

// SyscallConn returns a raw network connection.
// This implements the syscall.Conn interface.
//
// The returned RawConn only supports calling Control. Read and
// Write return an error.
func ( *TCPListener) () (syscall.RawConn, error) {
	if !.ok() {
		return nil, syscall.EINVAL
	}
	return newRawListener(.fd)
}

// AcceptTCP accepts the next incoming call and returns the new
// connection.
func ( *TCPListener) () (*TCPConn, error) {
	if !.ok() {
		return nil, syscall.EINVAL
	}
	,  := .accept()
	if  != nil {
		return nil, &OpError{Op: "accept", Net: .fd.net, Source: nil, Addr: .fd.laddr, Err: }
	}
	return , nil
}

// Accept implements the Accept method in the Listener interface; it
// waits for the next call and returns a generic Conn.
func ( *TCPListener) () (Conn, error) {
	if !.ok() {
		return nil, syscall.EINVAL
	}
	,  := .accept()
	if  != nil {
		return nil, &OpError{Op: "accept", Net: .fd.net, Source: nil, Addr: .fd.laddr, Err: }
	}
	return , nil
}

// Close stops listening on the TCP address.
// Already Accepted connections are not closed.
func ( *TCPListener) () error {
	if !.ok() {
		return syscall.EINVAL
	}
	if  := .close();  != nil {
		return &OpError{Op: "close", Net: .fd.net, Source: nil, Addr: .fd.laddr, Err: }
	}
	return nil
}

// Addr returns the listener's network address, a *TCPAddr.
// The Addr returned is shared by all invocations of Addr, so
// do not modify it.
func ( *TCPListener) () Addr { return .fd.laddr }

// SetDeadline sets the deadline associated with the listener.
// A zero time value disables the deadline.
func ( *TCPListener) ( time.Time) error {
	if !.ok() {
		return syscall.EINVAL
	}
	if  := .fd.pfd.SetDeadline();  != nil {
		return &OpError{Op: "set", Net: .fd.net, Source: nil, Addr: .fd.laddr, Err: }
	}
	return nil
}

// File returns a copy of the underlying os.File.
// It is the caller's responsibility to close f when finished.
// Closing l does not affect f, and closing f does not affect l.
//
// The returned os.File's file descriptor is different from the
// connection's. Attempting to change properties of the original
// using this duplicate may or may not have the desired effect.
func ( *TCPListener) () ( *os.File,  error) {
	if !.ok() {
		return nil, syscall.EINVAL
	}
	,  = .file()
	if  != nil {
		return nil, &OpError{Op: "file", Net: .fd.net, Source: nil, Addr: .fd.laddr, Err: }
	}
	return
}

// ListenTCP acts like Listen for TCP networks.
//
// The network must be a TCP network name; see func Dial for details.
//
// If the IP field of laddr is nil or an unspecified IP address,
// ListenTCP listens on all available unicast and anycast IP addresses
// of the local system.
// If the Port field of laddr is 0, a port number is automatically
// chosen.
func ( string,  *TCPAddr) (*TCPListener, error) {
	switch  {
	case "tcp", "tcp4", "tcp6":
	default:
		return nil, &OpError{Op: "listen", Net: , Source: nil, Addr: .opAddr(), Err: UnknownNetworkError()}
	}
	if  == nil {
		 = &TCPAddr{}
	}
	 := &sysListener{network: , address: .String()}
	,  := .listenTCP(context.Background(), )
	if  != nil {
		return nil, &OpError{Op: "listen", Net: , Source: nil, Addr: .opAddr(), Err: }
	}
	return , nil
}

// roundDurationUp rounds d to the next multiple of to.
func roundDurationUp( time.Duration,  time.Duration) time.Duration {
	return ( +  - 1) / 
}