From fffcc612379cc3be6955708ffaf6097023461d8a Mon Sep 17 00:00:00 2001
From: Cristian Maglie <c.maglie@bug.st>
Date: Mon, 15 Dec 2014 18:43:09 +0100
Subject: [PATCH] Added Set(...) method to set all comm-params altogether

---
 serial.go       |  6 ++--
 serial_linux.go | 77 +++++++++++++++++++++++++++++++++++++++----------
 2 files changed, 65 insertions(+), 18 deletions(-)

diff --git a/serial.go b/serial.go
index cbe0ad0..993c911 100644
--- a/serial.go
+++ b/serial.go
@@ -10,9 +10,6 @@ import "io"
 
 // SerialPort object
 type SerialPort interface {
-	// Read(p []byte) (n int, err error)
-	// Write(p []byte) (n int, err error)
-	// Close() error
 	io.ReadWriteCloser
 
 	// Set port speed
@@ -26,6 +23,9 @@ type SerialPort interface {
 
 	// Set stop bits
 	SetStopBits(bits StopBits) error
+
+	// Set all parameters together
+	Set(baudrate int, parity Parity, databits int, stopbits StopBits) error
 }
 
 type Parity int
diff --git a/serial_linux.go b/serial_linux.go
index 92edfba..589c2f6 100644
--- a/serial_linux.go
+++ b/serial_linux.go
@@ -91,6 +91,37 @@ func (port *linuxSerialPort) Write(p []byte) (n int, err error) {
 	return syscall.Write(port.handle, p)
 }
 
+func (port *linuxSerialPort) Set(baudrate int, parity Parity, databits int, stopbits StopBits) error {
+	settings, err := port.getTermSettings()
+	if err != nil {
+		return err
+	}
+	if err := setTermSettingsBaudrate(baudrate, settings); err != nil {
+		return err
+	}
+	if err := setTermSettingsParity(parity, settings); err != nil {
+		return err
+	}
+	if err := setTermSettingsDataBits(databits, settings); err != nil {
+		return err
+	}
+	if err := setTermSettingsStopBits(stopbits, settings); err != nil {
+		return err
+	}
+	return port.setTermSettings(settings)
+}
+
+func (port *linuxSerialPort) SetSpeed(speed int) error {
+	settings, err := port.getTermSettings()
+	if err != nil {
+		return err
+	}
+	if err := setTermSettingsBaudrate(speed, settings); err != nil {
+		return err
+	}
+	return port.setTermSettings(settings)
+}
+
 var baudrateMap = map[int]uint32{
 	50:      syscall.B50,
 	75:      syscall.B75,
@@ -124,15 +155,11 @@ var baudrateMap = map[int]uint32{
 	4000000: syscall.B4000000,
 }
 
-func (port *linuxSerialPort) SetSpeed(speed int) error {
+func setTermSettingsBaudrate(speed int, settings *syscall.Termios) error {
 	baudrate, ok := baudrateMap[speed]
 	if !ok {
 		return &SerialPortError{code: ERROR_INVALID_PORT_SPEED}
 	}
-	settings, err := port.getTermSettings()
-	if err != nil {
-		return err
-	}
 	// revert old baudrate
 	var BAUDMASK uint32 = 0
 	for _, rate := range baudrateMap {
@@ -143,16 +170,22 @@ func (port *linuxSerialPort) SetSpeed(speed int) error {
 	settings.Cflag |= baudrate
 	settings.Ispeed = baudrate
 	settings.Ospeed = baudrate
-	return port.setTermSettings(settings)
+	return nil
 }
 
 func (port *linuxSerialPort) SetParity(parity Parity) error {
-	const FIXED_PARITY_FLAG uint32 = 0 // may be CMSPAR or PAREXT
-
 	settings, err := port.getTermSettings()
 	if err != nil {
 		return err
 	}
+	if err := setTermSettingsParity(parity, settings); err != nil {
+		return err
+	}
+	return port.setTermSettings(settings)
+}
+
+func setTermSettingsParity(parity Parity, settings *syscall.Termios) error {
+	const FIXED_PARITY_FLAG uint32 = 0 // may be CMSPAR or PAREXT
 	switch parity {
 	case PARITY_NONE:
 		settings.Cflag &= ^uint32(syscall.PARENB | syscall.PARODD | FIXED_PARITY_FLAG)
@@ -173,7 +206,7 @@ func (port *linuxSerialPort) SetParity(parity Parity) error {
 		settings.Cflag |= syscall.PARENB | FIXED_PARITY_FLAG
 		settings.Iflag |= syscall.INPCK
 	}
-	return port.setTermSettings(settings)
+	return nil
 }
 
 var databitsMap = map[int]uint32{
@@ -184,17 +217,24 @@ var databitsMap = map[int]uint32{
 }
 
 func (port *linuxSerialPort) SetDataBits(bits int) error {
-	databits, ok := databitsMap[bits]
-	if !ok {
-		return &SerialPortError{code: ERROR_INVALID_PORT_DATA_BITS}
-	}
 	settings, err := port.getTermSettings()
 	if err != nil {
 		return err
 	}
+	if err := setTermSettingsDataBits(bits, settings); err != nil {
+		return err
+	}
+	return port.setTermSettings(settings)
+}
+
+func setTermSettingsDataBits(bits int, settings *syscall.Termios) error {
+	databits, ok := databitsMap[bits]
+	if !ok {
+		return &SerialPortError{code: ERROR_INVALID_PORT_DATA_BITS}
+	}
 	settings.Cflag &= ^uint32(syscall.CSIZE)
 	settings.Cflag |= databits
-	return port.setTermSettings(settings)
+	return nil
 }
 
 func (port *linuxSerialPort) SetStopBits(bits StopBits) error {
@@ -202,13 +242,20 @@ func (port *linuxSerialPort) SetStopBits(bits StopBits) error {
 	if err != nil {
 		return err
 	}
+	if err := setTermSettingsStopBits(bits, settings); err != nil {
+		return err
+	}
+	return port.setTermSettings(settings)
+}
+
+func setTermSettingsStopBits(bits StopBits, settings *syscall.Termios) error {
 	switch bits {
 	case STOPBITS_ONE:
 		settings.Cflag &= ^uint32(syscall.CSTOPB)
 	case STOPBITS_ONEPOINTFIVE, STOPBITS_TWO:
 		settings.Cflag |= syscall.CSTOPB
 	}
-	return port.setTermSettings(settings)
+	return nil
 }
 
 // native syscall wrapper functions