159 lines
3.4 KiB
Go
159 lines
3.4 KiB
Go
/*
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* ============================================================================
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* Projekt.....: rs2322tcp
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* Datei.......: serial.go
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* Copyright (C) 2026 Dieter Lang
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*
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* SPDX-License-Identifier: GPL-3.0-or-later
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*
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* Beschreibung:
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* Öffnet und verwaltet eine serielle Schnittstelle auf Basis der
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* konfigurierten Geräteparameter.
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* ============================================================================
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*/
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package serial
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import (
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"fmt"
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"io"
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bugserial "go.bug.st/serial"
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"git.lang-dieter.de/rs2322tcp/internal/config"
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)
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///////////////////////////////////////////////////////////////////////////////
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// Connection
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///////////////////////////////////////////////////////////////////////////////
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// Connection represents an opened serial connection.
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type Connection struct {
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port bugserial.Port
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}
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///////////////////////////////////////////////////////////////////////////////
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// Open
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///////////////////////////////////////////////////////////////////////////////
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// Open opens the serial device described by the configuration.
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func Open(device config.DeviceConfig) (*Connection, error) {
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mode, err := createMode(device)
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if err != nil {
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return nil, err
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}
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port, err := bugserial.Open(device.SerialPort, mode)
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if err != nil {
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return nil, fmt.Errorf(
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"open serial port %q: %w",
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device.SerialPort,
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err,
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)
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}
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return &Connection{
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port: port,
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}, nil
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}
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///////////////////////////////////////////////////////////////////////////////
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// Mode
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///////////////////////////////////////////////////////////////////////////////
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func createMode(device config.DeviceConfig) (*bugserial.Mode, error) {
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mode := &bugserial.Mode{
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BaudRate: device.BaudRate,
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DataBits: device.DataBits,
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Parity: bugserial.NoParity,
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StopBits: bugserial.OneStopBit,
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}
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if device.BaudRate <= 0 {
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return nil, fmt.Errorf(
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"invalid baud rate: %d",
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device.BaudRate,
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)
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}
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switch device.DataBits {
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case 5, 6, 7, 8:
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// Supported by go.bug.st/serial.
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default:
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return nil, fmt.Errorf(
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"unsupported data bits: %d",
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device.DataBits,
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)
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}
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switch device.Parity {
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case "none":
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mode.Parity = bugserial.NoParity
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case "odd":
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mode.Parity = bugserial.OddParity
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case "even":
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mode.Parity = bugserial.EvenParity
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default:
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return nil, fmt.Errorf(
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"unsupported parity: %q",
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device.Parity,
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)
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}
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switch device.StopBits {
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case 1:
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mode.StopBits = bugserial.OneStopBit
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case 2:
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mode.StopBits = bugserial.TwoStopBits
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default:
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return nil, fmt.Errorf(
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"unsupported stop bits: %d",
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device.StopBits,
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)
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}
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return mode, nil
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}
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///////////////////////////////////////////////////////////////////////////////
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// Read / Write
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///////////////////////////////////////////////////////////////////////////////
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// Read reads data from the serial connection.
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func (c *Connection) Read(p []byte) (int, error) {
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if c == nil || c.port == nil {
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return 0, io.ErrClosedPipe
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}
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return c.port.Read(p)
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}
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// Write writes data to the serial connection.
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func (c *Connection) Write(p []byte) (int, error) {
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if c == nil || c.port == nil {
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return 0, io.ErrClosedPipe
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}
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return c.port.Write(p)
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}
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///////////////////////////////////////////////////////////////////////////////
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// Close
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///////////////////////////////////////////////////////////////////////////////
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// Close closes the serial connection.
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func (c *Connection) Close() error {
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if c == nil || c.port == nil {
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return nil
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}
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err := c.port.Close()
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c.port = nil
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return err
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}
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