Abgabe

kawaii/gpio.cpp

@@ -0,0 +1,109 @@
+#include "gpio.hpp"
+
+#include <fstream>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+
+using namespace std;
+
+static string construct_filename(const string &prefix, int pin, const string &suffix)
+{
+	stringstream filename;
+	filename << prefix << pin << suffix;
+	return filename.str();
+}
+
+gpio::gpio(int pin, pin_direction direction, pin_type type, bool default_state)
+	: pin(pin),
+	  direction(direction),
+	  type(type),
+	  current_state(false)
+{
+	ofstream export_file("/sys/class/gpio/export");
+	export_file << pin;
+	export_file.close();
+	ofstream direction_file(construct_filename("/sys/class/gpio/gpio", pin, "/direction").c_str());
+	if (direction == pin_direction::INPUT)
+	{
+		direction_file << "in";
+	}
+	else
+	{
+		direction_file << "out";
+	}
+	direction_file.close();
+	if (direction == pin_direction::OUTPUT)
+	{
+		set_value(default_state, false);
+	}
+}
+
+gpio::gpio(gpio&& old)
+	: pin(old.pin),
+	  direction(old.direction),
+	  type(old.type),
+	  current_state(old.current_state)
+{
+	old.pin = -1;
+}
+
+gpio::~gpio()
+{
+	if (pin != -1)
+	{
+		ofstream unexport_file("/sys/class/gpio/unexport");
+		unexport_file << pin;
+	}
+}
+
+void gpio::set_value(bool on, bool use_cache)
+{
+	if (pin == -1)
+		throw logic_error("Usage of moved gpio");
+	if (direction == pin_direction::INPUT)
+	{
+		stringstream errormsg;
+		errormsg << "Cannot write to input pin " << pin;
+		throw logic_error(errormsg.str());
+	}
+	if (!use_cache || current_state != on)
+	{
+		bool value;
+		if (type == pin_type::HIGH_ON)
+			value = on;
+		else
+			value = !on;
+		ofstream value_file(construct_filename("/sys/class/gpio/gpio", pin, "/value"));
+		value_file << value;
+	}
+	current_state = on;
+}
+
+void gpio::set_value(bool on)
+{
+	set_value(on, true);
+}
+
+bool gpio::get_value()
+{
+	if (pin == -1)
+		throw logic_error("Usage of moved gpio");
+	if (direction == pin_direction::OUTPUT)
+		return current_state;
+	ifstream value_file(construct_filename("/sys/class/gpio/gpio", pin, "/value"));
+	bool value;
+	value_file >> value;
+	bool on;
+	if (type == pin_type::HIGH_ON)
+		on = value;
+	else
+		on = !value;
+	return on;
+}
+
+int gpio::get_pin() const
+{
+	return pin;
+}
+