readme: the Windows situation has been altered

Pray I do not alter it further.

src/Config.zig

@@ -92,7 +92,6 @@ pub fn validate(self: Config, err_writer: anytype) !void {
 rotctl: RotControlConfig = .{
     .listen_address = "127.0.0.1",
     .listen_port = 4533,
-    .autopark = false,
 },
 labjack: LabjackConfig = .{
     .device = .autodetect,
@@ -128,7 +127,6 @@ controller: ControllerConfig = .{
     // this is a symmetric mask, so the minimum usable elevation is elevation_mask deg
     // and the maximum usable elevation is 180 - elevation_mask deg
     .elevation_mask = 0.0,
-    .feedback_window_samples = 3,
 },
 
 pub const VoltAngle = struct { voltage: f64, angle: f64 };
@@ -152,7 +150,6 @@ pub const MinMax = struct {
 const RotControlConfig = struct {
     listen_address: []const u8,
     listen_port: u16,
-    autopark: bool,
 };
 
 const LabjackConfig = struct {
@@ -182,8 +179,6 @@ const ControllerConfig = struct {
     angle_offset: AzEl,
     elevation_mask: f64,
 
-    feedback_window_samples: u8,
-
     const OutPair = struct {
         increase: lj.DigitalOutputChannel,
         decrease: lj.DigitalOutputChannel,

src/RotCtl.zig

@@ -10,9 +10,12 @@ const log = std.log.scoped(.RotCtl);
 
 writer: std.io.BufferedWriter(512, std.net.Stream.Writer),
 running: bool,
-rotator: *YaesuController,
+rotator: YaesuController,
 
 pub fn run(allocator: std.mem.Allocator) !void {
+    // var server = std.net.StreamServer.init(.{ .reuse_address = true });
+    // defer server.deinit();
+
     const listen_addr = try std.net.Address.parseIp(
         config.rotctl.listen_address,
         config.rotctl.listen_port,
@@ -27,19 +30,20 @@ pub fn run(allocator: std.mem.Allocator) !void {
     var interface: RotCtl = .{
         .writer = undefined,
         .running = true,
-        .rotator = try YaesuController.create(allocator),
+        .rotator = try YaesuController.init(allocator),
     };
 
-    while (interface.running) {
+    while (true) {
         const client = try server.accept();
         defer {
             log.info("disconnecting client", .{});
-            if (!config.rotctl.autopark)
-                interface.rotator.stop();
+            interface.rotator.stop();
             client.stream.close();
         }
 
         interface.writer = .{ .unbuffered_writer = client.stream.writer() };
+        interface.running = true;
+        defer interface.running = false;
 
         log.info("client connected from {}", .{client.address});
 
@@ -56,13 +60,7 @@ pub fn run(allocator: std.mem.Allocator) !void {
                 std.mem.trim(u8, fbs.getWritten(), &std.ascii.whitespace),
             ) catch break;
         }
-
-        // loop ended due to client disconnect
-        if (interface.running and config.rotctl.autopark)
-            interface.rotator.startPark();
     }
-
-    interface.rotator.control_thread.join();
 }
 
 fn write(self: *RotCtl, buf: []const u8) !void {
@@ -174,6 +172,7 @@ fn handleHamlibCommand(
     if (first.len == 1 or first[0] == '\\') {
         switch (first[0]) {
             // NOTE: this is not technically supported by rotctld.
+            'q', 'Q' => try self.quit(first, &tokens),
             'S' => try self.stop(first, &tokens),
             'K' => try self.park(first, &tokens),
             'p' => try self.getPosition(first, &tokens),
@@ -244,8 +243,8 @@ const HamlibCommand = struct {
 };
 
 const rotctl_commands = [_]HamlibCommand{
-    .{ .long = "quit", .callback = quit },
-    .{ .long = "exit", .callback = quit },
+    .{ .short = 'q', .callback = quit }, // quit
+    .{ .short = 'Q', .callback = quit }, // quit
     .{ .long = "AOS", .callback = blindAck },
     .{ .long = "LOS", .callback = blindAck },
     .{ .short = 'P', .long = "set_pos", .callback = setPosition }, // azimuth: f64, elevation: f64

src/YaesuController.zig

@@ -8,8 +8,6 @@ const log = std.log.scoped(.yaesu_controller);
 
 const YaesuController = @This();
 
-pub var singleton: ?*YaesuController = null;
-
 control_thread: std.Thread,
 lock: *std.Thread.Mutex,
 controller: *const Controller,
@@ -25,7 +23,7 @@ pub const CalibrationRoutine = enum {
 };
 
 pub fn calibrate(allocator: std.mem.Allocator, routine: CalibrationRoutine) !void {
-    const controller = try YaesuController.create(allocator);
+    const controller = try YaesuController.init(allocator);
     defer {
         controller.quit();
         controller.control_thread.join();
@@ -37,29 +35,22 @@ pub fn calibrate(allocator: std.mem.Allocator, routine: CalibrationRoutine) !voi
     }
 }
 
-pub fn create(allocator: std.mem.Allocator) !*YaesuController {
-    if (singleton) |_| {
-        log.err("Controller singleton already exists.", .{});
-        return error.AlreadyInitialized;
-    }
+pub fn init(allocator: std.mem.Allocator) !YaesuController {
+    const lock = try allocator.create(std.Thread.Mutex);
+    errdefer allocator.destroy(lock);
+    lock.* = .{};
 
     const controller = try allocator.create(Controller);
     errdefer allocator.destroy(controller);
-    controller.* = try Controller.init(allocator);
-    errdefer controller.deinit(allocator);
+    controller.init(lock);
     // do this in the main thread so we can throw the error about it synchronously.
     try controller.connectLabjack();
 
-    const self = try allocator.create(YaesuController);
-    errdefer allocator.destroy(self);
-    self.* = .{
+    return .{
         .control_thread = try std.Thread.spawn(.{}, runController, .{controller}),
-        .lock = &controller.lock,
+        .lock = lock,
         .controller = controller,
     };
-
-    singleton = self;
-    return self;
 }
 
 fn inRange(request: f64, comptime dof: enum { azimuth, elevation }) bool {
@@ -100,7 +91,7 @@ pub fn setTarget(self: YaesuController, target: AzEl) error{OutOfRange}!void {
 
     const controller = @constCast(self.controller);
     controller.target = masked_target;
-    controller.requestState(.running);
+    controller.requested_state = .running;
 }
 
 pub fn currentPosition(self: YaesuController) AzEl {
@@ -110,15 +101,16 @@ pub fn currentPosition(self: YaesuController) AzEl {
     return self.controller.position;
 }
 
-pub fn waitForUpdate(self: YaesuController) AzEl {
-    const controller = @constCast(self.controller);
-
-    self.lock.lock();
-    defer self.lock.unlock();
-
-    controller.condition.wait(self.lock);
-
-    return controller.position;
+pub fn startCalibration(self: YaesuController) void {
+    // there are two different types of calibration:
+    // 1. feedback calibration, running to the extents of the rotator
+    // 2. sun calibration, which determines the azimuth and elevation angle
+    //    offset between the rotator's physical stops and geodetic north
+    //
+    // The former is (fairly) trivial to automate, just run until stall
+    // (assuming there's no deadband in the feedback). The latter requires
+    // manual input as the human is the feedback hardware in the loop.
+    _ = self;
 }
 
 pub fn quit(self: YaesuController) void {
@@ -126,7 +118,7 @@ pub fn quit(self: YaesuController) void {
     defer self.lock.unlock();
 
     const controller = @constCast(self.controller);
-    controller.requestState(.stopped);
+    controller.requested_state = .stopped;
 }
 
 pub fn stop(self: YaesuController) void {
@@ -135,7 +127,7 @@ pub fn stop(self: YaesuController) void {
 
     const controller = @constCast(self.controller);
     controller.target = controller.position;
-    controller.requestState(.idle);
+    controller.requested_state = .idle;
 }
 
 pub fn startPark(self: YaesuController) void {
@@ -163,77 +155,16 @@ fn runController(controller: *Controller) void {
     };
 }
 
-const FeedbackBuffer = struct {
-    samples: []f64,
-    index: usize = 0,
-
-    fn initZero(allocator: std.mem.Allocator, samples: usize) !FeedbackBuffer {
-        const buf = try allocator.alloc(f64, samples * 2);
-        @memset(buf, 0);
-        return .{ .samples = buf };
-    }
-
-    fn deinit(self: FeedbackBuffer, allocator: std.mem.Allocator) void {
-        allocator.free(self.samples);
-    }
-
-    fn push(self: *FeedbackBuffer, sample: [2]lj.AnalogReadResult) void {
-        const halfpoint = @divExact(self.samples.len, 2);
-        defer self.index = (self.index + 1) % halfpoint;
-
-        self.samples[self.index] = sample[0].voltage;
-        self.samples[self.index + halfpoint] = sample[1].voltage;
-    }
-
-    inline fn mean(data: []f64) f64 {
-        var accum: f64 = 0;
-        for (data) |pt| {
-            accum += pt;
-        }
-        return accum / @as(f64, @floatFromInt(data.len));
-    }
-
-    fn lerp(input: f64, cal_points: Config.MinMax) f64 {
-        return (input - cal_points.minimum.voltage) * cal_points.slope() + cal_points.minimum.angle;
-    }
-
-    fn get(self: FeedbackBuffer) AzEl {
-        const halfpoint = @divExact(self.samples.len, 2);
-
-        return .{
-            .azimuth = lerp(
-                mean(self.samples[0..halfpoint]),
-                config.labjack.feedback_calibration.azimuth,
-            ) + config.controller.angle_offset.azimuth,
-            .elevation = lerp(
-                mean(self.samples[halfpoint..]),
-                config.labjack.feedback_calibration.elevation,
-            ) + config.controller.angle_offset.elevation,
-        };
-    }
-
-    fn getRaw(self: FeedbackBuffer) AzEl {
-        const halfpoint = @divExact(self.samples.len, 2);
-        return .{
-            .azimuth = mean(self.samples[0..halfpoint]),
-            .elevation = mean(self.samples[halfpoint..]),
-        };
-    }
-};
-
 const Controller = struct {
     target: AzEl,
     position: AzEl,
-    feedback_buffer: FeedbackBuffer,
 
     current_state: ControllerState,
     requested_state: ControllerState,
 
+    lock: *std.Thread.Mutex,
     labjack: lj.Labjack,
 
-    lock: std.Thread.Mutex = .{},
-    condition: std.Thread.Condition = .{},
-
     const ControllerState = enum {
         initializing,
         idle,
@@ -242,13 +173,13 @@ const Controller = struct {
         stopped,
     };
 
-    fn init(allocator: std.mem.Allocator) !Controller {
-        return .{
+    fn init(self: *Controller, lock: *std.Thread.Mutex) void {
+        self.* = .{
             .target = .{ .azimuth = 0, .elevation = 0 },
             .position = .{ .azimuth = 0, .elevation = 0 },
-            .feedback_buffer = try FeedbackBuffer.initZero(allocator, config.controller.feedback_window_samples),
             .current_state = .stopped,
             .requested_state = .idle,
+            .lock = lock,
             .labjack = switch (config.labjack.device) {
                 .autodetect => lj.Labjack.autodetect(),
                 .serial_number => |sn| lj.Labjack.with_serial_number(sn),
@@ -256,28 +187,12 @@ const Controller = struct {
         };
     }
 
-    fn deinit(self: Controller, allocator: std.mem.Allocator) void {
-        self.feedback_buffer.deinit(allocator);
-    }
-
     fn connectLabjack(self: *Controller) !void {
         const info = try self.labjack.connect();
         try self.labjack.setAllDigitalOutputLow();
         self.labjack.id = info.local_id;
     }
 
-    // this function is run with the lock already acquired
-    fn propagateState(self: *Controller) void {
-        if (self.current_state == .stopped) return;
-        self.current_state = self.requested_state;
-    }
-
-    // this function is run with the lock already acquired
-    fn requestState(self: *Controller, request: ControllerState) void {
-        if (self.current_state == .stopped) return;
-        self.requested_state = request;
-    }
-
     fn lerpOne(input: f64, cal_points: Config.MinMax) f64 {
         return (input - cal_points.minimum.voltage) * cal_points.slope() + cal_points.minimum.angle;
     }
@@ -318,23 +233,26 @@ const Controller = struct {
             .positive;
     }
 
-    fn updateFeedback(self: *Controller) !void {
-        const inputs = .{
-            config.controller.azimuth_input,
-            config.controller.elevation_input,
-        };
+    fn updateAzEl(self: *const Controller) !AzEl {
+        const inputs = .{ config.controller.azimuth_input, config.controller.elevation_input };
 
         const raw = try self.labjack.readAnalogWriteDigital(
             2,
             inputs,
-            null,
+            .{false} ** 4,
             true,
         );
 
-        self.feedback_buffer.push(raw);
+        return lerpAndOffsetAngles(raw);
     }
 
-    fn drive(self: *const Controller, pos_error: AzEl) !void {
+    fn drive(self: *const Controller, pos_error: AzEl) !AzEl {
+        // NOTE: feedback will be roughly config.controller.loop_interval_ns out of
+        //       date. For high loop rates, this shouldn't be an issue.
+
+        const inputs = .{ config.controller.azimuth_input, config.controller.elevation_input };
+        var drive_signal: [4]bool = .{false} ** 4;
+
         const azsign = signDeadzone(
             pos_error.azimuth,
             config.controller.angle_tolerance.azimuth,
@@ -345,111 +263,108 @@ const Controller = struct {
             config.controller.angle_tolerance.elevation,
         );
 
-        var drive_signal: [4]bool = .{false} ** 4;
         drive_signal[config.controller.azimuth_outputs.increase.io] = azsign == .positive;
         drive_signal[config.controller.azimuth_outputs.decrease.io] = azsign == .negative;
         drive_signal[config.controller.elevation_outputs.increase.io] = elsign == .positive;
         drive_signal[config.controller.elevation_outputs.decrease.io] = elsign == .negative;
 
-        const raw = self.feedback_buffer.getRaw();
+        const raw = try self.labjack.readAnalogWriteDigital(2, inputs, drive_signal, true);
+        const angles = lerpAndOffsetAngles(raw);
 
         log.info(
             // -180.1 is 6 chars. -5.20 is 5 chars
             "az: {d: >6.1}° ({d: >5.2} V) Δ {d: >6.1}° => {u}, el: {d: >6.1}° ({d: >5.2} V) Δ {d: >6.1}° => {u}",
             .{
-                self.position.azimuth,
-                raw.azimuth,
+                angles.azimuth,
+                raw[0].voltage,
                 pos_error.azimuth,
                 azsign.symbol(),
-                self.position.elevation,
-                raw.elevation,
+                angles.elevation,
+                raw[1].voltage,
                 pos_error.elevation,
                 elsign.symbol(),
             },
         );
-
-        try self.labjack.writeIoLines(drive_signal);
-    }
-
-    fn setPosition(self: *Controller, position: AzEl) void {
-        self.position = position;
-        self.condition.broadcast();
+        return angles;
     }
 
     fn run(self: *Controller) !void {
         self.current_state = .initializing;
 
-        var timer = LoopTimer.init(config.controller.loop_interval_ns);
+        var timer: LoopTimer = .{ .interval_ns = config.controller.loop_interval_ns };
 
-        while (timer.mark()) : (timer.sleep()) {
-            const fbfail = if (self.updateFeedback()) |_| false else |_| true;
-
-            {
-                self.lock.lock();
-                defer self.lock.unlock();
-
-                self.setPosition(self.feedback_buffer.get());
-                if (fbfail) self.requestState(.stopped);
-                self.propagateState();
-            }
-
-            switch (self.current_state) {
-                .initializing, .idle => {},
-                .calibration => {
+        while (timer.mark()) : (timer.sleep()) switch (self.current_state) {
+            .initializing, .idle => {
+                const pos = self.updateAzEl() catch {
                     self.lock.lock();
                     defer self.lock.unlock();
 
-                    // run calibration routine. psych, this does nothing. gottem
-                    self.current_state = .idle;
-                    self.requestState(.idle);
-                },
-                .running => {
-                    const pos_error: AzEl = blk: {
-                        self.lock.lock();
-                        defer self.lock.unlock();
+                    self.current_state = .stopped;
+                    continue;
+                };
 
-                        break :blk .{
-                            .azimuth = self.target.azimuth - self.position.azimuth,
-                            .elevation = self.target.elevation - self.position.elevation,
-                        };
+                self.lock.lock();
+                defer self.lock.unlock();
+
+                self.position = pos;
+                self.current_state = self.requested_state;
+            },
+            .calibration => {
+                self.lock.lock();
+                defer self.lock.unlock();
+
+                // run calibration routine. psych, this does nothing. gottem
+                self.current_state = .idle;
+                self.requested_state = self.current_state;
+            },
+            .running => {
+                const pos_error: AzEl = blk: {
+                    self.lock.lock();
+                    defer self.lock.unlock();
+
+                    break :blk .{
+                        .azimuth = self.target.azimuth - self.position.azimuth,
+                        .elevation = self.target.elevation - self.position.elevation,
                     };
+                };
 
-                    self.drive(pos_error) catch {
-                        self.lock.lock();
-                        defer self.lock.unlock();
+                const pos = self.drive(pos_error) catch {
+                    self.lock.lock();
+                    defer self.lock.unlock();
 
-                        self.current_state = .stopped;
-                        continue;
-                    };
-                },
-                .stopped => {
-                    // attempt to reset the drive outputs
-                    try self.labjack.writeIoLines(.{false} ** 4);
-                    break;
-                },
-            }
-        }
+                    self.current_state = .stopped;
+                    continue;
+                };
+
+                self.lock.lock();
+                defer self.lock.unlock();
+
+                self.position = pos;
+                self.current_state = self.requested_state;
+            },
+            .stopped => {
+                // attempt to reset the drive outputs
+                _ = self.updateAzEl() catch {};
+                break;
+            },
+        };
     }
 };
 
 pub const LoopTimer = struct {
     interval_ns: u64,
-    timer: std.time.Timer,
 
-    pub fn init(interval_ns: u64) LoopTimer {
-        return .{
-            .interval_ns = interval_ns,
-            .timer = std.time.Timer.start() catch @panic("Could not create timer"),
-        };
-    }
+    start: i128 = 0,
 
     pub fn mark(self: *LoopTimer) bool {
-        self.timer.reset();
+        self.start = std.time.nanoTimestamp();
         return true;
     }
 
     pub fn sleep(self: *LoopTimer) void {
-        const elapsed = self.timer.read();
-        std.time.sleep(self.interval_ns -| elapsed);
+        const now = std.time.nanoTimestamp();
+        const elapsed: u64 = @intCast(now - self.start);
+
+        std.time.sleep(self.interval_ns - elapsed);
     }
 };

src/labjack.zig

@@ -68,30 +68,6 @@ pub const Labjack = struct {
             return status.toError();
     }
 
-    pub fn writeIoLines(self: Labjack, out: [4]bool) LabjackError!void {
-        var id = self.cId();
-
-        var d_modes: c_long = 0xFF_FF;
-        var d_outputs: c_long = 0;
-        var d_states: c_long = 0;
-        const io_modes: c_long = 0b1111;
-        var io_outputs: c_long = PackedOutput.fromBoolArray(out).toCLong();
-
-        const status = c_api.DigitalIO(
-            &id,
-            self.demo(),
-            &d_modes,
-            io_modes,
-            &d_outputs,
-            &io_outputs,
-            1, // actually update the pin modes
-            &d_states,
-        );
-
-        if (!status.okay())
-            return status.toError();
-    }
-
     /// Read one analog input channel, either single-ended or differential
     pub fn analogReadOne(self: Labjack, input: AnalogInput) LabjackError!AnalogReadResult {
         if (!input.channel.isDifferential() and input.gain_index != 0) {

src/main.zig

@@ -1,5 +1,4 @@
 const std = @import("std");
-const builtin = @import("builtin");
 
 const Config = @import("./Config.zig");
 const lj = @import("./labjack.zig");
@@ -10,62 +9,6 @@ const udev = @import("udev_rules");
 
 const log = std.log.scoped(.main);
 
-fn quit() noreturn {
-    if (YaesuController.singleton) |controller| {
-        controller.quit();
-        controller.control_thread.join();
-    }
-    std.process.exit(1);
-}
-
-const moreposix = struct {
-    pub extern "c" fn sigaddset(set: *std.posix.sigset_t, signo: c_int) c_int;
-    pub extern "c" fn sigdelset(set: *std.posix.sigset_t, signo: c_int) c_int;
-    pub extern "c" fn sigemptyset(set: *std.posix.sigset_t) c_int;
-    pub extern "c" fn sigfillset(set: *std.posix.sigset_t) c_int;
-    pub extern "c" fn sigismember(set: *const std.posix.sigset_t, signo: c_int) c_int;
-    // stdlib prototype is wrong, it doesn't take optional pointers.
-    pub extern "c" fn pthread_sigmask(how: c_int, noalias set: ?*const std.posix.sigset_t, noalias oldset: ?*std.posix.sigset_t) c_int;
-};
-
-const psigs = [_]c_int{ std.posix.SIG.INT, std.posix.SIG.HUP, std.posix.SIG.QUIT };
-
-fn posixSignalHandlerThread() void {
-    var set: std.posix.sigset_t = undefined;
-    _ = moreposix.sigemptyset(&set);
-    for (psigs) |sig|
-        _ = moreposix.sigaddset(&set, sig);
-
-    var sig: c_int = 0;
-    _ = std.posix.system.sigwait(&set, &sig);
-    log.info("Got exit signal", .{});
-    quit();
-}
-
-// Windows runs this handler in a thread, so calling quit directly should be safe.
-fn windowsEventHandler(code: std.os.windows.DWORD) callconv(std.os.windows.WINAPI) std.os.windows.BOOL {
-    _ = code;
-    log.info("Got exit signal", .{});
-    quit();
-}
-
-fn addExitHandler() !void {
-    if (comptime builtin.os.tag == .windows) {
-        try std.os.windows.SetConsoleCtrlHandler(windowsEventHandler, true);
-    } else if (comptime std.Thread.use_pthreads) {
-        var set: std.posix.sigset_t = undefined;
-        _ = moreposix.sigemptyset(&set);
-        for (psigs) |sig|
-            _ = moreposix.sigaddset(&set, sig);
-
-        _ = moreposix.pthread_sigmask(std.posix.SIG.BLOCK, &set, null);
-        // nobody cares about the thread
-        _ = try std.Thread.spawn(.{}, posixSignalHandlerThread, .{});
-    } else {
-        log.err("not windows and not pthreads = disaster", .{});
-    }
-}
-
 fn printStderr(comptime fmt: []const u8, args: anytype) void {
     std.debug.print(fmt ++ "\n", args);
 }
@@ -122,14 +65,9 @@ pub fn main() !u8 {
 
         defer Config.deinit();
 
-        addExitHandler() catch {
-            log.err("Could not install quit handler.", .{});
-            return 1;
-        };
-
         RotCtl.run(allocator) catch |err| {
             log.err("rotator controller ceased unexpectedly! {s}", .{@errorName(err)});
-            quit();
+            return 1;
         };
     } else if (std.mem.eql(u8, args[1], commands.calibrate)) {
         if (args.len < 3 or args.len > 4) {
@@ -147,14 +85,9 @@ pub fn main() !u8 {
             return 1;
         };
 
-        addExitHandler() catch {
-            log.err("Could not install quit handler.", .{});
-            return 1;
-        };
-
         YaesuController.calibrate(allocator, routine) catch |err| {
             log.err("Calibration failed: {s}", .{@errorName(err)});
-            quit();
+            return 1;
         };
     } else if (std.mem.eql(u8, args[1], commands.help)) {
         if (args.len != 3) {