rotctl: do range validation

This is at the interface layer though it should arguably be done at the
controller layer. Oh well.

src/Config.zig

@@ -37,6 +37,15 @@ rotctl: RotControlConfig = .{
 labjack: LabjackConfig = .{
     .device = .autodetect,
     .feedback_calibration = .{
+        // NOTE: these min and max angles are treated as hardware limits. This serves
+        //       two purposes: first, it means that feedback is always interpolated,
+        //       never extrapolated (though with a two point calibration, that doesn't
+        //       matter much). Second, it prevents having a redundant set of bounds
+        //       values that could potentially desync from these and cause problems.
+        //
+        // The functional min and max are these plus the angle offset values. For
+        // example, given controller.angle_offset.azimuth = -6, the practical minimum
+        // azimuth would be -6 deg and the practical maximum would be 444 deg.
         .azimuth = .{
             .minimum = .{ .voltage = 0.0, .angle = 0.0 },
             .maximum = .{ .voltage = 5.0, .angle = 450.0 },

src/RotCtl.zig

@@ -1,6 +1,7 @@
 const std = @import("std");
 
-const config = @import("./Config.zig").global;
+const Config = @import("./Config.zig");
+const config = Config.global;
 const LabjackYaesu = @import("./LabjackYaesu.zig");
 
 const RotCtl = @This();
@@ -113,6 +114,27 @@ fn getPosition(self: *RotCtl, _: []const u8, tokens: *TokenIter) CommandError!vo
     self.printReply("{d:.1}\n{d:.1}", .{ pos.azimuth, pos.elevation }) catch return error.BadOutput;
 }
 
+fn inRange(request: f64, comptime dof: enum { azimuth, elevation }) bool {
+    return switch (dof) {
+        // zig fmt: off
+        .azimuth => request >= (
+                  config.labjack.feedback_calibration.azimuth.minimum.angle
+                + config.controller.angle_offset.azimuth
+            ) and request <= (
+                  config.labjack.feedback_calibration.azimuth.maximum.angle
+                + config.controller.angle_offset.azimuth
+        ),
+        .elevation => request >= (
+                  config.labjack.feedback_calibration.elevation.minimum.angle
+                + config.controller.angle_offset.elevation
+            ) and request <= (
+                  config.labjack.feedback_calibration.elevation.maximum.angle
+                + config.controller.angle_offset.elevation
+        ),
+        // zig fmt: on
+    };
+}
+
 fn setPosition(self: *RotCtl, _: []const u8, tokens: *TokenIter) CommandError!void {
     const azimuth = std.fmt.parseFloat(f64, tokens.next() orelse {
         return self.replyStatus(.invalid_parameter) catch error.BadOutput;
@@ -120,12 +142,18 @@ fn setPosition(self: *RotCtl, _: []const u8, tokens: *TokenIter) CommandError!vo
         return self.replyStatus(.invalid_parameter) catch error.BadOutput;
     };
 
+    if (!inRange(azimuth, .azimuth))
+        return self.replyStatus(.invalid_parameter) catch error.BadOutput;
+
     const elevation = std.fmt.parseFloat(f64, tokens.next() orelse {
         return self.replyStatus(.invalid_parameter) catch error.BadOutput;
     }) catch {
         return self.replyStatus(.invalid_parameter) catch error.BadOutput;
     };
 
+    if (!inRange(elevation, .elevation))
+        return self.replyStatus(.invalid_parameter) catch error.BadOutput;
+
     self.rotator.setTarget(.{ .azimuth = azimuth, .elevation = elevation });
     return self.replyStatus(.okay) catch error.BadOutput;
 }