Finish work on CPU widget.

src/main.zig

@@ -9,7 +9,7 @@ const weatherWidget = @import("widgets/weather/weather.zig");
 const timeWidget = @import("widgets/time/time.zig");
 const batteryWidget = @import("widgets/battery/battery.zig");
 const memoryWidget = @import("widgets/memory/memory.zig");
-const cpuWidget = @import("widgets/memory/memory.zig");
+const cpuWidget = @import("widgets/cpu/cpu.zig");
 
 const DebugAllocator = @import("debug_allocator.zig");
 const Info = @import("types/info.zig");
@@ -32,11 +32,11 @@ pub fn main() !void {
     const widgets = [_]*Widget{
         //&Widget.init(&textWidget.New("owo", "potato")), // 4KiB
         //&Widget.init(&textWidget.New("uwu", "tomato")), // 4KiB
-        &Widget.init(&cpuWidget.New(&br)), // Unknown
-        &Widget.init(&memoryWidget.New(&br)), // 4.08KiB
-        &Widget.init(&weatherWidget.New(allocator, &br, @import("build_options").weather_location)), // 16.16KiB
-        &Widget.init(&batteryWidget.New(allocator, &br)), // 12.11KiB
-        &Widget.init(&timeWidget.New(allocator, &br)), // 32.46KiB
+        &Widget.init(&cpuWidget.New(&br)), // 4.08KiB
+        //&Widget.init(&memoryWidget.New(&br)), // 4.08KiB
+        //&Widget.init(&weatherWidget.New(allocator, &br, @import("build_options").weather_location)), // 16.16KiB
+        //&Widget.init(&batteryWidget.New(allocator, &br)), // 12.11KiB
+        //&Widget.init(&timeWidget.New(allocator, &br)), // 32.46KiB
     };
     bar.widgets = widgets[0..];
     try br.start();

src/widgets/cpu/cpu.zig

@@ -4,8 +4,63 @@ const Bar = @import("../../types/bar.zig").Bar;
 const colour = @import("../../formatting/colour.zig").colour;
 const comptimeColour = @import("../../formatting/colour.zig").comptimeColour;
 const MouseEvent = @import("../../types/mouseevent.zig");
-const LoopingCounter = @import("../../types/loopingcounter.zig").LoopingCounter;
 
+fn formatCPUPercent(allocator: *std.mem.Allocator, percent: f64) ![]const u8 {
+    var percentColour: []const u8 = "";
+    if (percent > 80) {
+        percentColour = "red";
+    } else if (percent > 60) {
+        percentColour = "orange";
+    } else if (percent > 30) {
+        percentColour = "yellow";
+    } else {
+        percentColour = "green";
+    }
+    const percentString = try std.fmt.allocPrint(allocator, "{d:.2}" ++ comptimeColour("accentdark", "%"), .{ percent });
+
+    return colour(allocator, percentColour, percentString);
+}
+
+fn parseFloat(buf: []const u8) !f64 {
+    return try std.fmt.parseFloat(f64, buf);
+}
+
+fn fetchCPU() ![2]f64 {
+    var stat_file = try std.fs.cwd().openFile("/proc/stat", .{ .read = true, .write = false });
+    defer stat_file.close();
+    // data[0] = idle usage
+    // data[1] = non-idle usage
+    var data: [2]f64 = [2]f64{0.0,0.0};
+
+    var line_buffer: [128]u8 = undefined;
+    const line_opt = try stat_file.inStream().readUntilDelimiterOrEof(&line_buffer, '\n');
+    if (line_opt) |line| {
+        var it = std.mem.tokenize(line, " ");
+        const stat_type = it.next().?;
+        if (!std.mem.eql(u8, stat_type, "cpu")) {
+            std.debug.print("First stat line wasn't CPU, Add while loop to find it.\n", .{});
+            unreachable;
+        }
+        // Here are the fields.
+        // Ones marked with (i) are idle.
+        // The order for these is:
+        // user nice system idle(i) iowait(i) irq softirq steal guest guest_nice
+        data[1] += try parseFloat(it.next().?); // user
+        data[1] += try parseFloat(it.next().?); // nice
+        data[1] += try parseFloat(it.next().?); // system
+        data[0] += try parseFloat(it.next().?); // idle
+        data[0] += try parseFloat(it.next().?); // iowait
+        data[1] += try parseFloat(it.next().?); // irq
+        data[1] += try parseFloat(it.next().?); // softirq
+        data[1] += try parseFloat(it.next().?); // steal
+        data[1] += try parseFloat(it.next().?); // guest
+        data[1] += try parseFloat(it.next().?); // guest_nice
+    } else {
+        unreachable;
+    }
+
+    return data;
+}
 
 pub const CPUWidget = struct {
     bar: *Bar,
@@ -23,12 +78,41 @@ pub const CPUWidget = struct {
     pub fn mouse_event(self: *CPUWidget, event: MouseEvent) void {}
 
     fn update_bar(self: *CPUWidget) !void {
+        // We need to calculate the difference between readings to get a more accurate reading.
+        // In order to do this we need a time difference.
+        const previous_stats = try fetchCPU();
+        std.time.sleep(1000 * std.time.ns_per_ms);
+        const next_stats = try fetchCPU();
+        // Reminder that for data:
+        // data[0] = idle usage
+        // data[1] = non-idle usage
+        const previous_total = previous_stats[0] + previous_stats[1];
+        const next_total = next_stats[0] + next_stats[1];
+        // Get the differences.
+        const total_difference = next_total - previous_total;
+        const idle_difference = next_stats[0] - previous_stats[0];
+        // Work out CPU Percentage.
+        const percentage = ((total_difference - idle_difference)/total_difference)*100;
+
+
+        var buffer: [256]u8 = undefined;
+        var fba = std.heap.FixedBufferAllocator.init(&buffer);
+        var allocator = &fba.allocator;
+        try self.bar.add(Info{
+            .name = "cpu",
+            .full_text = try std.fmt.allocPrint(allocator, "{} {}", .{
+                comptimeColour("accentlight", "cpu"),
+                formatCPUPercent(allocator, percentage),
+            }),
+            .markup = "pango",
+        });
     }
 
     pub fn start(self: *CPUWidget) anyerror!void {
-        //while (self.bar.keep_running()) {
-        //    self.update_bar() catch {};
-        //}
+        //try self.update_bar();
+        while (self.bar.keep_running()) {
+            try self.update_bar();
+        }
     }
 };
 

src/widgets/memory/memory.zig

@@ -35,8 +35,7 @@ fn formatMemoryPercent(allocator: *std.mem.Allocator, percent: f64) ![]const u8
     } else {
         percentColour = "green";
     }
-    const percentString = try std.fmt.allocPrint(allocator, "{d:.3}{}", .{ percent, comptimeColour("accentdark", "%") });
-
+    const percentString = try std.fmt.allocPrint(allocator, "{d:.2}" ++ comptimeColour("accentdark", "%"), .{ percent });
     return colour(allocator, percentColour, percentString);
 }