80 lines
2.0 KiB
Zig
80 lines
2.0 KiB
Zig
const std = @import("std");
|
|
const Self = @This();
|
|
|
|
fh: std.fs.File,
|
|
buf: []u8,
|
|
stats: Stats,
|
|
perc: u8 = 0,
|
|
|
|
pub fn init(self: *Self, alloc: std.mem.Allocator) !void {
|
|
self.fh = try std.fs.openFileAbsolute("/proc/stat", .{ .mode = .read_only });
|
|
errdefer self.fh.close();
|
|
|
|
self.buf = try alloc.alloc(u8, 256);
|
|
errdefer alloc.free(self.buf);
|
|
|
|
self.stats = try self.get();
|
|
}
|
|
|
|
pub const Stats = struct {
|
|
all: u32,
|
|
all_idle: u32,
|
|
all_active: u32,
|
|
};
|
|
|
|
pub fn update(self: *Self) ![]const u8 {
|
|
const delta = try self.get_delta();
|
|
if (delta.all != 0) {
|
|
self.perc = @intCast(@divFloor(1 + 2 * 100 * delta.all_active, 2 * delta.all));
|
|
}
|
|
return try std.fmt.bufPrint(self.buf, "cpu: {d:0>2}%", .{self.perc});
|
|
}
|
|
|
|
pub fn deinit(self: Self, alloc: std.mem.Allocator) void {
|
|
self.fh.close();
|
|
alloc.free(self.buf);
|
|
}
|
|
|
|
fn get(self: Self) !Stats {
|
|
try self.fh.seekTo(0);
|
|
const line = try self.fh.reader().readUntilDelimiter(self.buf, '\n');
|
|
|
|
var tokens = std.mem.tokenizeScalar(u8, line, ' ');
|
|
_ = tokens.next(); // skip "cpu"
|
|
|
|
var raw: struct {
|
|
user: u32,
|
|
nice: u32,
|
|
system: u32,
|
|
idle: u32,
|
|
iowait: u32,
|
|
irq: u32,
|
|
softirq: u32,
|
|
steal: u32,
|
|
guest: u32,
|
|
guest_nice: u32,
|
|
} = undefined;
|
|
|
|
inline for (std.meta.fields(@TypeOf(raw))) |f| {
|
|
const token = tokens.next() orelse return error.MissingStat;
|
|
@field(raw, f.name) = try std.fmt.parseInt(f.type, token, 10);
|
|
}
|
|
|
|
const idle = raw.idle + raw.iowait;
|
|
const active = raw.user + raw.nice + raw.system + raw.irq + raw.softirq + raw.steal;
|
|
|
|
return .{ .all = idle + active, .all_idle = idle, .all_active = active };
|
|
}
|
|
|
|
fn get_delta(self: *Self) !Stats {
|
|
const prev = self.stats;
|
|
const next = try self.get();
|
|
self.stats = next;
|
|
|
|
return .{
|
|
.all = next.all - prev.all,
|
|
.all_idle = next.all_idle - prev.all_idle,
|
|
.all_active = next.all_active - prev.all_active,
|
|
};
|
|
}
|