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[batteryviewer] / batteryviewer.c
1 #include "chart.h"
2 #include <ctype.h>
3 #include <errno.h>
4 #include <gtk/gtk.h>
5 #include <math.h>
6 #include <stdio.h>
7 #include <stdlib.h>
8
9 const char voltage_filename[] = "/sys/class/power_supply/BAT0/voltage_now";
10 const char current_filename[] = "/sys/class/power_supply/BAT0/current_now";
11
12 struct State {
13 BVChart *voltage;
14 BVChart *current;
15 };
16
17 static float fatof(const char *filename) {
18 FILE *f = fopen(filename, "r");
19 if (f == NULL) {
20 return NAN;
21 }
22
23 const int bufsize = 1024;
24 char buf[bufsize];
25 const int read = fread(buf, sizeof(char), bufsize, f);
26 if (read == 0 || read == bufsize || ferror(f)) {
27 fclose(f);
28 return NAN;
29 }
30 fclose(f);
31
32 char *end;
33 errno = 0;
34 float val = strtof(buf, &end);
35 int parsed = end - buf;
36 gboolean parsed_all = parsed == read;
37 gboolean parsed_all_but_space = parsed == read - 1 && isspace(*end);
38 gboolean parse_ok = parsed_all || parsed_all_but_space;
39 if (errno != 0 || parsed == 0 || !parse_ok) {
40 return NAN;
41 }
42 return val;
43 }
44
45 static gboolean collect_data(struct State *state __attribute__((unused))) {
46 fprintf(stderr, "Voltage: %f, current: %f\n", fatof(voltage_filename),
47 fatof(current_filename));
48 return TRUE;
49 }
50
51 static void activate(GtkApplication *app, gpointer user_data) {
52
53 GtkWidget *window = gtk_application_window_new(app);
54 gtk_window_set_title(GTK_WINDOW(window), "BatteryViewer");
55 gtk_window_set_default_size(GTK_WINDOW(window), 200, 200);
56
57 GtkWidget *box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 1);
58 gtk_container_add(GTK_CONTAINER(window), box);
59
60 struct State *state = (struct State *)user_data;
61 state->voltage = BV_CHART(bv_chart_new());
62 bv_chart_add_point(state->voltage, 0.0, 0.0);
63 bv_chart_add_point(state->voltage, 1.0, 1.0);
64 bv_chart_add_point(state->voltage, 3.0, 2.0);
65 gboolean expand = TRUE;
66 gboolean fill = TRUE;
67 guint padding = 0;
68 gtk_box_pack_start(GTK_BOX(box), GTK_WIDGET(state->voltage), expand, fill,
69 padding);
70
71 state->current = BV_CHART(bv_chart_new());
72 bv_chart_add_point(state->current, 0.0, 1.0);
73 bv_chart_add_point(state->current, 1.0, 0.0);
74 gtk_box_pack_end(GTK_BOX(box), GTK_WIDGET(state->current), expand, fill,
75 padding);
76
77 gtk_widget_show_all(window);
78
79 g_timeout_add_seconds(1, (GSourceFunc)collect_data, user_data);
80 }
81
82 int main(int argc, char **argv) {
83 struct State state;
84
85 GtkApplication *app = gtk_application_new("com.scottworley.batteryviewer",
86 G_APPLICATION_DEFAULT_FLAGS);
87 g_signal_connect(app, "activate", G_CALLBACK(activate), &state);
88 int status = g_application_run(G_APPLICATION(app), argc, argv);
89 g_object_unref(app);
90
91 return status;
92 }