Rewrite in state machine look

- Also add new option to control internal delay of programmatic key
  sequences, when they're necessary.

README.md

@@ -37,10 +37,11 @@ $ cmake --build build
 ```
 caps2esc - transforming the most useless key ever in the most useful one
 
-usage: caps2esc [-h] [-m mode]
+usage: caps2esc [-h] [-m mode] [-t delay]
 
 options:
     -h        show this message and exit
+    -t        delay used for key sequences (default: 20000 microseconds)
     -m mode   0: default
                  - caps as esc/ctrl
                  - esc as caps
@@ -117,7 +118,7 @@ As always, there's always a caveat:
 I can't recall when I started using CAPSLOCK as both ESC and CTRL but it has
 been quite some time already. It started when I was on OS X where it was quite
 easy to achieve using the [Karabiner][], which already provides an option to
-turn CTRL into CTRL/ESC (which can be coupled with OS X system settings that
+turn CTRL into ESC/CTRL (which can be coupled with OS X system settings that
 turn CAPSLOCK into CTRL).
 
 Moving on, permanently making Linux my home, I searched and tweaked a similar

caps2esc.c

@@ -6,16 +6,11 @@
 
 // clang-format off
 const struct input_event
+syn         = {.type = EV_SYN, .code = SYN_REPORT,   .value = 0},
 esc_up      = {.type = EV_KEY, .code = KEY_ESC,      .value = 0},
 ctrl_up     = {.type = EV_KEY, .code = KEY_LEFTCTRL, .value = 0},
-capslock_up     = {.type = EV_KEY, .code = KEY_CAPSLOCK, .value = 0},
 esc_down    = {.type = EV_KEY, .code = KEY_ESC,      .value = 1},
-ctrl_down       = {.type = EV_KEY, .code = KEY_LEFTCTRL, .value = 1},
+ctrl_down   = {.type = EV_KEY, .code = KEY_LEFTCTRL, .value = 1};
-capslock_down   = {.type = EV_KEY, .code = KEY_CAPSLOCK, .value = 1},
-esc_repeat      = {.type = EV_KEY, .code = KEY_ESC,      .value = 2},
-ctrl_repeat     = {.type = EV_KEY, .code = KEY_LEFTCTRL, .value = 2},
-capslock_repeat = {.type = EV_KEY, .code = KEY_CAPSLOCK, .value = 2},
-syn             = {.type = EV_SYN, .code = SYN_REPORT,   .value = 0};
 // clang-format on
 
 void print_usage(FILE *stream, const char *program) {
@@ -23,10 +18,11 @@ void print_usage(FILE *stream, const char *program) {
     fprintf(stream,
             "caps2esc - transforming the most useless key ever in the most useful one\n"
             "\n"
-            "usage: %s [-h] [-m mode]\n"
+            "usage: %s [-h] [-m mode] [-t delay]\n"
             "\n"
             "options:\n"
             "    -h        show this message and exit\n"
+            "    -t        delay used for key sequences (default: 20000 microseconds)\n"
             "    -m mode   0: default\n"
             "                 - caps as esc/ctrl\n"
             "                 - esc as caps\n"
@@ -40,11 +36,6 @@ void print_usage(FILE *stream, const char *program) {
     // clang-format on
 }
 
-int equal(const struct input_event *first, const struct input_event *second) {
-    return first->type == second->type && first->code == second->code &&
-           first->value == second->value;
-}
-
 int read_event(struct input_event *event) {
     return fread(event, sizeof(struct input_event), 1, stdin) == 1;
 }
@@ -54,22 +45,45 @@ void write_event(const struct input_event *event) {
         exit(EXIT_FAILURE);
 }
 
+void write_event_with_mode(struct input_event *event, int mode) {
+    switch (mode) {
+        case 0:
+            if (event->code == KEY_ESC)
+                event->code = KEY_CAPSLOCK;
+            break;
+        case 2:
+            switch (event->code) {
+                case KEY_ESC:
+                    event->code = KEY_GRAVE;
+                    break;
+                case KEY_GRAVE:
+                    event->code = KEY_CAPSLOCK;
+                    break;
+            }
+            break;
+    }
+    write_event(event);
+}
+
 int main(int argc, char *argv[]) {
-    int opt, mode = 0;
+    int opt, mode = 0, delay = 20000;
-    while ((opt = getopt(argc, argv, "hm:")) != -1) {
+    while ((opt = getopt(argc, argv, "ht:m:")) != -1) {
         switch (opt) {
             case 'h':
                 return print_usage(stdout, argv[0]), EXIT_SUCCESS;
+            case 't':
+                delay = atoi(optarg);
+                continue;
             case 'm':
-                mode = optarg[0] - '0';
+                mode = atoi(optarg);
                 continue;
         }
 
         return print_usage(stderr, argv[0]), EXIT_FAILURE;
     }
 
-    int capslock_is_down = 0, esc_give_up = 0;
     struct input_event input;
+    enum { START, CAPSLOCK_HELD, CAPSLOCK_IS_CTRL } state = START;
 
     setbuf(stdin, NULL), setbuf(stdout, NULL);
 
@@ -82,53 +96,40 @@ int main(int argc, char *argv[]) {
             continue;
         }
 
-        if (capslock_is_down) {
+        switch (state) {
-            if (equal(&input, &capslock_down) ||
+            case START:
-                equal(&input, &capslock_repeat))
+                if (input.code == KEY_CAPSLOCK && input.value)
-                continue;
+                    state = CAPSLOCK_HELD;
-
+                else
-            if (equal(&input, &capslock_up)) {
+                    write_event_with_mode(&input, mode);
-                capslock_is_down = 0;
+                break;
-                if (esc_give_up) {
+            case CAPSLOCK_HELD:
-                    esc_give_up = 0;
+                if (input.code == KEY_CAPSLOCK) {
-                    write_event(&ctrl_up);
+                    if (input.value == 0) {
-                    continue;
-                }
                         write_event(&esc_down);
                         write_event(&syn);
-                usleep(20000);
+                        usleep(delay);
                         write_event(&esc_up);
-                continue;
+                        state = START;
                     }
-
+                } else if (input.value == 1) {
-            if (!esc_give_up && input.value) {
-                esc_give_up = 1;
                     write_event(&ctrl_down);
                     write_event(&syn);
-                usleep(20000);
+                    usleep(delay);
-            }
+                    write_event_with_mode(&input, mode);
-        } else if (equal(&input, &capslock_down)) {
+                    state = CAPSLOCK_IS_CTRL;
-            capslock_is_down = 1;
+                } else
-            continue;
+                    write_event_with_mode(&input, mode);
-        }
-
-        switch (mode) {
-            case 0:
-                if (input.code == KEY_ESC)
-                    input.code = KEY_CAPSLOCK;
                 break;
-            case 2:
+            case CAPSLOCK_IS_CTRL:
-                switch (input.code) {
+                if (input.code == KEY_CAPSLOCK) {
-                    case KEY_ESC:
+                    input.code = KEY_LEFTCTRL;
-                        input.code = KEY_GRAVE;
-                        break;
-                    case KEY_GRAVE:
-                        input.code = KEY_CAPSLOCK;
-                        break;
-                }
-                break;
-        }
-
                     write_event(&input);
+                    if (input.value == 0)
+                        state = START;
+                } else
+                    write_event_with_mode(&input, mode);
+                break;
+        }
     }
 }