--- /dev/null
+/*
+ * Copyright (c) 2023, Matthew Mondor
+ * ALL RIGHTS RESERVED.
+ *
+ * Interactive curses user input test 7, derived from test 6
+ * This test adds temporary signal blocking when calling curses refresh,
+ * to avoid possible artifacts like syscalls returning EINTR because of our
+ * interrupting clock signal. An alternative would be using an auto-restart
+ * signal with SA_RESTART that takes care of all updates while taking care not
+ * to execute syscalls that are not signal handler safe.
+ *
+ * TODO
+ * - Consider another test keeping the time to determine if to delay again,
+ * instead of relying on signal interruption by an interval timer. This
+ * possibly could allow more reliable user input.
+ * - See if calling termios directly can be avoided with OSX still restoring
+ * the tty settings properly. Also look at
+ * reset_shell_mode()/reset_prog_mode(), def_shell_mode()/def_prog_mode().
+ *
+ * $ cc -Wall -O0 -g -o test7 test7.c -lcurses
+ */
+
+#include <curses.h>
+#include <err.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/time.h>
+
+
+#define TERM_COLUMNS 79
+#define TERM_LINES 24
+#define ANIM_FPS 15
+#define NOBJECTS 46
+
+
+/* Animation object */
+
+enum aobject_type {
+ AOT_AVATAR = 0,
+ AOT_STAR,
+ AOT_BUG
+};
+
+typedef struct aobject {
+ int t, x, y, col;
+ char c;
+} aobject_t;
+
+
+int main(void);
+static void cleanup(void);
+static void sighandler(int);
+static void safe_refresh(void);
+static void anim_init(void);
+static void anim_redraw(void);
+static void anim_update(void);
+
+
+/* To explicitly save/restore tty(4) state despite curses(3) */
+static struct termios old_tios;
+
+/* Curses window */
+static WINDOW *w = NULL;
+
+/* Clock */
+static bool refresh_expired = false;
+static sigset_t block_mask;
+
+/* Animation world */
+static aobject_t objects[NOBJECTS];
+static aobject_t avatar = { AOT_AVATAR,
+ TERM_COLUMNS / 2, TERM_LINES / 2,
+ 0, '?' };
+
+
+int
+main(void)
+{
+ struct sigaction act;
+ struct itimerval itv;
+ int c, uc;
+
+ /* Setup signal handler */
+ act.sa_handler = sighandler;
+ act.sa_flags = 0; /* ~SA_RESTART */
+ (void)sigemptyset(&act.sa_mask);
+ (void)sigaction(SIGALRM, &act, NULL);
+ (void)sigaction(SIGINT, &act, NULL);
+ (void)sigaction(SIGTERM, &act, NULL);
+ (void)sigaction(SIGHUP, &act, NULL);
+
+ /* Block mask */
+ (void)sigemptyset(&block_mask);
+ (void)sigaddset(&block_mask, SIGALRM);
+
+ /* Setup interval timer */
+ timerclear(&itv.it_interval);
+ timerclear(&itv.it_value);
+ itv.it_interval.tv_sec = 0;
+ itv.it_interval.tv_usec = 1000000 / ANIM_FPS;
+ itv.it_value.tv_sec = itv.it_interval.tv_sec;
+ itv.it_value.tv_usec = itv.it_interval.tv_usec;
+ if (setitimer(ITIMER_REAL, &itv, NULL) == -1)
+ goto err;
+
+ /* Setup curses */
+ (void)tcgetattr(STDIN_FILENO, &old_tios);
+ if ((w = initscr()) == NULL)
+ err(EXIT_FAILURE, "initscr()");
+ if (COLS < TERM_COLUMNS || LINES < TERM_LINES) {
+ cleanup();
+ (void)fprintf(stderr,
+ "The terminal must support at least %d columns by %d"
+ " lines for this program to work.\n",
+ TERM_COLUMNS, TERM_LINES);
+ exit(EXIT_FAILURE);
+ }
+
+ /* Exit cleanup hook to restore normal terminal */
+ (void)atexit(cleanup);
+
+ if (start_color() == ERR)
+ err(EXIT_FAILURE, "start_color()");
+ (void)init_pair(0, COLOR_WHITE, COLOR_BLACK);
+ (void)init_pair(1, COLOR_WHITE, COLOR_RED);
+ (void)init_pair(2, COLOR_WHITE, COLOR_GREEN);
+ (void)init_pair(3, COLOR_WHITE, COLOR_YELLOW);
+ (void)init_pair(4, COLOR_WHITE, COLOR_BLUE);
+ (void)init_pair(5, COLOR_WHITE, COLOR_MAGENTA);
+ (void)init_pair(6, COLOR_WHITE, COLOR_CYAN);
+ (void)init_pair(7, COLOR_WHITE, COLOR_WHITE);
+
+ (void)cbreak(); /* Use raw() if not wanting SIGINT */
+ (void)noecho();
+ (void)keypad(w, TRUE);
+ (void)timeout(-1);
+
+ /* Setup animation world */
+ anim_init();
+
+ /* Initialize screen */
+ (void)clear();
+ (void)clearok(w, FALSE);
+ safe_refresh();
+ (void)curs_set(0);
+
+ /* Animate until user requests to quit with q */
+ anim_redraw();
+ refresh_expired = false;
+ uc = -1;
+ for (;;) {
+
+ /* Blocking but SIGALRM may interrupt */
+ if ((c = wgetch(w)) != ERR)
+ uc = c;
+
+ if (refresh_expired) {
+ refresh_expired = false;
+ int x = -1, y = -1;
+
+ /* Process user input if any */
+ switch (uc) {
+ case -1:
+ break;
+ case 'q':
+ goto end;
+ break;
+
+ case KEY_UP:
+ case '8': /* FALLTHROUGH */
+ case 'i': /* FALLTHROUGH */
+ case 'a': /* FALLTHROUGH */
+ if (avatar.y > 0) {
+ y = avatar.y - 1;
+ x = avatar.x;
+ }
+ break;
+
+ case KEY_DOWN:
+ case '2': /* FALLTHROUGH */
+ case 'k': /* FALLTHROUGH */
+ case 'm': /* FALLTHROUGH */
+ case 'z': /* FALLTHROUGH */
+ if (avatar.y < TERM_LINES - 1) {
+ y = avatar.y + 1;
+ x = avatar.x;
+ }
+ break;
+
+ case KEY_LEFT:
+ case '4': /* FALLTHROUGH */
+ case 'j': /* FALLTHROUGH */
+ case ',': /* FALLTHROUGH */
+ if (avatar.x > 0) {
+ x = avatar.x - 1;
+ y = avatar.y;
+ }
+ break;
+
+ case KEY_RIGHT:
+ case '6': /* FALLTHROUGH */
+ case 'l': /* FALLTHROUGH */
+ case '.': /* FALLTHROUGH */
+ if (avatar.x < TERM_COLUMNS - 1) {
+ x = avatar.x + 1;
+ y = avatar.y;
+ }
+ break;
+ }
+
+ /* Update avatar if necessary */
+ if (x != -1 && y != -1) {
+ avatar.x = x;
+ avatar.y = y;
+ }
+
+ /* Animate */
+ anim_update();
+ anim_redraw();
+ uc = -1;
+ }
+ }
+end:
+
+ exit(EXIT_SUCCESS);
+
+err:
+ err(EXIT_FAILURE, "main()");
+}
+
+static void
+cleanup(void)
+{
+
+ (void)curs_set(1);
+ (void)endwin();
+ (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &old_tios);
+}
+
+static void
+sighandler(int sig)
+{
+
+ switch (sig) {
+ case SIGALRM:
+ refresh_expired = true;
+ break;
+ case SIGINT:
+ case SIGTERM: /* FALLTHROUGH */
+ case SIGHUP: /* FALLTHROUGH */
+ exit(EXIT_SUCCESS);
+ break;
+ }
+}
+
+static void
+safe_refresh(void)
+{
+ sigset_t set;
+
+ /* Temporarily block the SIGALRM signal during output syscalls */
+ set = block_mask;
+ (void)sigprocmask(SIG_BLOCK, &set, NULL);
+
+ (void)wrefresh(w);
+
+ set = block_mask;
+ (void)sigprocmask(SIG_UNBLOCK, &set, NULL);
+}
+
+static void
+anim_init(void)
+{
+ int i, col;
+
+ srandom(13);
+ col = 0;
+ for (i = 0; i < NOBJECTS; i++) {
+ aobject_t *o = &objects[i];
+
+ if (i <= 26) {
+ o->t = AOT_BUG;
+ o->c = 'A' + i;
+ o->col = ++col % 7;
+ } else {
+ o->t = AOT_STAR;
+ o->c = '.';
+ o->col = 0;
+ }
+ o->x = random() % (TERM_COLUMNS - 1);
+ o->y = random() % (TERM_LINES - 1);
+ }
+}
+
+static void
+anim_redraw(void)
+{
+ int i;
+
+ (void)attrset(COLOR_PAIR(0));
+ (void)clear();
+ (void)clearok(w, FALSE);
+ for (i = 0; i < NOBJECTS; i++) {
+ aobject_t *o = &objects[i];
+
+ (void)attrset(COLOR_PAIR(o->col));
+ (void)mvaddch(o->y, o->x, o->c);
+ }
+
+ /* Avatar */
+ (void)attr_on(A_REVERSE, NULL);
+ (void)mvaddch(avatar.y, avatar.x, avatar.c);
+ (void)attr_off(A_REVERSE, NULL);
+
+ safe_refresh();
+}
+
+static void
+anim_update(void)
+{
+ int i;
+
+ for (i = 0; i < NOBJECTS; i++) {
+ aobject_t *o = &objects[i];
+ int x = o->x, y = o->y, d = random() % 4;
+
+ if (o->t == AOT_STAR) {
+ if (x > 0)
+ x--;
+ else
+ x = TERM_COLUMNS - 1;
+ } else {
+ switch (d) {
+ case 0: /* Up */
+ if (y > 0)
+ y--;
+ break;
+ case 1: /* Down */
+ if (y < TERM_LINES - 1)
+ y++;
+ break;
+ case 2: /* Left */
+ if (x > 0)
+ x--;
+ break;
+ case 3: /* Right */
+ if (x < TERM_COLUMNS - 1)
+ x++;
+ break;
+ }
+ }
+ o->x = x;
+ o->y = y;
+ }
+}
Repositories / mmondor.git / commitdiff