add tmessage application

Makefile

@@ -44,7 +44,7 @@ sh:
 check:
 	shellcheck sh/*
 
-mkc: c/scream c/timer c/boid c/anaconda c/colors c/xgetnewwindow
+mkc: c/scream c/timer c/boid c/anaconda c/colors c/xgetnewwindow c/tmessage
 
 c/boid:
 	cc c/boid.c -o c/boid -lm -lX11
@@ -62,6 +62,7 @@ c:
 	cp -f c/anaconda $(DESTDIR)$(PREFIX)/bin
 	cp -f c/colors $(DESTDIR)$(PREFIX)/bin
 	cp -f c/xgetnewwindow $(DESTDIR)$(PREFIX)/bin
+	cp -f c/tmessage $(DESTDIR)$(PREFIX)/bin
 
 clean:
 	rm -f c/scream
@@ -70,3 +71,4 @@ clean:
 	rm -f c/anaconda
 	rm -f c/simplestatus
 	rm -f c/xgetnewwindow
+	rm -f c/tmessage

c/tmessage.c

@@ -0,0 +1,148 @@
+#include <sys/ioctl.h>
+#include <ctype.h>
+#include <termios.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+
+#define ESC_CLEAR "\033[2J"
+#define ESC_CUSHOME "\033[H"
+#define ESC_NEWLINE "\033[E\033[1C"
+
+const char MSG_OK[] = "(O)k";
+const char MSG_CANCEL[] = "(C)ancel";
+
+typedef struct winsize ws;
+
+int lines, cols;
+char *message;
+size_t message_len;
+
+struct termios original_termios;
+
+void render(char *message, int message_len, int lines, int cols);
+
+void rawmode_start() {
+	tcgetattr(STDIN_FILENO, &original_termios);
+	struct termios raw = original_termios;
+	raw.c_lflag &= ~(ECHO | ICANON);
+	tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw);
+}
+
+void rawmode_stop() {
+	tcsetattr(STDIN_FILENO, TCSAFLUSH, &original_termios);
+	printf("\n\n");
+	fflush(stdout);
+}
+
+ws *getWinSize(void) {
+	/* we're only going to use these values once per invocation,
+	 * so it's fine that it's static. */
+	static ws w;
+	ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
+
+	return &w;
+}
+
+void handler(int signal, siginfo_t *info, void *context) {
+	ws *w = getWinSize();
+	lines = w->ws_row;
+	cols = w->ws_col;
+
+	render(message, message_len, lines, cols);
+	return;
+}
+
+void termhandler(int signal, siginfo_t *info, void *context) {
+	rawmode_stop();
+
+	return;
+}
+
+int calculate_number_of_lines(int length, int cols) {
+	/* cols - 1 accounts for right padding */
+	return length / (cols - 1) + 1;
+}
+
+void go_to_initial_message_printing_pos(void) {
+	printf(ESC_CUSHOME "\033[1B\033[1C");
+}
+
+void print_message(char *message, int messagelen, int cols) {
+	int linecount = calculate_number_of_lines(messagelen, cols);
+	int adjcols = cols - 2;
+	int offset = 1;
+	for(int character = 0; character < messagelen; character++) {
+		if(character == adjcols * offset) {
+			printf(ESC_NEWLINE);
+			offset++;
+		}
+		putchar(message[character]);
+	}
+}
+
+void render(char *message, int messagelen, int lines, int cols) {
+	int cancel_length = sizeof(MSG_CANCEL) / sizeof(MSG_CANCEL[0]);
+
+	/* print the stuff */
+	printf(ESC_CLEAR "" ESC_CUSHOME);
+	go_to_initial_message_printing_pos();
+	print_message(message, message_len, cols);
+
+	printf(ESC_NEWLINE);
+	printf(ESC_NEWLINE);
+	printf("%s", MSG_OK);
+	printf("\033[1D\033[%iC\033[%iD%s", cols, cancel_length, MSG_CANCEL);
+	fflush(stdout);
+}
+
+int main(int argc, char **argv) {
+	int cancel_length = strlen(MSG_CANCEL);
+	char c;
+	struct sigaction resizeaction = {};
+	struct sigaction termaction = {};
+	ws *w;
+
+	/* check if we have a message */
+	if(argc > 1) {
+		message = argv[1]; /* second argument's a message */
+		message_len = strlen(message);
+	} else {
+		return 1;
+	}
+
+	/* setup sigaction handlers */
+	resizeaction.sa_sigaction = &handler;
+	if(sigaction(SIGWINCH, &resizeaction, NULL) == -1) {
+		return 1;
+	}
+
+	termaction.sa_sigaction = &termhandler;
+	if(sigaction(SIGTERM, &termaction, NULL) == -1) {
+		return 1;
+	}
+
+	rawmode_start();
+
+	/* get window properties */
+	w = getWinSize();
+	lines = w->ws_row;
+	cols = w->ws_col;
+
+	render(message, message_len, lines, cols);
+
+	for(;;) {
+		read(STDIN_FILENO, &c, 1);
+		if(c == 'o') {
+			return 2;
+			rawmode_stop();
+		} else if(c == 'c') {
+			return 3;
+			rawmode_stop();
+		}
+	}
+
+	return 0;
+}