From 05b4673efbeb372387b0a9359af5046afb87c8cf Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@member.fsf.org>
Date: Thu, 21 Nov 2019 04:39:27 +0200
Subject: [PATCH] starting a rough editor program as a scaffold to test and
 try the visor algorithms

---
 .gitignore            |    1 +
 visor/Makefile        |   23 ++++++++++++
 visor/src/main_unix.c |   95 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 119 insertions(+)
 create mode 100644 visor/Makefile
 create mode 100644 visor/src/main_unix.c

diff --git a/.gitignore b/.gitignore
index a8f9429..1f97476 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 *.swp
 *.a
 *.so
+visor/visor
diff --git a/visor/Makefile b/visor/Makefile
new file mode 100644
index 0000000..b97b548
--- /dev/null
+++ b/visor/Makefile
@@ -0,0 +1,23 @@
+src = $(wildcard src/*.c)
+obj = $(src:.c=.o)
+dep = $(obj:.o=.d)
+bin = visor
+
+CFLAGS = -pedantic -Wall -g
+
+$(bin): $(obj)
+	$(CC) -o $@ $(obj) $(LDFLAGS)
+
+-include $(dep)
+
+%.d: %.c
+	@echo dep $@
+	@$(CPP) $(CFLAGS) $< -MM -MT $(@:.d=.o) >$@
+
+.PHONY: clean
+clean:
+	rm -f $(obj) $(bin)
+
+.PHONY: cleandep
+cleandep:
+	rm -f $(dep)
diff --git a/visor/src/main_unix.c b/visor/src/main_unix.c
new file mode 100644
index 0000000..37406a0
--- /dev/null
+++ b/visor/src/main_unix.c
@@ -0,0 +1,95 @@
+#include <stdio.h>
+#include <signal.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <termios.h>
+#include <sys/ioctl.h>
+
+static int init(void);
+static void cleanup(void);
+static void sighandler(int s);
+
+int term_width, term_height;
+int ttyfd;
+struct termios saved_term;
+
+int main(int argc, char **argv)
+{
+	int res;
+	char c;
+
+	if(init() == -1) {
+		return 1;
+	}
+
+	for(;;) {
+		if((res = read(ttyfd, &c, 1)) == 0 || (res < 0 && errno != EINTR)) {
+			break;
+		}
+		/* proc input */
+	}
+
+	cleanup();
+	return 0;
+}
+
+static int init(void)
+{
+	struct termios term;
+	struct winsize winsz;
+
+	if((ttyfd = open("/dev/tty", O_RDWR)) == -1) {
+		perror("failed to open /dev/tty");
+		return -1;
+	}
+	if(tcgetattr(ttyfd, &term) == -1) {
+		perror("failed to get terminal attr");
+		return -1;
+	}
+	saved_term = term;
+	term.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
+	term.c_oflag &= ~OPOST;
+	term.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
+	term.c_cflag = (term.c_cflag & ~(CSIZE | PARENB)) | CS8;
+
+	if(tcsetattr(ttyfd, TCSAFLUSH, &term) == -1) {
+		perror("failed to change terminal attributes");
+		return -1;
+	}
+
+	ioctl(1, TIOCGWINSZ, &winsz);
+	term_width = winsz.ws_col;
+	term_height = winsz.ws_row;
+
+	signal(SIGWINCH, sighandler);
+
+	write(ttyfd, "\033[2J", 4);
+
+	return 0;
+}
+
+static void cleanup(void)
+{
+	tcsetattr(ttyfd, TCSAFLUSH, &saved_term);
+	close(ttyfd);
+}
+
+static void sighandler(int s)
+{
+	struct winsize winsz;
+
+	signal(s, sighandler);
+
+	switch(s) {
+	case SIGWINCH:
+		ioctl(1, TIOCGWINSZ, &winsz);
+		term_width = winsz.ws_col;
+		term_height = winsz.ws_row;
+		/* redraw */
+		break;
+
+	default:
+		break;
+	}
+}
-- 
1.7.10.4