From 9d5d4ea8c5ad3d28d005603de8c7e957d5f031e6 Mon Sep 17 00:00:00 2001
From: Hadeed Ahmad <hadeedji@gmail.com>
Date: Thu, 24 Aug 2023 16:09:03 +0500
Subject: [PATCH] Get window size

---
 kilo.c | 49 +++++++++++++++++++++++++++++++++++++------------
 1 file changed, 37 insertions(+), 12 deletions(-)

diff --git a/kilo.c b/kilo.c
index 9308feb..83b0f92 100644
--- a/kilo.c
+++ b/kilo.c
@@ -1,30 +1,34 @@
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/ioctl.h>
 #include <termios.h>
 #include <unistd.h>
 
 void enable_raw_mode();
 void disable_raw_mode();
+int get_window_size(int *, int *);
 
+void editor_init();
 void editor_redraw_screen();
 void editor_clear_screen();
 void editor_draw_rows();
 void editor_process_key();
 
-void die(const char *s);
+void die(const char *);
 
 #define CTRL_KEY(key) ((key) & 0x1f)
 
-struct termios orig_termios;
+struct {
+    struct termios orig_termios;
+    int rows;
+    int cols;
+} E;
 
 int main() {
-    if (!isatty(STDIN_FILENO)) {
-        printf("kilo only supports a terminal at standard in. Exiting.");
-        exit(1);
-    }
-
+    editor_init();
     enable_raw_mode();
+
     while (1) {
         editor_redraw_screen();
         editor_process_key();
@@ -34,20 +38,42 @@ int main() {
 }
 
 void enable_raw_mode() {
-    if (tcgetattr(STDIN_FILENO, &orig_termios) == -1) die("tcgetattr");
+    if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1) die("tcgetattr");
     atexit(disable_raw_mode);
 
-    struct termios raw = orig_termios;
+    struct termios raw = E.orig_termios;
     cfmakeraw(&raw);
 
     if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) die("tcsetattr");
 }
 
 void disable_raw_mode() {
-    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios) == -1)
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
         die("tcsetattr");
 }
 
+int get_window_size(int *rows, int *cols) {
+    struct winsize ws;
+
+    if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) != -1 && ws.ws_col != 0) {
+        *rows = ws.ws_row;
+        *cols = ws.ws_col;
+
+        return 0;
+    }
+
+    return -1;
+}
+
+void editor_init() {
+    if (!isatty(STDIN_FILENO)) {
+        printf("kilo only supports a terminal at standard in. Exiting.");
+        exit(1);
+    }
+
+    if (get_window_size(&E.rows, &E.cols) == -1) die("get_window_size");
+}
+
 void editor_redraw_screen() {
     editor_clear_screen();
 
@@ -62,8 +88,7 @@ void editor_clear_screen() {
 }
 
 void editor_draw_rows() {
-    int rows = 24;
-    for (int y = 0; y < rows - 1; y++)
+    for (int y = 0; y < E.rows - 1; y++)
         write(STDIN_FILENO, "~\r\n", 3);
     write(STDIN_FILENO, "~", 1);
 }