Added handler functions for right and left arrow keys, that check cursor position before moving the gap

editor.c

@@ -86,6 +86,12 @@ void buffer_right(Buffer* buffer) {
 	}
 }
 
+void right_key_handler(Buffer* buffer) {
+	if ((*(buffer->end) != '\n') || (getcury(mainwin) + 1 < getmaxy(mainwin))) {
+		buffer_right(buffer);
+	}
+}
+
 void buffer_left(Buffer* buffer) {
 	if (buffer->start != buffer->text) {
 		char c = *(buffer->start - 1);
@@ -96,7 +102,11 @@ void buffer_left(Buffer* buffer) {
 	}
 }
 
-
+void left_key_handler(Buffer* buffer) {
+	if ((getcurx(mainwin) > 0) || (getcury(mainwin) > 0)) {
+		buffer_left(buffer);
+	}
+}
 
 void scroll_page_down_handler(Buffer* buffer) {
 	while (*(buffer->text + index_to_start) != '\n') {
@@ -277,11 +287,11 @@ int main(int argc, char** argv) {
 				break;
 
 			case KEY_LEFT:
-				buffer_left(buffer);
+				left_key_handler(buffer);
 				break;
 
 			case KEY_RIGHT:
-				buffer_right(buffer);
+				right_key_handler(buffer);
 				break;
 
 			case 10:  /* Enter key */