Support files longer than terminal line-count

main.cpp

@@ -17,23 +17,16 @@ enum mode_type { insert, normal };
 // Global variables
 treap file;
 int row = 0, col = 0;
+int file_offset = 0;
 
 // Accessing the file
-string get_line(int r) { return file.find(r)->text; }
-char get(int r, int s) { return get_line(r)[s]; }
-void set(int r, int s, char ch) { file.find(r)->text[s] = ch; }
-void add_line(int r, string text = "") { file.insert(r, text); }
-void remove_line(int r) { file.remove(r); }
-void insert_char(int r, int s, char ch) { file.find(r)->text.insert(s, string{ch}); }
-void remove_char(int r, int s) { file.find(r)->text.erase(s,1); }
-
-// For normal mode not to write to terminal
-void step_back() {
-	move(row, col);
-	char ch = col < get_line(row).size() ? get(row, col) : ' ';
-	addch(ch);
-	move(row, col);
-}
+string get_line(int r) { return file.find(file_offset+r)->text; }
+char get(int r, int s) { return get_line(file_offset+r)[s]; }
+void set(int r, int s, char ch) { file.find(file_offset+r)->text[s] = ch; }
+void add_line(int r, string text = "") { file.insert(file_offset+r, text); }
+void insert_char(int r, int s, char ch) { file.find(file_offset+r)->text.insert(s, string{ch}); }
+void remove_char(int r, int s) { file.find(file_offset+r)->text.erase(s,1); }
+void remove_line(int r) { file.remove(file_offset+r); }
 
 
 // Load file to buffer
@@ -47,7 +40,6 @@ bool load(string filename) {
 		file.insert(file.size(), line);
 	return 0;
 }
-
 // Save file from buffer
 bool save(string filename) {
 	std::ofstream outfile(filename);
@@ -58,30 +50,30 @@ bool save(string filename) {
 	return 0;
 }
 
+
+// Print line
+void print_line(int pos) {
+	move(pos, 0);
+	clrtoeol();
+	move(pos, 0);
+	adds(get_line(pos));
+	move(row, col);
+}
 // Print file content
-// TODO only visible part
 void print_file() {
 	clear();
-	for(int i = 0; i < file.size(); i++) {
-		move(i, 0);
-		adds(get_line(i));
-	}
-	move(row, col);
-}
-// Print line
-void print_line(int r) {
-	move(r, 0);
-	clrtoeol();
-	move(r, 0);
-	adds(get_line(r));
+	for(int i = 0; i < LINES && file_offset+i < file.size(); i++)
+		print_line(i);
 	move(row, col);
 }
 
+
 // TODO skoky a přesuny
 // TODO kopirování
 // TODO hledání a nahrazování
 // TODO undo
 
+
 // Jump to end of line
 void jump_line_end() {
 	int line_size = get_line(row).size();
@@ -90,7 +82,6 @@ void jump_line_end() {
 		move(row, col);
 	}
 }
-
 // Cursor movement
 void move_cursor(char ch) {
 	switch(ch) {
@@ -100,10 +91,16 @@ void move_cursor(char ch) {
 			break;
 
 		case 'j':
-			if(row < file.size()-1) {
+			if(file_offset + row >= file.size()-1) break;
+			if(row < LINES-1) {
 				move(++row, col);
 				jump_line_end();
 			}
+			else if(row == LINES-1) {
+				file_offset++;
+				jump_line_end();
+				print_file();
+			}
 			break;
 
 		case 'k':
@@ -111,6 +108,11 @@ void move_cursor(char ch) {
 				move(--row, col);
 				jump_line_end();
 			}
+			else if(file_offset > 0) {
+				file_offset--;
+				jump_line_end();
+				print_file();
+			}
 			break;
 
 		case 'l':
@@ -120,6 +122,7 @@ void move_cursor(char ch) {
 	}
 }
 
+
 int main(int argc, char* argv[]) {
 	
 	// Init
@@ -143,7 +146,7 @@ int main(int argc, char* argv[]) {
 		char ch = getch();
 		switch(mode) {
 			case normal:
-				step_back();
+				print_line(row);
 				switch(ch) {
 					case 'h': case 'j': case 'k': case 'l':
 						move_cursor(ch);
@@ -169,7 +172,7 @@ int main(int argc, char* argv[]) {
 					case 'i':
 						mode = insert;
 						break;
-					case ESC:
+					default:
 						break;
 				}
 				break;
@@ -187,9 +190,6 @@ int main(int argc, char* argv[]) {
 		refresh();
 	}
 
-	if(argc > 1 && save(argv[1]))
-		return 1;
-
 	// End
 	endwin();
 	return 0;