1// SPDX-License-Identifier: GPL-2.0+
2/*
3 *  textbox.c -- implements the text box
4 *
5 *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
6 *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
7 */
8
9#include "dialog.h"
10
11static int hscroll;
12static int begin_reached, end_reached, page_length;
13static const char *buf, *page;
14static size_t start, end;
15
16/*
17 * Go back 'n' lines in text. Called by dialog_textbox().
18 * 'page' will be updated to point to the desired line in 'buf'.
19 */
20static void back_lines(int n)
21{
22	int i;
23
24	begin_reached = 0;
25	/* Go back 'n' lines */
26	for (i = 0; i < n; i++) {
27		if (*page == '\0') {
28			if (end_reached) {
29				end_reached = 0;
30				continue;
31			}
32		}
33		if (page == buf) {
34			begin_reached = 1;
35			return;
36		}
37		page--;
38		do {
39			if (page == buf) {
40				begin_reached = 1;
41				return;
42			}
43			page--;
44		} while (*page != '\n');
45		page++;
46	}
47}
48
49/*
50 * Return current line of text. Called by dialog_textbox() and print_line().
51 * 'page' should point to start of current line before calling, and will be
52 * updated to point to start of next line.
53 */
54static char *get_line(void)
55{
56	int i = 0;
57	static char line[MAX_LEN + 1];
58
59	end_reached = 0;
60	while (*page != '\n') {
61		if (*page == '\0') {
62			end_reached = 1;
63			break;
64		} else if (i < MAX_LEN)
65			line[i++] = *(page++);
66		else {
67			/* Truncate lines longer than MAX_LEN characters */
68			if (i == MAX_LEN)
69				line[i++] = '\0';
70			page++;
71		}
72	}
73	if (i <= MAX_LEN)
74		line[i] = '\0';
75	if (!end_reached)
76		page++;		/* move past '\n' */
77
78	return line;
79}
80
81/*
82 * Print a new line of text.
83 */
84static void print_line(WINDOW *win, int row, int width)
85{
86	char *line;
87
88	line = get_line();
89	line += MIN(strlen(line), hscroll);	/* Scroll horizontally */
90	wmove(win, row, 0);	/* move cursor to correct line */
91	waddch(win, ' ');
92	waddnstr(win, line, MIN(strlen(line), width - 2));
93
94	/* Clear 'residue' of previous line */
95	wclrtoeol(win);
96}
97
98/*
99 * Print a new page of text.
100 */
101static void print_page(WINDOW *win, int height, int width)
102{
103	int i, passed_end = 0;
104
105	page_length = 0;
106	for (i = 0; i < height; i++) {
107		print_line(win, i, width);
108		if (!passed_end)
109			page_length++;
110		if (end_reached && !passed_end)
111			passed_end = 1;
112	}
113	wnoutrefresh(win);
114}
115
116/*
117 * Print current position
118 */
119static void print_position(WINDOW *win)
120{
121	int percent;
122
123	wattrset(win, dlg.position_indicator.atr);
124	wbkgdset(win, dlg.position_indicator.atr & A_COLOR);
125	percent = (page - buf) * 100 / strlen(buf);
126	wmove(win, getmaxy(win) - 3, getmaxx(win) - 9);
127	wprintw(win, "(%3d%%)", percent);
128}
129
130/*
131 * refresh window content
132 */
133static void refresh_text_box(WINDOW *dialog, WINDOW *box, int boxh, int boxw,
134			     int cur_y, int cur_x)
135{
136	start = page - buf;
137
138	print_page(box, boxh, boxw);
139	print_position(dialog);
140	wmove(dialog, cur_y, cur_x);	/* Restore cursor position */
141	wrefresh(dialog);
142
143	end = page - buf;
144}
145
146/*
147 * Display text from a file in a dialog box.
148 *
149 * keys is a null-terminated array
150 */
151int dialog_textbox(const char *title, const char *tbuf, int initial_height,
152		   int initial_width, int *_vscroll, int *_hscroll,
153		   int (*extra_key_cb)(int, size_t, size_t, void *), void *data)
154{
155	int i, x, y, cur_x, cur_y, key = 0;
156	int height, width, boxh, boxw;
157	WINDOW *dialog, *box;
158	bool done = false;
159
160	begin_reached = 1;
161	end_reached = 0;
162	page_length = 0;
163	hscroll = 0;
164	buf = tbuf;
165	page = buf;	/* page is pointer to start of page to be displayed */
166
167	if (_vscroll && *_vscroll) {
168		begin_reached = 0;
169
170		for (i = 0; i < *_vscroll; i++)
171			get_line();
172	}
173	if (_hscroll)
174		hscroll = *_hscroll;
175
176do_resize:
177	getmaxyx(stdscr, height, width);
178	if (height < TEXTBOX_HEIGHT_MIN || width < TEXTBOX_WIDTH_MIN)
179		return -ERRDISPLAYTOOSMALL;
180	if (initial_height != 0)
181		height = initial_height;
182	else
183		if (height > 4)
184			height -= 4;
185		else
186			height = 0;
187	if (initial_width != 0)
188		width = initial_width;
189	else
190		if (width > 5)
191			width -= 5;
192		else
193			width = 0;
194
195	/* center dialog box on screen */
196	x = (getmaxx(stdscr) - width) / 2;
197	y = (getmaxy(stdscr) - height) / 2;
198
199	draw_shadow(stdscr, y, x, height, width);
200
201	dialog = newwin(height, width, y, x);
202	keypad(dialog, TRUE);
203
204	/* Create window for box region, used for scrolling text */
205	boxh = height - 4;
206	boxw = width - 2;
207	box = subwin(dialog, boxh, boxw, y + 1, x + 1);
208	wattrset(box, dlg.dialog.atr);
209	wbkgdset(box, dlg.dialog.atr & A_COLOR);
210
211	keypad(box, TRUE);
212
213	/* register the new window, along with its borders */
214	draw_box(dialog, 0, 0, height, width,
215		 dlg.dialog.atr, dlg.border.atr);
216
217	wattrset(dialog, dlg.border.atr);
218	mvwaddch(dialog, height - 3, 0, ACS_LTEE);
219	for (i = 0; i < width - 2; i++)
220		waddch(dialog, ACS_HLINE);
221	wattrset(dialog, dlg.dialog.atr);
222	wbkgdset(dialog, dlg.dialog.atr & A_COLOR);
223	waddch(dialog, ACS_RTEE);
224
225	print_title(dialog, title, width);
226
227	print_button(dialog, " Exit ", height - 2, width / 2 - 4, TRUE);
228	wnoutrefresh(dialog);
229	getyx(dialog, cur_y, cur_x);	/* Save cursor position */
230
231	/* Print first page of text */
232	attr_clear(box, boxh, boxw, dlg.dialog.atr);
233	refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x);
234
235	while (!done) {
236		key = wgetch(dialog);
237		switch (key) {
238		case 'E':	/* Exit */
239		case 'e':
240		case 'X':
241		case 'x':
242		case 'q':
243		case '\n':
244			done = true;
245			break;
246		case 'g':	/* First page */
247		case KEY_HOME:
248			if (!begin_reached) {
249				begin_reached = 1;
250				page = buf;
251				refresh_text_box(dialog, box, boxh, boxw,
252						 cur_y, cur_x);
253			}
254			break;
255		case 'G':	/* Last page */
256		case KEY_END:
257
258			end_reached = 1;
259			/* point to last char in buf */
260			page = buf + strlen(buf);
261			back_lines(boxh);
262			refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x);
263			break;
264		case 'K':	/* Previous line */
265		case 'k':
266		case KEY_UP:
267			if (begin_reached)
268				break;
269
270			back_lines(page_length + 1);
271			refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x);
272			break;
273		case 'B':	/* Previous page */
274		case 'b':
275		case 'u':
276		case KEY_PPAGE:
277			if (begin_reached)
278				break;
279			back_lines(page_length + boxh);
280			refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x);
281			break;
282		case 'J':	/* Next line */
283		case 'j':
284		case KEY_DOWN:
285			if (end_reached)
286				break;
287
288			back_lines(page_length - 1);
289			refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x);
290			break;
291		case KEY_NPAGE:	/* Next page */
292		case ' ':
293		case 'd':
294			if (end_reached)
295				break;
296
297			begin_reached = 0;
298			refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x);
299			break;
300		case '0':	/* Beginning of line */
301		case 'H':	/* Scroll left */
302		case 'h':
303		case KEY_LEFT:
304			if (hscroll <= 0)
305				break;
306
307			if (key == '0')
308				hscroll = 0;
309			else
310				hscroll--;
311			/* Reprint current page to scroll horizontally */
312			back_lines(page_length);
313			refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x);
314			break;
315		case 'L':	/* Scroll right */
316		case 'l':
317		case KEY_RIGHT:
318			if (hscroll >= MAX_LEN)
319				break;
320			hscroll++;
321			/* Reprint current page to scroll horizontally */
322			back_lines(page_length);
323			refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x);
324			break;
325		case KEY_ESC:
326			if (on_key_esc(dialog) == KEY_ESC)
327				done = true;
328			break;
329		case KEY_RESIZE:
330			back_lines(height);
331			delwin(box);
332			delwin(dialog);
333			on_key_resize();
334			goto do_resize;
335		default:
336			if (extra_key_cb && extra_key_cb(key, start, end, data)) {
337				done = true;
338				break;
339			}
340		}
341	}
342	delwin(box);
343	delwin(dialog);
344	if (_vscroll) {
345		const char *s;
346
347		s = buf;
348		*_vscroll = 0;
349		back_lines(page_length);
350		while (s < page && (s = strchr(s, '\n'))) {
351			(*_vscroll)++;
352			s++;
353		}
354	}
355	if (_hscroll)
356		*_hscroll = hscroll;
357	return key;
358}
359