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
11 static int hscroll;
12 static int begin_reached, end_reached, page_length;
13 static const char *buf, *page;
14 static 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 */
20 static 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 */
54 static 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 */
84 static 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 */
101 static 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 */
119 static 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 */
133 static 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 */
151 int 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
176 do_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 '': /* 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 == '')
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
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