Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.bin/less/less/../forwback.c	Lines:	90	116	77.6 %
Date:	2017-11-07	Branches:	68	110	61.8 %


/*
 * Copyright (C) 1984-2012  Mark Nudelman
 * Modified for use with illumos by Garrett D'Amore.
 * Copyright 2014 Garrett D'Amore <garrett@damore.org>
 *
 * You may distribute under the terms of either the GNU General Public
 * License or the Less License, as specified in the README file.
 *
 * For more information, see the README file.
 */

/*
 * Primitives for displaying the file on the screen,
 * scrolling either forward or backward.
 */

#include "less.h"
#include "position.h"

int screen_trashed;
int squished;
int no_back_scroll = 0;
int forw_prompt;

extern volatile sig_atomic_t sigs;
extern int top_scroll;
extern int quiet;
extern int sc_width, sc_height;
extern int plusoption;
extern int forw_scroll;
extern int back_scroll;
extern int ignore_eoi;
extern int clear_bg;
extern int final_attr;
extern int oldbot;
extern char *tagoption;

/*
 * Sound the bell to indicate user is trying to move past end of file.
 */
static void
eof_bell(void)
{
	if (quiet == NOT_QUIET)
		ring_bell();
	else
		vbell();
}

/*
 * Check to see if the end of file is currently displayed.
 */
int
eof_displayed(void)
{
	off_t pos;

	if (ignore_eoi)
		return (0);

	if (ch_length() == -1)
		/*
		 * If the file length is not known,
		 * we can't possibly be displaying EOF.
		 */
		return (0);

	/*
	 * If the bottom line is empty, we are at EOF.
	 * If the bottom line ends at the file length,
	 * we must be just at EOF.
	 */
	pos = position(BOTTOM_PLUS_ONE);
	return (pos == -1 || pos == ch_length());
}

/*
 * Check to see if the entire file is currently displayed.
 */
int
entire_file_displayed(void)
{
	off_t pos;

	/* Make sure last line of file is displayed. */
	if (!eof_displayed())
		return (0);

	/* Make sure first line of file is displayed. */
	pos = position(0);
	return (pos == -1 || pos == 0);
}

/*
 * If the screen is "squished", repaint it.
 * "Squished" means the first displayed line is not at the top
 * of the screen; this can happen when we display a short file
 * for the first time.
 */
void
squish_check(void)
{
	if (!squished)
		return;
	squished = 0;
	repaint();
}

/*
 * Display n lines, scrolling forward,
 * starting at position pos in the input file.
 * "force" means display the n lines even if we hit end of file.
 * "only_last" means display only the last screenful if n > screen size.
 * "nblank" is the number of blank lines to draw before the first
 *   real line.  If nblank > 0, the pos must be -1.
 *   The first real line after the blanks will start at ch_zero().
 */
void
forw(int n, off_t pos, int force, int only_last, int nblank)
{
	int nlines = 0;
	int do_repaint;
	static int first_time = 1;

	squish_check();

	/*
	 * do_repaint tells us not to display anything till the end,
	 * then just repaint the entire screen.
	 * We repaint if we are supposed to display only the last
	 * screenful and the request is for more than a screenful.
	 * Also if the request exceeds the forward scroll limit
	 * (but not if the request is for exactly a screenful, since
	 * repainting itself involves scrolling forward a screenful).
	 */
	do_repaint = (only_last && n > sc_height-1) ||
	    (forw_scroll >= 0 && n > forw_scroll && n != sc_height-1);

	if (!do_repaint) {
		if (top_scroll && n >= sc_height - 1 && pos != ch_length()) {
			/*
			 * Start a new screen.
			 * {{ This is not really desirable if we happen
			 *    to hit eof in the middle of this screen,
			 *    but we don't yet know if that will happen. }}
			 */
			pos_clear();
			add_forw_pos(pos);
			force = 1;
			do_clear();
			home();
		}

		if (pos != position(BOTTOM_PLUS_ONE) || empty_screen()) {
			/*
			 * This is not contiguous with what is
			 * currently displayed.  Clear the screen image
			 * (position table) and start a new screen.
			 */
			pos_clear();
			add_forw_pos(pos);
			force = 1;
			if (top_scroll) {
				do_clear();
				home();
			} else if (!first_time) {
				putstr("...skipping...\n");
			}
		}
	}

	while (--n >= 0) {
		/*
		 * Read the next line of input.
		 */
		if (nblank > 0) {
			/*
			 * Still drawing blanks; don't get a line
			 * from the file yet.
			 * If this is the last blank line, get ready to
			 * read a line starting at ch_zero() next time.
			 */
			if (--nblank == 0)
				pos = ch_zero();
		} else {
			/*
			 * Get the next line from the file.
			 */
			pos = forw_line(pos);
			if (pos == -1) {
				/*
				 * End of file: stop here unless the top line
				 * is still empty, or "force" is true.
				 * Even if force is true, stop when the last
				 * line in the file reaches the top of screen.
				 */
				if (!force && position(TOP) != -1)
					break;
				if (!empty_lines(0, 0) &&
				    !empty_lines(1, 1) &&
				    empty_lines(2, sc_height-1))
					break;
			}
		}
		/*
		 * Add the position of the next line to the position table.
		 * Display the current line on the screen.
		 */
		add_forw_pos(pos);
		nlines++;
		if (do_repaint)
			continue;
		/*
		 * If this is the first screen displayed and
		 * we hit an early EOF (i.e. before the requested
		 * number of lines), we "squish" the display down
		 * at the bottom of the screen.
		 * But don't do this if a + option or a -t option
		 * was given.  These options can cause us to
		 * start the display after the beginning of the file,
		 * and it is not appropriate to squish in that case.
		 */
		if (first_time && pos == -1 && !top_scroll &&
		    tagoption == NULL && !plusoption) {
			squished = 1;
			continue;
		}
		put_line();
		forw_prompt = 1;
	}

	if (nlines == 0)
		eof_bell();
	else if (do_repaint)
		repaint();
	first_time = 0;
	(void) currline(BOTTOM);
}

/*
 * Display n lines, scrolling backward.
 */
void
back(int n, off_t pos, int force, int only_last)
{
	int nlines = 0;
	int do_repaint;

	squish_check();
	do_repaint = (n > get_back_scroll() || (only_last && n > sc_height-1));
	while (--n >= 0) {
		/*
		 * Get the previous line of input.
		 */
		pos = back_line(pos);
		if (pos == -1) {
			/*
			 * Beginning of file: stop here unless "force" is true.
			 */
			if (!force)
				break;
		}
		/*
		 * Add the position of the previous line to the position table.
		 * Display the line on the screen.
		 */
		add_back_pos(pos);
		nlines++;
		if (!do_repaint) {
			home();
			add_line();
			put_line();
		}
	}

	if (nlines == 0)
		eof_bell();
	else if (do_repaint)
		repaint();
	else if (!oldbot)
		lower_left();
	(void) currline(BOTTOM);
}

/*
 * Display n more lines, forward.
 * Start just after the line currently displayed at the bottom of the screen.
 */
void
forward(int n, int force, int only_last)
{
	off_t pos;

	if (get_quit_at_eof() && eof_displayed() &&
	    !(ch_getflags() & CH_HELPFILE)) {
		/*
		 * If the -e flag is set and we're trying to go
		 * forward from end-of-file, go on to the next file.
		 */
		if (edit_next(1))
			quit(QUIT_OK);
		return;
	}

	pos = position(BOTTOM_PLUS_ONE);
	if (pos == -1 && (!force || empty_lines(2, sc_height-1))) {
		if (ignore_eoi) {
			/*
			 * ignore_eoi is to support A_F_FOREVER.
			 * Back up until there is a line at the bottom
			 * of the screen.
			 */
			if (empty_screen()) {
				pos = ch_zero();
			} else {
				do {
					back(1, position(TOP), 1, 0);
					pos = position(BOTTOM_PLUS_ONE);
				} while (pos == -1);
			}
		} else {
			eof_bell();
			return;
		}
	}
	forw(n, pos, force, only_last, 0);
}

/*
 * Display n more lines, backward.
 * Start just before the line currently displayed at the top of the screen.
 */
void
backward(int n, int force, int only_last)
{
	off_t pos;

	pos = position(TOP);
	if (pos == -1 && (!force || position(BOTTOM) == 0)) {
		eof_bell();
		return;
	}
	back(n, pos, force, only_last);
}

/*
 * Get the backwards scroll limit.
 * Must call this function instead of just using the value of
 * back_scroll, because the default case depends on sc_height and
 * top_scroll, as well as back_scroll.
 */
int
get_back_scroll(void)
{
	if (no_back_scroll)
		return (0);
	if (back_scroll >= 0)
		return (back_scroll);
	if (top_scroll)
		return (sc_height - 2);
	return (10000); /* infinity */
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/*
2			* Copyright (C) 1984-2012 Mark Nudelman
3			* Modified for use with illumos by Garrett D'Amore.
4			* Copyright 2014 Garrett D'Amore <garrett@damore.org>
5			*
6			* You may distribute under the terms of either the GNU General Public
7			* License or the Less License, as specified in the README file.
8			*
9			* For more information, see the README file.
10			*/
11
12			/*
13			* Primitives for displaying the file on the screen,
14			* scrolling either forward or backward.
15			*/
16
17			#include "less.h"
18			#include "position.h"
19
20			int screen_trashed;
21			int squished;
22			int no_back_scroll = 0;
23			int forw_prompt;
24
25			extern volatile sig_atomic_t sigs;
26			extern int top_scroll;
27			extern int quiet;
28			extern int sc_width, sc_height;
29			extern int plusoption;
30			extern int forw_scroll;
31			extern int back_scroll;
32			extern int ignore_eoi;
33			extern int clear_bg;
34			extern int final_attr;
35			extern int oldbot;
36			extern char *tagoption;
37
38			/*
39			* Sound the bell to indicate user is trying to move past end of file.
40			*/
41			static void
42			eof_bell(void)
43			{
44	✓✗	60	if (quiet == NOT_QUIET)
45		30	ring_bell();
46			else
47			vbell();
48		30	}
49
50			/*
51			* Check to see if the end of file is currently displayed.
52			*/
53			int
54			eof_displayed(void)
55			{
56			off_t pos;
57
58	✗✓	1932	if (ignore_eoi)
59			return (0);
60
61	✓✓	966	if (ch_length() == -1)
62			/*
63			* If the file length is not known,
64			* we can't possibly be displaying EOF.
65			*/
66		196	return (0);
67
68			/*
69			* If the bottom line is empty, we are at EOF.
70			* If the bottom line ends at the file length,
71			* we must be just at EOF.
72			*/
73		770	pos = position(BOTTOM_PLUS_ONE);
74	✓✓	2286	return (pos == -1 \|\| pos == ch_length());
75		966	}
76
77			/*
78			* Check to see if the entire file is currently displayed.
79			*/
80			int
81			entire_file_displayed(void)
82			{
83			off_t pos;
84
85			/* Make sure last line of file is displayed. */
86			if (!eof_displayed())
87			return (0);
88
89			/* Make sure first line of file is displayed. */
90			pos = position(0);
91			return (pos == -1 \|\| pos == 0);
92			}
93
94			/*
95			* If the screen is "squished", repaint it.
96			* "Squished" means the first displayed line is not at the top
97			* of the screen; this can happen when we display a short file
98			* for the first time.
99			*/
100			void
101			squish_check(void)
102			{
103	✗✓	1970	if (!squished)
104			return;
105			squished = 0;
106			repaint();
107		985	}
108
109			/*
110			* Display n lines, scrolling forward,
111			* starting at position pos in the input file.
112			* "force" means display the n lines even if we hit end of file.
113			* "only_last" means display only the last screenful if n > screen size.
114			* "nblank" is the number of blank lines to draw before the first
115			* real line. If nblank > 0, the pos must be -1.
116			* The first real line after the blanks will start at ch_zero().
117			*/
118			void
119			forw(int n, off_t pos, int force, int only_last, int nblank)
120			{
121			int nlines = 0;
122			int do_repaint;
123			static int first_time = 1;
124
125		1714	squish_check();
126
127			/*
128			* do_repaint tells us not to display anything till the end,
129			* then just repaint the entire screen.
130			* We repaint if we are supposed to display only the last
131			* screenful and the request is for more than a screenful.
132			* Also if the request exceeds the forward scroll limit
133			* (but not if the request is for exactly a screenful, since
134			* repainting itself involves scrolling forward a screenful).
135			*/
136	✓✓✓✗	2367	do_repaint = (only_last && n > sc_height-1) \|\|
137	✗✓✗✗	857	(forw_scroll >= 0 && n > forw_scroll && n != sc_height-1);
138
139	✓✗	857	if (!do_repaint) {
140	✓✓✓✓ ✓✗	2405	if (top_scroll && n >= sc_height - 1 && pos != ch_length()) {
141			/*
142			* Start a new screen.
143			* {{ This is not really desirable if we happen
144			* to hit eof in the middle of this screen,
145			* but we don't yet know if that will happen. }}
146			*/
147		745	pos_clear();
148		745	add_forw_pos(pos);
149			force = 1;
150		745	do_clear();
151		745	home();
152		745	}
153
154	✓✓✓✓	1707	if (pos != position(BOTTOM_PLUS_ONE) \|\| empty_screen()) {
155			/*
156			* This is not contiguous with what is
157			* currently displayed. Clear the screen image
158			* (position table) and start a new screen.
159			*/
160		42	pos_clear();
161		42	add_forw_pos(pos);
162			force = 1;
163	✓✓	42	if (top_scroll) {
164		35	do_clear();
165		35	home();
166	✓✓	42	} else if (!first_time) {
167		2	putstr("...skipping...\n");
168		2	}
169			}
170			}
171
172	✓✓	50787	while (--n >= 0) {
173			/*
174			* Read the next line of input.
175			*/
176	✗✓	24969	if (nblank > 0) {
177			/*
178			* Still drawing blanks; don't get a line
179			* from the file yet.
180			* If this is the last blank line, get ready to
181			* read a line starting at ch_zero() next time.
182			*/
183			if (--nblank == 0)
184			pos = ch_zero();
185			} else {
186			/*
187			* Get the next line from the file.
188			*/
189		24969	pos = forw_line(pos);
190	✓✓	24969	if (pos == -1) {
191			/*
192			* End of file: stop here unless the top line
193			* is still empty, or "force" is true.
194			* Even if force is true, stop when the last
195			* line in the file reaches the top of screen.
196			*/
197	✓✓✗✓	177	if (!force && position(TOP) != -1)
198			break;
199	✗✓✗✗	169	if (!empty_lines(0, 0) &&
200			!empty_lines(1, 1) &&
201			empty_lines(2, sc_height-1))
202			break;
203			}
204			}
205			/*
206			* Add the position of the next line to the position table.
207			* Display the current line on the screen.
208			*/
209		24965	add_forw_pos(pos);
210		24965	nlines++;
211	✗✓	24965	if (do_repaint)
212			continue;
213			/*
214			* If this is the first screen displayed and
215			* we hit an early EOF (i.e. before the requested
216			* number of lines), we "squish" the display down
217			* at the bottom of the screen.
218			* But don't do this if a + option or a -t option
219			* was given. These options can cause us to
220			* start the display after the beginning of the file,
221			* and it is not appropriate to squish in that case.
222			*/
223	✗✓	74895	if (first_time && pos == -1 && !top_scroll &&
224		49930	tagoption == NULL && !plusoption) {
225			squished = 1;
226			continue;
227			}
228		24965	put_line();
229		24965	forw_prompt = 1;
230			}
231
232	✗✓	857	if (nlines == 0)
233			eof_bell();
234	✗✓	857	else if (do_repaint)
235			repaint();
236		857	first_time = 0;
237		857	(void) currline(BOTTOM);
238		857	}
239
240			/*
241			* Display n lines, scrolling backward.
242			*/
243			void
244			back(int n, off_t pos, int force, int only_last)
245			{
246			int nlines = 0;
247			int do_repaint;
248
249		254	squish_check();
250	✓✓✓✓	309	do_repaint = (n > get_back_scroll() \|\| (only_last && n > sc_height-1));
251	✓✓	2677	while (--n >= 0) {
252			/*
253			* Get the previous line of input.
254			*/
255		2449	pos = back_line(pos);
256	✓✓	4898	if (pos == -1) {
257			/*
258			* Beginning of file: stop here unless "force" is true.
259			*/
260		2449	if (!force)
261			break;
262			}
263			/*
264			* Add the position of the previous line to the position table.
265			* Display the line on the screen.
266			*/
267		2423	add_back_pos(pos);
268		2423	nlines++;
269	✓✓	2423	if (!do_repaint) {
270		128	home();
271		128	add_line();
272		128	put_line();
273		128	}
274			}
275
276	✓✓	127	if (nlines == 0)
277		28	eof_bell();
278	✓✓	99	else if (do_repaint)
279		72	repaint();
280	✓✗	27	else if (!oldbot)
281		27	lower_left();
282		127	(void) currline(BOTTOM);
283		127	}
284
285			/*
286			* Display n more lines, forward.
287			* Start just after the line currently displayed at the bottom of the screen.
288			*/
289			void
290			forward(int n, int force, int only_last)
291			{
292			off_t pos;
293
294	✓✓✓✓ ✓✗	1515	if (get_quit_at_eof() && eof_displayed() &&
295		3	!(ch_getflags() & CH_HELPFILE)) {
296			/*
297			* If the -e flag is set and we're trying to go
298			* forward from end-of-file, go on to the next file.
299			*/
300	✓✗	3	if (edit_next(1))
301		3	quit(QUIT_OK);
302			return;
303			}
304
305		728	pos = position(BOTTOM_PLUS_ONE);
306	✓✓✗✓ ✗✗	730	if (pos == -1 && (!force \|\| empty_lines(2, sc_height-1))) {
307	✗✓	2	if (ignore_eoi) {
308			/*
309			* ignore_eoi is to support A_F_FOREVER.
310			* Back up until there is a line at the bottom
311			* of the screen.
312			*/
313			if (empty_screen()) {
314			pos = ch_zero();
315			} else {
316			do {
317			back(1, position(TOP), 1, 0);
318			pos = position(BOTTOM_PLUS_ONE);
319			} while (pos == -1);
320			}
321			} else {
322		2	eof_bell();
323		2	return;
324			}
325			}
326		726	forw(n, pos, force, only_last, 0);
327		1454	}
328
329			/*
330			* Display n more lines, backward.
331			* Start just before the line currently displayed at the top of the screen.
332			*/
333			void
334			backward(int n, int force, int only_last)
335			{
336			off_t pos;
337
338		242	pos = position(TOP);
339	✗✓✗✗ ✗✗	121	if (pos == -1 && (!force \|\| position(BOTTOM) == 0)) {
340			eof_bell();
341			return;
342			}
343		121	back(n, pos, force, only_last);
344		242	}
345
346			/*
347			* Get the backwards scroll limit.
348			* Must call this function instead of just using the value of
349			* back_scroll, because the default case depends on sc_height and
350			* top_scroll, as well as back_scroll.
351			*/
352			int
353			get_back_scroll(void)
354			{
355	✗✓	254	if (no_back_scroll)
356			return (0);
357	✗✓	127	if (back_scroll >= 0)
358			return (back_scroll);
359	✓✓	127	if (top_scroll)
360		113	return (sc_height - 2);
361		14	return (10000); /* infinity */
362		127	}