mark.c revision 240121 
1/*
2 * Copyright (C) 1984-2012  Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information, see the README file.
8 */
9
10
11#include "less.h"
12
13extern IFILE curr_ifile;
14extern int sc_height;
15extern int jump_sline;
16
17/*
18 * A mark is an ifile (input file) plus a position within the file.
19 */
20struct mark {
21	IFILE m_ifile;
22	struct scrpos m_scrpos;
23};
24
25/*
26 * The table of marks.
27 * Each mark is identified by a lowercase or uppercase letter.
28 * The final one is lmark, for the "last mark"; addressed by the apostrophe.
29 */
30#define	NMARKS		((2*26)+1)	/* a-z, A-Z, lastmark */
31#define	LASTMARK	(NMARKS-1)
32static struct mark marks[NMARKS];
33
34/*
35 * Initialize the mark table to show no marks are set.
36 */
37	public void
38init_mark()
39{
40	int i;
41
42	for (i = 0;  i < NMARKS;  i++)
43		marks[i].m_scrpos.pos = NULL_POSITION;
44}
45
46/*
47 * See if a mark letter is valid (between a and z).
48 */
49	static struct mark *
50getumark(c)
51	int c;
52{
53	if (c >= 'a' && c <= 'z')
54		return (&marks[c-'a']);
55
56	if (c >= 'A' && c <= 'Z')
57		return (&marks[c-'A'+26]);
58
59	error("Invalid mark letter", NULL_PARG);
60	return (NULL);
61}
62
63/*
64 * Get the mark structure identified by a character.
65 * The mark struct may come either from the mark table
66 * or may be constructed on the fly for certain characters like ^, $.
67 */
68	static struct mark *
69getmark(c)
70	int c;
71{
72	register struct mark *m;
73	static struct mark sm;
74
75	switch (c)
76	{
77	case '^':
78		/*
79		 * Beginning of the current file.
80		 */
81		m = &sm;
82		m->m_scrpos.pos = ch_zero();
83		m->m_scrpos.ln = 0;
84		m->m_ifile = curr_ifile;
85		break;
86	case '$':
87		/*
88		 * End of the current file.
89		 */
90		if (ch_end_seek())
91		{
92			error("Cannot seek to end of file", NULL_PARG);
93			return (NULL);
94		}
95		m = &sm;
96		m->m_scrpos.pos = ch_tell();
97		m->m_scrpos.ln = sc_height-1;
98		m->m_ifile = curr_ifile;
99		break;
100	case '.':
101		/*
102		 * Current position in the current file.
103		 */
104		m = &sm;
105		get_scrpos(&m->m_scrpos);
106		m->m_ifile = curr_ifile;
107		break;
108	case '\'':
109		/*
110		 * The "last mark".
111		 */
112		m = &marks[LASTMARK];
113		break;
114	default:
115		/*
116		 * Must be a user-defined mark.
117		 */
118		m = getumark(c);
119		if (m == NULL)
120			break;
121		if (m->m_scrpos.pos == NULL_POSITION)
122		{
123			error("Mark not set", NULL_PARG);
124			return (NULL);
125		}
126		break;
127	}
128	return (m);
129}
130
131/*
132 * Is a mark letter is invalid?
133 */
134	public int
135badmark(c)
136	int c;
137{
138	return (getmark(c) == NULL);
139}
140
141/*
142 * Set a user-defined mark.
143 */
144	public void
145setmark(c)
146	int c;
147{
148	register struct mark *m;
149	struct scrpos scrpos;
150
151	m = getumark(c);
152	if (m == NULL)
153		return;
154	get_scrpos(&scrpos);
155	m->m_scrpos = scrpos;
156	m->m_ifile = curr_ifile;
157}
158
159/*
160 * Set lmark (the mark named by the apostrophe).
161 */
162	public void
163lastmark()
164{
165	struct scrpos scrpos;
166
167	if (ch_getflags() & CH_HELPFILE)
168		return;
169	get_scrpos(&scrpos);
170	if (scrpos.pos == NULL_POSITION)
171		return;
172	marks[LASTMARK].m_scrpos = scrpos;
173	marks[LASTMARK].m_ifile = curr_ifile;
174}
175
176/*
177 * Go to a mark.
178 */
179	public void
180gomark(c)
181	int c;
182{
183	register struct mark *m;
184	struct scrpos scrpos;
185
186	m = getmark(c);
187	if (m == NULL)
188		return;
189
190	/*
191	 * If we're trying to go to the lastmark and
192	 * it has not been set to anything yet,
193	 * set it to the beginning of the current file.
194	 */
195	if (m == &marks[LASTMARK] && m->m_scrpos.pos == NULL_POSITION)
196	{
197		m->m_ifile = curr_ifile;
198		m->m_scrpos.pos = ch_zero();
199		m->m_scrpos.ln = jump_sline;
200	}
201
202	/*
203	 * If we're using lmark, we must save the screen position now,
204	 * because if we call edit_ifile() below, lmark will change.
205	 * (We save the screen position even if we're not using lmark.)
206	 */
207	scrpos = m->m_scrpos;
208	if (m->m_ifile != curr_ifile)
209	{
210		/*
211		 * Not in the current file; edit the correct file.
212		 */
213		if (edit_ifile(m->m_ifile))
214			return;
215	}
216
217	jump_loc(scrpos.pos, scrpos.ln);
218}
219
220/*
221 * Return the position associated with a given mark letter.
222 *
223 * We don't return which screen line the position
224 * is associated with, but this doesn't matter much,
225 * because it's always the first non-blank line on the screen.
226 */
227	public POSITION
228markpos(c)
229	int c;
230{
231	register struct mark *m;
232
233	m = getmark(c);
234	if (m == NULL)
235		return (NULL_POSITION);
236
237	if (m->m_ifile != curr_ifile)
238	{
239		error("Mark not in current file", NULL_PARG);
240		return (NULL_POSITION);
241	}
242	return (m->m_scrpos.pos);
243}
244
245/*
246 * Clear the marks associated with a specified ifile.
247 */
248	public void
249unmark(ifile)
250	IFILE ifile;
251{
252	int i;
253
254	for (i = 0;  i < NMARKS;  i++)
255		if (marks[i].m_ifile == ifile)
256			marks[i].m_scrpos.pos = NULL_POSITION;
257}
258