xref: /freebsd/contrib/nvi/vi/vs_relative.c (revision 38f0b757fd84d17d0fc24739a7cda160c4516d81)
1 /*-
2  * Copyright (c) 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  * Copyright (c) 1993, 1994, 1995, 1996
5  *	Keith Bostic.  All rights reserved.
6  *
7  * See the LICENSE file for redistribution information.
8  */
9 
10 #include "config.h"
11 
12 #ifndef lint
13 static const char sccsid[] = "$Id: vs_relative.c,v 10.19 2011/12/01 15:22:59 zy Exp $";
14 #endif /* not lint */
15 
16 #include <sys/types.h>
17 #include <sys/queue.h>
18 #include <sys/time.h>
19 
20 #include <bitstring.h>
21 #include <limits.h>
22 #include <stdio.h>
23 #include <string.h>
24 
25 #include "../common/common.h"
26 #include "vi.h"
27 
28 /*
29  * vs_column --
30  *	Return the logical column of the cursor in the line.
31  *
32  * PUBLIC: int vs_column __P((SCR *, size_t *));
33  */
34 int
35 vs_column(SCR *sp, size_t *colp)
36 {
37 	VI_PRIVATE *vip;
38 
39 	vip = VIP(sp);
40 
41 	*colp = (O_ISSET(sp, O_LEFTRIGHT) ?
42 	    vip->sc_smap->coff : (vip->sc_smap->soff - 1) * sp->cols) +
43 	    vip->sc_col - (O_ISSET(sp, O_NUMBER) ? O_NUMBER_LENGTH : 0);
44 	return (0);
45 }
46 
47 /*
48  * vs_screens --
49  *	Return the screens necessary to display the line, or if specified,
50  *	the physical character column within the line, including space
51  *	required for the O_NUMBER and O_LIST options.
52  *
53  * PUBLIC: size_t vs_screens __P((SCR *, recno_t, size_t *));
54  */
55 size_t
56 vs_screens(SCR *sp, recno_t lno, size_t *cnop)
57 {
58 	size_t cols, screens;
59 
60 	/* Left-right screens are simple, it's always 1. */
61 	if (O_ISSET(sp, O_LEFTRIGHT))
62 		return (1);
63 
64 	/*
65 	 * Check for a cached value.  We maintain a cache because, if the
66 	 * line is large, this routine gets called repeatedly.  One other
67 	 * hack, lots of time the cursor is on column one, which is an easy
68 	 * one.
69 	 */
70 	if (cnop == NULL) {
71 		if (VIP(sp)->ss_lno == lno)
72 			return (VIP(sp)->ss_screens);
73 	} else if (*cnop == 0)
74 		return (1);
75 
76 	/* Figure out how many columns the line/column needs. */
77 	cols = vs_columns(sp, NULL, lno, cnop, NULL);
78 
79 	screens = (cols / sp->cols + (cols % sp->cols ? 1 : 0));
80 	if (screens == 0)
81 		screens = 1;
82 
83 	/* Cache the value. */
84 	if (cnop == NULL) {
85 		VIP(sp)->ss_lno = lno;
86 		VIP(sp)->ss_screens = screens;
87 	}
88 	return (screens);
89 }
90 
91 /*
92  * vs_columns --
93  *	Return the screen columns necessary to display the line, or,
94  *	if specified, the physical character column within the line.
95  *
96  * PUBLIC: size_t vs_columns __P((SCR *, CHAR_T *, recno_t, size_t *, size_t *));
97  */
98 size_t
99 vs_columns(SCR *sp, CHAR_T *lp, recno_t lno, size_t *cnop, size_t *diffp)
100 {
101 	size_t chlen, cno, curoff, last = 0, len, scno;
102 	int ch, leftright, listset;
103 	CHAR_T *p;
104 
105 	/*
106 	 * Initialize the screen offset.
107 	 */
108 	scno = 0;
109 
110 	/* Leading number if O_NUMBER option set. */
111 	if (O_ISSET(sp, O_NUMBER))
112 		scno += O_NUMBER_LENGTH;
113 
114 	/* Need the line to go any further. */
115 	if (lp == NULL) {
116 		(void)db_get(sp, lno, 0, &lp, &len);
117 		if (len == 0)
118 			goto done;
119 	}
120 
121 	/* Missing or empty lines are easy. */
122 	if (lp == NULL) {
123 done:		if (diffp != NULL)		/* XXX */
124 			*diffp = 0;
125 		return scno;
126 	}
127 
128 	/* Store away the values of the list and leftright edit options. */
129 	listset = O_ISSET(sp, O_LIST);
130 	leftright = O_ISSET(sp, O_LEFTRIGHT);
131 
132 	/*
133 	 * Initialize the pointer into the buffer and current offset.
134 	 */
135 	p = lp;
136 	curoff = scno;
137 
138 	/* Macro to return the display length of any signal character. */
139 #define	CHLEN(val) (ch = *(UCHAR_T *)p++) == '\t' &&			\
140 	    !listset ? TAB_OFF(val) : KEY_COL(sp, ch);
141 
142 	/*
143 	 * If folding screens (the historic vi screen format), past the end
144 	 * of the current screen, and the character was a tab, reset the
145 	 * current screen column to 0, and the total screen columns to the
146 	 * last column of the screen.  Otherwise, display the rest of the
147 	 * character in the next screen.
148 	 */
149 #define	TAB_RESET {							\
150 	curoff += chlen;						\
151 	if (!leftright && curoff >= sp->cols)				\
152 		if (ch == '\t') {					\
153 			curoff = 0;					\
154 			scno -= scno % sp->cols;			\
155 		} else							\
156 			curoff -= sp->cols;				\
157 }
158 	if (cnop == NULL)
159 		while (len--) {
160 			chlen = CHLEN(curoff);
161 			last = scno;
162 			scno += chlen;
163 			TAB_RESET;
164 		}
165 	else
166 		for (cno = *cnop;; --cno) {
167 			chlen = CHLEN(curoff);
168 			last = scno;
169 			scno += chlen;
170 			TAB_RESET;
171 			if (cno == 0)
172 				break;
173 		}
174 
175 	/* Add the trailing '$' if the O_LIST option set. */
176 	if (listset && cnop == NULL)
177 		scno += KEY_LEN(sp, '$');
178 
179 	/*
180 	 * The text input screen code needs to know how much additional
181 	 * room the last two characters required, so that it can handle
182 	 * tab character displays correctly.
183 	 */
184 	if (diffp != NULL)
185 		*diffp = scno - last;
186 	return (scno);
187 }
188 
189 /*
190  * vs_rcm --
191  *	Return the physical column from the line that will display a
192  *	character closest to the currently most attractive character
193  *	position (which is stored as a screen column).
194  *
195  * PUBLIC: size_t vs_rcm __P((SCR *, recno_t, int));
196  */
197 size_t
198 vs_rcm(SCR *sp, recno_t lno, int islast)
199 {
200 	size_t len;
201 
202 	/* Last character is easy, and common. */
203 	if (islast) {
204 		if (db_get(sp, lno, 0, NULL, &len) || len == 0)
205 			return (0);
206 		return (len - 1);
207 	}
208 
209 	/* First character is easy, and common. */
210 	if (sp->rcm == 0)
211 		return (0);
212 
213 	return (vs_colpos(sp, lno, sp->rcm));
214 }
215 
216 /*
217  * vs_colpos --
218  *	Return the physical column from the line that will display a
219  *	character closest to the specified screen column.
220  *
221  * PUBLIC: size_t vs_colpos __P((SCR *, recno_t, size_t));
222  */
223 size_t
224 vs_colpos(SCR *sp, recno_t lno, size_t cno)
225 {
226 	size_t chlen, curoff, len, llen, off, scno;
227 	int ch = 0, leftright, listset;
228 	CHAR_T *lp, *p;
229 
230 	/* Need the line to go any further. */
231 	(void)db_get(sp, lno, 0, &lp, &llen);
232 
233 	/* Missing or empty lines are easy. */
234 	if (lp == NULL || llen == 0)
235 		return (0);
236 
237 	/* Store away the values of the list and leftright edit options. */
238 	listset = O_ISSET(sp, O_LIST);
239 	leftright = O_ISSET(sp, O_LEFTRIGHT);
240 
241 	/* Discard screen (logical) lines. */
242 	off = cno / sp->cols;
243 	cno %= sp->cols;
244 	for (scno = 0, p = lp, len = llen; off--;) {
245 		for (; len && scno < sp->cols; --len)
246 			scno += CHLEN(scno);
247 
248 		/*
249 		 * If reached the end of the physical line, return the last
250 		 * physical character in the line.
251 		 */
252 		if (len == 0)
253 			return (llen - 1);
254 
255 		/*
256 		 * If folding screens (the historic vi screen format), past
257 		 * the end of the current screen, and the character was a tab,
258 		 * reset the current screen column to 0.  Otherwise, the rest
259 		 * of the character is displayed in the next screen.
260 		 */
261 		if (leftright && ch == '\t')
262 			scno = 0;
263 		else
264 			scno -= sp->cols;
265 	}
266 
267 	/* Step through the line until reach the right character or EOL. */
268 	for (curoff = scno; len--;) {
269 		chlen = CHLEN(curoff);
270 
271 		/*
272 		 * If we've reached the specific character, there are three
273 		 * cases.
274 		 *
275 		 * 1: scno == cno, i.e. the current character ends at the
276 		 *    screen character we care about.
277 		 *	a: off < llen - 1, i.e. not the last character in
278 		 *	   the line, return the offset of the next character.
279 		 *	b: else return the offset of the last character.
280 		 * 2: scno != cno, i.e. this character overruns the character
281 		 *    we care about, return the offset of this character.
282 		 */
283 		if ((scno += chlen) >= cno) {
284 			off = p - lp;
285 			return (scno == cno ?
286 			    (off < llen - 1 ? off : llen - 1) : off - 1);
287 		}
288 
289 		TAB_RESET;
290 	}
291 
292 	/* No such character; return the start of the last character. */
293 	return (llen - 1);
294 }
295