xref: /freebsd/contrib/nvi/vi/vs_relative.c (revision a466cc55373fc3cf86837f09da729535b57e69a1)
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 #include <sys/types.h>
13 #include <sys/queue.h>
14 #include <sys/time.h>
15 
16 #include <bitstring.h>
17 #include <limits.h>
18 #include <stdio.h>
19 #include <string.h>
20 
21 #include "../common/common.h"
22 #include "vi.h"
23 
24 /*
25  * vs_column --
26  *	Return the logical column of the cursor in the line.
27  *
28  * PUBLIC: int vs_column(SCR *, size_t *);
29  */
30 int
31 vs_column(SCR *sp, size_t *colp)
32 {
33 	VI_PRIVATE *vip;
34 
35 	vip = VIP(sp);
36 
37 	*colp = (O_ISSET(sp, O_LEFTRIGHT) ?
38 	    vip->sc_smap->coff : (vip->sc_smap->soff - 1) * sp->cols) +
39 	    vip->sc_col - (O_ISSET(sp, O_NUMBER) ? O_NUMBER_LENGTH : 0);
40 	return (0);
41 }
42 
43 /*
44  * vs_screens --
45  *	Return the screens necessary to display the line, or if specified,
46  *	the physical character column within the line, including space
47  *	required for the O_NUMBER and O_LIST options.
48  *
49  * PUBLIC: size_t vs_screens(SCR *, recno_t, size_t *);
50  */
51 size_t
52 vs_screens(SCR *sp, recno_t lno, size_t *cnop)
53 {
54 	size_t cols, screens;
55 
56 	/* Left-right screens are simple, it's always 1. */
57 	if (O_ISSET(sp, O_LEFTRIGHT))
58 		return (1);
59 
60 	/*
61 	 * Check for a cached value.  We maintain a cache because, if the
62 	 * line is large, this routine gets called repeatedly.  One other
63 	 * hack, lots of time the cursor is on column one, which is an easy
64 	 * one.
65 	 */
66 	if (cnop == NULL) {
67 		if (VIP(sp)->ss_lno == lno)
68 			return (VIP(sp)->ss_screens);
69 	} else if (*cnop == 0)
70 		return (1);
71 
72 	/* Figure out how many columns the line/column needs. */
73 	cols = vs_columns(sp, NULL, lno, cnop, NULL);
74 
75 	screens = (cols / sp->cols + (cols % sp->cols ? 1 : 0));
76 	if (screens == 0)
77 		screens = 1;
78 
79 	/* Cache the value. */
80 	if (cnop == NULL) {
81 		VIP(sp)->ss_lno = lno;
82 		VIP(sp)->ss_screens = screens;
83 	}
84 	return (screens);
85 }
86 
87 /*
88  * vs_columns --
89  *	Return the screen columns necessary to display the line, or,
90  *	if specified, the physical character column within the line.
91  *
92  * PUBLIC: size_t vs_columns(SCR *, CHAR_T *, recno_t, size_t *, size_t *);
93  */
94 size_t
95 vs_columns(SCR *sp, CHAR_T *lp, recno_t lno, size_t *cnop, size_t *diffp)
96 {
97 	size_t chlen, cno, curoff, last = 0, len, scno;
98 	int ch, leftright, listset;
99 	CHAR_T *p;
100 
101 	/*
102 	 * Initialize the screen offset.
103 	 */
104 	scno = 0;
105 
106 	/* Leading number if O_NUMBER option set. */
107 	if (O_ISSET(sp, O_NUMBER))
108 		scno += O_NUMBER_LENGTH;
109 
110 	/* Need the line to go any further. */
111 	if (lp == NULL) {
112 		(void)db_get(sp, lno, 0, &lp, &len);
113 		if (len == 0)
114 			goto done;
115 	}
116 
117 	/* Missing or empty lines are easy. */
118 	if (lp == NULL) {
119 done:		if (diffp != NULL)		/* XXX */
120 			*diffp = 0;
121 		return scno;
122 	}
123 
124 	/* Store away the values of the list and leftright edit options. */
125 	listset = O_ISSET(sp, O_LIST);
126 	leftright = O_ISSET(sp, O_LEFTRIGHT);
127 
128 	/*
129 	 * Initialize the pointer into the buffer and current offset.
130 	 */
131 	p = lp;
132 	curoff = scno;
133 
134 	/* Macro to return the display length of any signal character. */
135 #define	CHLEN(val) (ch = *(UCHAR_T *)p++) == '\t' &&			\
136 	    !listset ? TAB_OFF(val) : KEY_COL(sp, ch);
137 
138 	/*
139 	 * If folding screens (the historic vi screen format), past the end
140 	 * of the current screen, and the character was a tab, reset the
141 	 * current screen column to 0, and the total screen columns to the
142 	 * last column of the screen.  Otherwise, display the rest of the
143 	 * character in the next screen.
144 	 */
145 #define	TAB_RESET do {							\
146 	curoff += chlen;						\
147 	if (!leftright && curoff >= sp->cols) {				\
148 		if (ch == '\t') {					\
149 			curoff = 0;					\
150 			scno -= scno % sp->cols;			\
151 		} else							\
152 			curoff -= sp->cols;				\
153 	}								\
154 } while (0)
155 	if (cnop == NULL)
156 		while (len--) {
157 			chlen = CHLEN(curoff);
158 			last = scno;
159 			scno += chlen;
160 			TAB_RESET;
161 		}
162 	else
163 		for (cno = *cnop;; --cno) {
164 			chlen = CHLEN(curoff);
165 			last = scno;
166 			scno += chlen;
167 			TAB_RESET;
168 			if (cno == 0)
169 				break;
170 		}
171 
172 	/* Add the trailing '$' if the O_LIST option set. */
173 	if (listset && cnop == NULL)
174 		scno += KEY_LEN(sp, '$');
175 
176 	/*
177 	 * The text input screen code needs to know how much additional
178 	 * room the last two characters required, so that it can handle
179 	 * tab character displays correctly.
180 	 */
181 	if (diffp != NULL)
182 		*diffp = scno - last;
183 	return (scno);
184 }
185 
186 /*
187  * vs_rcm --
188  *	Return the physical column from the line that will display a
189  *	character closest to the currently most attractive character
190  *	position (which is stored as a screen column).
191  *
192  * PUBLIC: size_t vs_rcm(SCR *, recno_t, int);
193  */
194 size_t
195 vs_rcm(SCR *sp, recno_t lno, int islast)
196 {
197 	size_t len;
198 
199 	/* Last character is easy, and common. */
200 	if (islast) {
201 		if (db_get(sp, lno, 0, NULL, &len) || len == 0)
202 			return (0);
203 		return (len - 1);
204 	}
205 
206 	/* First character is easy, and common. */
207 	if (sp->rcm == 0)
208 		return (0);
209 
210 	return (vs_colpos(sp, lno, sp->rcm));
211 }
212 
213 /*
214  * vs_colpos --
215  *	Return the physical column from the line that will display a
216  *	character closest to the specified screen column.
217  *
218  * PUBLIC: size_t vs_colpos(SCR *, recno_t, size_t);
219  */
220 size_t
221 vs_colpos(SCR *sp, recno_t lno, size_t cno)
222 {
223 	size_t chlen, curoff, len, llen, off, scno;
224 	int ch = 0, leftright, listset;
225 	CHAR_T *lp, *p;
226 
227 	/* Need the line to go any further. */
228 	(void)db_get(sp, lno, 0, &lp, &llen);
229 
230 	/* Missing or empty lines are easy. */
231 	if (lp == NULL || llen == 0)
232 		return (0);
233 
234 	/* Store away the values of the list and leftright edit options. */
235 	listset = O_ISSET(sp, O_LIST);
236 	leftright = O_ISSET(sp, O_LEFTRIGHT);
237 
238 	/* Discard screen (logical) lines. */
239 	off = cno / sp->cols;
240 	cno %= sp->cols;
241 	for (scno = 0, p = lp, len = llen; off--;) {
242 		for (; len && scno < sp->cols; --len)
243 			scno += CHLEN(scno);
244 
245 		/*
246 		 * If reached the end of the physical line, return the last
247 		 * physical character in the line.
248 		 */
249 		if (len == 0)
250 			return (llen - 1);
251 
252 		/*
253 		 * If folding screens (the historic vi screen format), past
254 		 * the end of the current screen, and the character was a tab,
255 		 * reset the current screen column to 0.  Otherwise, the rest
256 		 * of the character is displayed in the next screen.
257 		 */
258 		if (leftright && ch == '\t')
259 			scno = 0;
260 		else
261 			scno -= sp->cols;
262 	}
263 
264 	/* Step through the line until reach the right character or EOL. */
265 	for (curoff = scno; len--;) {
266 		chlen = CHLEN(curoff);
267 
268 		/*
269 		 * If we've reached the specific character, there are three
270 		 * cases.
271 		 *
272 		 * 1: scno == cno, i.e. the current character ends at the
273 		 *    screen character we care about.
274 		 *	a: off < llen - 1, i.e. not the last character in
275 		 *	   the line, return the offset of the next character.
276 		 *	b: else return the offset of the last character.
277 		 * 2: scno != cno, i.e. this character overruns the character
278 		 *    we care about, return the offset of this character.
279 		 */
280 		if ((scno += chlen) >= cno) {
281 			off = p - lp;
282 			return (scno == cno ?
283 			    (off < llen - 1 ? off : llen - 1) : off - 1);
284 		}
285 
286 		TAB_RESET;
287 	}
288 
289 	/* No such character; return the start of the last character. */
290 	return (llen - 1);
291 }
292