xref: /minix/external/bsd/nvi/dist/vi/vs_relative.c (revision ebfedea0)
1 /*	$NetBSD: vs_relative.c,v 1.2 2013/11/22 15:52:06 christos Exp $ */
2 /*-
3  * Copyright (c) 1993, 1994
4  *	The Regents of the University of California.  All rights reserved.
5  * Copyright (c) 1993, 1994, 1995, 1996
6  *	Keith Bostic.  All rights reserved.
7  *
8  * See the LICENSE file for redistribution information.
9  */
10 
11 #include "config.h"
12 
13 #ifndef lint
14 static const char sccsid[] = "Id: vs_relative.c,v 10.18 2001/07/08 13:02:48 skimo Exp  (Berkeley) Date: 2001/07/08 13:02:48 ";
15 #endif /* not lint */
16 
17 #include <sys/types.h>
18 #include <sys/queue.h>
19 #include <sys/time.h>
20 
21 #include <bitstring.h>
22 #include <limits.h>
23 #include <stdio.h>
24 #include <string.h>
25 
26 #include "../common/common.h"
27 #include "vi.h"
28 
29 /*
30  * vs_column --
31  *	Return the logical column of the cursor in the line.
32  *
33  * PUBLIC: int vs_column __P((SCR *, size_t *));
34  */
35 int
36 vs_column(SCR *sp, size_t *colp)
37 {
38 	VI_PRIVATE *vip;
39 
40 	vip = VIP(sp);
41 
42 	*colp = (O_ISSET(sp, O_LEFTRIGHT) ?
43 	    vip->sc_smap->coff : (vip->sc_smap->soff - 1) * sp->cols) +
44 	    vip->sc_col - (O_ISSET(sp, O_NUMBER) ? O_NUMBER_LENGTH : 0);
45 	return (0);
46 }
47 
48 /*
49  * vs_screens --
50  *	Return the screens necessary to display the line, or if specified,
51  *	the physical character column within the line, including space
52  *	required for the O_NUMBER and O_LIST options.
53  *
54  * PUBLIC: size_t vs_screens __P((SCR *, db_recno_t, size_t *));
55  */
56 size_t
57 vs_screens(SCR *sp, db_recno_t lno, size_t *cnop)
58 {
59 	size_t cols, screens;
60 
61 	/* Left-right screens are simple, it's always 1. */
62 	if (O_ISSET(sp, O_LEFTRIGHT))
63 		return (1);
64 
65 	/*
66 	 * Check for a cached value.  We maintain a cache because, if the
67 	 * line is large, this routine gets called repeatedly.  One other
68 	 * hack, lots of time the cursor is on column one, which is an easy
69 	 * one.
70 	 */
71 	if (cnop == NULL) {
72 		if (VIP(sp)->ss_lno == lno)
73 			return (VIP(sp)->ss_screens);
74 	} else if (*cnop == 0)
75 		return (1);
76 
77 	/* Figure out how many columns the line/column needs. */
78 	cols = vs_columns(sp, NULL, lno, cnop, NULL);
79 
80 	screens = (cols / sp->cols + (cols % sp->cols ? 1 : 0));
81 	if (screens == 0)
82 		screens = 1;
83 
84 	/* Cache the value. */
85 	if (cnop == NULL) {
86 		VIP(sp)->ss_lno = lno;
87 		VIP(sp)->ss_screens = screens;
88 	}
89 	return (screens);
90 }
91 
92 /*
93  * vs_columns --
94  *	Return the screen columns necessary to display the line, or,
95  *	if specified, the physical character column within the line.
96  *
97  * PUBLIC: size_t vs_columns __P((SCR *, CHAR_T *, db_recno_t, size_t *, size_t *));
98  */
99 size_t
100 vs_columns(SCR *sp, CHAR_T *lp, db_recno_t lno, size_t *cnop, size_t *diffp)
101 {
102 	size_t chlen, cno, curoff, last = 0, len, scno;
103 	int ch, leftright, listset;
104 	CHAR_T *p;
105 
106 	/*
107 	 * Initialize the screen offset.
108 	 */
109 	scno = 0;
110 
111 	/* Leading number if O_NUMBER option set. */
112 	if (O_ISSET(sp, O_NUMBER))
113 		scno += O_NUMBER_LENGTH;
114 
115 	/* Need the line to go any further. */
116 	if (lp == NULL) {
117 		(void)db_get(sp, lno, 0, &lp, &len);
118 		if (len == 0)
119 			goto done;
120 	}
121 
122 	/* Missing or empty lines are easy. */
123 	if (lp == NULL) {
124 done:		if (diffp != NULL)		/* XXX */
125 			*diffp = 0;
126 		return scno;
127 	}
128 
129 	/* Store away the values of the list and leftright edit options. */
130 	listset = O_ISSET(sp, O_LIST);
131 	leftright = O_ISSET(sp, O_LEFTRIGHT);
132 
133 	/*
134 	 * Initialize the pointer into the buffer and current offset.
135 	 */
136 	p = lp;
137 	curoff = 0;
138 
139 	/* Macro to return the display length of any signal character. */
140 #define	CHLEN(val) (ch = *(UCHAR_T *)p++) == '\t' &&			\
141 	    !listset ? TAB_OFF(val) : KEY_COL(sp, ch);
142 
143 	/*
144 	 * If folding screens (the historic vi screen format), past the end
145 	 * of the current screen, and the character was a tab, reset the
146 	 * current screen column to 0, and the total screen columns to the
147 	 * last column of the screen.  Otherwise, display the rest of the
148 	 * character in the next screen.
149 	 */
150 #define	TAB_RESET {							\
151 	curoff += chlen;						\
152 	if (!leftright && curoff >= sp->cols) {				\
153 		if (ch == '\t') {					\
154 			curoff = 0;					\
155 			scno -= scno % sp->cols;			\
156 		} else							\
157 			curoff -= sp->cols;				\
158 	}								\
159 }
160 	if (cnop == NULL)
161 		while (len--) {
162 			chlen = CHLEN(curoff);
163 			last = scno;
164 			scno += chlen;
165 			TAB_RESET;
166 		}
167 	else
168 		for (cno = *cnop;; --cno) {
169 			chlen = CHLEN(curoff);
170 			last = scno;
171 			scno += chlen;
172 			TAB_RESET;
173 			if (cno == 0)
174 				break;
175 		}
176 
177 	/* Add the trailing '$' if the O_LIST option set. */
178 	if (listset && cnop == NULL)
179 		scno += KEY_LEN(sp, '$');
180 
181 	/*
182 	 * The text input screen code needs to know how much additional
183 	 * room the last two characters required, so that it can handle
184 	 * tab character displays correctly.
185 	 */
186 	if (diffp != NULL)
187 		*diffp = scno - last;
188 	return (scno);
189 }
190 
191 /*
192  * vs_rcm --
193  *	Return the physical column from the line that will display a
194  *	character closest to the currently most attractive character
195  *	position (which is stored as a screen column).
196  *
197  * PUBLIC: size_t vs_rcm __P((SCR *, db_recno_t, int));
198  */
199 size_t
200 vs_rcm(SCR *sp, db_recno_t lno, int islast)
201 {
202 	size_t len;
203 
204 	/* Last character is easy, and common. */
205 	if (islast) {
206 		if (db_get(sp, lno, 0, NULL, &len) || len == 0)
207 			return (0);
208 		return (len - 1);
209 	}
210 
211 	/* First character is easy, and common. */
212 	if (sp->rcm == 0)
213 		return (0);
214 
215 	return (vs_colpos(sp, lno, sp->rcm));
216 }
217 
218 /*
219  * vs_colpos --
220  *	Return the physical column from the line that will display a
221  *	character closest to the specified screen column.
222  *
223  * PUBLIC: size_t vs_colpos __P((SCR *, db_recno_t, size_t));
224  */
225 size_t
226 vs_colpos(SCR *sp, db_recno_t lno, size_t cno)
227 {
228 	size_t chlen, curoff, len, llen, off, scno;
229 	int ch = 0, leftright, listset;
230 	CHAR_T *lp, *p;
231 
232 	/* Need the line to go any further. */
233 	(void)db_get(sp, lno, 0, &lp, &llen);
234 
235 	/* Missing or empty lines are easy. */
236 	if (lp == NULL || llen == 0)
237 		return (0);
238 
239 	/* Store away the values of the list and leftright edit options. */
240 	listset = O_ISSET(sp, O_LIST);
241 	leftright = O_ISSET(sp, O_LEFTRIGHT);
242 
243 	/* Discard screen (logical) lines. */
244 	off = cno / sp->cols;
245 	cno %= sp->cols;
246 	for (scno = 0, p = lp, len = llen; off--;) {
247 		for (; len && scno < sp->cols; --len)
248 			scno += CHLEN(scno);
249 
250 		/*
251 		 * If reached the end of the physical line, return the last
252 		 * physical character in the line.
253 		 */
254 		if (len == 0)
255 			return (llen - 1);
256 
257 		/*
258 		 * If folding screens (the historic vi screen format), past
259 		 * the end of the current screen, and the character was a tab,
260 		 * reset the current screen column to 0.  Otherwise, the rest
261 		 * of the character is displayed in the next screen.
262 		 */
263 		if (leftright && ch == '\t')
264 			scno = 0;
265 		else
266 			scno -= sp->cols;
267 	}
268 
269 	/* Step through the line until reach the right character or EOL. */
270 	for (curoff = scno; len--;) {
271 		chlen = CHLEN(curoff);
272 
273 		/*
274 		 * If we've reached the specific character, there are three
275 		 * cases.
276 		 *
277 		 * 1: scno == cno, i.e. the current character ends at the
278 		 *    screen character we care about.
279 		 *	a: off < llen - 1, i.e. not the last character in
280 		 *	   the line, return the offset of the next character.
281 		 *	b: else return the offset of the last character.
282 		 * 2: scno != cno, i.e. this character overruns the character
283 		 *    we care about, return the offset of this character.
284 		 */
285 		if ((scno += chlen) >= cno) {
286 			off = p - lp;
287 			return (scno == cno ?
288 			    (off < llen - 1 ? off : llen - 1) : off - 1);
289 		}
290 
291 		TAB_RESET;
292 	}
293 
294 	/* No such character; return the start of the last character. */
295 	return (llen - 1);
296 }
297