xref: /openbsd/usr.bin/vi/ex/ex_shift.c (revision 404b540a)
1 /*	$OpenBSD: ex_shift.c,v 1.5 2002/02/16 21:27:57 millert Exp $	*/
2 
3 /*-
4  * Copyright (c) 1992, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  * Copyright (c) 1992, 1993, 1994, 1995, 1996
7  *	Keith Bostic.  All rights reserved.
8  *
9  * See the LICENSE file for redistribution information.
10  */
11 
12 #include "config.h"
13 
14 #ifndef lint
15 static const char sccsid[] = "@(#)ex_shift.c	10.11 (Berkeley) 9/15/96";
16 #endif /* not lint */
17 
18 #include <sys/types.h>
19 #include <sys/queue.h>
20 
21 #include <bitstring.h>
22 #include <limits.h>
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <string.h>
26 
27 #include "../common/common.h"
28 
29 enum which {LEFT, RIGHT};
30 static int shift(SCR *, EXCMD *, enum which);
31 
32 /*
33  * ex_shiftl -- :<[<...]
34  *
35  *
36  * PUBLIC: int ex_shiftl(SCR *, EXCMD *);
37  */
38 int
39 ex_shiftl(sp, cmdp)
40 	SCR *sp;
41 	EXCMD *cmdp;
42 {
43 	return (shift(sp, cmdp, LEFT));
44 }
45 
46 /*
47  * ex_shiftr -- :>[>...]
48  *
49  * PUBLIC: int ex_shiftr(SCR *, EXCMD *);
50  */
51 int
52 ex_shiftr(sp, cmdp)
53 	SCR *sp;
54 	EXCMD *cmdp;
55 {
56 	return (shift(sp, cmdp, RIGHT));
57 }
58 
59 /*
60  * shift --
61  *	Ex shift support.
62  */
63 static int
64 shift(sp, cmdp, rl)
65 	SCR *sp;
66 	EXCMD *cmdp;
67 	enum which rl;
68 {
69 	recno_t from, to;
70 	size_t blen, len, newcol, newidx, oldcol, oldidx, sw;
71 	int curset;
72 	char *p, *bp, *tbp;
73 
74 	NEEDFILE(sp, cmdp);
75 
76 	if (O_VAL(sp, O_SHIFTWIDTH) == 0) {
77 		msgq(sp, M_INFO, "152|shiftwidth option set to 0");
78 		return (0);
79 	}
80 
81 	/* Copy the lines being shifted into the unnamed buffer. */
82 	if (cut(sp, NULL, &cmdp->addr1, &cmdp->addr2, CUT_LINEMODE))
83 		return (1);
84 
85 	/*
86 	 * The historic version of vi permitted the user to string any number
87 	 * of '>' or '<' characters together, resulting in an indent of the
88 	 * appropriate levels.  There's a special hack in ex_cmd() so that
89 	 * cmdp->argv[0] points to the string of '>' or '<' characters.
90 	 *
91 	 * Q: What's the difference between the people adding features
92 	 *    to vi and the Girl Scouts?
93 	 * A: The Girl Scouts have mint cookies and adult supervision.
94 	 */
95 	for (p = cmdp->argv[0]->bp, sw = 0; *p == '>' || *p == '<'; ++p)
96 		sw += O_VAL(sp, O_SHIFTWIDTH);
97 
98 	GET_SPACE_RET(sp, bp, blen, 256);
99 
100 	curset = 0;
101 	for (from = cmdp->addr1.lno, to = cmdp->addr2.lno; from <= to; ++from) {
102 		if (db_get(sp, from, DBG_FATAL, &p, &len))
103 			goto err;
104 		if (!len) {
105 			if (sp->lno == from)
106 				curset = 1;
107 			continue;
108 		}
109 
110 		/*
111 		 * Calculate the old indent amount and the number of
112 		 * characters it used.
113 		 */
114 		for (oldidx = 0, oldcol = 0; oldidx < len; ++oldidx)
115 			if (p[oldidx] == ' ')
116 				++oldcol;
117 			else if (p[oldidx] == '\t')
118 				oldcol += O_VAL(sp, O_TABSTOP) -
119 				    oldcol % O_VAL(sp, O_TABSTOP);
120 			else
121 				break;
122 
123 		/* Calculate the new indent amount. */
124 		if (rl == RIGHT)
125 			newcol = oldcol + sw;
126 		else {
127 			newcol = oldcol < sw ? 0 : oldcol - sw;
128 			if (newcol == oldcol) {
129 				if (sp->lno == from)
130 					curset = 1;
131 				continue;
132 			}
133 		}
134 
135 		/* Get a buffer that will hold the new line. */
136 		ADD_SPACE_RET(sp, bp, blen, newcol + len);
137 
138 		/*
139 		 * Build a new indent string and count the number of
140 		 * characters it uses.
141 		 */
142 		for (tbp = bp, newidx = 0;
143 		    newcol >= O_VAL(sp, O_TABSTOP); ++newidx) {
144 			*tbp++ = '\t';
145 			newcol -= O_VAL(sp, O_TABSTOP);
146 		}
147 		for (; newcol > 0; --newcol, ++newidx)
148 			*tbp++ = ' ';
149 
150 		/* Add the original line. */
151 		memcpy(tbp, p + oldidx, len - oldidx);
152 
153 		/* Set the replacement line. */
154 		if (db_set(sp, from, bp, (tbp + (len - oldidx)) - bp)) {
155 err:			FREE_SPACE(sp, bp, blen);
156 			return (1);
157 		}
158 
159 		/*
160 		 * !!!
161 		 * The shift command in historic vi had the usual bizarre
162 		 * collection of cursor semantics.  If called from vi, the
163 		 * cursor was repositioned to the first non-blank character
164 		 * of the lowest numbered line shifted.  If called from ex,
165 		 * the cursor was repositioned to the first non-blank of the
166 		 * highest numbered line shifted.  Here, if the cursor isn't
167 		 * part of the set of lines that are moved, move it to the
168 		 * first non-blank of the last line shifted.  (This makes
169 		 * ":3>>" in vi work reasonably.)  If the cursor is part of
170 		 * the shifted lines, it doesn't get moved at all.  This
171 		 * permits shifting of marked areas, i.e. ">'a." shifts the
172 		 * marked area twice, something that couldn't be done with
173 		 * historic vi.
174 		 */
175 		if (sp->lno == from) {
176 			curset = 1;
177 			if (newidx > oldidx)
178 				sp->cno += newidx - oldidx;
179 			else if (sp->cno >= oldidx - newidx)
180 				sp->cno -= oldidx - newidx;
181 		}
182 	}
183 	if (!curset) {
184 		sp->lno = to;
185 		sp->cno = 0;
186 		(void)nonblank(sp, to, &sp->cno);
187 	}
188 
189 	FREE_SPACE(sp, bp, blen);
190 
191 	sp->rptlines[L_SHIFT] += cmdp->addr2.lno - cmdp->addr1.lno + 1;
192 	return (0);
193 }
194