ex/ex_shift.c

   1 /*-
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * %sccs.include.redist.c%
   6  */
   7
   8 #ifndef lint
   9 static char sccsid[] = "$Id: ex_shift.c,v 8.8 1993/11/30 16:30:50 bostic Exp $ (Berkeley) $Date: 1993/11/30 16:30:50 $";
  10 #endif /* not lint */
  11
  12 #include <sys/types.h>
  13
  14 #include <stdlib.h>
  15 #include <string.h>
  16
  17 #include "vi.h"
  18 #include "excmd.h"
  19
  20 enum which {LEFT, RIGHT};
  21 static int shift __P((SCR *, EXF *, EXCMDARG *, enum which));
  22
  23 int
  24 ex_shiftl(sp, ep, cmdp)
  25         SCR *sp;
  26         EXF *ep;
  27         EXCMDARG *cmdp;
  28 {
  29         return (shift(sp, ep, cmdp, LEFT));
  30 }
  31
  32 int
  33 ex_shiftr(sp, ep, cmdp)
  34         SCR *sp;
  35         EXF *ep;
  36         EXCMDARG *cmdp;
  37 {
  38         return (shift(sp, ep, cmdp, RIGHT));
  39 }
  40
  41 static int
  42 shift(sp, ep, cmdp, rl)
  43         SCR *sp;
  44         EXF *ep;
  45         EXCMDARG *cmdp;
  46         enum which rl;
  47 {
  48         recno_t from, to;
  49         size_t blen, len, newcol, newidx, oldcol, oldidx, sw;
  50         int curset;
  51         char *p, *bp, *tbp;
  52
  53         if (O_VAL(sp, O_SHIFTWIDTH) == 0) {
  54                 msgq(sp, M_INFO, "shiftwidth option set to 0");
  55                 return (0);
  56         }
  57
  58         /*
  59          * The historic version of vi permitted the user to string any number
  60          * of '>' or '<' characters together, resulting in an indent of the
  61          * appropriate levels.  There's a special hack in ex_cmd() so that
  62          * cmdp->argv[0] points to the string of '>' or '<' characters, but it
  63          * may not be nul terminated.
  64          *
  65          * Q: What's the difference between the people adding features
  66          *    to vi and the Girl Scouts?
  67          * A: The Girl Scouts have mint cookies and adult supervision.
  68          */
  69         for (p = cmdp->argv[0], sw = 0; *p == '>' || *p == '<'; ++p)
  70                 sw += O_VAL(sp, O_SHIFTWIDTH);
  71
  72         GET_SPACE(sp, bp, blen, 256);
  73
  74         curset = 0;
  75         for (from = cmdp->addr1.lno, to = cmdp->addr2.lno; from <= to; ++from) {
  76                 if ((p = file_gline(sp, ep, from, &len)) == NULL)
  77                         goto err;
  78                 if (!len) {
  79                         if (sp->lno == from)
  80                                 curset = 1;
  81                         continue;
  82                 }
  83
  84                 /*
  85                  * Calculate the old indent amount and the number of
  86                  * characters it used.
  87                  */
  88                 for (oldidx = 0, oldcol = 0; oldidx < len; ++oldidx)
  89                         if (p[oldidx] == ' ')
  90                                 ++oldcol;
  91                         else if (p[oldidx] == '\t')
  92                                 oldcol += O_VAL(sp, O_TABSTOP) -
  93                                     oldcol % O_VAL(sp, O_TABSTOP);
  94                         else
  95                                 break;
  96
  97                 /* Calculate the new indent amount. */
  98                 if (rl == RIGHT)
  99                         newcol = oldcol + sw;
 100                 else {
 101                         newcol = oldcol < sw ? 0 : oldcol - sw;
 102                         if (newcol == oldcol) {
 103                                 if (sp->lno == from)
 104                                         curset = 1;
 105                                 continue;
 106                         }
 107                 }
 108
 109                 /* Get a buffer that will hold the new line. */
 110                 ADD_SPACE(sp, bp, blen, newcol + len);
 111
 112                 /*
 113                  * Build a new indent string and count the number of
 114                  * characters it uses.
 115                  */
 116                 for (tbp = bp, newidx = 0;
 117                     newcol >= O_VAL(sp, O_TABSTOP); ++newidx) {
 118                         *tbp++ = '\t';
 119                         newcol -= O_VAL(sp, O_TABSTOP);
 120                 }
 121                 for (; newcol > 0; --newcol, ++newidx)
 122                         *tbp++ = ' ';
 123
 124                 /* Add the original line. */
 125                 memmove(tbp, p + oldidx, len - oldidx);
 126
 127                 /* Set the replacement line. */
 128                 if (file_sline(sp, ep, from, bp, (tbp + (len - oldidx)) - bp)) {
 129 err:                    FREE_SPACE(sp, bp, blen);
 130                         return (1);
 131                 }
 132
 133                 /*
 134                  * !!!
 135                  * The shift command in historic vi had the usual bizarre
 136                  * collection of cursor semantics.  If called from vi, the
 137                  * cursor was repositioned to the first non-blank character
 138                  * of the lowest numbered line shifted.  If called from ex,
 139                  * the cursor was repositioned to the first non-blank of the
 140                  * highest numbered line shifted.  Here, if the cursor isn't
 141                  * part of the set of lines that are moved, move it to the
 142                  * first non-blank of the last line shifted.  (This makes
 143                  * ":3>>" in vi work reasonably.)  If the cursor is part of
 144                  * the shifted lines, it doesn't get moved at all.  This
 145                  * permits shifting of marked areas, i.e. ">'a." shifts the
 146                  * marked area twice, something that couldn't be done with
 147                  * historic vi.
 148                  */
 149                 if (sp->lno == from) {
 150                         curset = 1;
 151                         if (newidx > oldidx)
 152                                 sp->cno += newidx - oldidx;
 153                         else if (sp->cno >= oldidx - newidx)
 154                                 sp->cno -= oldidx - newidx;
 155                 }
 156         }
 157         if (!curset) {
 158                 sp->lno = to;
 159                 sp->cno = 0;
 160                 (void)nonblank(sp, ep, to, &sp->cno);
 161         }
 162
 163         FREE_SPACE(sp, bp, blen);
 164
 165         sp->rptlines[rl == RIGHT ? L_RSHIFT : L_LSHIFT] +=
 166             cmdp->addr2.lno - cmdp->addr1.lno + 1;
 167
 168         F_SET(sp, S_AUTOPRINT);
 169         return (0);
 170 }