common/mark.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: mark.c,v 8.11 1993/12/09 19:42:11 bostic Exp $ (Berkeley) $Date: 1993/12/09 19:42:11 $";
  10 #endif /* not lint */
  11
  12 #include <sys/types.h>
  13
  14 #include <errno.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17
  18 #include "vi.h"
  19
  20 static MARK *mark_find __P((SCR *, EXF *, ARG_CHAR_T));
  21
  22 /*
  23  * Marks are maintained in a key sorted doubly linked list.  We can't
  24  * use arrays because we have no idea how big an index key could be.
  25  * The underlying assumption is that users don't have more than, say,
  26  * 10 marks at any one time, so this will be is fast enough.
  27  *
  28  * Marks are fixed, and modifications to the line don't update the mark's
  29  * position in the line.  This can be hard.  If you add text to the line,
  30  * place a mark in that text, undo the addition and use ` to move to the
  31  * mark, the location will have disappeared.  It's tempting to try to adjust
  32  * the mark with the changes in the line, but this is hard to do, especially
  33  * if we've given the line to v_ntext.c:v_ntext() for editing.  Historic vi
  34  * would move to the first non-blank on the line when the mark location was
  35  * past the end of the line.  This can be complicated by deleting to a mark
  36  * that has disappeared using the ` command.  Historic vi vi treated this as
  37  * a line-mode motion and deleted the line.  This implementation complains to
  38  * the user.
  39  *
  40  * In historic vi, marks returned if the operation was undone, unless the
  41  * mark had been subsequently reset.  Tricky.  This is hard to start with,
  42  * but in the presence of repeated undo it gets nasty.  When a line is
  43  * deleted, we delete (and log) any marks on that line.  An undo will create
  44  * the mark.  Any mark creations are noted as to whether the user created
  45  * it or if it was created by an undo.  The former cannot be reset by another
  46  * undo, but the latter may.
  47  *
  48  * All of these routines translate ABSMARK2 to ABSMARK1.  Setting either of
  49  * the absolute mark locations sets both, so that "m'" and "m`" work like
  50  * they, ah, for lack of a better word, "should".
  51  */
  52
  53 /*
  54  * mark_init --
  55  *      Set up the marks.
  56  */
  57 int
  58 mark_init(sp, ep)
  59         SCR *sp;
  60         EXF *ep;
  61 {
  62         MARK *mp;
  63
  64         /*
  65          * Make sure the marks have been set up.  If they
  66          * haven't, do so, and create the absolute mark.
  67          */
  68         MALLOC_RET(sp, mp, MARK *, sizeof(MARK));
  69         mp->lno = 1;
  70         mp->cno = 0;
  71         mp->name = ABSMARK1;
  72         mp->flags = 0;
  73         LIST_INSERT_HEAD(&ep->marks, mp, q);
  74         return (0);
  75 }
  76
  77 /*
  78  * mark_end --
  79  *      Free up the marks.
  80  */
  81 int
  82 mark_end(sp, ep)
  83         SCR *sp;
  84         EXF *ep;
  85 {
  86         MARK *mp;
  87
  88         while ((mp = ep->marks.lh_first) != NULL) {
  89                 LIST_REMOVE(mp, q);
  90                 FREE(mp, sizeof(MARK));
  91         }
  92         return (0);
  93 }
  94
  95 /*
  96  * mark_get --
  97  *      Get the location referenced by a mark.
  98  */
  99 MARK *
 100 mark_get(sp, ep, key)
 101         SCR *sp;
 102         EXF *ep;
 103         ARG_CHAR_T key;
 104 {
 105         MARK *mp;
 106         size_t len;
 107         char *p;
 108
 109         if (key == ABSMARK2)
 110                 key = ABSMARK1;
 111
 112         mp = mark_find(sp, ep, key);
 113         if (mp == NULL || mp->name != key) {
 114                 msgq(sp, M_BERR, "Mark %s: not set.", charname(sp, key));
 115                 return (NULL);
 116         }
 117         if (F_ISSET(mp, MARK_DELETED)) {
 118                 msgq(sp, M_BERR,
 119                     "Mark %s: the line was deleted.", charname(sp, key));
 120                 return (NULL);
 121         }
 122         if ((p = file_gline(sp, ep, mp->lno, &len)) == NULL ||
 123             mp->cno > len || mp->cno == len && len != 0) {
 124                 msgq(sp, M_BERR, "Mark %s: cursor position no longer exists.",
 125                     charname(sp, key));
 126                 return (NULL);
 127         }
 128         return (mp);
 129 }
 130
 131 /*
 132  * mark_set --
 133  *      Set the location referenced by a mark.
 134  */
 135 int
 136 mark_set(sp, ep, key, value, userset)
 137         SCR *sp;
 138         EXF *ep;
 139         ARG_CHAR_T key;
 140         MARK *value;
 141         int userset;
 142 {
 143         MARK *mp, *mt;
 144
 145         if (key == ABSMARK2)
 146                 key = ABSMARK1;
 147
 148         /*
 149          * The rules are simple.  If the user is setting a mark (if it's a
 150          * new mark this is always true), it always happens.  If not, it's
 151          * an undo, and we set it if it's not already set or if it was set
 152          * by a previous undo.
 153          */
 154         mp = mark_find(sp, ep, key);
 155         if (mp == NULL || mp->name != key) {
 156                 MALLOC_RET(sp, mt, MARK *, sizeof(MARK));
 157                 if (mp == NULL) {
 158                         LIST_INSERT_HEAD(&ep->marks, mt, q);
 159                 } else
 160                         LIST_INSERT_AFTER(mp, mt, q);
 161                 mp = mt;
 162         } else if (!userset &&
 163             !F_ISSET(mp, MARK_DELETED) && F_ISSET(mp, MARK_USERSET))
 164                 return (0);
 165
 166         mp->lno = value->lno;
 167         mp->cno = value->cno;
 168         mp->name = key;
 169         mp->flags = userset ? MARK_USERSET : 0;
 170         return (0);
 171 }
 172
 173 /*
 174  * mark_find --
 175  *      Find the requested mark, or, the slot immediately before
 176  *      where it would go.
 177  */
 178 static MARK *
 179 mark_find(sp, ep, key)
 180         SCR *sp;
 181         EXF *ep;
 182         ARG_CHAR_T key;
 183 {
 184         MARK *mp, *lastmp;
 185
 186         /*
 187          * Return the requested mark or the slot immediately before
 188          * where it should go.
 189          */
 190         for (lastmp = NULL, mp = ep->marks.lh_first;
 191             mp != NULL; lastmp = mp, mp = mp->q.le_next)
 192                 if (mp->name >= key)
 193                         return (mp->name == key ? mp : lastmp);
 194         return (lastmp);
 195 }
 196
 197 /*
 198  * mark_delete --
 199  *      Update the marks based on a deletion.
 200  */
 201 void
 202 mark_delete(sp, ep, lno)
 203         SCR *sp;
 204         EXF *ep;
 205         recno_t lno;
 206 {
 207         MARK *mp;
 208
 209         for (mp = ep->marks.lh_first; mp != NULL; mp = mp->q.le_next)
 210                 if (mp->lno >= lno)
 211                         if (mp->lno == lno) {
 212                                 F_SET(mp, MARK_DELETED);
 213                                 (void)log_mark(sp, ep, mp);
 214                         } else
 215                                 --mp->lno;
 216 }
 217
 218 /*
 219  * mark_insert --
 220  *      Update the marks based on an insertion.
 221  */
 222 void
 223 mark_insert(sp, ep, lno)
 224         SCR *sp;
 225         EXF *ep;
 226         recno_t lno;
 227 {
 228         MARK *mp;
 229
 230         for (mp = ep->marks.lh_first; mp != NULL; mp = mp->q.le_next)
 231                 if (mp->lno >= lno)
 232                         ++mp->lno;
 233 }