ex/ex_z.c

   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 #ifndef lint
  13 static const char sccsid[] = "$Id: ex_z.c,v 10.12 2001/06/25 15:19:22 skimo Exp $ (Berkeley) $Date: 2001/06/25 15:19:22 $";
  14 #endif /* not lint */
  15
  16 #include <sys/types.h>
  17 #include <sys/queue.h>
  18
  19 #include <bitstring.h>
  20 #include <limits.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 #include "../common/common.h"
  26
  27 /*
  28  * ex_z -- :[line] z [^-.+=] [count] [flags]
  29  *      Adjust window.
  30  *
  31  * PUBLIC: int ex_z __P((SCR *, EXCMD *));
  32  */
  33 int
  34 ex_z(SCR *sp, EXCMD *cmdp)
  35 {
  36         MARK abs;
  37         db_recno_t cnt, equals, lno;
  38         int eofcheck;
  39
  40         NEEDFILE(sp, cmdp);
  41
  42         /*
  43          * !!!
  44          * If no count specified, use either two times the size of the
  45          * scrolling region, or the size of the window option.  POSIX
  46          * 1003.2 claims that the latter is correct, but historic ex/vi
  47          * documentation and practice appear to use the scrolling region.
  48          * I'm using the window size as it means that the entire screen
  49          * is used instead of losing a line to roundoff.  Note, we drop
  50          * a line from the cnt if using the window size to leave room for
  51          * the next ex prompt.
  52          */
  53         if (FL_ISSET(cmdp->iflags, E_C_COUNT))
  54                 cnt = cmdp->count;
  55         else
  56 #ifdef HISTORIC_PRACTICE
  57                 cnt = O_VAL(sp, O_SCROLL) * 2;
  58 #else
  59                 cnt = O_VAL(sp, O_WINDOW) - 1;
  60 #endif
  61
  62         equals = 0;
  63         eofcheck = 0;
  64         lno = cmdp->addr1.lno;
  65
  66         switch (FL_ISSET(cmdp->iflags,
  67             E_C_CARAT | E_C_DASH | E_C_DOT | E_C_EQUAL | E_C_PLUS)) {
  68         case E_C_CARAT:         /* Display cnt * 2 before the line. */
  69                 eofcheck = 1;
  70                 if (lno > cnt * 2)
  71                         cmdp->addr1.lno = (lno - cnt * 2) + 1;
  72                 else
  73                         cmdp->addr1.lno = 1;
  74                 cmdp->addr2.lno = (cmdp->addr1.lno + cnt) - 1;
  75                 break;
  76         case E_C_DASH:          /* Line goes at the bottom of the screen. */
  77                 cmdp->addr1.lno = lno > cnt ? (lno - cnt) + 1 : 1;
  78                 cmdp->addr2.lno = lno;
  79                 break;
  80         case E_C_DOT:           /* Line goes in the middle of the screen. */
  81                 /*
  82                  * !!!
  83                  * Historically, the "middleness" of the line overrode the
  84                  * count, so that "3z.19" or "3z.20" would display the first
  85                  * 12 lines of the file, i.e. (N - 1) / 2 lines before and
  86                  * after the specified line.
  87                  */
  88                 eofcheck = 1;
  89                 cnt = (cnt - 1) / 2;
  90                 cmdp->addr1.lno = lno > cnt ? lno - cnt : 1;
  91                 cmdp->addr2.lno = lno + cnt;
  92
  93                 /*
  94                  * !!!
  95                  * Historically, z. set the absolute cursor mark.
  96                  */
  97                 abs.lno = sp->lno;
  98                 abs.cno = sp->cno;
  99                 (void)mark_set(sp, ABSMARK1, &abs, 1);
 100                 break;
 101         case E_C_EQUAL:         /* Center with hyphens. */
 102                 /*
 103                  * !!!
 104                  * Strangeness.  The '=' flag is like the '.' flag (see the
 105                  * above comment, it applies here as well) but with a special
 106                  * little hack.  Print out lines of hyphens before and after
 107                  * the specified line.  Additionally, the cursor remains set
 108                  * on that line.
 109                  */
 110                 eofcheck = 1;
 111                 cnt = (cnt - 1) / 2;
 112                 cmdp->addr1.lno = lno > cnt ? lno - cnt : 1;
 113                 cmdp->addr2.lno = lno - 1;
 114                 if (ex_pr(sp, cmdp))
 115                         return (1);
 116                 (void)ex_puts(sp, "----------------------------------------\n");
 117                 cmdp->addr2.lno = cmdp->addr1.lno = equals = lno;
 118                 if (ex_pr(sp, cmdp))
 119                         return (1);
 120                 (void)ex_puts(sp, "----------------------------------------\n");
 121                 cmdp->addr1.lno = lno + 1;
 122                 cmdp->addr2.lno = (lno + cnt) - 1;
 123                 break;
 124         default:
 125                 /* If no line specified, move to the next one. */
 126                 if (F_ISSET(cmdp, E_ADDR_DEF))
 127                         ++lno;
 128                 /* FALLTHROUGH */
 129         case E_C_PLUS:          /* Line goes at the top of the screen. */
 130                 eofcheck = 1;
 131                 cmdp->addr1.lno = lno;
 132                 cmdp->addr2.lno = (lno + cnt) - 1;
 133                 break;
 134         }
 135
 136         if (eofcheck) {
 137                 if (db_last(sp, &lno))
 138                         return (1);
 139                 if (cmdp->addr2.lno > lno)
 140                         cmdp->addr2.lno = lno;
 141         }
 142
 143         if (ex_pr(sp, cmdp))
 144                 return (1);
 145         if (equals)
 146                 sp->lno = equals;
 147         return (0);
 148 }