contrib/nvi/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[] = "@(#)ex_z.c        10.10 (Berkeley) 3/6/96";
  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(sp, cmdp)
  35         SCR *sp;
  36         EXCMD *cmdp;
  37 {
  38         MARK abs;
  39         recno_t cnt, equals, lno;
  40         int eofcheck;
  41
  42         NEEDFILE(sp, cmdp);
  43
  44         /*
  45          * !!!
  46          * If no count specified, use either two times the size of the
  47          * scrolling region, or the size of the window option.  POSIX
  48          * 1003.2 claims that the latter is correct, but historic ex/vi
  49          * documentation and practice appear to use the scrolling region.
  50          * I'm using the window size as it means that the entire screen
  51          * is used instead of losing a line to roundoff.  Note, we drop
  52          * a line from the cnt if using the window size to leave room for
  53          * the next ex prompt.
  54          */
  55         if (FL_ISSET(cmdp->iflags, E_C_COUNT))
  56                 cnt = cmdp->count;
  57         else
  58 #ifdef HISTORIC_PRACTICE
  59                 cnt = O_VAL(sp, O_SCROLL) * 2;
  60 #else
  61                 cnt = O_VAL(sp, O_WINDOW) - 1;
  62 #endif
  63
  64         equals = 0;
  65         eofcheck = 0;
  66         lno = cmdp->addr1.lno;
  67
  68         switch (FL_ISSET(cmdp->iflags,
  69             E_C_CARAT | E_C_DASH | E_C_DOT | E_C_EQUAL | E_C_PLUS)) {
  70         case E_C_CARAT:         /* Display cnt * 2 before the line. */
  71                 eofcheck = 1;
  72                 if (lno > cnt * 2)
  73                         cmdp->addr1.lno = (lno - cnt * 2) + 1;
  74                 else
  75                         cmdp->addr1.lno = 1;
  76                 cmdp->addr2.lno = (cmdp->addr1.lno + cnt) - 1;
  77                 break;
  78         case E_C_DASH:          /* Line goes at the bottom of the screen. */
  79                 cmdp->addr1.lno = lno > cnt ? (lno - cnt) + 1 : 1;
  80                 cmdp->addr2.lno = lno;
  81                 break;
  82         case E_C_DOT:           /* Line goes in the middle of the screen. */
  83                 /*
  84                  * !!!
  85                  * Historically, the "middleness" of the line overrode the
  86                  * count, so that "3z.19" or "3z.20" would display the first
  87                  * 12 lines of the file, i.e. (N - 1) / 2 lines before and
  88                  * after the specified line.
  89                  */
  90                 eofcheck = 1;
  91                 cnt = (cnt - 1) / 2;
  92                 cmdp->addr1.lno = lno > cnt ? lno - cnt : 1;
  93                 cmdp->addr2.lno = lno + cnt;
  94
  95                 /*
  96                  * !!!
  97                  * Historically, z. set the absolute cursor mark.
  98                  */
  99                 abs.lno = sp->lno;
 100                 abs.cno = sp->cno;
 101                 (void)mark_set(sp, ABSMARK1, &abs, 1);
 102                 break;
 103         case E_C_EQUAL:         /* Center with hyphens. */
 104                 /*
 105                  * !!!
 106                  * Strangeness.  The '=' flag is like the '.' flag (see the
 107                  * above comment, it applies here as well) but with a special
 108                  * little hack.  Print out lines of hyphens before and after
 109                  * the specified line.  Additionally, the cursor remains set
 110                  * on that line.
 111                  */
 112                 eofcheck = 1;
 113                 cnt = (cnt - 1) / 2;
 114                 cmdp->addr1.lno = lno > cnt ? lno - cnt : 1;
 115                 cmdp->addr2.lno = lno - 1;
 116                 if (ex_pr(sp, cmdp))
 117                         return (1);
 118                 (void)ex_puts(sp, "----------------------------------------\n");
 119                 cmdp->addr2.lno = cmdp->addr1.lno = equals = lno;
 120                 if (ex_pr(sp, cmdp))
 121                         return (1);
 122                 (void)ex_puts(sp, "----------------------------------------\n");
 123                 cmdp->addr1.lno = lno + 1;
 124                 cmdp->addr2.lno = (lno + cnt) - 1;
 125                 break;
 126         default:
 127                 /* If no line specified, move to the next one. */
 128                 if (F_ISSET(cmdp, E_ADDR_DEF))
 129                         ++lno;
 130                 /* FALLTHROUGH */
 131         case E_C_PLUS:          /* Line goes at the top of the screen. */
 132                 eofcheck = 1;
 133                 cmdp->addr1.lno = lno;
 134                 cmdp->addr2.lno = (lno + cnt) - 1;
 135                 break;
 136         }
 137
 138         if (eofcheck) {
 139                 if (db_last(sp, &lno))
 140                         return (1);
 141                 if (cmdp->addr2.lno > lno)
 142                         cmdp->addr2.lno = lno;
 143         }
 144
 145         if (ex_pr(sp, cmdp))
 146                 return (1);
 147         if (equals)
 148                 sp->lno = equals;
 149         return (0);
 150 }