ex/ex_z.c

   1 /*-
   2  * Copyright (c) 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_z.c,v 8.4 1993/12/02 14:02:39 bostic Exp $ (Berkeley) $Date: 1993/12/02 14:02:39 $";
  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 /*
  21  * ex_z -- :[line] z [^-.+=] [count] [flags]
  22  *
  23  *      Adjust window.
  24  */
  25 int
  26 ex_z(sp, ep, cmdp)
  27         SCR *sp;
  28         EXF *ep;
  29         EXCMDARG *cmdp;
  30 {
  31         recno_t cnt, equals, lno;
  32         int eofcheck;
  33
  34         /*
  35          * !!!
  36          * If no count specified, use either two times the size of the
  37          * scrolling region, or the size of the window option.  POSIX
  38          * 1003.2 claims that the latter is correct, but historic ex/vi
  39          * documentation and practice appear to use the scrolling region.
  40          * I'm using the window size as it means that the entire screen
  41          * is used instead of losing a line to roundoff.  Note, we drop
  42          * a line from the cnt if using the window size to leave room for
  43          * the next ex prompt.
  44          */
  45         if (F_ISSET(cmdp, E_COUNT))
  46                 cnt = cmdp->count;
  47         else
  48 #ifdef HISTORIC_PRACTICE
  49                 cnt = O_VAL(sp, O_SCROLL) * 2;
  50 #else
  51                 cnt = O_VAL(sp, O_WINDOW) - 1;
  52 #endif
  53
  54         equals = 0;
  55         eofcheck = 0;
  56         lno = cmdp->addr1.lno;
  57
  58         switch (F_ISSET(cmdp,
  59             E_F_CARAT | E_F_DASH | E_F_DOT | E_F_EQUAL | E_F_PLUS)) {
  60         case E_F_CARAT:         /* Display cnt * 2 before the line. */
  61                 eofcheck = 1;
  62                 if (lno > cnt * 2)
  63                         cmdp->addr1.lno = (lno - cnt * 2) + 1;
  64                 else
  65                         cmdp->addr1.lno = 1;
  66                 cmdp->addr2.lno = (cmdp->addr1.lno + cnt) - 1;
  67                 break;
  68         case E_F_DASH:          /* Line goes at the bottom of the screen. */
  69                 cmdp->addr1.lno = lno > cnt ? (lno - cnt) + 1 : 1;
  70                 cmdp->addr2.lno = lno;
  71                 break;
  72         case E_F_DOT:           /* Line goes in the middle of the screen. */
  73                 /*
  74                  * !!!
  75                  * Historically, the "middleness" of the line overrode the
  76                  * count, so that "3z.19" or "3z.20" would display the first
  77                  * 12 lines of the file, i.e. (N - 1) / 2 lines before and
  78                  * after the specified line.
  79                  */
  80                 eofcheck = 1;
  81                 cnt = (cnt - 1) / 2;
  82                 cmdp->addr1.lno = lno > cnt ? lno - cnt : 1;
  83                 cmdp->addr2.lno = lno + cnt;
  84                 break;
  85         case E_F_EQUAL:         /* Center with hyphens. */
  86                 /*
  87                  * !!!
  88                  * Strangeness.  The '=' flag is like the '.' flag (see the
  89                  * above comment, it applies here as well) but with a special
  90                  * little hack.  Print out lines of hyphens before and after
  91                  * the specified line.  Additionally, the cursor remains set
  92                  * on that line.
  93                  */
  94                 eofcheck = 1;
  95                 cnt = (cnt - 1) / 2;
  96                 cmdp->addr1.lno = lno > cnt ? lno - cnt : 1;
  97                 cmdp->addr2.lno = lno - 1;
  98                 if (ex_pr(sp, ep, cmdp))
  99                         return (1);
 100                 (void)ex_printf(EXCOOKIE,
 101                     "%s", "----------------------------------------\n");
 102                 cmdp->addr2.lno = cmdp->addr1.lno = equals = lno;
 103                 if (ex_pr(sp, ep, cmdp))
 104                         return (1);
 105                 (void)ex_printf(EXCOOKIE,
 106                     "%s", "----------------------------------------\n");
 107                 cmdp->addr1.lno = lno + 1;
 108                 cmdp->addr2.lno = (lno + cnt) - 1;
 109                 break;
 110         default:
 111                 /* If no line specified, move to the next one. */
 112                 if (F_ISSET(cmdp, E_ADDRDEF))
 113                         ++lno;
 114                 /* FALLTHROUGH */
 115         case E_F_PLUS:          /* Line goes at the top of the screen. */
 116                 eofcheck = 1;
 117                 cmdp->addr1.lno = lno;
 118                 cmdp->addr2.lno = (lno + cnt) - 1;
 119                 break;
 120         }
 121
 122         if (eofcheck) {
 123                 if (file_lline(sp, ep, &lno))
 124                         return (1);
 125                 if (cmdp->addr2.lno > lno)
 126                         cmdp->addr2.lno = lno;
 127         }
 128
 129         if (ex_pr(sp, ep, cmdp))
 130                 return (1);
 131         if (equals)
 132                 sp->lno = equals;
 133         return (0);
 134 }