add directory study

study/linux-travel/MINIX-1.5/1.5/Source/commands/elvis/move4.c

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+/* move4.c */
+
+/* Author:
+ *	Steve Kirkendall
+ *	16820 SW Tallac Way
+ *	Beaverton, OR 97006
+ *	kirkenda@jove.cs.pdx.edu, or ...uunet!tektronix!psueea!jove!kirkenda
+ */
+
+
+/* This file contains movement functions which are screen-relative */
+
+#include "vi.h"
+
+/* This moves the cursor to a particular row on the screen */
+MARK moverow(m, cnt, key)
+	MARK	m;	/* the cursor position */
+	long	cnt;	/* the row we'll move to */
+	int	key;	/* the keystroke of this move - H/L/M */
+{
+	DEFAULT(1);
+
+	/* calculate destination line based on key */
+	cnt--;
+	switch (key)
+	{
+	  case 'H':
+		cnt = topline + cnt;
+		break;
+
+	  case 'M':
+		cnt = topline + (LINES - 1) / 2;
+		break;
+
+	  case 'L':
+		cnt = botline - cnt;
+		break;
+	}
+
+	/* return the mark of the destination line */
+	return MARK_AT_LINE(cnt);
+}
+
+
+/* This function repositions the current line to show on a given row */
+MARK movez(m, cnt, key)
+	MARK	m;	/* the cursor */
+	long	cnt;	/* the line number we're repositioning */
+	int	key;	/* key struck after the z */
+{
+	long	newtop;
+
+	/* Which line are we talking about? */
+	if (cnt < 0 || cnt > nlines)
+	{
+		return MARK_UNSET;
+	}
+	if (cnt)
+	{
+		m = MARK_AT_LINE(cnt);
+		newtop = cnt;
+	}
+	else
+	{
+		newtop = markline(m);
+	}
+
+	/* allow a "window size" number to be entered, but ignore it */
+	while (key >= '0' && key <= '9')
+	{
+		key = getkey(0);
+	}
+
+	/* figure out which line will have to be at the top of the screen */
+	switch (key)
+	{
+	  case '\n':
+	  case '\r':
+	  case '+':
+		break;
+
+	  case '.':
+	  case 'z':
+		newtop -= LINES / 2;
+		break;
+
+	  case '-':
+		newtop -= LINES - 1;
+		break;
+
+	  default:
+		return MARK_UNSET;
+	}
+
+	/* make the new topline take effect */
+	if (newtop >= 1)
+	{
+		topline = newtop;
+	}
+	else
+	{
+		topline = 1L;
+	}
+	mustredraw = TRUE;
+
+	/* The cursor doesn't move */
+	return m;
+}
+
+
+/* This function scrolls the screen.  It does this by calling redraw() with
+ * an off-screen line as the argument.  It will move the cursor if necessary
+ * so that the cursor is on the new screen.
+ */
+MARK movescroll(m, cnt, key)
+	MARK	m;	/* the cursor position */
+	long	cnt;	/* for some keys: the number of lines to scroll */
+	int	key;	/* keystroke that causes this movement */
+{
+	MARK	tmp;	/* a temporary mark, used as arg to redraw() */
+
+	/* adjust cnt, and maybe *o_scroll, depending of key */
+	switch (key)
+	{
+	  case ctrl('F'):
+	  case ctrl('B'):
+		DEFAULT(1);
+		mustredraw = TRUE;
+		cnt = cnt * (LINES - 1) - 1; /* keeps one old line on screen */
+		break;
+
+	  case ctrl('E'):
+	  case ctrl('Y'):
+		DEFAULT(1);
+		break;
+
+	  case ctrl('U'):
+	  case ctrl('D'):
+		if (cnt == 0) /* default */
+		{
+			cnt = *o_scroll;
+		}
+		else
+		{
+			if (cnt > LINES - 1)
+			{
+				cnt = LINES - 1;
+			}
+			*o_scroll = cnt;
+		}
+		break;
+	}
+
+	/* scroll up or down, depending on key */
+	switch (key)
+	{
+	  case ctrl('B'):
+	  case ctrl('Y'):
+	  case ctrl('U'):
+		cnt = topline - cnt;
+		if (cnt < 1L)
+		{
+			cnt = 1L;
+			m = MARK_FIRST;
+		}
+		tmp = MARK_AT_LINE(cnt) + markidx(m);
+		redraw(tmp, FALSE);
+		if (markline(m) > botline)
+		{
+			m = MARK_AT_LINE(botline);
+		}
+		break;
+
+	  case ctrl('F'):
+	  case ctrl('E'):
+	  case ctrl('D'):
+		cnt = botline + cnt;
+		if (cnt > nlines)
+		{
+			cnt = nlines;
+			m = MARK_LAST;
+		}
+		tmp = MARK_AT_LINE(cnt) + markidx(m);
+		redraw(tmp, FALSE);
+		if (markline(m) < topline)
+		{
+			m = MARK_AT_LINE(topline);
+		}
+		break;
+	}
+
+	/* arrange for ctrl-B and ctrl-F to redraw the smart line */
+	if (key == ctrl('B') || key == ctrl('F'))
+	{
+		changes++;
+	}
+
+	return m;
+}