Imported from /srv/lorry/lorry-area/less/less-451.tar.gz.HEADless-451masterbaserock/morph

1 files changed, 1249 insertions, 0 deletions

diff --git a/line.c b/line.c
new file mode 100755
index 0000000..1eb3914
--- /dev/null
+++ b/line.c
@@ -0,0 +1,1249 @@
+/*
+ * Copyright (C) 1984-2012  Mark Nudelman
+ *
+ * You may distribute under the terms of either the GNU General Public
+ * License or the Less License, as specified in the README file.
+ *
+ * For more information, see the README file.
+ */
+
+
+/*
+ * Routines to manipulate the "line buffer".
+ * The line buffer holds a line of output as it is being built
+ * in preparation for output to the screen.
+ */
+
+#include "less.h"
+#include "charset.h"
+
+static char *linebuf = NULL;	/* Buffer which holds the current output line */
+static char *attr = NULL;	/* Extension of linebuf to hold attributes */
+public int size_linebuf = 0;	/* Size of line buffer (and attr buffer) */
+
+static int cshift;		/* Current left-shift of output line buffer */
+public int hshift;		/* Desired left-shift of output line buffer */
+public int tabstops[TABSTOP_MAX] = { 0 }; /* Custom tabstops */
+public int ntabstops = 1;	/* Number of tabstops */
+public int tabdefault = 8;	/* Default repeated tabstops */
+public POSITION highest_hilite;	/* Pos of last hilite in file found so far */
+
+static int curr;		/* Index into linebuf */
+static int column;		/* Printable length, accounting for
+				   backspaces, etc. */
+static int overstrike;		/* Next char should overstrike previous char */
+static int last_overstrike = AT_NORMAL;
+static int is_null_line;	/* There is no current line */
+static int lmargin;		/* Left margin */
+static char pendc;
+static POSITION pendpos;
+static char *end_ansi_chars;
+static char *mid_ansi_chars;
+
+static int attr_swidth();
+static int attr_ewidth();
+static int do_append();
+
+extern int sigs;
+extern int bs_mode;
+extern int linenums;
+extern int ctldisp;
+extern int twiddle;
+extern int binattr;
+extern int status_col;
+extern int auto_wrap, ignaw;
+extern int bo_s_width, bo_e_width;
+extern int ul_s_width, ul_e_width;
+extern int bl_s_width, bl_e_width;
+extern int so_s_width, so_e_width;
+extern int sc_width, sc_height;
+extern int utf_mode;
+extern POSITION start_attnpos;
+extern POSITION end_attnpos;
+
+static char mbc_buf[MAX_UTF_CHAR_LEN];
+static int mbc_buf_len = 0;
+static int mbc_buf_index = 0;
+static POSITION mbc_pos;
+
+/*
+ * Initialize from environment variables.
+ */
+	public void
+init_line()
+{
+	end_ansi_chars = lgetenv("LESSANSIENDCHARS");
+	if (end_ansi_chars == NULL || *end_ansi_chars == '\0')
+		end_ansi_chars = "m";
+
+	mid_ansi_chars = lgetenv("LESSANSIMIDCHARS");
+	if (mid_ansi_chars == NULL || *mid_ansi_chars == '\0')
+		mid_ansi_chars = "0123456789;[?!\"'#%()*+ ";
+
+	linebuf = (char *) ecalloc(LINEBUF_SIZE, sizeof(char));
+	attr = (char *) ecalloc(LINEBUF_SIZE, sizeof(char));
+	size_linebuf = LINEBUF_SIZE;
+}
+
+/*
+ * Expand the line buffer.
+ */
+	static int
+expand_linebuf()
+{
+	/* Double the size of the line buffer. */
+	int new_size = size_linebuf * 2;
+
+	/* Just realloc to expand the buffer, if we can. */
+#if HAVE_REALLOC
+	char *new_buf = (char *) realloc(linebuf, new_size);
+	char *new_attr = (char *) realloc(attr, new_size);
+#else
+	char *new_buf = (char *) calloc(new_size, sizeof(char));
+	char *new_attr = (char *) calloc(new_size, sizeof(char));
+#endif
+	if (new_buf == NULL || new_attr == NULL)
+	{
+		if (new_attr != NULL)
+			free(new_attr);
+		if (new_buf != NULL)
+			free(new_buf);
+		return 1;
+	}
+#if HAVE_REALLOC
+	/*
+	 * We realloc'd the buffers; they already have the old contents.
+	 */
+	#if 0
+	memset(new_buf + size_linebuf, 0, new_size - size_linebuf);
+	memset(new_attr + size_linebuf, 0, new_size - size_linebuf);
+	#endif
+#else
+	/*
+	 * We just calloc'd the buffers; copy the old contents.
+	 */
+	memcpy(new_buf, linebuf, size_linebuf * sizeof(char));
+	memcpy(new_attr, attr, size_linebuf * sizeof(char));
+	free(attr);
+	free(linebuf);
+#endif
+	linebuf = new_buf;
+	attr = new_attr;
+	size_linebuf = new_size;
+	return 0;
+}
+
+/*
+ * Is a character ASCII?
+ */
+	public int
+is_ascii_char(ch)
+	LWCHAR ch;
+{
+	return (ch <= 0x7F);
+}
+
+/*
+ * Rewind the line buffer.
+ */
+	public void
+prewind()
+{
+	curr = 0;
+	column = 0;
+	cshift = 0;
+	overstrike = 0;
+	last_overstrike = AT_NORMAL;
+	mbc_buf_len = 0;
+	is_null_line = 0;
+	pendc = '\0';
+	lmargin = 0;
+	if (status_col)
+		lmargin += 1;
+}
+
+/*
+ * Insert the line number (of the given position) into the line buffer.
+ */
+	public void
+plinenum(pos)
+	POSITION pos;
+{
+	register LINENUM linenum = 0;
+	register int i;
+
+	if (linenums == OPT_ONPLUS)
+	{
+		/*
+		 * Get the line number and put it in the current line.
+		 * {{ Note: since find_linenum calls forw_raw_line,
+		 *    it may seek in the input file, requiring the caller 
+		 *    of plinenum to re-seek if necessary. }}
+		 * {{ Since forw_raw_line modifies linebuf, we must
+		 *    do this first, before storing anything in linebuf. }}
+		 */
+		linenum = find_linenum(pos);
+	}
+
+	/*
+	 * Display a status column if the -J option is set.
+	 */
+	if (status_col)
+	{
+		linebuf[curr] = ' ';
+		if (start_attnpos != NULL_POSITION &&
+		    pos >= start_attnpos && pos < end_attnpos)
+			attr[curr] = AT_NORMAL|AT_HILITE;
+		else
+			attr[curr] = AT_NORMAL;
+		curr++;
+		column++;
+	}
+	/*
+	 * Display the line number at the start of each line
+	 * if the -N option is set.
+	 */
+	if (linenums == OPT_ONPLUS)
+	{
+		char buf[INT_STRLEN_BOUND(pos) + 2];
+		int n;
+
+		linenumtoa(linenum, buf);
+		n = strlen(buf);
+		if (n < MIN_LINENUM_WIDTH)
+			n = MIN_LINENUM_WIDTH;
+		sprintf(linebuf+curr, "%*s ", n, buf);
+		n++;  /* One space after the line number. */
+		for (i = 0; i < n; i++)
+			attr[curr+i] = AT_NORMAL;
+		curr += n;
+		column += n;
+		lmargin += n;
+	}
+
+	/*
+	 * Append enough spaces to bring us to the lmargin.
+	 */
+	while (column < lmargin)
+	{
+		linebuf[curr] = ' ';
+		attr[curr++] = AT_NORMAL;
+		column++;
+	}
+}
+
+/*
+ * Shift the input line left.
+ * This means discarding N printable chars at the start of the buffer.
+ */
+	static void
+pshift(shift)
+	int shift;
+{
+	LWCHAR prev_ch = 0;
+	unsigned char c;
+	int shifted = 0;
+	int to;
+	int from;
+	int len;
+	int width;
+	int prev_attr;
+	int next_attr;
+
+	if (shift > column - lmargin)
+		shift = column - lmargin;
+	if (shift > curr - lmargin)
+		shift = curr - lmargin;
+
+	to = from = lmargin;
+	/*
+	 * We keep on going when shifted == shift
+	 * to get all combining chars.
+	 */
+	while (shifted <= shift && from < curr)
+	{
+		c = linebuf[from];
+		if (ctldisp == OPT_ONPLUS && IS_CSI_START(c))
+		{
+			/* Keep cumulative effect.  */
+			linebuf[to] = c;
+			attr[to++] = attr[from++];
+			while (from < curr && linebuf[from])
+			{
+				linebuf[to] = linebuf[from];
+				attr[to++] = attr[from];
+				if (!is_ansi_middle(linebuf[from++]))
+					break;
+			} 
+			continue;
+		}
+
+		width = 0;
+
+		if (!IS_ASCII_OCTET(c) && utf_mode)
+		{
+			/* Assumes well-formedness validation already done.  */
+			LWCHAR ch;
+
+			len = utf_len(c);
+			if (from + len > curr)
+				break;
+			ch = get_wchar(linebuf + from);
+			if (!is_composing_char(ch) && !is_combining_char(prev_ch, ch))
+				width = is_wide_char(ch) ? 2 : 1;
+			prev_ch = ch;
+		} else
+		{
+			len = 1;
+			if (c == '\b')
+				/* XXX - Incorrect if several '\b' in a row.  */
+				width = (utf_mode && is_wide_char(prev_ch)) ? -2 : -1;
+			else if (!control_char(c))
+				width = 1;
+			prev_ch = 0;
+		}
+
+		if (width == 2 && shift - shifted == 1) {
+			/* Should never happen when called by pshift_all().  */
+			attr[to] = attr[from];
+			/*
+			 * Assume a wide_char will never be the first half of a
+			 * combining_char pair, so reset prev_ch in case we're
+			 * followed by a '\b'.
+			 */
+			prev_ch = linebuf[to++] = ' ';
+			from += len;
+			shifted++;
+			continue;
+		}
+
+		/* Adjust width for magic cookies. */
+		prev_attr = (to > 0) ? attr[to-1] : AT_NORMAL;
+		next_attr = (from + len < curr) ? attr[from + len] : prev_attr;
+		if (!is_at_equiv(attr[from], prev_attr) && 
+			!is_at_equiv(attr[from], next_attr))
+		{
+			width += attr_swidth(attr[from]);
+			if (from + len < curr)
+				width += attr_ewidth(attr[from]);
+			if (is_at_equiv(prev_attr, next_attr))
+			{
+				width += attr_ewidth(prev_attr);
+				if (from + len < curr)
+					width += attr_swidth(next_attr);
+			}
+		}
+
+		if (shift - shifted < width)
+			break;
+		from += len;
+		shifted += width;
+		if (shifted < 0)
+			shifted = 0;
+	}
+	while (from < curr)
+	{
+		linebuf[to] = linebuf[from];
+		attr[to++] = attr[from++];
+	}
+	curr = to;
+	column -= shifted;
+	cshift += shifted;
+}
+
+/*
+ *
+ */
+	public void
+pshift_all()
+{
+	pshift(column);
+}
+
+/*
+ * Return the printing width of the start (enter) sequence
+ * for a given character attribute.
+ */
+	static int
+attr_swidth(a)
+	int a;
+{
+	int w = 0;
+
+	a = apply_at_specials(a);
+
+	if (a & AT_UNDERLINE)
+		w += ul_s_width;
+	if (a & AT_BOLD)
+		w += bo_s_width;
+	if (a & AT_BLINK)
+		w += bl_s_width;
+	if (a & AT_STANDOUT)
+		w += so_s_width;
+
+	return w;
+}
+
+/*
+ * Return the printing width of the end (exit) sequence
+ * for a given character attribute.
+ */
+	static int
+attr_ewidth(a)
+	int a;
+{
+	int w = 0;
+
+	a = apply_at_specials(a);
+
+	if (a & AT_UNDERLINE)
+		w += ul_e_width;
+	if (a & AT_BOLD)
+		w += bo_e_width;
+	if (a & AT_BLINK)
+		w += bl_e_width;
+	if (a & AT_STANDOUT)
+		w += so_e_width;
+
+	return w;
+}
+
+/*
+ * Return the printing width of a given character and attribute,
+ * if the character were added to the current position in the line buffer.
+ * Adding a character with a given attribute may cause an enter or exit
+ * attribute sequence to be inserted, so this must be taken into account.
+ */
+	static int
+pwidth(ch, a, prev_ch)
+	LWCHAR ch;
+	int a;
+	LWCHAR prev_ch;
+{
+	int w;
+
+	if (ch == '\b')
+		/*
+		 * Backspace moves backwards one or two positions.
+		 * XXX - Incorrect if several '\b' in a row.
+		 */
+		return (utf_mode && is_wide_char(prev_ch)) ? -2 : -1;
+
+	if (!utf_mode || is_ascii_char(ch))
+	{
+		if (control_char((char)ch))
+		{
+			/*
+			 * Control characters do unpredictable things,
+			 * so we don't even try to guess; say it doesn't move.
+			 * This can only happen if the -r flag is in effect.
+			 */
+			return (0);
+		}
+	} else
+	{
+		if (is_composing_char(ch) || is_combining_char(prev_ch, ch))
+		{
+			/*
+			 * Composing and combining chars take up no space.
+			 *
+			 * Some terminals, upon failure to compose a
+			 * composing character with the character(s) that
+			 * precede(s) it will actually take up one column
+			 * for the composing character; there isn't much
+			 * we could do short of testing the (complex)
+			 * composition process ourselves and printing
+			 * a binary representation when it fails.
+			 */
+			return (0);
+		}
+	}
+
+	/*
+	 * Other characters take one or two columns,
+	 * plus the width of any attribute enter/exit sequence.
+	 */
+	w = 1;
+	if (is_wide_char(ch))
+		w++;
+	if (curr > 0 && !is_at_equiv(attr[curr-1], a))
+		w += attr_ewidth(attr[curr-1]);
+	if ((apply_at_specials(a) != AT_NORMAL) &&
+	    (curr == 0 || !is_at_equiv(attr[curr-1], a)))
+		w += attr_swidth(a);
+	return (w);
+}
+
+/*
+ * Delete to the previous base character in the line buffer.
+ * Return 1 if one is found.
+ */
+	static int
+backc()
+{
+	LWCHAR prev_ch;
+	char *p = linebuf + curr;
+	LWCHAR ch = step_char(&p, -1, linebuf + lmargin);
+	int width;
+
+	/* This assumes that there is no '\b' in linebuf.  */
+	while (   curr > lmargin
+	       && column > lmargin
+	       && (!(attr[curr - 1] & (AT_ANSI|AT_BINARY))))
+	{
+		curr = p - linebuf;
+		prev_ch = step_char(&p, -1, linebuf + lmargin);
+		width = pwidth(ch, attr[curr], prev_ch);
+		column -= width;
+		if (width > 0)
+			return 1;
+		ch = prev_ch;
+	}
+
+	return 0;
+}
+
+/*
+ * Are we currently within a recognized ANSI escape sequence?
+ */
+	static int
+in_ansi_esc_seq()
+{
+	char *p;
+
+	/*
+	 * Search backwards for either an ESC (which means we ARE in a seq);
+	 * or an end char (which means we're NOT in a seq).
+	 */
+	for (p = &linebuf[curr];  p > linebuf; )
+	{
+		LWCHAR ch = step_char(&p, -1, linebuf);
+		if (IS_CSI_START(ch))
+			return (1);
+		if (!is_ansi_middle(ch))
+			return (0);
+	}
+	return (0);
+}
+
+/*
+ * Is a character the end of an ANSI escape sequence?
+ */
+	public int
+is_ansi_end(ch)
+	LWCHAR ch;
+{
+	if (!is_ascii_char(ch))
+		return (0);
+	return (strchr(end_ansi_chars, (char) ch) != NULL);
+}
+
+/*
+ *
+ */
+	public int
+is_ansi_middle(ch)
+	LWCHAR ch;
+{
+	if (!is_ascii_char(ch))
+		return (0);
+	if (is_ansi_end(ch))
+		return (0);
+	return (strchr(mid_ansi_chars, (char) ch) != NULL);
+}
+
+/*
+ * Append a character and attribute to the line buffer.
+ */
+#define	STORE_CHAR(ch,a,rep,pos) \
+	do { \
+		if (store_char((ch),(a),(rep),(pos))) return (1); \
+	} while (0)
+
+	static int
+store_char(ch, a, rep, pos)
+	LWCHAR ch;
+	int a;
+	char *rep;
+	POSITION pos;
+{
+	int w;
+	int replen;
+	char cs;
+
+	w = (a & (AT_UNDERLINE|AT_BOLD));	/* Pre-use w.  */
+	if (w != AT_NORMAL)
+		last_overstrike = w;
+
+#if HILITE_SEARCH
+	{
+		int matches;
+		if (is_hilited(pos, pos+1, 0, &matches))
+		{
+			/*
+			 * This character should be highlighted.
+			 * Override the attribute passed in.
+			 */
+			if (a != AT_ANSI)
+			{
+				if (highest_hilite != NULL_POSITION &&
+				    pos > highest_hilite)
+				    	highest_hilite = pos;
+				a |= AT_HILITE;
+			}
+		}
+	}
+#endif
+
+	if (ctldisp == OPT_ONPLUS && in_ansi_esc_seq())
+	{
+		if (!is_ansi_end(ch) && !is_ansi_middle(ch)) {
+			/* Remove whole unrecognized sequence.  */
+			char *p = &linebuf[curr];
+			LWCHAR bch;
+			do {
+				bch = step_char(&p, -1, linebuf);
+			} while (p > linebuf && !IS_CSI_START(bch));
+			curr = p - linebuf;
+			return 0;
+		}
+		a = AT_ANSI;	/* Will force re-AT_'ing around it.  */
+		w = 0;
+	}
+	else if (ctldisp == OPT_ONPLUS && IS_CSI_START(ch))
+	{
+		a = AT_ANSI;	/* Will force re-AT_'ing around it.  */
+		w = 0;
+	}
+	else
+	{
+		char *p = &linebuf[curr];
+		LWCHAR prev_ch = step_char(&p, -1, linebuf);
+		w = pwidth(ch, a, prev_ch);
+	}
+
+	if (ctldisp != OPT_ON && column + w + attr_ewidth(a) > sc_width)
+		/*
+		 * Won't fit on screen.
+		 */
+		return (1);
+
+	if (rep == NULL)
+	{
+		cs = (char) ch;
+		rep = &cs;
+		replen = 1;
+	} else
+	{
+		replen = utf_len(rep[0]);
+	}
+	if (curr + replen >= size_linebuf-6)
+	{
+		/*
+		 * Won't fit in line buffer.
+		 * Try to expand it.
+		 */
+		if (expand_linebuf())
+			return (1);
+	}
+
+	while (replen-- > 0)
+	{
+		linebuf[curr] = *rep++;
+		attr[curr] = a;
+		curr++;
+	}
+	column += w;
+	return (0);
+}
+
+/*
+ * Append a tab to the line buffer.
+ * Store spaces to represent the tab.
+ */
+#define	STORE_TAB(a,pos) \
+	do { if (store_tab((a),(pos))) return (1); } while (0)
+
+	static int
+store_tab(attr, pos)
+	int attr;
+	POSITION pos;
+{
+	int to_tab = column + cshift - lmargin;
+	int i;
+
+	if (ntabstops < 2 || to_tab >= tabstops[ntabstops-1])
+		to_tab = tabdefault -
+		     ((to_tab - tabstops[ntabstops-1]) % tabdefault);
+	else
+	{
+		for (i = ntabstops - 2;  i >= 0;  i--)
+			if (to_tab >= tabstops[i])
+				break;
+		to_tab = tabstops[i+1] - to_tab;
+	}
+
+	if (column + to_tab - 1 + pwidth(' ', attr, 0) + attr_ewidth(attr) > sc_width)
+		return 1;
+
+	do {
+		STORE_CHAR(' ', attr, " ", pos);
+	} while (--to_tab > 0);
+	return 0;
+}
+
+#define STORE_PRCHAR(c, pos) \
+	do { if (store_prchar((c), (pos))) return 1; } while (0)
+
+	static int
+store_prchar(c, pos)
+	char c;
+	POSITION pos;
+{
+	char *s;
+
+	/*
+	 * Convert to printable representation.
+	 */
+	s = prchar(c);
+
+	/*
+	 * Make sure we can get the entire representation
+	 * of the character on this line.
+	 */
+	if (column + (int) strlen(s) - 1 +
+            pwidth(' ', binattr, 0) + attr_ewidth(binattr) > sc_width)
+		return 1;
+
+	for ( ;  *s != 0;  s++)
+		STORE_CHAR(*s, AT_BINARY, NULL, pos);
+
+	return 0;
+}
+
+	static int
+flush_mbc_buf(pos)
+	POSITION pos;
+{
+	int i;
+
+	for (i = 0; i < mbc_buf_index; i++)
+		if (store_prchar(mbc_buf[i], pos))
+			return mbc_buf_index - i;
+
+	return 0;
+}
+
+/*
+ * Append a character to the line buffer.
+ * Expand tabs into spaces, handle underlining, boldfacing, etc.
+ * Returns 0 if ok, 1 if couldn't fit in buffer.
+ */
+	public int
+pappend(c, pos)
+	char c;
+	POSITION pos;
+{
+	int r;
+
+	if (pendc)
+	{
+		if (do_append(pendc, NULL, pendpos))
+			/*
+			 * Oops.  We've probably lost the char which
+			 * was in pendc, since caller won't back up.
+			 */
+			return (1);
+		pendc = '\0';
+	}
+
+	if (c == '\r' && bs_mode == BS_SPECIAL)
+	{
+		if (mbc_buf_len > 0)  /* utf_mode must be on. */
+		{
+			/* Flush incomplete (truncated) sequence. */
+			r = flush_mbc_buf(mbc_pos);
+			mbc_buf_index = r + 1;
+			mbc_buf_len = 0;
+			if (r)
+				return (mbc_buf_index);
+		}
+
+		/*
+		 * Don't put the CR into the buffer until we see 
+		 * the next char.  If the next char is a newline,
+		 * discard the CR.
+		 */
+		pendc = c;
+		pendpos = pos;
+		return (0);
+	}
+
+	if (!utf_mode)
+	{
+		r = do_append((LWCHAR) c, NULL, pos);
+	} else
+	{
+		/* Perform strict validation in all possible cases. */
+		if (mbc_buf_len == 0)
+		{
+		retry:
+			mbc_buf_index = 1;
+			*mbc_buf = c;
+			if (IS_ASCII_OCTET(c))
+				r = do_append((LWCHAR) c, NULL, pos);
+			else if (IS_UTF8_LEAD(c))
+			{
+				mbc_buf_len = utf_len(c);
+				mbc_pos = pos;
+				return (0);
+			} else
+				/* UTF8_INVALID or stray UTF8_TRAIL */
+				r = flush_mbc_buf(pos);
+		} else if (IS_UTF8_TRAIL(c))
+		{
+			mbc_buf[mbc_buf_index++] = c;
+			if (mbc_buf_index < mbc_buf_len)
+				return (0);
+			if (is_utf8_well_formed(mbc_buf))
+				r = do_append(get_wchar(mbc_buf), mbc_buf, mbc_pos);
+			else
+				/* Complete, but not shortest form, sequence. */
+				mbc_buf_index = r = flush_mbc_buf(mbc_pos);
+			mbc_buf_len = 0;
+		} else
+		{
+			/* Flush incomplete (truncated) sequence.  */
+			r = flush_mbc_buf(mbc_pos);
+			mbc_buf_index = r + 1;
+			mbc_buf_len = 0;
+			/* Handle new char.  */
+			if (!r)
+				goto retry;
+ 		}
+	}
+
+	/*
+	 * If we need to shift the line, do it.
+	 * But wait until we get to at least the middle of the screen,
+	 * so shifting it doesn't affect the chars we're currently
+	 * pappending.  (Bold & underline can get messed up otherwise.)
+	 */
+	if (cshift < hshift && column > sc_width / 2)
+	{
+		linebuf[curr] = '\0';
+		pshift(hshift - cshift);
+	}
+	if (r)
+	{
+		/* How many chars should caller back up? */
+		r = (!utf_mode) ? 1 : mbc_buf_index;
+	}
+	return (r);
+}
+
+	static int
+do_append(ch, rep, pos)
+	LWCHAR ch;
+	char *rep;
+	POSITION pos;
+{
+	register int a;
+	LWCHAR prev_ch;
+
+	a = AT_NORMAL;
+
+	if (ch == '\b')
+	{
+		if (bs_mode == BS_CONTROL)
+			goto do_control_char;
+
+		/*
+		 * A better test is needed here so we don't
+		 * backspace over part of the printed
+		 * representation of a binary character.
+		 */
+		if (   curr <= lmargin
+		    || column <= lmargin
+		    || (attr[curr - 1] & (AT_ANSI|AT_BINARY)))
+			STORE_PRCHAR('\b', pos);
+		else if (bs_mode == BS_NORMAL)
+			STORE_CHAR(ch, AT_NORMAL, NULL, pos);
+		else if (bs_mode == BS_SPECIAL)
+			overstrike = backc();
+
+		return 0;
+	}
+
+	if (overstrike > 0)
+	{
+		/*
+		 * Overstrike the character at the current position
+		 * in the line buffer.  This will cause either 
+		 * underline (if a "_" is overstruck), 
+		 * bold (if an identical character is overstruck),
+		 * or just deletion of the character in the buffer.
+		 */
+		overstrike = utf_mode ? -1 : 0;
+		/* To be correct, this must be a base character.  */
+		prev_ch = get_wchar(linebuf + curr);
+		a = attr[curr];
+		if (ch == prev_ch)
+		{
+			/*
+			 * Overstriking a char with itself means make it bold.
+			 * But overstriking an underscore with itself is
+			 * ambiguous.  It could mean make it bold, or
+			 * it could mean make it underlined.
+			 * Use the previous overstrike to resolve it.
+			 */
+			if (ch == '_')
+			{
+				if ((a & (AT_BOLD|AT_UNDERLINE)) != AT_NORMAL)
+					a |= (AT_BOLD|AT_UNDERLINE);
+				else if (last_overstrike != AT_NORMAL)
+					a |= last_overstrike;
+				else
+					a |= AT_BOLD;
+			} else
+				a |= AT_BOLD;
+		} else if (ch == '_')
+		{
+			a |= AT_UNDERLINE;
+			ch = prev_ch;
+			rep = linebuf + curr;
+		} else if (prev_ch == '_')
+		{
+			a |= AT_UNDERLINE;
+		}
+		/* Else we replace prev_ch, but we keep its attributes.  */
+	} else if (overstrike < 0)
+	{
+		if (   is_composing_char(ch)
+		    || is_combining_char(get_wchar(linebuf + curr), ch))
+			/* Continuation of the same overstrike.  */
+			a = last_overstrike;
+		else
+			overstrike = 0;
+	}
+
+	if (ch == '\t') 
+	{
+		/*
+		 * Expand a tab into spaces.
+		 */
+		switch (bs_mode)
+		{
+		case BS_CONTROL:
+			goto do_control_char;
+		case BS_NORMAL:
+		case BS_SPECIAL:
+			STORE_TAB(a, pos);
+			break;
+		}
+	} else if ((!utf_mode || is_ascii_char(ch)) && control_char((char)ch))
+	{
+	do_control_char:
+		if (ctldisp == OPT_ON || (ctldisp == OPT_ONPLUS && IS_CSI_START(ch)))
+		{
+			/*
+			 * Output as a normal character.
+			 */
+			STORE_CHAR(ch, AT_NORMAL, rep, pos);
+		} else 
+		{
+			STORE_PRCHAR((char) ch, pos);
+		}
+	} else if (utf_mode && ctldisp != OPT_ON && is_ubin_char(ch))
+	{
+		char *s;
+
+		s = prutfchar(ch);
+
+		if (column + (int) strlen(s) - 1 +
+		    pwidth(' ', binattr, 0) + attr_ewidth(binattr) > sc_width)
+			return (1);
+
+		for ( ;  *s != 0;  s++)
+			STORE_CHAR(*s, AT_BINARY, NULL, pos);
+ 	} else
+	{
+		STORE_CHAR(ch, a, rep, pos);
+	}
+ 	return (0);
+}
+
+/*
+ *
+ */
+	public int
+pflushmbc()
+{
+	int r = 0;
+
+	if (mbc_buf_len > 0)
+	{
+		/* Flush incomplete (truncated) sequence.  */
+		r = flush_mbc_buf(mbc_pos);
+		mbc_buf_len = 0;
+	}
+	return r;
+}
+
+/*
+ * Terminate the line in the line buffer.
+ */
+	public void
+pdone(endline, forw)
+	int endline;
+	int forw;
+{
+	(void) pflushmbc();
+
+	if (pendc && (pendc != '\r' || !endline))
+		/*
+		 * If we had a pending character, put it in the buffer.
+		 * But discard a pending CR if we are at end of line
+		 * (that is, discard the CR in a CR/LF sequence).
+		 */
+		(void) do_append(pendc, NULL, pendpos);
+
+	/*
+	 * Make sure we've shifted the line, if we need to.
+	 */
+	if (cshift < hshift)
+		pshift(hshift - cshift);
+
+	if (ctldisp == OPT_ONPLUS && is_ansi_end('m'))
+	{
+		/* Switch to normal attribute at end of line. */
+		char *p = "\033[m";
+		for ( ;  *p != '\0';  p++)
+		{
+			linebuf[curr] = *p;
+			attr[curr++] = AT_ANSI;
+		}
+	}
+
+	/*
+	 * Add a newline if necessary,
+	 * and append a '\0' to the end of the line.
+	 * We output a newline if we're not at the right edge of the screen,
+	 * or if the terminal doesn't auto wrap,
+	 * or if this is really the end of the line AND the terminal ignores
+	 * a newline at the right edge.
+	 * (In the last case we don't want to output a newline if the terminal 
+	 * doesn't ignore it since that would produce an extra blank line.
+	 * But we do want to output a newline if the terminal ignores it in case
+	 * the next line is blank.  In that case the single newline output for
+	 * that blank line would be ignored!)
+	 */
+	if (column < sc_width || !auto_wrap || (endline && ignaw) || ctldisp == OPT_ON)
+	{
+		linebuf[curr] = '\n';
+		attr[curr] = AT_NORMAL;
+		curr++;
+	} 
+	else if (ignaw && column >= sc_width && forw)
+	{
+		/*
+		 * Terminals with "ignaw" don't wrap until they *really* need
+		 * to, i.e. when the character *after* the last one to fit on a
+		 * line is output. But they are too hard to deal with when they
+		 * get in the state where a full screen width of characters
+		 * have been output but the cursor is sitting on the right edge
+		 * instead of at the start of the next line.
+		 * So we nudge them into wrapping by outputting a space 
+		 * character plus a backspace.  But do this only if moving 
+		 * forward; if we're moving backward and drawing this line at
+		 * the top of the screen, the space would overwrite the first
+		 * char on the next line.  We don't need to do this "nudge" 
+		 * at the top of the screen anyway.
+		 */
+		linebuf[curr] = ' ';
+		attr[curr++] = AT_NORMAL;
+		linebuf[curr] = '\b'; 
+		attr[curr++] = AT_NORMAL;
+	}
+	linebuf[curr] = '\0';
+	attr[curr] = AT_NORMAL;
+}
+
+/*
+ *
+ */
+	public void
+set_status_col(c)
+	char c;
+{
+	linebuf[0] = c;
+	attr[0] = AT_NORMAL|AT_HILITE;
+}
+
+/*
+ * Get a character from the current line.
+ * Return the character as the function return value,
+ * and the character attribute in *ap.
+ */
+	public int
+gline(i, ap)
+	register int i;
+	register int *ap;
+{
+	if (is_null_line)
+	{
+		/*
+		 * If there is no current line, we pretend the line is
+		 * either "~" or "", depending on the "twiddle" flag.
+		 */
+		if (twiddle)
+		{
+			if (i == 0)
+			{
+				*ap = AT_BOLD;
+				return '~';
+			}
+			--i;
+		}
+		/* Make sure we're back to AT_NORMAL before the '\n'.  */
+		*ap = AT_NORMAL;
+		return i ? '\0' : '\n';
+	}
+
+	*ap = attr[i];
+	return (linebuf[i] & 0xFF);
+}
+
+/*
+ * Indicate that there is no current line.
+ */
+	public void
+null_line()
+{
+	is_null_line = 1;
+	cshift = 0;
+}
+
+/*
+ * Analogous to forw_line(), but deals with "raw lines":
+ * lines which are not split for screen width.
+ * {{ This is supposed to be more efficient than forw_line(). }}
+ */
+	public POSITION
+forw_raw_line(curr_pos, linep, line_lenp)
+	POSITION curr_pos;
+	char **linep;
+	int *line_lenp;
+{
+	register int n;
+	register int c;
+	POSITION new_pos;
+
+	if (curr_pos == NULL_POSITION || ch_seek(curr_pos) ||
+		(c = ch_forw_get()) == EOI)
+		return (NULL_POSITION);
+
+	n = 0;
+	for (;;)
+	{
+		if (c == '\n' || c == EOI || ABORT_SIGS())
+		{
+			new_pos = ch_tell();
+			break;
+		}
+		if (n >= size_linebuf-1)
+		{
+			if (expand_linebuf())
+			{
+				/*
+				 * Overflowed the input buffer.
+				 * Pretend the line ended here.
+				 */
+				new_pos = ch_tell() - 1;
+				break;
+			}
+		}
+		linebuf[n++] = c;
+		c = ch_forw_get();
+	}
+	linebuf[n] = '\0';
+	if (linep != NULL)
+		*linep = linebuf;
+	if (line_lenp != NULL)
+		*line_lenp = n;
+	return (new_pos);
+}
+
+/*
+ * Analogous to back_line(), but deals with "raw lines".
+ * {{ This is supposed to be more efficient than back_line(). }}
+ */
+	public POSITION
+back_raw_line(curr_pos, linep, line_lenp)
+	POSITION curr_pos;
+	char **linep;
+	int *line_lenp;
+{
+	register int n;
+	register int c;
+	POSITION new_pos;
+
+	if (curr_pos == NULL_POSITION || curr_pos <= ch_zero() ||
+		ch_seek(curr_pos-1))
+		return (NULL_POSITION);
+
+	n = size_linebuf;
+	linebuf[--n] = '\0';
+	for (;;)
+	{
+		c = ch_back_get();
+		if (c == '\n' || ABORT_SIGS())
+		{
+			/*
+			 * This is the newline ending the previous line.
+			 * We have hit the beginning of the line.
+			 */
+			new_pos = ch_tell() + 1;
+			break;
+		}
+		if (c == EOI)
+		{
+			/*
+			 * We have hit the beginning of the file.
+			 * This must be the first line in the file.
+			 * This must, of course, be the beginning of the line.
+			 */
+			new_pos = ch_zero();
+			break;
+		}
+		if (n <= 0)
+		{
+			int old_size_linebuf = size_linebuf;
+			char *fm;
+			char *to;
+			if (expand_linebuf())
+			{
+				/*
+				 * Overflowed the input buffer.
+				 * Pretend the line ended here.
+				 */
+				new_pos = ch_tell() + 1;
+				break;
+			}
+			/*
+			 * Shift the data to the end of the new linebuf.
+			 */
+			for (fm = linebuf + old_size_linebuf - 1,
+			      to = linebuf + size_linebuf - 1;
+			     fm >= linebuf;  fm--, to--)
+				*to = *fm;
+			n = size_linebuf - old_size_linebuf;
+		}
+		linebuf[--n] = c;
+	}
+	if (linep != NULL)
+		*linep = &linebuf[n];
+	if (line_lenp != NULL)
+		*line_lenp = size_linebuf - 1 - n;
+	return (new_pos);
+}