Import of unmolested less-290.

1 files changed, 1197 insertions, 0 deletions

diff --git a/usr.bin/less/search.c b/usr.bin/less/search.c
new file mode 100644
index 00000000000..73486878dd5
--- /dev/null
+++ b/usr.bin/less/search.c
@@ -0,0 +1,1197 @@
+/*
+ * Copyright (c) 1984,1985,1989,1994,1995  Mark Nudelman
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice in the documentation and/or other materials provided with 
+ *    the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN 
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+/*
+ * Routines to search a file for a pattern.
+ */
+
+#include "less.h"
+#include "position.h"
+
+#define	MINPOS(a,b)	(((a) < (b)) ? (a) : (b))
+#define	MAXPOS(a,b)	(((a) > (b)) ? (a) : (b))
+
+#if HAVE_POSIX_REGCOMP
+#include <regex.h>
+#endif
+#if HAVE_RE_COMP
+char *re_comp();
+int re_exec();
+#endif
+#if HAVE_REGCMP
+char *regcmp();
+char *regex();
+extern char *__loc1;
+#endif
+#if HAVE_V8_REGCOMP
+#include "regexp.h"
+#endif
+#if NO_REGEX
+static int match();
+#endif
+
+extern int sigs;
+extern int how_search;
+extern int caseless;
+extern int linenums;
+extern int sc_height;
+extern int jump_sline;
+extern int bs_mode;
+#if HILITE_SEARCH
+extern int hilite_search;
+extern int screen_trashed;
+extern int size_linebuf;
+static int hide_hilite;
+static POSITION prep_startpos;
+static POSITION prep_endpos;
+
+struct hilite
+{
+	struct hilite *hl_next;
+	POSITION hl_startpos;
+	POSITION hl_endpos;
+};
+static struct hilite hilite_anchor = { NULL };
+#define	hl_first	hl_next
+#endif
+
+/*
+ * These are the static variables that represent the "remembered"
+ * search pattern.  
+ */
+#if HAVE_POSIX_REGCOMP
+static regex_t *regpattern = NULL;
+#endif
+#if HAVE_RE_COMP
+int re_pattern = 0;
+#endif
+#if HAVE_REGCMP
+static char *cpattern = NULL;
+#endif
+#if HAVE_V8_REGCOMP
+static struct regexp *regpattern = NULL;
+#endif
+#if NO_REGEX
+static char *last_pattern = NULL;
+#endif
+
+static int is_caseless;
+static int is_ucase_pattern;
+
+/*
+ * Convert text.  Perform one or more of these transformations:
+ */
+#define	CVT_TO_LC	01	/* Convert upper-case to lower-case */
+#define	CVT_BS		02	/* Do backspace processing */
+
+	static void
+cvt_text(odst, osrc, ops)
+	char *odst;
+	char *osrc;
+	int ops;
+{
+	register char *dst;
+	register char *src;
+
+	for (src = osrc, dst = odst;  *src != '\0';  src++, dst++)
+	{
+		if ((ops & CVT_TO_LC) && isupper(*src))
+			/* Convert uppercase to lowercase. */
+			*dst = tolower(*src);
+		else if ((ops & CVT_BS) && *src == '\b' && dst > odst)
+			/* Delete BS and preceding char. */
+			dst -= 2;
+		else 
+			/* Just copy. */
+			*dst = *src;
+	}
+	*dst = '\0';
+}
+
+/*
+ * Are there any uppercase letters in this string?
+ */
+	static int
+is_ucase(s)
+	char *s;
+{
+	register char *p;
+
+	for (p = s;  *p != '\0';  p++)
+		if (isupper(*p))
+			return (1);
+	return (0);
+}
+
+/*
+ * Is there a previous (remembered) search pattern?
+ */
+	static int
+prev_pattern()
+{
+#if HAVE_POSIX_REGCOMP
+	return (regpattern != NULL);
+#endif
+#if HAVE_RE_COMP
+	return (re_pattern != 0);
+#endif
+#if HAVE_REGCMP
+	return (cpattern != NULL);
+#endif
+#if HAVE_V8_REGCOMP
+	return (regpattern != NULL);
+#endif
+#if NO_REGEX
+	return (last_pattern != NULL);
+#endif
+}
+
+#if HILITE_SEARCH
+/*
+ * Repaint the hilites currently displayed on the screen.
+ * Repaint each line which contains highlighted text.
+ * If on==0, force all hilites off.
+ */
+	public void
+repaint_hilite(on)
+	int on;
+{
+	int slinenum;
+	POSITION pos;
+	POSITION epos;
+	int save_hide_hilite;
+	extern int can_goto_line;
+
+	save_hide_hilite = hide_hilite;
+	if (!on)
+	{
+		if (hide_hilite)
+			return;
+		hide_hilite = 1;
+	}
+
+	if (!can_goto_line)
+	{
+		repaint();
+		hide_hilite = save_hide_hilite;
+		return;
+	}
+
+	for (slinenum = TOP;  slinenum < TOP + sc_height-1;  slinenum++)
+	{
+		pos = position(slinenum);
+		if (pos == NULL_POSITION)
+			continue;
+		epos = position(slinenum+1);
+		/*
+		 * If any character in the line is highlighted, 
+		 * repaint the line.
+		 */
+		if (is_hilited(pos, epos, 1))
+		{
+			(void) forw_line(pos);
+			goto_line(slinenum);
+			put_line();
+		}
+	}
+	hide_hilite = save_hide_hilite;
+}
+#endif
+
+/*
+ * Hide search string highlighting.
+ */
+	public void
+undo_search()
+{
+	if (!prev_pattern())
+	{
+		error("No previous regular expression", NULL_PARG);
+		return;
+	}
+#if HILITE_SEARCH
+	hide_hilite = !hide_hilite;
+	repaint_hilite(1);
+#endif
+}
+
+/*
+ * Compile a search pattern, for future use by match_pattern.
+ */
+	static int
+compile_pattern(pattern)
+	char *pattern;
+{
+#if HAVE_POSIX_REGCOMP
+	regex_t *s = (regex_t *) ecalloc(1, sizeof(regex_t));
+	if (regcomp(s, pattern, 0))
+	{
+		free(s);
+		error("Invalid pattern", NULL_PARG);
+		return (-1);
+	}
+	if (regpattern != NULL)
+		regfree(regpattern);
+	regpattern = s;
+#endif
+#if HAVE_RE_COMP
+	PARG parg;
+	if ((parg.p_string = re_comp(pattern)) != NULL)
+	{
+		error("%s", &parg);
+		return (-1);
+	}
+	re_pattern = 1;
+#endif
+#if HAVE_REGCMP
+	char *s;
+	if ((s = regcmp(pattern, 0)) == NULL)
+	{
+		error("Invalid pattern", NULL_PARG);
+		return (-1);
+	}
+	if (cpattern != NULL)
+		free(cpattern);
+	cpattern = s;
+#endif
+#if HAVE_V8_REGCOMP
+	struct regexp *s;
+	if ((s = regcomp(pattern)) == NULL)
+	{
+		/*
+		 * regcomp has already printed error message via regerror().
+		 */
+		return (-1);
+	}
+	if (regpattern != NULL)
+		free(regpattern);
+	regpattern = s;
+#endif
+#if NO_REGEX
+	static char lpbuf[100];
+	strcpy(lpbuf, pattern);
+	last_pattern = lpbuf;
+#endif
+	return (0);
+}
+
+/*
+ * Forget that we have a compiled pattern.
+ */
+	static void
+uncompile_pattern()
+{
+#if HAVE_POSIX_REGCOMP
+	if (regpattern != NULL)
+		regfree(regpattern);
+	regpattern = NULL;
+#endif
+#if HAVE_RE_COMP
+	re_pattern = 0;
+#endif
+#if HAVE_REGCMP
+	if (cpattern != NULL)
+		free(cpattern);
+	cpattern = NULL;
+#endif
+#if HAVE_V8_REGCOMP
+	if (regpattern != NULL)
+		free(regpattern);
+	regpattern = NULL;
+#endif
+#if NO_REGEX
+	last_pattern = NULL;
+#endif
+}
+
+/*
+ * Perform a pattern match with the previously compiled pattern.
+ * Set sp and ep to the start and end of the matched string.
+ */
+	static int
+match_pattern(line, sp, ep)
+	char *line;
+	char **sp;
+	char **ep;
+{
+	int matched;
+#if HAVE_POSIX_REGCOMP
+	regmatch_t rm;
+	matched = !regexec(regpattern, line, 1, &rm, 0);
+	if (!matched)
+		return (0);
+	*sp = line + rm.rm_so;
+	*ep = line + rm.rm_eo;
+#endif
+#if HAVE_RE_COMP
+	matched = (re_exec(line) == 1);
+	/*
+	 * re_exec doesn't seem to provide a way to get the matched string.
+	 */
+	*sp = *ep = NULL;
+#endif
+#if HAVE_REGCMP
+	*ep = regex(cpattern, line);
+	matched = (*ep != NULL);
+	if (!matched)
+		return (0);
+	*sp = __loc1;
+#endif
+#if HAVE_V8_REGCOMP
+	matched = regexec(regpattern, line);
+	if (!matched)
+		return (0);
+	*sp = regpattern->startp[0];
+	*ep = regpattern->endp[0];
+#endif
+#if NO_REGEX
+	matched = match(last_pattern, line, sp, ep);
+#endif
+	return (matched);
+}
+
+#if HILITE_SEARCH
+/*
+ * Clear the hilite list.
+ */
+	public void
+clr_hilite()
+{
+	struct hilite *hl;
+	struct hilite *nexthl;
+
+	for (hl = hilite_anchor.hl_first;  hl != NULL;  hl = nexthl)
+	{
+		nexthl = hl->hl_next;
+		free((void*)hl);
+	}
+	hilite_anchor.hl_first = NULL;
+	prep_startpos = prep_endpos = NULL_POSITION;
+}
+
+/*
+ * Should any characters in a specified range be highlighted?
+ * If nohide is nonzero, don't consider hide_hilite.
+ */
+	public int
+is_hilited(pos, epos, nohide)
+	POSITION pos;
+	POSITION epos;
+	int nohide;
+{
+	struct hilite *hl;
+
+	if (hilite_search == 0)
+		/*
+		 * Not doing highlighting.
+		 */
+		return (0);
+
+	if (!nohide && hide_hilite)
+		/*
+		 * Highlighting is hidden.
+		 */
+		return (0);
+
+	/*
+	 * Look at each highlight and see if any part of it falls in the range.
+	 */
+	for (hl = hilite_anchor.hl_first;  hl != NULL;  hl = hl->hl_next)
+	{
+		if (hl->hl_endpos > pos &&
+		    (epos == NULL_POSITION || epos > hl->hl_startpos))
+			return (1);
+	}
+	return (0);
+}
+
+/*
+ * Add a new hilite to a hilite list.
+ */
+	static void
+add_hilite(anchor, hl)
+	struct hilite *anchor;
+	struct hilite *hl;
+{
+	struct hilite *ihl;
+
+	/*
+	 * Hilites are sorted in the list; find where new one belongs.
+	 * Insert new one after ihl.
+	 */
+	for (ihl = anchor;  ihl->hl_next != NULL;  ihl = ihl->hl_next)
+	{
+		if (ihl->hl_next->hl_startpos > hl->hl_startpos)
+			break;
+	}
+
+	/*
+	 * Truncate hilite so it doesn't overlap any existing ones
+	 * above and below it.
+	 */
+	if (ihl != anchor)
+		hl->hl_startpos = MAXPOS(hl->hl_startpos, ihl->hl_endpos);
+	if (ihl->hl_next != NULL)
+		hl->hl_endpos = MINPOS(hl->hl_endpos, ihl->hl_next->hl_startpos);
+	if (hl->hl_startpos >= hl->hl_endpos)
+	{
+		/*
+		 * Hilite was truncated out of existence.
+		 */
+		free(hl);
+		return;
+	}
+	hl->hl_next = ihl->hl_next;
+	ihl->hl_next = hl;
+}
+
+/*
+ * Adjust hl_startpos & hl_endpos to account for backspace processing.
+ */
+	static void
+adj_hilite(anchor, linepos)
+	struct hilite *anchor;
+	POSITION linepos;
+{
+	char *line;
+	struct hilite *hl;
+	int checkstart;
+	POSITION opos;
+	POSITION npos;
+
+	/*
+	 * The line was already scanned and hilites were added (in hilite_line).
+	 * But it was assumed that each char position in the line 
+	 * correponds to one char position in the file.
+	 * This may not be true if there are backspaces in the line.
+	 * Get the raw line again.  Look at each character.
+	 */
+	(void) forw_raw_line(linepos, &line);
+	opos = npos = linepos;
+	hl = anchor->hl_first;
+	checkstart = TRUE;
+	while (hl != NULL)
+	{
+		/*
+		 * See if we need to adjust the current hl_startpos or 
+		 * hl_endpos.  After adjusting startpos[i], move to endpos[i].
+		 * After adjusting endpos[i], move to startpos[i+1].
+		 * The hilite list must be sorted thus: 
+		 * startpos[0] < endpos[0] <= startpos[1] < endpos[1] <= etc.
+		 */
+		if (checkstart && hl->hl_startpos == opos)
+		{
+			hl->hl_startpos = npos;
+			checkstart = FALSE;
+			continue; /* {{ not really necessary }} */
+		} else if (!checkstart && hl->hl_endpos == opos)
+		{
+			hl->hl_endpos = npos;
+			checkstart = TRUE;
+			hl = hl->hl_next;
+			continue; /* {{ necessary }} */
+		}
+		if (*line == '\0')
+			break;
+		opos++;
+		npos++;
+		line++;
+		while (line[0] == '\b' && line[1] != '\0')
+		{
+			/*
+			 * Found a backspace.  The file position moves
+			 * forward by 2 relative to the processed line
+			 * which was searched in hilite_line.
+			 */
+			npos += 2;
+			line += 2;
+		}
+	}
+}
+
+/*
+ * Make a hilite for each string in a physical line which matches 
+ * the current pattern.
+ * sp,ep delimit the first match already found.
+ */
+	static void
+hilite_line(linepos, line, sp, ep)
+	POSITION linepos;
+	char *line;
+	char *sp;
+	char *ep;
+{
+	char *searchp;
+	struct hilite *hl;
+	struct hilite hilites;
+
+	if (sp == NULL || ep == NULL)
+		return;
+	/*
+	 * sp and ep delimit the first match in the line.
+	 * Mark the corresponding file positions, then
+	 * look for further matches and mark them.
+	 * {{ This technique, of calling match_pattern on subsequent
+	 *    substrings of the line, may mark more than is correct
+	 *    if, for example, the pattern starts with "^". }}
+	 */
+	searchp = line;
+	/*
+	 * Put the hilites into a temporary list until they're adjusted.
+	 */
+	hilites.hl_first = NULL;
+	do {
+		if (ep > sp)
+		{
+			/*
+			 * Assume that each char position in the "line"
+			 * buffer corresponds to one char position in the file.
+			 * This is not quite true; we need to adjust later.
+			 */
+			hl = (struct hilite *) ecalloc(1, sizeof(struct hilite));
+			hl->hl_startpos = linepos + (sp-line);
+			hl->hl_endpos = linepos + (ep-line);
+			add_hilite(&hilites, hl);
+		}
+		/*
+		 * If we matched more than zero characters,
+		 * move to the first char after the string we matched.
+		 * If we matched zero, just move to the next char.
+		 */
+		if (ep > searchp)
+			searchp = ep;
+		else if (*searchp != '\0')
+			searchp++;
+		else /* end of line */
+			break;
+	} while (match_pattern(searchp, &sp, &ep));
+
+	if (bs_mode == BS_SPECIAL) 
+	{
+		/*
+		 * If there were backspaces in the original line, they
+		 * were removed, and hl_startpos/hl_endpos are not correct.
+		 * {{ This is very ugly. }}
+		 */
+		adj_hilite(&hilites, linepos);
+	}
+	/*
+	 * Now put the hilites into the real list.
+	 */
+	while ((hl = hilites.hl_next) != NULL)
+	{
+		hilites.hl_next = hl->hl_next;
+		add_hilite(&hilite_anchor, hl);
+	}
+}
+#endif
+
+/*
+ * Change the caseless-ness of searches.  
+ * Updates the internal search state to reflect a change in the -i flag.
+ */
+	public void
+chg_caseless()
+{
+	if (!is_ucase_pattern)
+		/*
+		 * Pattern did not have uppercase.
+		 * Just set the search caselessness to the global caselessness.
+		 */
+		is_caseless = caseless;
+	else
+		/*
+		 * Pattern did have uppercase.
+		 * Discard the pattern; we can't change search caselessness now.
+		 */
+		uncompile_pattern();
+}
+
+#if HILITE_SEARCH
+/*
+ * Find matching text which is currently on screen and highlight it.
+ */
+	static void
+hilite_screen()
+{
+	struct scrpos scrpos;
+
+	get_scrpos(&scrpos);
+	if (scrpos.pos == NULL_POSITION)
+		return;
+	prep_hilite(scrpos.pos, position(BOTTOM_PLUS_ONE));
+	repaint_hilite(1);
+}
+
+/*
+ * Change highlighting parameters.
+ */
+	public void
+chg_hilite()
+{
+	/*
+	 * Erase any highlights currently on screen.
+	 */
+	clr_hilite();
+	hide_hilite = 0;
+
+	if (hilite_search == OPT_ONPLUS)
+		/*
+		 * Display highlights.
+		 */
+		hilite_screen();
+}
+#endif
+
+/*
+ * Figure out where to start a search.
+ */
+	static POSITION
+search_pos(search_type)
+	int search_type;
+{
+	POSITION pos;
+	int linenum;
+
+	if (empty_screen())
+	{
+		/*
+		 * Start at the beginning (or end) of the file.
+		 * The empty_screen() case is mainly for 
+		 * command line initiated searches;
+		 * for example, "+/xyz" on the command line.
+		 * Also for multi-file (SRCH_PAST_EOF) searches.
+		 */
+		if (search_type & SRCH_FORW)
+		{
+			return (ch_zero());
+		} else
+		{
+			pos = ch_length();
+			if (pos == NULL_POSITION)
+			{
+				(void) ch_end_seek();
+				pos = ch_length();
+			}
+			return (pos);
+		}
+	}
+	if (how_search)
+	{
+		/*
+		 * Search does not include current screen.
+		 */
+		if (search_type & SRCH_FORW)
+			linenum = BOTTOM_PLUS_ONE;
+		else
+			linenum = TOP;
+		pos = position(linenum);
+	} else
+	{
+		/*
+		 * Search includes current screen.
+		 * It starts at the jump target (if searching backwards),
+		 * or at the jump target plus one (if forwards).
+		 */
+		linenum = adjsline(jump_sline);
+		pos = position(linenum);
+		if (search_type & SRCH_FORW)
+			pos = forw_raw_line(pos, (char **)NULL);
+	}
+	return (pos);
+}
+
+/*
+ * Search a subset of the file, specified by start/end position.
+ */
+	static int
+search_range(pos, endpos, search_type, n, plinepos, pendpos)
+	POSITION pos;
+	POSITION endpos;
+	int search_type;
+	int n;
+	POSITION *plinepos;
+	POSITION *pendpos;
+{
+	char *line;
+	int linenum;
+	char *sp, *ep;
+	int line_match;
+	POSITION linepos, oldpos;
+
+	linenum = find_linenum(pos);
+	oldpos = pos;
+	for (;;)
+	{
+		/*
+		 * Get lines until we find a matching one or until
+		 * we hit end-of-file (or beginning-of-file if we're 
+		 * going backwards), or until we hit the end position.
+		 */
+		if (ABORT_SIGS())
+		{
+			/*
+			 * A signal aborts the search.
+			 */
+			return (-1);
+		}
+
+		if (endpos != NULL_POSITION && pos >= endpos)
+		{
+			/*
+			 * Reached end position without a match.
+			 */
+			if (pendpos != NULL)
+				*pendpos = pos;
+			return (n);
+		}
+
+		if (search_type & SRCH_FORW)
+		{
+			/*
+			 * Read the next line, and save the 
+			 * starting position of that line in linepos.
+			 */
+			linepos = pos;
+			pos = forw_raw_line(pos, &line);
+			if (linenum != 0)
+				linenum++;
+		} else
+		{
+			/*
+			 * Read the previous line and save the
+			 * starting position of that line in linepos.
+			 */
+			pos = back_raw_line(pos, &line);
+			linepos = pos;
+			if (linenum != 0)
+				linenum--;
+		}
+
+		if (pos == NULL_POSITION)
+		{
+			/*
+			 * Reached EOF/BOF without a match.
+			 */
+			if (pendpos != NULL)
+				*pendpos = NULL_POSITION;
+			return (n);
+		}
+
+		/*
+		 * If we're using line numbers, we might as well
+		 * remember the information we have now (the position
+		 * and line number of the current line).
+		 * Don't do it for every line because it slows down
+		 * the search.  Remember the line number only if
+		 * we're "far" from the last place we remembered it.
+		 */
+		if (linenums && abs((int)(pos - oldpos)) > 1024)
+		{
+			add_lnum(linenum, pos);
+			oldpos = pos;
+		}
+
+		/*
+		 * If it's a caseless search, convert the line to lowercase.
+		 * If we're doing backspace processing, delete backspaces.
+		 */
+		if (is_caseless || bs_mode == BS_SPECIAL)
+		{
+			int ops = 0;
+			if (is_caseless) 
+				ops |= CVT_TO_LC;
+			if (bs_mode == BS_SPECIAL)
+				ops |= CVT_BS;
+			cvt_text(line, line, ops);
+		}
+
+		/*
+		 * Test the next line to see if we have a match.
+		 * We are successful if we either want a match and got one,
+		 * or if we want a non-match and got one.
+		 */
+		line_match = match_pattern(line, &sp, &ep);
+		line_match = (!(search_type & SRCH_NOMATCH) && line_match) ||
+				((search_type & SRCH_NOMATCH) && !line_match);
+		if (!line_match)
+			continue;
+		/*
+		 * Got a match.
+		 */
+		if (search_type & SRCH_FIND_ALL)
+		{
+#if HILITE_SEARCH
+			/*
+			 * We are supposed to find all matches in the range.
+			 * Just add the matches in this line to the 
+			 * hilite list and keep searching.
+			 */
+			if (line_match)
+				hilite_line(linepos, line, sp, ep);
+#endif
+		} else if (--n <= 0)
+		{
+			/*
+			 * Found the one match we're looking for.
+			 * Return it.
+			 */
+#if HILITE_SEARCH
+			if (hilite_search == 1)
+			{
+				/*
+				 * Clear the hilite list and add only
+				 * the matches in this one line.
+				 */
+				clr_hilite();
+				if (line_match)
+					hilite_line(linepos, line, sp, ep);
+			}
+#endif
+			if (plinepos != NULL)
+				*plinepos = linepos;
+			return (0);
+		}
+	}
+}
+
+/*
+ * Search for the n-th occurrence of a specified pattern, 
+ * either forward or backward.
+ * Return the number of matches not yet found in this file
+ * (that is, n minus the number of matches found).
+ * Return -1 if the search should be aborted.
+ * Caller may continue the search in another file 
+ * if less than n matches are found in this file.
+ */
+	public int
+search(search_type, pattern, n)
+	int search_type;
+	char *pattern;
+	int n;
+{
+	POSITION pos;
+	int ucase;
+
+	if (pattern == NULL || *pattern == '\0')
+	{
+		/*
+		 * A null pattern means use the previously compiled pattern.
+		 */
+		if (!prev_pattern())
+		{
+			error("No previous regular expression", NULL_PARG);
+			return (-1);
+		}
+#if HILITE_SEARCH
+		if (hilite_search == OPT_ON)
+		{
+			/*
+			 * Erase the highlights currently on screen.
+			 * If the search fails, we'll redisplay them later.
+			 */
+			repaint_hilite(0);
+		}
+		if (hilite_search == OPT_ONPLUS && hide_hilite)
+		{
+			/*
+			 * Highlight any matches currently on screen,
+			 * before we actually start the search.
+			 */
+			hide_hilite = 0;
+			hilite_screen();
+		}
+		hide_hilite = 0;
+#endif
+	} else
+	{
+		/*
+		 * Compile the pattern.
+		 */
+		ucase = is_ucase(pattern);
+		if (caseless == OPT_ONPLUS)
+			cvt_text(pattern, pattern, CVT_TO_LC);
+		if (compile_pattern(pattern) < 0)
+			return (-1);
+		/*
+		 * Ignore case if -I is set OR
+		 * -i is set AND the pattern is all lowercase.
+		 */
+		is_ucase_pattern = ucase;
+		if (is_ucase_pattern && caseless != OPT_ONPLUS)
+			is_caseless = 0;
+		else
+			is_caseless = caseless;
+#if HILITE_SEARCH
+		if (hilite_search)
+		{
+			/*
+			 * Erase the highlights currently on screen.
+			 * Also permanently delete them from the hilite list.
+			 */
+			repaint_hilite(0);
+			hide_hilite = 0;
+			clr_hilite();
+		}
+		if (hilite_search == OPT_ONPLUS)
+		{
+			/*
+			 * Highlight any matches currently on screen,
+			 * before we actually start the search.
+			 */
+			hilite_screen();
+		}
+#endif
+	}
+
+	/*
+	 * Figure out where to start the search.
+	 */
+	pos = search_pos(search_type);
+	if (pos == NULL_POSITION)
+	{
+		/*
+		 * Can't find anyplace to start searching from.
+		 */
+		if (search_type & SRCH_PAST_EOF)
+			return (n);
+		error("Nothing to search", NULL_PARG);
+		return (-1);
+	}
+
+	n = search_range(pos, NULL_POSITION, search_type, n, 
+			&pos, (POSITION*)NULL);
+	if (n != 0)
+	{
+		/*
+		 * Search was unsuccessful.
+		 */
+#if HILITE_SEARCH
+		if (hilite_search == OPT_ON && n > 0)
+			/*
+			 * Redisplay old hilites.
+			 */
+			repaint_hilite(1);
+#endif
+		return (n);
+	}
+
+	/*
+	 * Go to the matching line.
+	 */
+	jump_loc(pos, jump_sline);
+
+#if HILITE_SEARCH
+	if (hilite_search == OPT_ON)
+		/*
+		 * Display new hilites in the matching line.
+		 */
+		repaint_hilite(1);
+#endif
+	return (0);
+}
+
+#if HILITE_SEARCH
+/*
+ * Prepare hilites in a given range of the file.
+ *
+ * The pair (prep_startpos,prep_endpos) delimits a contiguous region
+ *  of the file that has been "prepared"; that is, scanned for matches for
+ * the current search pattern, and hilites have been created for such matches.
+ * If prep_startpos == NULL_POSITION, the prep region is empty.
+ * If prep_endpos == NULL_POSITION, the prep region extends to EOF.
+ * prep_hilite asks that the range (spos,epos) be covered by the prep region.
+ */
+	public void
+prep_hilite(spos, epos)
+	POSITION spos;
+	POSITION epos;
+{
+	POSITION nprep_startpos = prep_startpos;
+	POSITION nprep_endpos = prep_endpos;
+/*
+ * Search beyond where we're asked to search, so the prep region covers
+ * more than we need.  Do one big search instead of a bunch of small ones.
+ */
+#define	SEARCH_MORE (3*size_linebuf)
+
+	if (!prev_pattern())
+		return;
+	/*
+	 * Find two ranges:
+	 * The range that we need to search (spos,epos); and the range that
+	 * the "prep" region will then cover (nprep_startpos,nprep_endpos).
+	 */
+
+	if (prep_startpos == NULL_POSITION ||
+	    (epos != NULL_POSITION && epos < prep_startpos) ||
+	    (prep_endpos != NULL_POSITION && spos > prep_endpos))
+	{
+		/*
+		 * New range is not contiguous with old prep region.
+		 * Discard the old prep region and start a new one.
+		 */
+		clr_hilite();
+		if (epos != NULL_POSITION)
+			epos += SEARCH_MORE;
+		nprep_startpos = spos;
+		nprep_endpos = epos;
+	} else
+	{
+		/*
+		 * New range partially or completely overlaps old prep region.
+		 */
+		if (epos == NULL_POSITION)
+		{
+			/*
+			 * New range goes to end of file.
+			 */
+			nprep_endpos = NULL_POSITION;
+		} else if (epos > prep_endpos)
+		{
+			/*
+			 * New range ends after old prep region.
+			 * Extend prep region to end at end of new range.
+			 */
+			epos += SEARCH_MORE;
+			nprep_endpos = epos;
+		} else /* (epos <= prep_endpos) */
+		{
+			/*
+			 * New range ends within old prep region.
+			 * Truncate search to end at start of old prep region.
+			 */
+			epos = prep_startpos;
+		}
+
+		if (spos < prep_startpos)
+		{
+			/*
+			 * New range starts before old prep region.
+			 * Extend old prep region backwards to start at 
+			 * start of new range.
+			 */
+			if (spos < SEARCH_MORE)
+				spos = 0;
+			else
+				spos -= SEARCH_MORE;
+			nprep_startpos = spos;
+		} else /* (spos >= prep_startpos) */
+		{
+			/*
+			 * New range starts within or after old prep region.
+			 * Trim search to start near end of old prep region
+			 * (actually, one linebuf before end of old range).
+			 */
+			if (prep_endpos == NULL_POSITION)
+				return;
+			else if (prep_endpos < size_linebuf)
+				spos = 0;
+			else 
+				spos = prep_endpos - size_linebuf;
+		}
+	}
+
+	if (epos == NULL_POSITION || epos > spos)
+	{
+		if (search_range(spos, epos, SRCH_FORW|SRCH_FIND_ALL, 0,
+				(POSITION*)NULL, &epos) >= 0)
+		{
+			if (epos == NULL_POSITION || epos > nprep_endpos)
+				nprep_endpos = epos;
+		}
+	}
+	prep_startpos = nprep_startpos;
+	prep_endpos = nprep_endpos;
+}
+#endif
+
+#if NO_REGEX
+/*
+ * We have no pattern matching function from the library.
+ * We use this function to do simple pattern matching.
+ * It supports no metacharacters like *, etc.
+ */
+	static int
+match(pattern, buf, pfound, pend)
+	char *pattern, *buf;
+	char **pfound, **pend;
+{
+	register char *pp, *lp;
+
+	for ( ;  *buf != '\0';  buf++)
+	{
+		for (pp = pattern, lp = buf;  *pp == *lp;  pp++, lp++)
+			if (*pp == '\0' || *lp == '\0')
+				break;
+		if (*pp == '\0')
+		{
+			if (pfound != NULL)
+				*pfound = buf;
+			if (pend != NULL)
+				*pend = lp;
+			return (1);
+		}
+	}
+	return (0);
+}
+#endif
+
+#if HAVE_V8_REGCOMP
+/*
+ * This function is called by the V8 regcomp to report 
+ * errors in regular expressions.
+ */
+	void 
+regerror(s) 
+	char *s; 
+{
+	PARG parg;
+
+	parg.p_string = s;
+	error("%s", &parg);
+}
+#endif
+
+#if !HAVE_STRCHR
+/*
+ * strchr is used by regexp.c.
+ */
+	char *
+strchr(s, c)
+	char *s;
+	int c;
+{
+	for ( ;  *s != '\0';  s++)
+		if (*s == c)
+			return (s);
+	if (c == '\0')
+		return (s);
+	return (NULL);
+}
+#endif
+