From 92417c82c1b8ad2827a5a2e452e6cba96208894c Mon Sep 17 00:00:00 2001
From: dholland <dholland@NetBSD.org>
Date: Thu, 2 Dec 2010 04:35:17 +0000
Subject: [PATCH] Fix up bodgy code for printing completion matches; it used to
 sometimes skip entries, print (null), run off the end of the array, or
 occasionally receive SIGSEGV, and now will, hopefully at least, do none of
 that.

Based in part on the patch in PR 44183 from Sergio Acereda; I also
did some tidyup and fixed it to print top-to-bottom first like ls(1).
---
 lib/libedit/filecomplete.c | 57 +++++++++++++++++++++-----------------
 1 file changed, 32 insertions(+), 25 deletions(-)

diff --git a/lib/libedit/filecomplete.c b/lib/libedit/filecomplete.c
index 8413eb592b3b..d001a99c01e1 100644
--- a/lib/libedit/filecomplete.c
+++ b/lib/libedit/filecomplete.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: filecomplete.c,v 1.20 2010/11/15 21:24:31 christos Exp $	*/
+/*	$NetBSD: filecomplete.c,v 1.21 2010/12/02 04:35:17 dholland Exp $	*/
 
 /*-
  * Copyright (c) 1997 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
 
 #include "config.h"
 #if !defined(lint) && !defined(SCCSID)
-__RCSID("$NetBSD: filecomplete.c,v 1.20 2010/11/15 21:24:31 christos Exp $");
+__RCSID("$NetBSD: filecomplete.c,v 1.21 2010/12/02 04:35:17 dholland Exp $");
 #endif /* not lint && not SCCSID */
 
 #include <sys/types.h>
@@ -338,39 +338,45 @@ _fn_qsort_string_compare(const void *i1, const void *i2)
 
 /*
  * Display list of strings in columnar format on readline's output stream.
- * 'matches' is list of strings, 'len' is number of strings in 'matches',
- * 'max' is maximum length of string in 'matches'.
+ * 'matches' is list of strings, 'num' is number of strings in 'matches',
+ * 'width' is maximum length of string in 'matches'.
+ *
+ * matches[0] is not one of the match strings, so the strings are
+ * matches[1] *through* matches[num].
  */
 void
-fn_display_match_list (EditLine *el, char **matches, size_t len, size_t max)
+fn_display_match_list (EditLine *el, char **matches, size_t num, size_t width)
 {
-	size_t i, idx, limit, count;
+	size_t line, lines, col, cols, thisguy;
 	int screenwidth = el->el_term.t_size.h;
 
+	/* Ignore matches[0]. Avoid 1-based array logic below. */
+	matches++;
+
 	/*
-	 * Find out how many entries can be put on one line, count
-	 * with two spaces between strings.
+	 * Find out how many entries can be put on one line; count
+	 * with one space between strings the same way it's printed.
 	 */
-	limit = screenwidth / (max + 2);
-	if (limit == 0)
-		limit = 1;
+	cols = screenwidth / (width + 1);
+	if (cols == 0)
+		cols = 1;
 
-	/* how many lines of output */
-	count = len / limit;
-	if (count * limit < len)
-		count++;
+	/* how many lines of output, rounded up */
+	lines = (num + cols - 1) / cols;
 
-	/* Sort the items if they are not already sorted. */
-	qsort(&matches[1], (size_t)(len - 1), sizeof(char *),
-	    _fn_qsort_string_compare);
+	/* Sort the items. */
+	qsort(matches, num, sizeof(char *), _fn_qsort_string_compare);
 
-	idx = 1;
-	for(; count > 0; count--) {
-		int more = limit > 0 && matches[0];
-		for(i = 0; more; i++, idx++) {
-			more = i < limit && matches[idx + 1];
-			(void)fprintf(el->el_outfile, "%-*s%s", (int)max,
-			    matches[idx], more ? " " : "");
+	/*
+	 * On the ith line print elements i, i+lines, i+lines*2, etc.
+	 */
+	for (line = 0; line < lines; line++) {
+		for (col = 0; col < cols; col++) {
+			thisguy = line + col * lines;
+			if (thisguy >= num)
+				break;
+			(void)fprintf(el->el_outfile, "%s%-*s",
+			    col == 0 ? "" : " ", (int)width, matches[thisguy]);
 		}
 		(void)fprintf(el->el_outfile, "\n");
 	}
@@ -492,6 +498,7 @@ fn_complete(EditLine *el,
 				if (match_len > maxlen)
 					maxlen = match_len;
 			}
+			/* matches[1] through matches[i-1] are available */
 			matches_num = i - 1;
 				
 			/* newline to get on next line from command line */