From d6dce0799c82bace61d4ce35ace8de5b2aa3da7b Mon Sep 17 00:00:00 2001
From: cheloha <cheloha@openbsd.org>
Date: Fri, 24 Dec 2021 17:59:28 +0000
Subject: [PATCH] uniq(1): skip() each input line only once

In uniq(1), skip() is very expensive.  We should only do it once per
input line.  Doing it more than once is redundant, anyway.

Thread: https://marc.info/?l=openbsd-tech&m=163950278018535&w=2

ok millert@
---
 usr.bin/uniq/uniq.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/usr.bin/uniq/uniq.c b/usr.bin/uniq/uniq.c
index 7356d922390..fa2b0e7ebaa 100644
--- a/usr.bin/uniq/uniq.c
+++ b/usr.bin/uniq/uniq.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uniq.c,v 1.29 2021/11/17 23:09:38 cheloha Exp $	*/
+/*	$OpenBSD: uniq.c,v 1.30 2021/12/24 17:59:28 cheloha Exp $	*/
 /*	$NetBSD: uniq.c,v 1.7 1995/08/31 22:03:48 jtc Exp $	*/
 
 /*
@@ -57,7 +57,7 @@ __dead void	usage(void);
 int
 main(int argc, char *argv[])
 {
-	char *prevline, *t1, *t2, *thisline;
+	char *p, *prevline, *t, *thisline, *tmp;
 	FILE *ifp = NULL, *ofp = NULL;
 	size_t prevsize, thissize, tmpsize;
 	ssize_t len;
@@ -142,6 +142,10 @@ main(int argc, char *argv[])
 	}
 	if (prevline[len - 1] == '\n')
 		prevline[len - 1] = '\0';
+	if (numfields || numchars)
+		p = skip(prevline);
+	else
+		p = prevline;
 	
 	thissize = 0;
 	thisline = NULL;
@@ -150,20 +154,20 @@ main(int argc, char *argv[])
 			thisline[len - 1] = '\0';
 
 		/* If requested get the chosen fields + character offsets. */
-		if (numfields || numchars) {
-			t1 = skip(thisline);
-			t2 = skip(prevline);
-		} else {
-			t1 = thisline;
-			t2 = prevline;
-		}
+		if (numfields || numchars)
+			t = skip(thisline);
+		else
+			t = thisline;
 
 		/* If different, print; set previous to new value. */
-		if ((iflag ? strcasecmp : strcmp)(t1, t2)) {
+		if ((iflag ? strcasecmp : strcmp)(p, t)) {
 			show(ofp, prevline);
-			t1 = prevline;
+			tmp = prevline;
 			prevline = thisline;
-			thisline = t1;
+			thisline = tmp;
+			tmp = p;
+			p = t;
+			t = tmp;
 			tmpsize = prevsize;
 			prevsize = thissize;
 			thissize = tmpsize;
-- 
2.20.1