From: Sami Kerola <kerolasa@iki.fi>
Date: Sat, 3 Aug 2013 23:15:20 +0000 (+0100)
Subject: more: make output redirection more efficient
X-Git-Tag: v2.24-rc1~404
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2587c5937c506eb399e2012141c6d6b7d381552b;p=thirdparty%2Futil-linux.git

more: make output redirection more efficient

Especially with large inputs the change improves performance
considerably.

old> time more /boot/vmlinuz >/dev/null
real    0m0.224s

new> more /boot/vmlinuz >/dev/null
real    0m0.009s

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
---

diff --git a/text-utils/more.c b/text-utils/more.c
index ac35acc0bd..598e048963 100644
--- a/text-utils/more.c
+++ b/text-utils/more.c
@@ -780,10 +780,11 @@ void __attribute__((__noreturn__)) end_it(int dummy __attribute__((__unused__)))
 
 void copy_file(register FILE *f)
 {
-	register int c;
+	char buf[BUFSIZ];
+	size_t sz;
 
-	while ((c = getc(f)) != EOF)
-		putchar(c);
+	while ((sz = fread(&buf, sizeof(char), sizeof(buf), f)) > 0)
+		fwrite(&buf, sizeof(char), sz, stdout);
 }
 
 #define ringbell()	putcerr('\007')