From d92f64bad488975b4675afbfac0d9832a4fd17e9 Mon Sep 17 00:00:00 2001
From: Ted Unangst <tedu@cvs.openbsd.org>
Date: Mon, 8 Dec 2014 20:40:54 +0000
Subject: don't do silly (and slow) one byte reads in unbuffered mode. from enh
 at google

---
 lib/libc/stdio/fread.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

(limited to 'lib/libc')

diff --git a/lib/libc/stdio/fread.c b/lib/libc/stdio/fread.c
index 8a592f6d3f1..6e957623e1f 100644
--- a/lib/libc/stdio/fread.c
+++ b/lib/libc/stdio/fread.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fread.c,v 1.12 2014/05/01 16:40:36 deraadt Exp $ */
+/*	$OpenBSD: fread.c,v 1.13 2014/12/08 20:40:53 tedu Exp $ */
 /*-
  * Copyright (c) 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
@@ -68,6 +68,21 @@ fread(void *buf, size_t size, size_t count, FILE *fp)
 		fp->_r = 0;
 	total = resid;
 	p = buf;
+
+	if ((fp->_flags & __SNBF) != 0) {
+		/*
+		 * We know if we're unbuffered that our buffer is empty, so
+		 * we can just read directly. This is much faster than the
+		 * loop below which will perform a series of one byte reads.
+		 */
+		while (resid > 0 && (r = (*fp->_read)(fp->_cookie, p, resid)) > 0) {
+			p += r;
+			resid -= r;
+		}
+		FUNLOCKFILE(fp);
+		return ((total - resid) / size);
+	}
+
 	while (resid > (r = fp->_r)) {
 		(void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
 		fp->_p += r;
-- 
cgit v1.2.3