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string/FreeBSD/strlen.c Libc-825.26 Libc-320
--- Libc/Libc-825.26/string/FreeBSD/strlen.c
+++ Libc/Libc-320/string/FreeBSD/strlen.c
@@ -1,6 +1,6 @@
 /*-
- * Copyright (c) 2009 Xin LI <delphij@FreeBSD.org>
- * All rights reserved.
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -10,11 +10,18 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
  *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 OR CONTRIBUTORS BE LIABLE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS 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)
@@ -24,87 +31,21 @@
  * SUCH DAMAGE.
  */
 
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)strlen.c	8.1 (Berkeley) 6/4/93";
+#endif /* LIBC_SCCS and not lint */
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: src/lib/libc/string/strlen.c,v 1.7 2009/01/26 07:31:28 delphij Exp $");
+__FBSDID("$FreeBSD: src/lib/libc/string/strlen.c,v 1.4 2002/03/21 18:44:54 obrien Exp $");
 
-#include <limits.h>
-#include <sys/types.h>
 #include <string.h>
 
-/*
- * Portable strlen() for 32-bit and 64-bit systems.
- *
- * Rationale: it is generally much more efficient to do word length
- * operations and avoid branches on modern computer systems, as
- * compared to byte-length operations with a lot of branches.
- *
- * The expression:
- *
- *	((x - 0x01....01) & ~x & 0x80....80)
- *
- * would evaluate to a non-zero value iff any of the bytes in the
- * original word is zero.  However, we can further reduce ~1/3 of
- * time if we consider that strlen() usually operate on 7-bit ASCII
- * by employing the following expression, which allows false positive
- * when high bit of 1 and use the tail case to catch these case:
- *
- *	((x - 0x01....01) & 0x80....80)
- *
- * This is more than 5.2 times as fast as the raw implementation on
- * Intel T7300 under long mode for strings longer than word length.
- */
+size_t
+strlen(str)
+	const char *str;
+{
+	const char *s;
 
-/* Magic numbers for the algorithm */
-#if LONG_BIT == 32
-static const unsigned long mask01 = 0x01010101;
-static const unsigned long mask80 = 0x80808080;
-#elif LONG_BIT == 64
-static const unsigned long mask01 = 0x0101010101010101;
-static const unsigned long mask80 = 0x8080808080808080;
-#else
-#error Unsupported word size
-#endif
-
-#define	LONGPTR_MASK (sizeof(long) - 1)
-
-/*
- * Helper macro to return string length if we caught the zero
- * byte.
- */
-#define testbyte(x)				\
-	do {					\
-		if (p[x] == '\0')		\
-		    return (p - str + x);	\
-	} while (0)
-
-size_t
-strlen(const char *str)
-{
-	const char *p;
-	const unsigned long *lp;
-
-	/* Skip the first few bytes until we have an aligned p */
-	for (p = str; (uintptr_t)p & LONGPTR_MASK; p++)
-	    if (*p == '\0')
-		return (p - str);
-
-	/* Scan the rest of the string using word sized operation */
-	for (lp = (const unsigned long *)p; ; lp++)
-	    if ((*lp - mask01) & mask80) {
-		p = (const char *)(lp);
-		testbyte(0);
-		testbyte(1);
-		testbyte(2);
-		testbyte(3);
-#if (LONG_BIT >= 64)
-		testbyte(4);
-		testbyte(5);
-		testbyte(6);
-		testbyte(7);
-#endif
-	    }
-
-	/* NOTREACHED */
-	return (0);
+	for (s = str; *s; ++s);
+	return(s - str);
 }