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/*
* Copyright (c) 1994-2009 Red Hat, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 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. Neither the name of the copyright holder 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/* This file is copied from newlib-1.19 */
/*
FUNCTION
<<strlen>>---character string length
INDEX
strlen
ANSI_SYNOPSIS
#include <string.h>
size_t strlen(const char *<[str]>);
TRAD_SYNOPSIS
#include <string.h>
size_t strlen(<[str]>)
char *<[src]>;
DESCRIPTION
The <<strlen>> function works out the length of the string
starting at <<*<[str]>>> by counting chararacters until it
reaches a <<NULL>> character.
RETURNS
<<strlen>> returns the character count.
PORTABILITY
<<strlen>> is ANSI C.
<<strlen>> requires no supporting OS subroutines.
QUICKREF
strlen ansi pure
*/
#include "_ansi.h"
#include <string.h>
#include <limits.h>
#define LBLOCKSIZE (sizeof(long))
#define UNALIGNED(X) ((long)X & (LBLOCKSIZE - 1))
#if LONG_MAX == 2147483647L
#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
#else
#if LONG_MAX == 9223372036854775807L
/* Nonzero if X (a long int) contains a NULL byte. */
#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
#else
#error long int is not a 32bit or 64bit type.
#endif
#endif
#ifndef DETECTNULL
#error long int is not a 32bit or 64bit byte
#endif
size_t _DEFUN(strlen, (str), _CONST char *str)
{
_CONST char *start = str;
#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
unsigned long *aligned_addr;
/* Align the pointer, so we can search a word at a time. */
while (UNALIGNED(str)) {
if (!*str)
return str - start;
str++;
}
/* If the string is word-aligned, we can check for the presence of
a null in each word-sized block. */
aligned_addr = (unsigned long *)str;
while (!DETECTNULL(*aligned_addr))
aligned_addr++;
/* Once a null is detected, we check each byte in that block for a
precise position of the null. */
str = (char *)aligned_addr;
#endif /* not PREFER_SIZE_OVER_SPEED */
while (*str)
str++;
return str - start;
}
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