-/* Copyright (C) 1991, 1993 Free Software Foundation, Inc.
- Based on strlen implemention by Torbjorn Granlund (tege@sics.se),
+/* Copyright (C) 1991, 1993, 1996, 1997, 1999, 2000, 2003, 2004, 2006 Free
+ Software Foundation, Inc.
+
+ Based on strlen implementation by Torbjorn Granlund (tege@sics.se),
with help from Dan Sahlin (dan@sics.se) and
commentary by Jim Blandy (jimb@ai.mit.edu);
adaptation to memchr suggested by Dick Karpinski (dick@cca.ucsf.edu),
and implemented by Roland McGrath (roland@ai.mit.edu).
-The GNU C Library is free software; you can redistribute it and/or
-modify it under the terms of the GNU Library General Public License as
-published by the Free Software Foundation; either version 2 of the
-License, or (at your option) any later version.
+NOTE: The canonical source of this file is maintained with the GNU C Library.
+Bugs can be reported to bug-glibc@prep.ai.mit.edu.
+
+This program is free software: you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 3 of the License, or any
+later version.
-The GNU C Library is distributed in the hope that it will be useful,
+This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-Library General Public License for more details.
-
-You should have received a copy of the GNU Library General Public
-License along with the GNU C Library; see the file COPYING.LIB. If
-not, write to the Free Software Foundation, Inc., 675 Mass Ave,
-Cambridge, MA 02139, USA. */
-
-#ifdef HAVE_CONFIG_H
-#if defined (CONFIG_BROKETS)
-/* We use <config.h> instead of "config.h" so that a compilation
- using -I. -I$srcdir will use ./config.h rather than $srcdir/config.h
- (which it would do because it found this file in $srcdir). */
-#include <config.h>
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#ifndef _LIBC
+# include <config.h>
+#endif
+
+#include <string.h>
+
+#include <stddef.h>
+
+#if defined _LIBC
+# include <memcopy.h>
#else
-#include "config.h"
+# define reg_char char
#endif
+
+#include <limits.h>
+
+#if HAVE_BP_SYM_H || defined _LIBC
+# include <bp-sym.h>
+#else
+# define BP_SYM(sym) sym
#endif
-/* Search no more than N bytes of S for C. */
+#undef memchr
+#undef __memchr
-char *
-memchr (s, c, n)
- unsigned char *s;
- int c;
- unsigned n;
+/* Search no more than N bytes of S for C. */
+void *
+__memchr (void const *s, int c_in, size_t n)
{
const unsigned char *char_ptr;
const unsigned long int *longword_ptr;
unsigned long int longword, magic_bits, charmask;
+ unsigned reg_char c;
+ int i;
- c = (unsigned char) c;
+ c = (unsigned char) c_in;
/* Handle the first few characters by reading one character at a time.
Do this until CHAR_PTR is aligned on a longword boundary. */
- for (char_ptr = s; n > 0 && ((unsigned long int) char_ptr
- & (sizeof (longword) - 1)) != 0;
+ for (char_ptr = (const unsigned char *) s;
+ n > 0 && (size_t) char_ptr % sizeof longword != 0;
--n, ++char_ptr)
if (*char_ptr == c)
- return (char *) char_ptr;
+ return (void *) char_ptr;
/* All these elucidatory comments refer to 4-byte longwords,
- but the theory applies equally well to 8-byte longwords. */
+ but the theory applies equally well to any size longwords. */
- longword_ptr = (unsigned long int *) char_ptr;
+ longword_ptr = (const unsigned long int *) char_ptr;
/* Bits 31, 24, 16, and 8 of this number are zero. Call these bits
the "holes." Note that there is a hole just to the left of
The 1-bits make sure that carries propagate to the next 0-bit.
The 0-bits provide holes for carries to fall into. */
-#ifdef LONG_64_BITS
- /* 64-bit version of the magic. */
- magic_bits = ((unsigned long int) 0x7efefefe << 32) | 0xfefefeff;
-#else
- magic_bits = 0x7efefeff;
-#endif /* LONG_64_BITS */
- /* Set up a longword, each of whose bytes is C. */
+ /* Set MAGIC_BITS to be this pattern of 1 and 0 bits.
+ Set CHARMASK to be a longword, each of whose bytes is C. */
+
+ magic_bits = 0xfefefefe;
charmask = c | (c << 8);
charmask |= charmask << 16;
-#ifdef LONG_64_BITS
+#if 0xffffffffU < ULONG_MAX
+ magic_bits |= magic_bits << 32;
charmask |= charmask << 32;
-#endif /* LONG_64_BITS */
- if (sizeof (longword) > 8)
- abort ();
-
+ if (8 < sizeof longword)
+ for (i = 64; i < sizeof longword * 8; i *= 2)
+ {
+ magic_bits |= magic_bits << i;
+ charmask |= charmask << i;
+ }
+#endif
+ magic_bits = (ULONG_MAX >> 1) & (magic_bits | 1);
/* Instead of the traditional loop which tests each character,
we will test a longword at a time. The tricky part is testing
if *any of the four* bytes in the longword in question are zero. */
- while (n >= sizeof (longword))
+ while (n >= sizeof longword)
{
/* We tentatively exit the loop if adding MAGIC_BITS to
LONGWORD fails to change any of the hole bits of LONGWORD.
/* Add MAGIC_BITS to LONGWORD. */
if ((((longword + magic_bits)
- /* Set those bits that were unchanged by the addition. */
+ /* Set those bits that were unchanged by the addition. */
^ ~longword)
- /* Look at only the hole bits. If any of the hole bits
+ /* Look at only the hole bits. If any of the hole bits
are unchanged, most likely one of the bytes was a
zero. */
& ~magic_bits) != 0)
const unsigned char *cp = (const unsigned char *) (longword_ptr - 1);
if (cp[0] == c)
- return (char *) cp;
+ return (void *) cp;
if (cp[1] == c)
- return (char *) &cp[1];
+ return (void *) &cp[1];
if (cp[2] == c)
- return (char *) &cp[2];
+ return (void *) &cp[2];
if (cp[3] == c)
- return (char *) &cp[3];
-#ifdef LONG_64_BITS
- if (cp[4] == c)
- return (char *) &cp[4];
- if (cp[5] == c)
- return (char *) &cp[5];
- if (cp[6] == c)
- return (char *) &cp[6];
- if (cp[7] == c)
- return (char *) &cp[7];
-#endif /* LONG_64_BITS */
+ return (void *) &cp[3];
+ if (4 < sizeof longword && cp[4] == c)
+ return (void *) &cp[4];
+ if (5 < sizeof longword && cp[5] == c)
+ return (void *) &cp[5];
+ if (6 < sizeof longword && cp[6] == c)
+ return (void *) &cp[6];
+ if (7 < sizeof longword && cp[7] == c)
+ return (void *) &cp[7];
+ if (8 < sizeof longword)
+ for (i = 8; i < sizeof longword; i++)
+ if (cp[i] == c)
+ return (void *) &cp[i];
}
- n -= sizeof (longword);
+ n -= sizeof longword;
}
char_ptr = (const unsigned char *) longword_ptr;
while (n-- > 0)
{
if (*char_ptr == c)
- return (char *) char_ptr;
+ return (void *) char_ptr;
else
++char_ptr;
}
return 0;
}
+#ifdef weak_alias
+weak_alias (__memchr, BP_SYM (memchr))
+#endif
projects / gnulib.git / blobdiff