-/* Copyright (C) 1991, 1993, 1997, 1999, 2000 Free Software Foundation, Inc.
+/* 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);
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
+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 2, or (at your option) any
+Free Software Foundation; either version 3 of the License, or any
later version.
This program is distributed in the hope that it will be useful,
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, write to the Free Software
-Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
-USA. */
+along with this program. If not, see <http://www.gnu.org/licenses/>. */
-#ifdef HAVE_CONFIG_H
+#ifndef _LIBC
# include <config.h>
#endif
-#undef __ptr_t
-#if defined (__cplusplus) || (defined (__STDC__) && __STDC__)
-# define __ptr_t void *
-#else /* Not C++ or ANSI C. */
-# define __ptr_t char *
-#endif /* C++ or ANSI C. */
+#include <string.h>
-#if defined (_LIBC)
-# include <string.h>
-#endif
+#include <stddef.h>
-#if defined (HAVE_LIMITS_H) || defined (_LIBC)
-# include <limits.h>
+#if defined _LIBC
+# include <memcopy.h>
+#else
+# define reg_char char
#endif
-#define LONG_MAX_32_BITS 2147483647
+#include <limits.h>
-#ifndef LONG_MAX
-# define LONG_MAX LONG_MAX_32_BITS
+#if HAVE_BP_SYM_H || defined _LIBC
+# include <bp-sym.h>
+#else
+# define BP_SYM(sym) sym
#endif
-#include <sys/types.h>
-
+#undef memchr
+#undef __memchr
/* Search no more than N bytes of S for C. */
-
-__ptr_t
-memchr (s, c, n)
- const __ptr_t s;
- int c;
- size_t n;
+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 = (const unsigned char *) s;
- n > 0 && ((unsigned long int) char_ptr
- & (sizeof (longword) - 1)) != 0;
+ n > 0 && (size_t) char_ptr % sizeof longword != 0;
--n, ++char_ptr)
if (*char_ptr == c)
- return (__ptr_t) 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. */
- if (sizeof (longword) != 4 && sizeof (longword) != 8)
- abort ();
+ /* Set MAGIC_BITS to be this pattern of 1 and 0 bits.
+ Set CHARMASK to be a longword, each of whose bytes is C. */
-#if LONG_MAX <= LONG_MAX_32_BITS
- magic_bits = 0x7efefeff;
-#else
- magic_bits = ((unsigned long int) 0x7efefefe << 32) | 0xfefefeff;
-#endif
-
- /* Set up a longword, each of whose bytes is C. */
+ magic_bits = 0xfefefefe;
charmask = c | (c << 8);
charmask |= charmask << 16;
-#if LONG_MAX > LONG_MAX_32_BITS
+#if 0xffffffffU < ULONG_MAX
+ magic_bits |= magic_bits << 32;
charmask |= charmask << 32;
+ 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.
const unsigned char *cp = (const unsigned char *) (longword_ptr - 1);
if (cp[0] == c)
- return (__ptr_t) cp;
+ return (void *) cp;
if (cp[1] == c)
- return (__ptr_t) &cp[1];
+ return (void *) &cp[1];
if (cp[2] == c)
- return (__ptr_t) &cp[2];
+ return (void *) &cp[2];
if (cp[3] == c)
- return (__ptr_t) &cp[3];
-#if LONG_MAX > 2147483647
- if (cp[4] == c)
- return (__ptr_t) &cp[4];
- if (cp[5] == c)
- return (__ptr_t) &cp[5];
- if (cp[6] == c)
- return (__ptr_t) &cp[6];
- if (cp[7] == c)
- return (__ptr_t) &cp[7];
-#endif
+ 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 (__ptr_t) 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