mirror of
https://git.savannah.gnu.org/git/bison.git
synced 2026-03-21 10:13:03 +00:00
* lib/basename.c, lib/dirname.h, lib/dirname.c, lib/memrchr.c:
New, stolen from the Fileutils 4.1. * lib/Makefile.am (libbison_a_SOURCES): Adjust. * configure.in: Check for the presence of memrchr, and of its prototype.
This commit is contained in:
@@ -1,3 +1,11 @@
|
|||||||
|
2002-01-08 Akim Demaille <akim@epita.fr>
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||||||
|
|
||||||
|
* lib/basename.c, lib/dirname.h, lib/dirname.c, lib/memrchr.c:
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||||||
|
New, stolen from the Fileutils 4.1.
|
||||||
|
* lib/Makefile.am (libbison_a_SOURCES): Adjust.
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||||||
|
* configure.in: Check for the presence of memrchr, and of its
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||||||
|
prototype.
|
||||||
|
|
||||||
2002-01-07 Tim Van Holder <tim.van.holder@pandora.be>
|
2002-01-07 Tim Van Holder <tim.van.holder@pandora.be>
|
||||||
|
|
||||||
* lib/hash.h (__P): Added definition for this macro.
|
* lib/hash.h (__P): Added definition for this macro.
|
||||||
|
|||||||
@@ -87,8 +87,8 @@ AC_FUNC_ALLOCA
|
|||||||
AC_FUNC_OBSTACK
|
AC_FUNC_OBSTACK
|
||||||
AC_FUNC_ERROR_AT_LINE
|
AC_FUNC_ERROR_AT_LINE
|
||||||
AC_CHECK_FUNCS(mkstemp setlocale)
|
AC_CHECK_FUNCS(mkstemp setlocale)
|
||||||
AC_CHECK_DECLS([stpcpy, strchr, strspn, strnlen, memchr])
|
AC_CHECK_DECLS([stpcpy, strchr, strspn, strnlen, memchr, memrchr])
|
||||||
AC_REPLACE_FUNCS(stpcpy strchr strnlen strspn memchr)
|
AC_REPLACE_FUNCS(stpcpy strchr strnlen strspn memchr memrchr)
|
||||||
jm_FUNC_MALLOC
|
jm_FUNC_MALLOC
|
||||||
jm_FUNC_REALLOC
|
jm_FUNC_REALLOC
|
||||||
jm_PREREQ_QUOTEARG
|
jm_PREREQ_QUOTEARG
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||||||
|
|||||||
@@ -1,4 +1,4 @@
|
|||||||
## Copyright 2001 Free Software Foundation, Inc.
|
## Copyright 2001, 2002 Free Software Foundation, Inc.
|
||||||
|
|
||||||
## This program is free software; you can redistribute it and/or modify
|
## 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
|
## it under the terms of the GNU General Public License as published by
|
||||||
@@ -35,6 +35,7 @@ INCLUDES = -I$(top_builddir)/intl \
|
|||||||
EXTRA_DIST = malloc.c realloc.c
|
EXTRA_DIST = malloc.c realloc.c
|
||||||
|
|
||||||
libbison_a_SOURCES = \
|
libbison_a_SOURCES = \
|
||||||
|
basename.c dirname.h dirname.c \
|
||||||
getopt.h getopt.c getopt1.c \
|
getopt.h getopt.c getopt1.c \
|
||||||
hash.h hash.c \
|
hash.h hash.c \
|
||||||
quote.h quote.c quotearg.h quotearg.c \
|
quote.h quote.c quotearg.h quotearg.c \
|
||||||
|
|||||||
71
lib/basename.c
Normal file
71
lib/basename.c
Normal file
@@ -0,0 +1,71 @@
|
|||||||
|
/* basename.c -- return the last element in a path
|
||||||
|
Copyright (C) 1990, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
|
||||||
|
|
||||||
|
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 later version.
|
||||||
|
|
||||||
|
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 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. */
|
||||||
|
|
||||||
|
#if HAVE_CONFIG_H
|
||||||
|
# include <config.h>
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#include <stdio.h>
|
||||||
|
#include <assert.h>
|
||||||
|
|
||||||
|
#ifndef FILESYSTEM_PREFIX_LEN
|
||||||
|
# define FILESYSTEM_PREFIX_LEN(Filename) 0
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#ifndef PARAMS
|
||||||
|
# if defined PROTOTYPES || (defined __STDC__ && __STDC__)
|
||||||
|
# define PARAMS(Args) Args
|
||||||
|
# else
|
||||||
|
# define PARAMS(Args) ()
|
||||||
|
# endif
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#ifndef ISSLASH
|
||||||
|
# define ISSLASH(C) ((C) == '/')
|
||||||
|
#endif
|
||||||
|
|
||||||
|
char *base_name PARAMS ((char const *name));
|
||||||
|
|
||||||
|
/* In general, we can't use the builtin `basename' function if available,
|
||||||
|
since it has different meanings in different environments.
|
||||||
|
In some environments the builtin `basename' modifies its argument.
|
||||||
|
If NAME is all slashes, be sure to return `/'. */
|
||||||
|
|
||||||
|
char *
|
||||||
|
base_name (char const *name)
|
||||||
|
{
|
||||||
|
char const *base = name += FILESYSTEM_PREFIX_LEN (name);
|
||||||
|
int all_slashes = 1;
|
||||||
|
char const *p;
|
||||||
|
|
||||||
|
for (p = name; *p; p++)
|
||||||
|
{
|
||||||
|
if (ISSLASH (*p))
|
||||||
|
base = p + 1;
|
||||||
|
else
|
||||||
|
all_slashes = 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* If NAME is all slashes, arrange to return `/'. */
|
||||||
|
if (*base == '\0' && ISSLASH (*name) && all_slashes)
|
||||||
|
--base;
|
||||||
|
|
||||||
|
/* Make sure the last byte is not a slash. */
|
||||||
|
assert (all_slashes || !ISSLASH (*(p - 1)));
|
||||||
|
|
||||||
|
return (char *) base;
|
||||||
|
}
|
||||||
189
lib/dirname.c
Normal file
189
lib/dirname.c
Normal file
@@ -0,0 +1,189 @@
|
|||||||
|
/* dirname.c -- return all but the last element in a path
|
||||||
|
Copyright (C) 1990, 1998, 2000 Free Software Foundation, Inc.
|
||||||
|
|
||||||
|
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 later version.
|
||||||
|
|
||||||
|
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 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. */
|
||||||
|
|
||||||
|
#if HAVE_CONFIG_H
|
||||||
|
# include <config.h>
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#ifdef STDC_HEADERS
|
||||||
|
# include <stdlib.h>
|
||||||
|
#else
|
||||||
|
char *malloc ();
|
||||||
|
#endif
|
||||||
|
#if defined STDC_HEADERS || defined HAVE_STRING_H
|
||||||
|
# include <string.h>
|
||||||
|
#else
|
||||||
|
# include <strings.h>
|
||||||
|
# ifndef strrchr
|
||||||
|
# define strrchr rindex
|
||||||
|
# endif
|
||||||
|
#endif
|
||||||
|
#include <assert.h>
|
||||||
|
|
||||||
|
#ifndef HAVE_DECL_MEMRCHR
|
||||||
|
"this configure-time declaration test was not run"
|
||||||
|
#endif
|
||||||
|
#if !HAVE_DECL_MEMRCHR
|
||||||
|
void *memrchr ();
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#include "dirname.h"
|
||||||
|
|
||||||
|
#ifndef FILESYSTEM_PREFIX_LEN
|
||||||
|
# define FILESYSTEM_PREFIX_LEN(Filename) 0
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#ifndef ISSLASH
|
||||||
|
# define ISSLASH(C) ((C) == '/')
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#define BACKSLASH_IS_PATH_SEPARATOR ISSLASH ('\\')
|
||||||
|
|
||||||
|
/* Return the length of `dirname (PATH)' and set *RESULT to point
|
||||||
|
to PATH or to `"."', as appropriate. Works properly even if
|
||||||
|
there are trailing slashes (by effectively ignoring them).
|
||||||
|
WARNING: This function doesn't work for cwd-relative names like
|
||||||
|
`a:foo' that are specified with a drive-letter prefix. That case
|
||||||
|
is handled in the caller. */
|
||||||
|
static size_t
|
||||||
|
dir_name_r (char const *path, char const **result)
|
||||||
|
{
|
||||||
|
char const *slash;
|
||||||
|
size_t length; /* Length of result, not including NUL. */
|
||||||
|
|
||||||
|
slash = strrchr (path, '/');
|
||||||
|
if (BACKSLASH_IS_PATH_SEPARATOR)
|
||||||
|
{
|
||||||
|
char const *b = strrchr (path, '\\');
|
||||||
|
if (b && slash < b)
|
||||||
|
slash = b;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* If the last byte of PATH is a slash, decrement SLASH until it's
|
||||||
|
pointing at the leftmost in a sequence of trailing slashes. */
|
||||||
|
if (slash && slash[1] == 0)
|
||||||
|
{
|
||||||
|
while (path < slash && ISSLASH (slash[-1]))
|
||||||
|
{
|
||||||
|
--slash;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (path < slash)
|
||||||
|
{
|
||||||
|
size_t len = slash - path;
|
||||||
|
slash = memrchr (path, '/', len);
|
||||||
|
if (BACKSLASH_IS_PATH_SEPARATOR)
|
||||||
|
{
|
||||||
|
char const *b = memrchr (path, '\\', len);
|
||||||
|
if (b && slash < b)
|
||||||
|
slash = b;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
if (slash == 0)
|
||||||
|
{
|
||||||
|
/* File is in the current directory. */
|
||||||
|
|
||||||
|
length = FILESYSTEM_PREFIX_LEN (path);
|
||||||
|
|
||||||
|
if (length == 0)
|
||||||
|
{
|
||||||
|
path = ".";
|
||||||
|
length = 1;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
else
|
||||||
|
{
|
||||||
|
/* Remove any trailing slashes from the result. If we have a
|
||||||
|
canonicalized "d:/path", leave alone the root case "d:/". */
|
||||||
|
char const *lim = path + FILESYSTEM_PREFIX_LEN (path);
|
||||||
|
|
||||||
|
while (lim < slash && ISSLASH (*slash))
|
||||||
|
--slash;
|
||||||
|
|
||||||
|
length = slash - path + 1;
|
||||||
|
}
|
||||||
|
|
||||||
|
*result = path;
|
||||||
|
return length;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Return the leading directories part of PATH,
|
||||||
|
allocated with malloc. If out of memory, return 0.
|
||||||
|
Works properly even if there are trailing slashes
|
||||||
|
(by effectively ignoring them). */
|
||||||
|
|
||||||
|
char *
|
||||||
|
dir_name (char const *path)
|
||||||
|
{
|
||||||
|
char const *result;
|
||||||
|
size_t length = dir_name_r (path, &result);
|
||||||
|
int append_dot = (length && length == FILESYSTEM_PREFIX_LEN (newpath));
|
||||||
|
char *newpath = (char *) malloc (length + append_dot + 1);
|
||||||
|
if (newpath == 0)
|
||||||
|
return 0;
|
||||||
|
strncpy (newpath, result, length);
|
||||||
|
/* If PATH is "d:foo", return "d:.", the CWD on drive d: */
|
||||||
|
if (append_dot)
|
||||||
|
newpath[length++] = '.';
|
||||||
|
newpath[length] = 0;
|
||||||
|
return newpath;
|
||||||
|
}
|
||||||
|
|
||||||
|
#ifdef TEST_DIRNAME
|
||||||
|
/*
|
||||||
|
|
||||||
|
Run the test like this (expect no output):
|
||||||
|
gcc -DHAVE_CONFIG_H -DTEST_DIRNAME -I.. -O -Wall memrchr.c dirname.c
|
||||||
|
sed -n '/^BEGIN-DATA$/,/^END-DATA$/p' dirname.c|grep -v DATA|./a.out
|
||||||
|
|
||||||
|
BEGIN-DATA
|
||||||
|
foo//// .
|
||||||
|
bar/foo//// bar
|
||||||
|
foo/ .
|
||||||
|
/ /
|
||||||
|
. .
|
||||||
|
a .
|
||||||
|
END-DATA
|
||||||
|
|
||||||
|
*/
|
||||||
|
|
||||||
|
# define MAX_BUFF_LEN 1024
|
||||||
|
# include <stdio.h>
|
||||||
|
# include <stdlib.h>
|
||||||
|
|
||||||
|
int
|
||||||
|
main ()
|
||||||
|
{
|
||||||
|
char buff[MAX_BUFF_LEN + 1];
|
||||||
|
|
||||||
|
buff[MAX_BUFF_LEN] = 0;
|
||||||
|
while (fgets (buff, MAX_BUFF_LEN, stdin) && buff[0])
|
||||||
|
{
|
||||||
|
char path[MAX_BUFF_LEN];
|
||||||
|
char expected_result[MAX_BUFF_LEN];
|
||||||
|
char const *result;
|
||||||
|
sscanf (buff, "%s %s", path, expected_result);
|
||||||
|
result = dir_name (path);
|
||||||
|
if (strcmp (result, expected_result))
|
||||||
|
printf ("%s: got %s, expected %s\n", path, result, expected_result);
|
||||||
|
}
|
||||||
|
exit (0);
|
||||||
|
|
||||||
|
}
|
||||||
|
#endif
|
||||||
31
lib/dirname.h
Normal file
31
lib/dirname.h
Normal file
@@ -0,0 +1,31 @@
|
|||||||
|
/* Copyright (C) 1998 Free Software Foundation, Inc.
|
||||||
|
|
||||||
|
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 later version.
|
||||||
|
|
||||||
|
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 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. */
|
||||||
|
|
||||||
|
#ifndef DIRNAME_H_
|
||||||
|
# define DIRNAME_H_ 1
|
||||||
|
|
||||||
|
# ifndef PARAMS
|
||||||
|
# if defined PROTOTYPES || (defined __STDC__ && __STDC__)
|
||||||
|
# define PARAMS(Args) Args
|
||||||
|
# else
|
||||||
|
# define PARAMS(Args) ()
|
||||||
|
# endif
|
||||||
|
# endif
|
||||||
|
|
||||||
|
char *
|
||||||
|
dir_name PARAMS ((const char *path));
|
||||||
|
|
||||||
|
#endif /* not DIRNAME_H_ */
|
||||||
209
lib/memrchr.c
Normal file
209
lib/memrchr.c
Normal file
@@ -0,0 +1,209 @@
|
|||||||
|
/* memrchr -- find the last occurrence of a byte in a memory block
|
||||||
|
Copyright (C) 1991, 93, 96, 97, 99, 2000 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.
|
||||||
|
|
||||||
|
The GNU C Library 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., 59 Temple Place - Suite 330,
|
||||||
|
Boston, MA 02111-1307, USA. */
|
||||||
|
|
||||||
|
#ifdef HAVE_CONFIG_H
|
||||||
|
# include <config.h>
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#include <stdlib.h>
|
||||||
|
|
||||||
|
#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. */
|
||||||
|
|
||||||
|
#if defined (_LIBC)
|
||||||
|
# include <string.h>
|
||||||
|
# include <memcopy.h>
|
||||||
|
#else
|
||||||
|
# define reg_char char
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#if defined (HAVE_LIMITS_H) || defined (_LIBC)
|
||||||
|
# include <limits.h>
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#define LONG_MAX_32_BITS 2147483647
|
||||||
|
|
||||||
|
#ifndef LONG_MAX
|
||||||
|
# define LONG_MAX LONG_MAX_32_BITS
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#include <sys/types.h>
|
||||||
|
|
||||||
|
#undef __memrchr
|
||||||
|
#undef memrchr
|
||||||
|
|
||||||
|
#ifndef weak_alias
|
||||||
|
# define __memrchr memrchr
|
||||||
|
#endif
|
||||||
|
|
||||||
|
/* Search no more than N bytes of S for C. */
|
||||||
|
__ptr_t
|
||||||
|
__memrchr (s, c_in, n)
|
||||||
|
const __ptr_t 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;
|
||||||
|
|
||||||
|
c = (unsigned char) c_in;
|
||||||
|
|
||||||
|
/* Handle the last 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;
|
||||||
|
n > 0 && ((unsigned long int) char_ptr
|
||||||
|
& (sizeof (longword) - 1)) != 0;
|
||||||
|
--n)
|
||||||
|
if (*--char_ptr == c)
|
||||||
|
return (__ptr_t) char_ptr;
|
||||||
|
|
||||||
|
/* All these elucidatory comments refer to 4-byte longwords,
|
||||||
|
but the theory applies equally well to 8-byte longwords. */
|
||||||
|
|
||||||
|
longword_ptr = (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
|
||||||
|
each byte, with an extra at the end:
|
||||||
|
|
||||||
|
bits: 01111110 11111110 11111110 11111111
|
||||||
|
bytes: AAAAAAAA BBBBBBBB CCCCCCCC DDDDDDDD
|
||||||
|
|
||||||
|
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 ();
|
||||||
|
|
||||||
|
#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. */
|
||||||
|
charmask = c | (c << 8);
|
||||||
|
charmask |= charmask << 16;
|
||||||
|
#if LONG_MAX > LONG_MAX_32_BITS
|
||||||
|
charmask |= charmask << 32;
|
||||||
|
#endif
|
||||||
|
|
||||||
|
/* 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))
|
||||||
|
{
|
||||||
|
/* We tentatively exit the loop if adding MAGIC_BITS to
|
||||||
|
LONGWORD fails to change any of the hole bits of LONGWORD.
|
||||||
|
|
||||||
|
1) Is this safe? Will it catch all the zero bytes?
|
||||||
|
Suppose there is a byte with all zeros. Any carry bits
|
||||||
|
propagating from its left will fall into the hole at its
|
||||||
|
least significant bit and stop. Since there will be no
|
||||||
|
carry from its most significant bit, the LSB of the
|
||||||
|
byte to the left will be unchanged, and the zero will be
|
||||||
|
detected.
|
||||||
|
|
||||||
|
2) Is this worthwhile? Will it ignore everything except
|
||||||
|
zero bytes? Suppose every byte of LONGWORD has a bit set
|
||||||
|
somewhere. There will be a carry into bit 8. If bit 8
|
||||||
|
is set, this will carry into bit 16. If bit 8 is clear,
|
||||||
|
one of bits 9-15 must be set, so there will be a carry
|
||||||
|
into bit 16. Similarly, there will be a carry into bit
|
||||||
|
24. If one of bits 24-30 is set, there will be a carry
|
||||||
|
into bit 31, so all of the hole bits will be changed.
|
||||||
|
|
||||||
|
The one misfire occurs when bits 24-30 are clear and bit
|
||||||
|
31 is set; in this case, the hole at bit 31 is not
|
||||||
|
changed. If we had access to the processor carry flag,
|
||||||
|
we could close this loophole by putting the fourth hole
|
||||||
|
at bit 32!
|
||||||
|
|
||||||
|
So it ignores everything except 128's, when they're aligned
|
||||||
|
properly.
|
||||||
|
|
||||||
|
3) But wait! Aren't we looking for C, not zero?
|
||||||
|
Good point. So what we do is XOR LONGWORD with a longword,
|
||||||
|
each of whose bytes is C. This turns each byte that is C
|
||||||
|
into a zero. */
|
||||||
|
|
||||||
|
longword = *--longword_ptr ^ charmask;
|
||||||
|
|
||||||
|
/* Add MAGIC_BITS to LONGWORD. */
|
||||||
|
if ((((longword + magic_bits)
|
||||||
|
|
||||||
|
/* Set those bits that were unchanged by the addition. */
|
||||||
|
^ ~longword)
|
||||||
|
|
||||||
|
/* 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)
|
||||||
|
{
|
||||||
|
/* Which of the bytes was C? If none of them were, it was
|
||||||
|
a misfire; continue the search. */
|
||||||
|
|
||||||
|
const unsigned char *cp = (const unsigned char *) longword_ptr;
|
||||||
|
|
||||||
|
#if LONG_MAX > 2147483647
|
||||||
|
if (cp[7] == c)
|
||||||
|
return (__ptr_t) &cp[7];
|
||||||
|
if (cp[6] == c)
|
||||||
|
return (__ptr_t) &cp[6];
|
||||||
|
if (cp[5] == c)
|
||||||
|
return (__ptr_t) &cp[5];
|
||||||
|
if (cp[4] == c)
|
||||||
|
return (__ptr_t) &cp[4];
|
||||||
|
#endif
|
||||||
|
if (cp[3] == c)
|
||||||
|
return (__ptr_t) &cp[3];
|
||||||
|
if (cp[2] == c)
|
||||||
|
return (__ptr_t) &cp[2];
|
||||||
|
if (cp[1] == c)
|
||||||
|
return (__ptr_t) &cp[1];
|
||||||
|
if (cp[0] == c)
|
||||||
|
return (__ptr_t) cp;
|
||||||
|
}
|
||||||
|
|
||||||
|
n -= sizeof (longword);
|
||||||
|
}
|
||||||
|
|
||||||
|
char_ptr = (const unsigned char *) longword_ptr;
|
||||||
|
|
||||||
|
while (n-- > 0)
|
||||||
|
{
|
||||||
|
if (*--char_ptr == c)
|
||||||
|
return (__ptr_t) char_ptr;
|
||||||
|
}
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
#ifdef weak_alias
|
||||||
|
weak_alias (__memrchr, memrchr)
|
||||||
|
#endif
|
||||||
@@ -117,7 +117,11 @@ size_t strnlen PARAMS ((const char *s, size_t maxlen));
|
|||||||
#endif
|
#endif
|
||||||
|
|
||||||
#if !HAVE_DECL_MEMCHR
|
#if !HAVE_DECL_MEMCHR
|
||||||
void *memchr(const void *s, int c, size_t n);
|
void *memchr PARAMS ((const void *s, int c, size_t n));
|
||||||
|
#endif
|
||||||
|
|
||||||
|
#if !HAVE_DECL_MEMRCHR
|
||||||
|
void *memrchr PARAMS ((const void *s, int c, size_t n));
|
||||||
#endif
|
#endif
|
||||||
|
|
||||||
|
|
||||||
|
|||||||
Reference in New Issue
Block a user