string.h

Glibc 2.3.2源代码(解压后有100多M)

/* Optimized, inlined string functions.  i486 version.
   Copyright (C) 1997,1998,1999,2000,2001,2002,2003
   	Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#ifndef _STRING_H
# error "Never use <bits/string.h> directly; include <string.h> instead."
#endif

/* The ix86 processors can access unaligned multi-byte variables.  */
#define _STRING_ARCH_unaligned	1


/* We only provide optimizations if the user selects them and if
   GNU CC is used.  */
#if !defined __NO_STRING_INLINES && defined __USE_STRING_INLINES \
    && defined __GNUC__ && __GNUC__ >= 2 && !__BOUNDED_POINTERS__

#ifndef __STRING_INLINE
# ifdef __cplusplus
#  define __STRING_INLINE inline
# else
#  define __STRING_INLINE extern __inline
# endif
#endif

/* The macros are used in some of the optimized implementations below.  */
#define __STRING_SMALL_GET16(src, idx) \
  ((((__const unsigned char *) (src))[idx + 1] << 8)			      \
   | ((__const unsigned char *) (src))[idx])
#define __STRING_SMALL_GET32(src, idx) \
  (((((__const unsigned char *) (src))[idx + 3] << 8			      \
     | ((__const unsigned char *) (src))[idx + 2]) << 8			      \
    | ((__const unsigned char *) (src))[idx + 1]) << 8			      \
   | ((__const unsigned char *) (src))[idx])


/* Copy N bytes of SRC to DEST.  */
#define _HAVE_STRING_ARCH_memcpy 1
#define memcpy(dest, src, n) \
  (__extension__ (__builtin_constant_p (n)				      \
		  ? __memcpy_c ((dest), (src), (n))			      \
		  : __memcpy_g ((dest), (src), (n))))
#define __memcpy_c(dest, src, n) \
  ((n) == 0								      \
   ? (dest)								      \
   : (((n) % 4 == 0)							      \
      ? __memcpy_by4 (dest, src, n)					      \
      : (((n) % 2 == 0)							      \
	 ? __memcpy_by2 (dest, src, n)					      \
	 : __memcpy_g (dest, src, n))))

__STRING_INLINE void *__memcpy_by4 (void *__dest, __const void *__src,
				    size_t __n);

__STRING_INLINE void *
__memcpy_by4 (void *__dest, __const void *__src, size_t __n)
{
  register unsigned long int __d0, __d1;
  register void *__tmp = __dest;
  __asm__ __volatile__
    ("1:\n\t"
     "movl	(%2),%0\n\t"
     "leal	4(%2),%2\n\t"
     "movl	%0,(%1)\n\t"
     "leal	4(%1),%1\n\t"
     "decl	%3\n\t"
     "jnz	1b"
     : "=&r" (__d0), "=&r" (__tmp), "=&r" (__src), "=&r" (__d1)
     : "1" (__tmp), "2" (__src), "3" (__n / 4)
     : "memory", "cc");
  return __dest;
}

__STRING_INLINE void *__memcpy_by2 (void *__dest, __const void *__src,
				    size_t __n);

__STRING_INLINE void *
__memcpy_by2 (void *__dest, __const void *__src, size_t __n)
{
  register unsigned long int __d0, __d1;
  register void *__tmp = __dest;
  __asm__ __volatile__
    ("shrl	$1,%3\n\t"
     "jz	2f\n"                 /* only a word */
     "1:\n\t"
     "movl	(%2),%0\n\t"
     "leal	4(%2),%2\n\t"
     "movl	%0,(%1)\n\t"
     "leal	4(%1),%1\n\t"
     "decl	%3\n\t"
     "jnz	1b\n"
     "2:\n\t"
     "movw	(%2),%w0\n\t"
     "movw	%w0,(%1)"
     : "=&q" (__d0), "=&r" (__tmp), "=&r" (__src), "=&r" (__d1)
     : "1" (__tmp), "2" (__src), "3" (__n / 2)
     : "memory", "cc");
  return __dest;
}

__STRING_INLINE void *__memcpy_g (void *__dest, __const void *__src,
				  size_t __n);

__STRING_INLINE void *
__memcpy_g (void *__dest, __const void *__src, size_t __n)
{
  register unsigned long int __d0, __d1, __d2;
  register void *__tmp = __dest;
  __asm__ __volatile__
    ("cld\n\t"
     "shrl	$1,%%ecx\n\t"
     "jnc	1f\n\t"
     "movsb\n"
     "1:\n\t"
     "shrl	$1,%%ecx\n\t"
     "jnc	2f\n\t"
     "movsw\n"
     "2:\n\t"
     "rep; movsl"
     : "=&c" (__d0), "=&D" (__d1), "=&S" (__d2),
       "=m" ( *(struct { __extension__ char __x[__n]; } *)__dest)
     : "0" (__n), "1" (__tmp), "2" (__src),
       "m" ( *(struct { __extension__ char __x[__n]; } *)__src)
     : "cc");
  return __dest;
}

#define _HAVE_STRING_ARCH_memmove 1
#ifndef _FORCE_INLINES
/* Copy N bytes of SRC to DEST, guaranteeing
   correct behavior for overlapping strings.  */
__STRING_INLINE void *
memmove (void *__dest, __const void *__src, size_t __n)
{
  register unsigned long int __d0, __d1, __d2;
  register void *__tmp = __dest;
  if (__dest < __src)
    __asm__ __volatile__
      ("cld\n\t"
       "rep; movsb"
       : "=&c" (__d0), "=&S" (__d1), "=&D" (__d2),
	 "=m" ( *(struct { __extension__ char __x[__n]; } *)__dest)
       : "0" (__n), "1" (__src), "2" (__tmp),
	 "m" ( *(struct { __extension__ char __x[__n]; } *)__src));
  else
    __asm__ __volatile__
      ("std\n\t"
       "rep; movsb\n\t"
       "cld"
       : "=&c" (__d0), "=&S" (__d1), "=&D" (__d2),
	 "=m" ( *(struct { __extension__ char __x[__n]; } *)__dest)
       : "0" (__n), "1" (__n - 1 + (__const char *) __src),
	 "2" (__n - 1 + (char *) __tmp),
	 "m" ( *(struct { __extension__ char __x[__n]; } *)__src));
  return __dest;
}
#endif

/* Compare N bytes of S1 and S2.  */
#define _HAVE_STRING_ARCH_memcmp 1
#ifndef _FORCE_INLINES
# ifndef __PIC__
/* gcc has problems to spill registers when using PIC.  */
__STRING_INLINE int
memcmp (__const void *__s1, __const void *__s2, size_t __n)
{
  register unsigned long int __d0, __d1, __d2;
  register int __res;
  __asm__ __volatile__
    ("cld\n\t"
     "testl %3,%3\n\t"
     "repe; cmpsb\n\t"
     "je	1f\n\t"
     "sbbl	%0,%0\n\t"
     "orl	$1,%0\n"
     "1:"
     : "=&a" (__res), "=&S" (__d0), "=&D" (__d1), "=&c" (__d2)
     : "0" (0), "1" (__s1), "2" (__s2), "3" (__n),
       "m" ( *(struct { __extension__ char __x[__n]; } *)__s1),
       "m" ( *(struct { __extension__ char __x[__n]; } *)__s2)
     : "cc");
  return __res;
}
# endif
#endif

/* Set N bytes of S to C.  */
#define _HAVE_STRING_ARCH_memset 1
#define _USE_STRING_ARCH_memset 1
#define memset(s, c, n) \
  (__extension__ (__builtin_constant_p (n) && (n) <= 16			      \
		  ? ((n) == 1						      \
		     ? __memset_c1 ((s), (c))				      \
		     : __memset_gc ((s), (c), (n)))			      \
		  : (__builtin_constant_p (c)				      \
		     ? (__builtin_constant_p (n)			      \
			? __memset_ccn ((s), (c), (n))			      \
			: memset ((s), (c), (n)))			      \
		     : (__builtin_constant_p (n)			      \
			? __memset_gcn ((s), (c), (n))			      \
			: memset ((s), (c), (n))))))

#define __memset_c1(s, c) ({ void *__s = (s);				      \
			     *((unsigned char *) __s) = (unsigned char) (c);  \
			     __s; })

#define __memset_gc(s, c, n) \
  ({ void *__s = (s);							      \
     union {								      \
       unsigned int __ui;						      \
       unsigned short int __usi;					      \
       unsigned char __uc;						      \
     } *__u = __s;							      \
     unsigned int __c = ((unsigned int) ((unsigned char) (c))) * 0x01010101;  \
									      \
     /* We apply a trick here.  `gcc' would implement the following	      \
	assignments using immediate operands.  But this uses to much	      \
	memory (7, instead of 4 bytes).  So we force the value in a	      \
	registers.  */							      \
     if ((n) == 3 || (n) >= 5)						      \
       __asm__ __volatile__ ("" : "=r" (__c) : "0" (__c));		      \
									      \
     /* This `switch' statement will be removed at compile-time.  */	      \
     switch (n)								      \
       {								      \
       case 15:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 11:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 7:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 3:								      \
	 __u->__usi = (unsigned short int) __c;				      \
	 __u = __extension__ ((void *) __u + 2);			      \
	 __u->__uc = (unsigned char) __c;				      \
	 break;								      \
									      \
       case 14:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 10:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 6:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 2:								      \
	 __u->__usi = (unsigned short int) __c;				      \
	 break;								      \
									      \
       case 13:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 9:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 5:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 1:								      \
	 __u->__uc = (unsigned char) __c;				      \
	 break;								      \
									      \
       case 16:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 12:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 8:								      \
	 __u->__ui = __c;						      \
	 __u = __extension__ ((void *) __u + 4);			      \
       case 4:								      \
	 __u->__ui = __c;						      \
       case 0:								      \
	 break;								      \
       }								      \
									      \
     __s; })

#define __memset_ccn(s, c, n) \
  (((n) % 4 == 0)							      \
   ? __memset_ccn_by4 (s, ((unsigned int) ((unsigned char) (c))) * 0x01010101,\
		       n)						      \
   : (((n) % 2 == 0)							      \
      ? __memset_ccn_by2 (s,						      \
			  ((unsigned int) ((unsigned char) (c))) * 0x01010101,\
			   n)						      \
      : memset (s, c, n)))

__STRING_INLINE void *__memset_ccn_by4 (void *__s, unsigned int __c,
					size_t __n);

__STRING_INLINE void *
__memset_ccn_by4 (void *__s, unsigned int __c, size_t __n)
{
  register void *__tmp = __s;
  register unsigned long int __d0;
#ifdef __i686__
  __asm__ __volatile__
    ("cld\n\t"
     "rep; stosl"
     : "=&a" (__c), "=&D" (__tmp), "=&c" (__d0),
       "=m" ( *(struct { __extension__ char __x[__n]; } *)__s)
     : "0" ((unsigned int) __c), "1" (__tmp), "2" (__n / 4)
     : "cc");
#else
  __asm__ __volatile__
    ("1:\n\t"
     "movl	%0,(%1)\n\t"
     "addl	$4,%1\n\t"
     "decl	%2\n\t"
     "jnz	1b\n"
     : "=&r" (__c), "=&r" (__tmp), "=&r" (__d0),
       "=m" ( *(struct { __extension__ char __x[__n]; } *)__s)
     : "0" ((unsigned int) __c), "1" (__tmp), "2" (__n / 4)
     : "cc");
#endif
  return __s;
}

__STRING_INLINE void *__memset_ccn_by2 (void *__s, unsigned int __c,
					size_t __n);

__STRING_INLINE void *
__memset_ccn_by2 (void *__s, unsigned int __c, size_t __n)
{
  register unsigned long int __d0, __d1;
  register void *__tmp = __s;
#ifdef __i686__
  __asm__ __volatile__
    ("cld\n\t"
     "rep; stosl\n"
     "stosw"
     : "=&a" (__d0), "=&D" (__tmp), "=&c" (__d1),
       "=m" ( *(struct { __extension__ char __x[__n]; } *)__s)
     : "0" ((unsigned int) __c), "1" (__tmp), "2" (__n / 4)
     : "cc");
#else
  __asm__ __volatile__
    ("1:\tmovl	%0,(%1)\n\t"
     "leal	4(%1),%1\n\t"
     "decl	%2\n\t"
     "jnz	1b\n"
     "movw	%w0,(%1)"
     : "=&q" (__d0), "=&r" (__tmp), "=&r" (__d1),
       "=m" ( *(struct { __extension__ char __x[__n]; } *)__s)
     : "0" ((unsigned int) __c), "1" (__tmp), "2" (__n / 4)
     : "cc");
#endif
  return __s;
}

#define __memset_gcn(s, c, n) \
  (((n) % 4 == 0)							      \
   ? __memset_gcn_by4 (s, c, n)						      \
   : (((n) % 2 == 0)							      \
      ? __memset_gcn_by2 (s, c, n)					      \
      : memset (s, c, n)))

__STRING_INLINE void *__memset_gcn_by4 (void *__s, int __c, size_t __n);

__STRING_INLINE void *
__memset_gcn_by4 (void *__s, int __c, size_t __n)
{
  register void *__tmp = __s;
  register unsigned long int __d0;
  __asm__ __volatile__
    ("movb	%b0,%h0\n"
     "pushw	%w0\n\t"
     "shll	$16,%0\n\t"
     "popw	%w0\n"
     "1:\n\t"
     "movl	%0,(%1)\n\t"
     "addl	$4,%1\n\t"
     "decl	%2\n\t"
     "jnz	1b\n"
     : "=&q" (__c), "=&r" (__tmp), "=&r" (__d0),
       "=m" ( *(struct { __extension__ char __x[__n]; } *)__s)
     : "0" ((unsigned int) __c), "1" (__tmp), "2" (__n / 4)
     : "cc");
  return __s;
}

__STRING_INLINE void *__memset_gcn_by2 (void *__s, int __c, size_t __n);

__STRING_INLINE void *
__memset_gcn_by2 (void *__s, int __c, size_t __n)
{
  register unsigned long int __d0, __d1;
  register void *__tmp = __s;
  __asm__ __volatile__
    ("movb	%b0,%h0\n\t"
     "pushw	%w0\n\t"
     "shll	$16,%0\n\t"
     "popw	%w0\n"
     "1:\n\t"
     "movl	%0,(%1)\n\t"
     "leal	4(%1),%1\n\t"
     "decl	%2\n\t"
     "jnz	1b\n"
     "movw	%w0,(%1)"
     : "=&q" (__d0), "=&r" (__tmp), "=&r" (__d1),
       "=m" ( *(struct { __extension__ char __x[__n]; } *)__s)
     : "0" ((unsigned int) __c), "1" (__tmp), "2" (__n / 4)
     : "cc");
  return __s;
}


/* Search N bytes of S for C.  */
#define _HAVE_STRING_ARCH_memchr 1
#ifndef _FORCE_INLINES
__STRING_INLINE void *
memchr (__const void *__s, int __c, size_t __n)
{
  register unsigned long int __d0;
#ifdef __i686__
  register unsigned long int __d1;
#endif
  register unsigned char *__res;
  if (__n == 0)
    return NULL;
#ifdef __i686__
  __asm__ __volatile__
    ("cld\n\t"
     "repne; scasb\n\t"
     "cmovne %2,%0"
     : "=D" (__res), "=&c" (__d0), "=&r" (__d1)
     : "a" (__c), "0" (__s), "1" (__n), "2" (1),
       "m" ( *(struct { __extension__ char __x[__n]; } *)__s)
     : "cc");
#else
  __asm__ __volatile__
    ("cld\n\t"
     "repne; scasb\n\t"
     "je	1f\n\t"
     "movl	$1,%0\n"
     "1:"
     : "=D" (__res), "=&c" (__d0)
     : "a" (__c), "0" (__s), "1" (__n),
       "m" ( *(struct { __extension__ char __x[__n]; } *)__s)
     : "cc");
#endif
  return __res - 1;
}
#endif

#define _HAVE_STRING_ARCH_memrchr 1
#ifndef _FORCE_INLINES
__STRING_INLINE void *__memrchr (__const void *__s, int __c, size_t __n);

__STRING_INLINE void *
__memrchr (__const void *__s, int __c, size_t __n)
{
  register unsigned long int __d0;
# ifdef __i686__
  register unsigned long int __d1;
# endif
  register void *__res;
  if (__n == 0)
    return NULL;
# ifdef __i686__
  __asm__ __volatile__
    ("std\n\t"
     "repne; scasb\n\t"
     "cmovne %2,%0\n\t"
     "cld"
     : "=D" (__res), "=&c" (__d0), "=&r" (__d1)
     : "a" (__c), "0" (__s + __n - 1), "1" (__n), "2" (-1),
       "m" ( *(struct { __extension__ char __x[__n]; } *)__s)
     : "cc");
# else