string.h

它通过提供glibc兼容使得应用程序移植到较小的c 库时相当得容易. 它能够应用到带虚拟存储的Linux和uClinux上.在大多数带MMU部件的平台上为使它更加紧凑,它也能够编译成共享库.uClib

/* Compare S1 and S2.  */
#define _HAVE_STRING_ARCH_strcmp 1
#ifndef _FORCE_INLINES
__STRING_INLINE int
strcmp (__const char *__s1, __const char *__s2)
{
  register unsigned long int __d0, __d1;
  register int __res;
  __asm__ __volatile__
    ("cld\n"
     "1:\n\t"
     "lodsb\n\t"
     "scasb\n\t"
     "jne	2f\n\t"
     "testb	%%al,%%al\n\t"
     "jne	1b\n\t"
     "xorl	%%eax,%%eax\n\t"
     "jmp	3f\n"
     "2:\n\t"
     "sbbl	%%eax,%%eax\n\t"
     "orb	$1,%%al\n"
     "3:"
     : "=a" (__res), "=&S" (__d0), "=&D" (__d1)
     : "1" (__s1), "2" (__s2)
     : "cc");
  return __res;
}
#endif

/* Compare N characters of S1 and S2.  */
#define _HAVE_STRING_ARCH_strncmp 1
#ifndef _FORCE_INLINES
__STRING_INLINE int
strncmp (__const char *__s1, __const char *__s2, size_t __n)
{
  register unsigned long int __d0, __d1, __d2;
  register int __res;
  __asm__ __volatile__
    ("cld\n"
     "1:\n\t"
     "decl	%3\n\t"
     "js	2f\n\t"
     "lodsb\n\t"
     "scasb\n\t"
     "jne	3f\n\t"
     "testb	%%al,%%al\n\t"
     "jne	1b\n"
     "2:\n\t"
     "xorl	%%eax,%%eax\n\t"
     "jmp	4f\n"
     "3:\n\t"
     "sbbl	%%eax,%%eax\n\t"
     "orb	$1,%%al\n"
     "4:"
     : "=a" (__res), "=&S" (__d0), "=&D" (__d1), "=&c" (__d2)
     : "1" (__s1), "2" (__s2), "3" (__n)
     : "cc");
  return __res;
}
#endif

/* Find the first occurrence of C in S.  */
#define _HAVE_STRING_ARCH_strchr 1
#define _USE_STRING_ARCH_strchr 1
#define strchr(s, c) \
  (__extension__ (__builtin_constant_p (c)				      \
		  ? __strchr_c (s, ((c) & 0xff) << 8)			      \
		  : __strchr_g (s, c)))

__STRING_INLINE char *__strchr_g (__const char *__s, int __c);

__STRING_INLINE char *
__strchr_g (__const char *__s, int __c)
{
  register unsigned long int __d0;
  register char *__res;
  __asm__ __volatile__
    ("cld\n\t"
     "movb	%%al,%%ah\n"
     "1:\n\t"
     "lodsb\n\t"
     "cmpb	%%ah,%%al\n\t"
     "je	2f\n\t"
     "testb	%%al,%%al\n\t"
     "jne	1b\n\t"
     "movl	$1,%1\n"
     "2:\n\t"
     "movl	%1,%0"
     : "=a" (__res), "=&S" (__d0)
     : "0" (__c), "1" (__s)
     : "cc");
  return __res - 1;
}

__STRING_INLINE char *__strchr_c (__const char *__s, int __c);

__STRING_INLINE char *
__strchr_c (__const char *__s, int __c)
{
  register unsigned long int __d0;
  register char *__res;
  __asm__ __volatile__
    ("cld\n\t"
     "1:\n\t"
     "lodsb\n\t"
     "cmpb	%%ah,%%al\n\t"
     "je	2f\n\t"
     "testb	%%al,%%al\n\t"
     "jne	1b\n\t"
     "movl	$1,%1\n"
     "2:\n\t"
     "movl	%1,%0"
     : "=a" (__res), "=&S" (__d0)
     : "0" (__c), "1" (__s)
     : "cc");
  return __res - 1;
}


/* Find the first occurrence of C in S or the final NUL byte.  */
#define _HAVE_STRING_ARCH_strchrnul 1
#define __strchrnul(s, c) \
  (__extension__ (__builtin_constant_p (c)				      \
		  ? ((c) == '\0'					      \
		     ? (char *) __rawmemchr (s, c)			      \
		     : __strchrnul_c (s, ((c) & 0xff) << 8))		      \
		  : __strchrnul_g (s, c)))

__STRING_INLINE char *__strchrnul_g (__const char *__s, int __c);

__STRING_INLINE char *
__strchrnul_g (__const char *__s, int __c)
{
  register unsigned long int __d0;
  register char *__res;
  __asm__ __volatile__
    ("cld\n\t"
     "movb	%%al,%%ah\n"
     "1:\n\t"
     "lodsb\n\t"
     "cmpb	%%ah,%%al\n\t"
     "je	2f\n\t"
     "testb	%%al,%%al\n\t"
     "jne	1b\n\t"
     "2:\n\t"
     "movl	%1,%0"
     : "=a" (__res), "=&S" (__d0)
     : "0" (__c), "1" (__s)
     : "cc");
  return __res - 1;
}

__STRING_INLINE char *__strchrnul_c (__const char *__s, int __c);

__STRING_INLINE char *
__strchrnul_c (__const char *__s, int __c)
{
  register unsigned long int __d0;
  register char *__res;
  __asm__ __volatile__
    ("cld\n\t"
     "1:\n\t"
     "lodsb\n\t"
     "cmpb	%%ah,%%al\n\t"
     "je	2f\n\t"
     "testb	%%al,%%al\n\t"
     "jne	1b\n\t"
     "2:\n\t"
     "movl	%1,%0"
     : "=a" (__res), "=&S" (__d0)
     : "0" (__c), "1" (__s)
     : "cc");
  return __res - 1;
}
#ifdef __USE_GNU
# define strchrnul(s, c) __strchrnul (s, c)
#endif


/* Return the length of the initial segment of S which
   consists entirely of characters not in REJECT.  */
#define _HAVE_STRING_ARCH_strcspn 1
#ifndef _FORCE_INLINES
# ifdef __PIC__
__STRING_INLINE size_t
strcspn (__const char *__s, __const char *__reject)
{
  register unsigned long int __d0, __d1, __d2;
  register char *__res;
  __asm__ __volatile__
    ("pushl	%%ebx\n\t"
     "cld\n\t"
     "movl	%4,%%edi\n\t"
     "repne; scasb\n\t"
     "notl	%%ecx\n\t"
     "decl	%%ecx\n\t"
     "movl	%%ecx,%%ebx\n"
     "1:\n\t"
     "lodsb\n\t"
     "testb	%%al,%%al\n\t"
     "je	2f\n\t"
     "movl	%4,%%edi\n\t"
     "movl	%%ebx,%%ecx\n\t"
     "repne; scasb\n\t"
     "jne	1b\n"
     "2:\n\t"
     "popl	%%ebx"
     : "=&S" (__res), "=&a" (__d0), "=&c" (__d1), "=&D" (__d2)
     : "d" (__reject), "0" (__s), "1" (0), "2" (0xffffffff)
     : "cc");
  return (__res - 1) - __s;
}
# else
__STRING_INLINE size_t
strcspn (__const char *__s, __const char *__reject)
{
  register unsigned long int __d0, __d1, __d2, __d3;
  register char *__res;
  __asm__ __volatile__
    ("cld\n\t"
     "movl	%5,%%edi\n\t"
     "repne; scasb\n\t"
     "notl	%%ecx\n\t"
     "decl	%%ecx\n\t"
     "movl	%%ecx,%%edx\n"
     "1:\n\t"
     "lodsb\n\t"
     "testb	%%al,%%al\n\t"
     "je	2f\n\t"
     "movl	%5,%%edi\n\t"
     "movl	%%edx,%%ecx\n\t"
     "repne; scasb\n\t"
     "jne	1b\n"
     "2:"
     : "=&S" (__res), "=&a" (__d0), "=&c" (__d1), "=&d" (__d2), "=&D" (__d3)
     : "g" (__reject), "0" (__s), "1" (0), "2" (0xffffffff)
     : "cc");
  return (__res - 1) - __s;
}
# endif
#endif


/* Return the length of the initial segment of S which
   consists entirely of characters in ACCEPT.  */
#define _HAVE_STRING_ARCH_strspn 1
#ifndef _FORCE_INLINES
# ifdef __PIC__
__STRING_INLINE size_t
strspn (__const char *__s, __const char *__accept)
{
  register unsigned long int __d0, __d1, __d2;
  register char *__res;
  __asm__ __volatile__
    ("pushl	%%ebx\n\t"
     "cld\n\t"
     "movl	%4,%%edi\n\t"
     "repne; scasb\n\t"
     "notl	%%ecx\n\t"
     "decl	%%ecx\n\t"
     "movl	%%ecx,%%ebx\n"
     "1:\n\t"
     "lodsb\n\t"
     "testb	%%al,%%al\n\t"
     "je	2f\n\t"
     "movl	%4,%%edi\n\t"
     "movl	%%ebx,%%ecx\n\t"
     "repne; scasb\n\t"
     "je	1b\n"
     "2:\n\t"
     "popl	%%ebx"
     : "=&S" (__res), "=&a" (__d0), "=&c" (__d1), "=&D" (__d2)
     : "r" (__accept), "0" (__s), "1" (0), "2" (0xffffffff)
     : "cc");
  return (__res - 1) - __s;
}
# else
__STRING_INLINE size_t
strspn (__const char *__s, __const char *__accept)
{
  register unsigned long int __d0, __d1, __d2, __d3;
  register char *__res;
  __asm__ __volatile__
    ("cld\n\t"
     "movl	%5,%%edi\n\t"
     "repne; scasb\n\t"
     "notl	%%ecx\n\t"
     "decl	%%ecx\n\t"
     "movl	%%ecx,%%edx\n"
     "1:\n\t"
     "lodsb\n\t"
     "testb	%%al,%%al\n\t"
     "je	2f\n\t"
     "movl	%5,%%edi\n\t"
     "movl	%%edx,%%ecx\n\t"
     "repne; scasb\n\t"
     "je	1b\n"
     "2:"
     : "=&S" (__res), "=&a" (__d0), "=&c" (__d1), "=&d" (__d2), "=&D" (__d3)
     : "g" (__accept), "0" (__s), "1" (0), "2" (0xffffffff)
     : "cc");
  return (__res - 1) - __s;
}
# endif
#endif


/* Find the first occurrence in S of any character in ACCEPT.  */
#define _HAVE_STRING_ARCH_strpbrk 1
#ifndef _FORCE_INLINES
# ifdef __PIC__
__STRING_INLINE char *
strpbrk (__const char *__s, __const char *__accept)
{
  unsigned long int __d0, __d1, __d2;
  register char *__res;
  __asm__ __volatile__
    ("pushl	%%ebx\n\t"
     "cld\n\t"
     "movl	%4,%%edi\n\t"
     "repne; scasb\n\t"
     "notl	%%ecx\n\t"
     "decl	%%ecx\n\t"
     "movl	%%ecx,%%ebx\n"
     "1:\n\t"
     "lodsb\n\t"
     "testb	%%al,%%al\n\t"
     "je	2f\n\t"
     "movl	%4,%%edi\n\t"
     "movl	%%ebx,%%ecx\n\t"
     "repne; scasb\n\t"
     "jne	1b\n\t"
     "decl	%0\n\t"
     "jmp	3f\n"
     "2:\n\t"
     "xorl	%0,%0\n"
     "3:\n\t"
     "popl	%%ebx"
     : "=&S" (__res), "=&a" (__d0), "=&c" (__d1), "=&D" (__d2)
     : "r" (__accept), "0" (__s), "1" (0), "2" (0xffffffff)
     : "cc");
  return __res;
}
# else
__STRING_INLINE char *
strpbrk (__const char *__s, __const char *__accept)
{
  register unsigned long int __d0, __d1, __d2, __d3;
  register char *__res;
  __asm__ __volatile__
    ("cld\n\t"
     "movl	%5,%%edi\n\t"
     "repne; scasb\n\t"
     "notl	%%ecx\n\t"
     "decl	%%ecx\n\t"
     "movl	%%ecx,%%edx\n"
     "1:\n\t"
     "lodsb\n\t"
     "testb	%%al,%%al\n\t"
     "je	2f\n\t"
     "movl	%5,%%edi\n\t"
     "movl	%%edx,%%ecx\n\t"
     "repne; scasb\n\t"
     "jne	1b\n\t"
     "decl	%0\n\t"
     "jmp	3f\n"
     "2:\n\t"
     "xorl	%0,%0\n"
     "3:"
     : "=&S" (__res), "=&a" (__d0), "=&c" (__d1), "=&d" (__d2), "=&D" (__d3)
     : "g" (__accept), "0" (__s), "1" (0), "2" (0xffffffff)
     : "cc");
  return __res;
}
# endif
#endif


/* Find the first occurrence of NEEDLE in HAYSTACK.  */
#define _HAVE_STRING_ARCH_strstr 1
#ifndef _FORCE_INLINES
# ifdef __PIC__
__STRING_INLINE char *
strstr (__const char *__haystack, __const char *__needle)
{
  register unsigned long int __d0, __d1, __d2;
  register char *__res;
  __asm__ __volatile__
    ("pushl	%%ebx\n\t"
     "cld\n\t" \
     "movl	%4,%%edi\n\t"
     "repne; scasb\n\t"
     "notl	%%ecx\n\t"
     "decl	%%ecx\n\t"	/* NOTE! This also sets Z if searchstring='' */
     "movl	%%ecx,%%ebx\n"
     "1:\n\t"
     "movl	%4,%%edi\n\t"
     "movl	%%esi,%%eax\n\t"
     "movl	%%ebx,%%ecx\n\t"
     "repe; cmpsb\n\t"
     "je	2f\n\t"		/* also works for empty string, see above */
     "xchgl	%%eax,%%esi\n\t"
     "incl	%%esi\n\t"
     "cmpb	$0,-1(%%eax)\n\t"
     "jne	1b\n\t"
     "xorl	%%eax,%%eax\n\t"
     "2:\n\t"
     "popl	%%ebx"
     : "=&a" (__res), "=&c" (__d0), "=&S" (__d1), "=&D" (__d2)
     : "r" (__needle), "0" (0), "1" (0xffffffff), "2" (__haystack)
     : "cc");
  return __res;
}
# else
__STRING_INLINE char *
strstr (__const char *__haystack, __const char *__needle)
{
  register unsigned long int __d0, __d1, __d2, __d3;
  register char *__res;
  __asm__ __volatile__
    ("cld\n\t" \
     "movl	%5,%%edi\n\t"
     "repne; scasb\n\t"
     "notl	%%ecx\n\t"
     "decl	%%ecx\n\t"	/* NOTE! This also sets Z if searchstring='' */
     "movl	%%ecx,%%edx\n"
     "1:\n\t"
     "movl	%5,%%edi\n\t"
     "movl	%%esi,%%eax\n\t"
     "movl	%%edx,%%ecx\n\t"
     "repe; cmpsb\n\t"
     "je	2f\n\t"		/* also works for empty string, see above */
     "xchgl	%%eax,%%esi\n\t"
     "incl	%%esi\n\t"
     "cmpb	$0,-1(%%eax)\n\t"
     "jne	1b\n\t"
     "xorl	%%eax,%%eax\n\t"
     "2:"
     : "=&a" (__res), "=&c" (__d0), "=&S" (__d1), "=&d" (__d2), "=&D" (__d3)
     : "g" (__needle), "0" (0), "1" (0xffffffff), "2" (__haystack)
     : "cc");
  return __res;
}
# endif
#endif

#ifndef _FORCE_INLINES
# undef __STRING_INLINE
#endif

#endif	/* use string inlines && GNU CC */