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/*

FUNCTION

        <<stpcpy>>---copy string returning a pointer to its end

INDEX

        stpcpy

ANSI_SYNOPSIS

        #include <string.h>

        char *stpcpy(char *<[dst]>, const char *<[src]>);

TRAD_SYNOPSIS

        #include <string.h>

        char *stpcpy(<[dst]>, <[src]>)

        char *<[dst]>;

        char *<[src]>;

DESCRIPTION

        <<stpcpy>> copies the string pointed to by <[src]>

        (including the terminating null character) to the array

        pointed to by <[dst]>.

RETURNS

        This function returns a pointer to the end of the destination string,

        thus pointing to the trailing '\0'.

PORTABILITY

<<stpcpy>> is a GNU extension, candidate for inclusion into POSIX/SUSv4.

<<stpcpy>> requires no supporting OS subroutines.

QUICKREF

        stpcpy gnu

*/

#include <string.h>

#include <limits.h>

/*SUPPRESS 560*/

/*SUPPRESS 530*/

/* Nonzero if either X or Y is not aligned on a "long" boundary.  */

#define UNALIGNED(X, Y) \

  (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1)))

#if LONG_MAX == 2147483647L

#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)

#else

#if LONG_MAX == 9223372036854775807L

/* Nonzero if X (a long int) contains a NULL byte. */

#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)

#else

#error long int is not a 32bit or 64bit type.

#endif

#endif

#ifndef DETECTNULL

#error long int is not a 32bit or 64bit byte

#endif

char*

_DEFUN (stpcpy, (dst, src),

        char *dst _AND

        _CONST char *src)

{

#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)

  long *aligned_dst;

  _CONST long *aligned_src;

  /* If SRC or DEST is unaligned, then copy bytes.  */

  if (!UNALIGNED (src, dst))

    {

      aligned_dst = (long*)dst;

      aligned_src = (long*)src;

      /* SRC and DEST are both "long int" aligned, try to do "long int"

         sized copies.  */

      while (!DETECTNULL(*aligned_src))

        {

          *aligned_dst++ = *aligned_src++;

        }

      dst = (char*)aligned_dst;

      src = (char*)aligned_src;

    }

#endif /* not PREFER_SIZE_OVER_SPEED */

  while ((*dst++ = *src++))

    ;

  return --dst;

}