Retro68/gcc/newlib/libc/string/stpcpy.c
2017-10-07 02:16:47 +02:00

92 lines
2.0 KiB
C

/*
FUNCTION
<<stpcpy>>---copy string returning a pointer to its end
INDEX
stpcpy
ANSI_SYNOPSIS
#include <string.h>
char *stpcpy(char *restrict <[dst]>, const char *restrict <[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 *__restrict dst _AND
_CONST char *__restrict 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;
}