115 lines
2.7 KiB
C
115 lines
2.7 KiB
C
|
/*
|
||
|
|
FUNCTION
|
||
|
|
<<stpncpy>>---counted copy string returning a pointer to its end
|
||
|
|
|
||
|
|
INDEX
|
||
|
|
stpncpy
|
||
|
|
|
||
|
|
ANSI_SYNOPSIS
|
||
|
|
#include <string.h>
|
||
|
|
char *stpncpy(char *<[dst]>, const char *<[src]>, size_t <[length]>);
|
||
|
|
|
||
|
|
TRAD_SYNOPSIS
|
||
|
|
#include <string.h>
|
||
|
|
char *stpncpy(<[dst]>, <[src]>, <[length]>)
|
||
|
|
char *<[dst]>;
|
||
|
|
char *<[src]>;
|
||
|
|
size_t <[length]>;
|
||
|
|
|
||
|
|
DESCRIPTION
|
||
|
|
<<stpncpy>> copies not more than <[length]> characters from the
|
||
|
|
the string pointed to by <[src]> (including the terminating
|
||
|
|
null character) to the array pointed to by <[dst]>. If the
|
||
|
|
string pointed to by <[src]> is shorter than <[length]>
|
||
|
|
characters, null characters are appended to the destination
|
||
|
|
array until a total of <[length]> characters have been
|
||
|
|
written.
|
||
|
|
|
||
|
|
RETURNS
|
||
|
|
This function returns a pointer to the end of the destination string,
|
||
|
|
thus pointing to the trailing '\0', or, if the destination string is
|
||
|
|
not null-terminated, pointing to dst + n.
|
||
|
|
|
||
|
|
PORTABILITY
|
||
|
|
<<stpncpy>> is a GNU extension, candidate for inclusion into POSIX/SUSv4.
|
||
|
|
|
||
|
|
<<stpncpy>> requires no supporting OS subroutines.
|
||
|
|
|
||
|
|
QUICKREF
|
||
|
|
stpncpy 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
|
||
|
|
|
||
|
|
#define TOO_SMALL(LEN) ((LEN) < sizeof (long))
|
||
|
|
|
||
|
|
char *
|
||
|
|
_DEFUN (stpncpy, (dst, src),
|
||
|
|
char *dst _AND
|
||
|
|
_CONST char *src _AND
|
||
|
|
size_t count)
|
||
|
|
{
|
||
|
|
char *ret = NULL;
|
||
|
|
|
||
|
|
#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
|
||
|
|
long *aligned_dst;
|
||
|
|
_CONST long *aligned_src;
|
||
|
|
|
||
|
|
/* If SRC and DEST is aligned and count large enough, then copy words. */
|
||
|
|
if (!UNALIGNED (src, dst) && !TOO_SMALL (count))
|
||
|
|
{
|
||
|
|
aligned_dst = (long*)dst;
|
||
|
|
aligned_src = (long*)src;
|
||
|
|
|
||
|
|
/* SRC and DEST are both "long int" aligned, try to do "long int"
|
||
|
|
sized copies. */
|
||
|
|
while (count >= sizeof (long int) && !DETECTNULL(*aligned_src))
|
||
|
|
{
|
||
|
|
count -= sizeof (long int);
|
||
|
|
*aligned_dst++ = *aligned_src++;
|
||
|
|
}
|
||
|
|
|
||
|
|
dst = (char*)aligned_dst;
|
||
|
|
src = (char*)aligned_src;
|
||
|
|
}
|
||
|
|
#endif /* not PREFER_SIZE_OVER_SPEED */
|
||
|
|
|
||
|
|
while (count > 0)
|
||
|
|
{
|
||
|
|
--count;
|
||
|
|
if ((*dst++ = *src++) == '\0')
|
||
|
|
{
|
||
|
|
ret = dst - 1;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
while (count-- > 0)
|
||
|
|
*dst++ = '\0';
|
||
|
|
|
||
|
|
return ret ? ret : dst;
|
||
|
|
}
|