forked from len0rd/rockbox
125 lines
2.7 KiB
C
125 lines
2.7 KiB
C
/*
|
|
FUNCTION
|
|
<<strncpy>>---counted copy string
|
|
|
|
INDEX
|
|
strncpy
|
|
|
|
ANSI_SYNOPSIS
|
|
#include <string.h>
|
|
char *strncpy(char *<[dst]>, const char *<[src]>, size_t <[length]>);
|
|
|
|
TRAD_SYNOPSIS
|
|
#include <string.h>
|
|
char *strncpy(<[dst]>, <[src]>, <[length]>)
|
|
char *<[dst]>;
|
|
char *<[src]>;
|
|
size_t <[length]>;
|
|
|
|
DESCRIPTION
|
|
<<strncpy>> 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 the initial value of <[dst]>.
|
|
|
|
PORTABILITY
|
|
<<strncpy>> is ANSI C.
|
|
|
|
<<strncpy>> requires no supporting OS subroutines.
|
|
|
|
QUICKREF
|
|
strncpy ansi pure
|
|
*/
|
|
|
|
#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 (strncpy, (dst0, src0),
|
|
char *dst0 _AND
|
|
_CONST char *src0 _AND
|
|
size_t count)
|
|
{
|
|
#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
|
|
char *dscan;
|
|
_CONST char *sscan;
|
|
|
|
dscan = dst0;
|
|
sscan = src0;
|
|
while (count > 0)
|
|
{
|
|
--count;
|
|
if ((*dscan++ = *sscan++) == '\0')
|
|
break;
|
|
}
|
|
while (count-- > 0)
|
|
*dscan++ = '\0';
|
|
|
|
return dst0;
|
|
#else
|
|
char *dst = dst0;
|
|
_CONST char *src = src0;
|
|
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;
|
|
}
|
|
|
|
while (count > 0)
|
|
{
|
|
--count;
|
|
if ((*dst++ = *src++) == '\0')
|
|
break;
|
|
}
|
|
|
|
while (count-- > 0)
|
|
*dst++ = '\0';
|
|
|
|
return dst0;
|
|
#endif /* not PREFER_SIZE_OVER_SPEED */
|
|
}
|