newlib-cygwin/newlib/libc/string/strcpy.c

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/*
FUNCTION
<<strcpy>>---copy string
INDEX
strcpy
SYNOPSIS
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#include <string.h>
char *strcpy(char *<[dst]>, const char *<[src]>);
DESCRIPTION
<<strcpy>> copies the string pointed to by <[src]>
(including the terminating null character) to the array
pointed to by <[dst]>.
RETURNS
This function returns the initial value of <[dst]>.
PORTABILITY
<<strcpy>> is ANSI C.
<<strcpy>> requires no supporting OS subroutines.
QUICKREF
strcpy 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
char*
strcpy (char *dst0,
const char *src0)
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{
#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
char *s = dst0;
while (*dst0++ = *src0++)
;
return s;
#else
char *dst = dst0;
const char *src = src0;
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long *aligned_dst;
const long *aligned_src;
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/* 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;
}
while ((*dst++ = *src++))
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;
return dst0;
#endif /* not PREFER_SIZE_OVER_SPEED */
}