toolchain/gcc/newlib/libc/string/strcpy.c

   1 /*
   2 FUNCTION
   3         <<strcpy>>---copy string
   4
   5 INDEX
   6         strcpy
   7
   8 ANSI_SYNOPSIS
   9         #include <string.h>
  10         char *strcpy(char *<[dst]>, const char *<[src]>);
  11
  12 TRAD_SYNOPSIS
  13         #include <string.h>
  14         char *strcpy(<[dst]>, <[src]>)
  15         char *<[dst]>;
  16         char *<[src]>;
  17
  18 DESCRIPTION
  19         <<strcpy>> copies the string pointed to by <[src]>
  20         (including the terminating null character) to the array
  21         pointed to by <[dst]>.
  22
  23 RETURNS
  24         This function returns the initial value of <[dst]>.
  25
  26 PORTABILITY
  27 <<strcpy>> is ANSI C.
  28
  29 <<strcpy>> requires no supporting OS subroutines.
  30
  31 QUICKREF
  32         strcpy ansi pure
  33 */
  34
  35 #include <string.h>
  36 #include <limits.h>
  37
  38 /*SUPPRESS 560*/
  39 /*SUPPRESS 530*/
  40
  41 /* Nonzero if either X or Y is not aligned on a "long" boundary.  */
  42 #define UNALIGNED(X, Y) \
  43   (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1)))
  44
  45 #if LONG_MAX == 2147483647L
  46 #define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
  47 #else
  48 #if LONG_MAX == 9223372036854775807L
  49 /* Nonzero if X (a long int) contains a NULL byte. */
  50 #define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
  51 #else
  52 #error long int is not a 32bit or 64bit type.
  53 #endif
  54 #endif
  55
  56 #ifndef DETECTNULL
  57 #error long int is not a 32bit or 64bit byte
  58 #endif
  59
  60 char*
  61 _DEFUN (strcpy, (dst0, src0),
  62         char *dst0 _AND
  63         _CONST char *src0)
  64 {
  65 #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
  66   char *s = dst0;
  67
  68   while (*dst0++ = *src0++)
  69     ;
  70
  71   return s;
  72 #else
  73   char *dst = dst0;
  74   _CONST char *src = src0;
  75   long *aligned_dst;
  76   _CONST long *aligned_src;
  77
  78   /* If SRC or DEST is unaligned, then copy bytes.  */
  79   if (!UNALIGNED (src, dst))
  80     {
  81       aligned_dst = (long*)dst;
  82       aligned_src = (long*)src;
  83
  84       /* SRC and DEST are both "long int" aligned, try to do "long int"
  85          sized copies.  */
  86       while (!DETECTNULL(*aligned_src))
  87         {
  88           *aligned_dst++ = *aligned_src++;
  89         }
  90
  91       dst = (char*)aligned_dst;
  92       src = (char*)aligned_src;
  93     }
  94
  95   while (*dst++ = *src++)
  96     ;
  97   return dst0;
  98 #endif /* not PREFER_SIZE_OVER_SPEED */
  99 }