firmware/libc/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 #include "_ansi.h" /* for _DEFUN */
  38
  39 /*SUPPRESS 560*/
  40 /*SUPPRESS 530*/
  41
  42 /* Nonzero if either X or Y is not aligned on a "long" boundary.  */
  43 #define UNALIGNED(X, Y) \
  44   (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1)))
  45
  46 #if LONG_MAX == 2147483647L
  47 #define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
  48 #else
  49 #if LONG_MAX == 9223372036854775807L
  50 /* Nonzero if X (a long int) contains a NULL byte. */
  51 #define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
  52 #else
  53 #error long int is not a 32bit or 64bit type.
  54 #endif
  55 #endif
  56
  57 #ifndef DETECTNULL
  58 #error long int is not a 32bit or 64bit byte
  59 #endif
  60
  61 char*
  62 _DEFUN (strcpy, (dst0, src0),
  63         char *dst0 _AND
  64         _CONST char *src0)
  65 {
  66 #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
  67   char *s = dst0;
  68
  69   while ((*dst0++ = *src0++))
  70     ;
  71
  72   return s;
  73 #else
  74   char *dst = dst0;
  75   _CONST char *src = src0;
  76   long *aligned_dst;
  77   _CONST long *aligned_src;
  78
  79   /* If SRC or DEST is unaligned, then copy bytes.  */
  80   if (!UNALIGNED (src, dst))
  81     {
  82       aligned_dst = (long*)dst;
  83       aligned_src = (long*)src;
  84
  85       /* SRC and DEST are both "long int" aligned, try to do "long int"
  86          sized copies.  */
  87       while (!DETECTNULL(*aligned_src))
  88         {
  89           *aligned_dst++ = *aligned_src++;
  90         }
  91
  92       dst = (char*)aligned_dst;
  93       src = (char*)aligned_src;
  94     }
  95
  96   while ((*dst++ = *src++))
  97     ;
  98   return dst0;
  99 #endif /* not PREFER_SIZE_OVER_SPEED */
 100 }