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

   1 /*
   2 FUNCTION
   3         <<strxfrm>>---transform string
   4
   5 INDEX
   6         strxfrm
   7
   8 ANSI_SYNOPSIS
   9         #include <string.h>
  10         size_t strxfrm(char *<[s1]>, const char *<[s2]>, size_t <[n]>);
  11
  12 TRAD_SYNOPSIS
  13         #include <string.h>
  14         size_t strxfrm(<[s1]>, <[s2]>, <[n]>);
  15         char *<[s1]>;
  16         char *<[s2]>;
  17         size_t <[n]>;
  18
  19 DESCRIPTION
  20         This function transforms the string pointed to by <[s2]> and
  21         places the resulting string into the array pointed to by
  22         <[s1]>. The transformation is such that if the <<strcmp>>
  23         function is applied to the two transformed strings, it returns
  24         a value greater than, equal to, or less than zero,
  25         correspoinding to the result of a <<strcoll>> function applied
  26         to the same two original strings.
  27
  28         No more than <[n]> characters are placed into the resulting
  29         array pointed to by <[s1]>, including the terminating null
  30         character. If <[n]> is zero, <[s1]> may be a null pointer. If
  31         copying takes place between objects that overlap, the behavior
  32         is undefined.
  33
  34         With a C locale, this function just copies.
  35
  36 RETURNS
  37         The <<strxfrm>> function returns the length of the transformed string
  38         (not including the terminating null character). If the value returned
  39         is <[n]> or more, the contents of the array pointed to by
  40         <[s1]> are indeterminate.
  41
  42 PORTABILITY
  43 <<strxfrm>> is ANSI C.
  44
  45 <<strxfrm>> requires no supporting OS subroutines.
  46
  47 QUICKREF
  48         strxfrm ansi pure
  49 */
  50
  51 #include <string.h>
  52
  53 size_t
  54 _DEFUN (strxfrm, (s1, s2, n),
  55         char *s1 _AND
  56         _CONST char *s2 _AND
  57         size_t n)
  58 {
  59   size_t res;
  60   res = 0;
  61   while (n-- > 0)
  62     {
  63       if ((*s1++ = *s2++) != '\0')
  64         ++res;
  65       else
  66         return res;
  67     }
  68   while (*s2)
  69     {
  70       ++s2;
  71       ++res;
  72     }
  73
  74   return res;
  75 }