newlib/libc/string/strxfrm_l.c

   1 /*
   2 FUNCTION
   3         <<strxfrm_l>>---transform string
   4
   5 INDEX
   6         strxfrm_l
   7
   8 SYNOPSIS
   9         #include <string.h>
  10         size_t strxfrm_l(char *restrict <[s1]>, const char *restrict <[s2]>,
  11                        size_t <[n]>, locale_t <[locale]>);
  12
  13 DESCRIPTION
  14         This function transforms the string pointed to by <[s2]> and
  15         places the resulting string into the array pointed to by
  16         <[s1]>. The transformation is such that if the <<strcmp>>
  17         function is applied to the two transformed strings, it returns
  18         a value greater than, equal to, or less than zero,
  19         correspoinding to the result of a <<strcoll>> function applied
  20         to the same two original strings.
  21
  22         No more than <[n]> characters are placed into the resulting
  23         array pointed to by <[s1]>, including the terminating null
  24         character. If <[n]> is zero, <[s1]> may be a null pointer. If
  25         copying takes place between objects that overlap, the behavior
  26         is undefined.
  27
  28         (NOT Cygwin:) The current implementation of <<strxfrm_l>> simply copies
  29         the input and does not support any language-specific transformations.
  30
  31         If <[locale]> is LC_GLOBAL_LOCALE or not a valid locale object, the
  32         behaviour is undefined.
  33
  34 RETURNS
  35         The <<strxfrm_l>> function returns the length of the transformed string
  36         (not including the terminating null character). If the value returned
  37         is <[n]> or more, the contents of the array pointed to by
  38         <[s1]> are indeterminate.
  39
  40 PORTABILITY
  41 <<strxfrm_l>> is POSIX-1.2008.
  42
  43 <<strxfrm_l>> requires no supporting OS subroutines.
  44
  45 QUICKREF
  46         strxfrm_l ansi pure
  47 */
  48
  49 #include <string.h>
  50
  51 size_t
  52 strxfrm_l (char *__restrict s1, const char *__restrict s2, size_t n,
  53            struct __locale_t *locale)
  54 {
  55   size_t res;
  56   res = 0;
  57   while (n-- > 0)
  58     {
  59       if ((*s1++ = *s2++) != '\0')
  60         ++res;
  61       else
  62         return res;
  63     }
  64   while (*s2)
  65     {
  66       ++s2;
  67       ++res;
  68     }
  69
  70   return res;
  71 }