newlib/libc/string/wcscasecmp.c

   1 /*
   2 FUNCTION
   3         <<wcscasecmp>>---case-insensitive wide character string compare
   4
   5 INDEX
   6         wcscasecmp
   7
   8 SYNOPSIS
   9         #include <wchar.h>
  10         int wcscasecmp(const wchar_t *<[a]>, const wchar_t *<[b]>);
  11
  12 DESCRIPTION
  13         <<wcscasecmp>> compares the wide character string at <[a]> to
  14         the wide character string at <[b]> in a case-insensitive manner.
  15
  16 RETURNS
  17
  18         If <<*<[a]>>> sorts lexicographically after <<*<[b]>>> (after
  19         both are converted to uppercase), <<wcscasecmp>> returns a
  20         number greater than zero.  If the two strings match,
  21         <<wcscasecmp>> returns zero.  If <<*<[a]>>> sorts
  22         lexicographically before <<*<[b]>>>, <<wcscasecmp>> returns a
  23         number less than zero.
  24
  25 PORTABILITY
  26 POSIX-1.2008
  27
  28 <<wcscasecmp>> requires no supporting OS subroutines. It uses
  29 tolower() from elsewhere in this library.
  30
  31 QUICKREF
  32         wcscasecmp
  33 */
  34
  35 #include <wchar.h>
  36 #include <wctype.h>
  37
  38 int
  39 wcscasecmp (const wchar_t *s1,
  40         const wchar_t *s2)
  41 {
  42   int d = 0;
  43   for ( ; ; )
  44     {
  45       const int c1 = towlower (*s1++);
  46       const int c2 = towlower (*s2++);
  47       if (((d = c1 - c2) != 0) || (c2 == '\0'))
  48         break;
  49     }
  50   return d;
  51 }