newlib/libc/string/strcasecmp_l.c

   1 /*
   2 FUNCTION
   3         <<strcasecmp_l>>---case-insensitive character string compare
   4
   5 INDEX
   6         strcasecmp_l
   7
   8 SYNOPSIS
   9         #include <strings.h>
  10         int strcasecmp_l(const char *<[a]>, const char *<[b]>,
  11                          locale_t <[locale]>);
  12
  13 DESCRIPTION
  14         <<strcasecmp_l>> compares the string at <[a]> to
  15         the string at <[b]> in a case-insensitive manner.
  16
  17         if <[locale]> is LC_GLOBAL_LOCALE or not a valid locale object, the
  18         behaviour is undefined.
  19
  20 RETURNS
  21
  22         If <<*<[a]>>> sorts lexicographically after <<*<[b]>>> (after
  23         both are converted to lowercase), <<strcasecmp_l>> returns a
  24         number greater than zero.  If the two strings match,
  25         <<strcasecmp_l>> returns zero.  If <<*<[a]>>> sorts
  26         lexicographically before <<*<[b]>>>, <<strcasecmp_l>> returns a
  27         number less than zero.
  28
  29 PORTABILITY
  30 <<strcasecmp_l>> is POSIX-1.2008.
  31
  32 <<strcasecmp_l>> requires no supporting OS subroutines. It uses
  33 tolower_l() from elsewhere in this library.
  34
  35 QUICKREF
  36         strcasecmp_l
  37 */
  38
  39 #include <strings.h>
  40 #include <ctype.h>
  41
  42 int
  43 strcasecmp_l (const char *s1, const char *s2, struct __locale_t *locale)
  44 {
  45   int d = 0;
  46   for ( ; ; )
  47     {
  48       const int c1 = tolower_l (*s1++, locale);
  49       const int c2 = tolower_l (*s2++, locale);
  50       if (((d = c1 - c2) != 0) || (c2 == '\0'))
  51         break;
  52     }
  53   return d;
  54 }