wctype/cname-lookup.h

   1 /* Copyright (C) 1996 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3 Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>.
   4
   5 The GNU C Library is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 License, or (at your option) any later version.
   9
  10 The GNU C Library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18 Boston, MA 02111-1307, USA.  */
  19
  20 #include "../locale/localeinfo.h"
  21
  22 /* Some words on the runtime of this functions.  Although there is a
  23    loop in the function the runtime is asymptotically quasi constant.
  24    The reason is that even for the largest character sets HASH_LAYERS
  25    will not grow beyond 15 (a guess!).  */
  26 static __inline size_t
  27 cname_lookup (wint_t wc)
  28 {
  29   extern unsigned int *__ctype_names;
  30   unsigned int hash_size, hash_layers;
  31   size_t result, cnt;
  32
  33   hash_size = _NL_CURRENT_WORD (LC_CTYPE, _NL_CTYPE_HASH_SIZE);
  34   hash_layers = _NL_CURRENT_WORD (LC_CTYPE, _NL_CTYPE_HASH_LAYERS);
  35
  36   result = wc % hash_size;
  37   for (cnt = 0; cnt < hash_layers; ++cnt)
  38     {
  39       if (__ctype_names[result] == wc)
  40         break;
  41       result += hash_size;
  42     }
  43
  44   return cnt < hash_layers ? result : ~((size_t) 0);
  45 }