gnulib/lib/unicase/ignorable.c

/* Test whether a Unicode character is case-ignorable.
   Copyright (C) 2002, 2006-2007, 2009-2025 Free Software Foundation, Inc.
   Written by Bruno Haible <bruno@clisp.org>, 2009.

   This file is free software.
   It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
   You can redistribute it and/or modify it under either
     - the terms of the GNU Lesser General Public License as published
       by the Free Software Foundation, either version 3, or (at your
       option) any later version, or
     - the terms of the GNU General Public License as published by the
       Free Software Foundation; either version 2, or (at your option)
       any later version, or
     - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".

   This file is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License and the GNU General Public License
   for more details.

   You should have received a copy of the GNU Lesser General Public
   License and of the GNU General Public License along with this
   program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include "caseprop.h"

/* Quoting the Unicode standard:
     Definition: A character is defined to be "case-ignorable" if it has the
     value MidLetter {or the value MidNumLet} for the Word_Break property or
     its General_Category is one of Nonspacing_Mark (Mn), Enclosing_Mark (Me),
     Format (Cf), Modifier_Letter (Lm), or Modifier_Symbol (Sk).
   The text marked in braces was added in Unicode 5.1.0, see
   <https://www.unicode.org/versions/Unicode5.1.0/> section "Update of
   Definition of case-ignorable".   */
/* Since this predicate is only used for the "Before C" and "After C"
   conditions of FINAL_SIGMA, we exclude the "cased" characters here.
   This simplifies the evaluation of the regular expressions
     \p{cased} (\p{case-ignorable})* C
   and
     C (\p{case-ignorable})* \p{cased}
 */

#if 0

#include "unictype.h"
#include "uniwbrk.h"

bool
uc_is_case_ignorable (ucs4_t uc)
{
  int wbp = uc_wordbreak_property (uc);

  return (wbp == WBP_MIDLETTER || wbp == WBP_MIDNUMLET
          || uc_is_general_category_withtable (uc, UC_CATEGORY_MASK_Mn
                                                   | UC_CATEGORY_MASK_Me
                                                   | UC_CATEGORY_MASK_Cf
                                                   | UC_CATEGORY_MASK_Lm
                                                   | UC_CATEGORY_MASK_Sk))
         && !uc_is_cased (uc);
}

#else

#include "unictype/bitmap.h"

/* Define u_casing_property_case_ignorable table.  */
#include "ignorable.h"

bool
uc_is_case_ignorable (ucs4_t uc)
{
  return bitmap_lookup (&u_casing_property_case_ignorable, uc);
}

#endif