root/maint/gnulib/lib/unicase/u-prefix-context.h

/* */

INCLUDED FROM

DEFINITIONS

1. FUNC1
2. FUNC2

   1 /* Case-mapping context of prefix UTF-8/UTF-16/UTF-32 string.
   2    Copyright (C) 2009-2021 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2009.
   4 
   5    This file is free software.
   6    It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
   7    You can redistribute it and/or modify it under either
   8      - the terms of the GNU Lesser General Public License as published
   9        by the Free Software Foundation; either version 3, or (at your
  10        option) any later version, or
  11      - the terms of the GNU General Public License as published by the
  12        Free Software Foundation; either version 2, or (at your option)
  13        any later version, or
  14      - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
  15 
  16    This file is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19    Lesser General Public License and the GNU General Public License
  20    for more details.
  21 
  22    You should have received a copy of the GNU Lesser General Public
  23    License and of the GNU General Public License along with this
  24    program.  If not, see <https://www.gnu.org/licenses/>.  */
  25 
  26 casing_prefix_context_t
  27 FUNC1 (const UNIT *s, size_t n)
     /*  */
  28 {
  29   return FUNC2 (s, n, unicase_empty_prefix_context);
  30 }
  31 
  32 casing_prefix_context_t
  33 FUNC2 (const UNIT *s, size_t n, casing_prefix_context_t a_context)
     /*  */
  34 {
  35 #if 0
  36   /* Forward iteration.  Slow for long strings.  */
  37   casing_prefix_context_t context = a_context;
  38   const UNIT *s_end = s + n;
  39 
  40   while (s < s_end)
  41     {
  42       ucs4_t uc;
  43       int count = U_MBTOUC_UNSAFE (&uc, s, s_end - s);
  44 
  45       if (!uc_is_case_ignorable (uc))
  46         context.last_char_except_ignorable = uc;
  47 
  48       {
  49         int ccc = uc_combining_class (uc);
  50         if (ccc == UC_CCC_A || ccc == UC_CCC_NR)
  51           context.last_char_normal_or_above = uc;
  52       }
  53 
  54       s += count;
  55     }
  56 
  57   return context;
  58 #else
  59   /* Iterate backwards, only as far as needed.  */
  60   casing_prefix_context_t context;
  61   ucs4_t last_char_except_ignorable = (ucs4_t)(-1);
  62   ucs4_t last_char_normal_or_above = (ucs4_t)(-1);
  63   const UNIT *p = s + n;
  64 
  65   for (;;)
  66     {
  67       ucs4_t uc;
  68       p = U_PREV (&uc, p, s);
  69       if (p == NULL)
  70         break;
  71 
  72       if (last_char_except_ignorable == (ucs4_t)(-1))
  73         {
  74           if (!uc_is_case_ignorable (uc))
  75             last_char_except_ignorable = uc;
  76         }
  77 
  78       if (last_char_normal_or_above == (ucs4_t)(-1))
  79         {
  80           int ccc = uc_combining_class (uc);
  81           if (ccc == UC_CCC_A || ccc == UC_CCC_NR)
  82             last_char_normal_or_above = uc;
  83         }
  84 
  85       if (last_char_except_ignorable != (ucs4_t)(-1)
  86           && last_char_normal_or_above != (ucs4_t)(-1))
  87         break;
  88     }
  89   context.last_char_except_ignorable =
  90     (last_char_except_ignorable != (ucs4_t)(-1)
  91      ? last_char_except_ignorable
  92      : a_context.last_char_except_ignorable);
  93   context.last_char_normal_or_above =
  94     (last_char_normal_or_above != (ucs4_t)(-1)
  95      ? last_char_normal_or_above
  96      : a_context.last_char_normal_or_above);
  97 
  98   return context;
  99 #endif
 100 }

/* */