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/* Case-mapping context of prefix UTF-8/UTF-16/UTF-32 string.
Copyright (C) 2009-2013 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2009.
This program is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
casing_prefix_context_t
FUNC1 (const UNIT *s, size_t n)
{
return FUNC2 (s, n, unicase_empty_prefix_context);
}
casing_prefix_context_t
FUNC2 (const UNIT *s, size_t n, casing_prefix_context_t a_context)
{
#if 0
/* Forward iteration. Slow for long strings. */
casing_prefix_context_t context = a_context;
const UNIT *s_end = s + n;
while (s < s_end)
{
ucs4_t uc;
int count = U_MBTOUC_UNSAFE (&uc, s, s_end - s);
if (!uc_is_case_ignorable (uc))
context.last_char_except_ignorable = uc;
{
int ccc = uc_combining_class (uc);
if (ccc == UC_CCC_A || ccc == UC_CCC_NR)
context.last_char_normal_or_above = uc;
}
s += count;
}
return context;
#else
/* Iterate backwards, only as far as needed. */
casing_prefix_context_t context;
ucs4_t last_char_except_ignorable = (ucs4_t)(-1);
ucs4_t last_char_normal_or_above = (ucs4_t)(-1);
const UNIT *p = s + n;
for (;;)
{
ucs4_t uc;
p = U_PREV (&uc, p, s);
if (p == NULL)
break;
if (last_char_except_ignorable == (ucs4_t)(-1))
{
if (!uc_is_case_ignorable (uc))
last_char_except_ignorable = uc;
}
if (last_char_normal_or_above == (ucs4_t)(-1))
{
int ccc = uc_combining_class (uc);
if (ccc == UC_CCC_A || ccc == UC_CCC_NR)
last_char_normal_or_above = uc;
}
if (last_char_except_ignorable != (ucs4_t)(-1)
&& last_char_normal_or_above != (ucs4_t)(-1))
break;
}
context.last_char_except_ignorable =
(last_char_except_ignorable != (ucs4_t)(-1)
? last_char_except_ignorable
: a_context.last_char_except_ignorable);
context.last_char_normal_or_above =
(last_char_normal_or_above != (ucs4_t)(-1)
? last_char_normal_or_above
: a_context.last_char_normal_or_above);
return context;
#endif
}
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