101 lines
3.1 KiB
C
Executable File
101 lines
3.1 KiB
C
Executable File
/* Case-mapping context of prefix UTF-8/UTF-16/UTF-32 string.
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Copyright (C) 2009-2024 Free Software Foundation, Inc.
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Written by Bruno Haible <bruno@clisp.org>, 2009.
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This file is free software.
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It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
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You can redistribute it and/or modify it under either
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- the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation, either version 3, or (at your
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option) any later version, or
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- the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2, or (at your option)
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any later version, or
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- the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License and the GNU General Public License
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for more details.
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You should have received a copy of the GNU Lesser General Public
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License and of the GNU General Public License along with this
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program. If not, see <https://www.gnu.org/licenses/>. */
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casing_prefix_context_t
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FUNC1 (const UNIT *s, size_t n)
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{
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return FUNC2 (s, n, unicase_empty_prefix_context);
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}
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casing_prefix_context_t
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FUNC2 (const UNIT *s, size_t n, casing_prefix_context_t a_context)
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{
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#if 0
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/* Forward iteration. Slow for long strings. */
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casing_prefix_context_t context = a_context;
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const UNIT *s_end = s + n;
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while (s < s_end)
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{
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ucs4_t uc;
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int count = U_MBTOUC_UNSAFE (&uc, s, s_end - s);
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if (!uc_is_case_ignorable (uc))
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context.last_char_except_ignorable = uc;
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{
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int ccc = uc_combining_class (uc);
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if (ccc == UC_CCC_A || ccc == UC_CCC_NR)
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context.last_char_normal_or_above = uc;
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}
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s += count;
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}
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return context;
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#else
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/* Iterate backwards, only as far as needed. */
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casing_prefix_context_t context;
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ucs4_t last_char_except_ignorable = (ucs4_t)(-1);
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ucs4_t last_char_normal_or_above = (ucs4_t)(-1);
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const UNIT *p = s + n;
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for (;;)
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{
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ucs4_t uc;
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p = U_PREV (&uc, p, s);
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if (p == NULL)
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break;
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if (last_char_except_ignorable == (ucs4_t)(-1))
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{
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if (!uc_is_case_ignorable (uc))
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last_char_except_ignorable = uc;
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}
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if (last_char_normal_or_above == (ucs4_t)(-1))
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{
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int ccc = uc_combining_class (uc);
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if (ccc == UC_CCC_A || ccc == UC_CCC_NR)
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last_char_normal_or_above = uc;
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}
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if (last_char_except_ignorable != (ucs4_t)(-1)
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&& last_char_normal_or_above != (ucs4_t)(-1))
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break;
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}
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context.last_char_except_ignorable =
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(last_char_except_ignorable != (ucs4_t)(-1)
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? last_char_except_ignorable
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: a_context.last_char_except_ignorable);
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context.last_char_normal_or_above =
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(last_char_normal_or_above != (ucs4_t)(-1)
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? last_char_normal_or_above
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: a_context.last_char_normal_or_above);
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return context;
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#endif
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}
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