162 lines
6.7 KiB
C
Executable File
162 lines
6.7 KiB
C
Executable File
/* Grapheme cluster break function.
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Copyright (C) 2010-2024 Free Software Foundation, Inc.
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Written by Ben Pfaff <blp@cs.stanford.edu>, 2010.
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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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/* This file implements section 3 "Grapheme Cluster Boundaries"
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of Unicode Standard Annex #29 <https://www.unicode.org/reports/tr29/>. */
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void
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FUNC (const UNIT *s, size_t n, char *p)
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{
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if (n > 0)
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{
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const UNIT *s_end = s + n;
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/* Grapheme Cluster break property of the last character.
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-1 at the very beginning of the string. */
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int last_char_prop = -1;
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/* True if the last character ends a sequence of Indic_Conjunct_Break
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values: consonant {extend|linker}* */
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bool incb_consonant_extended = false;
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/* True if the last character ends a sequence of Indic_Conjunct_Break
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values: consonant {extend|linker}* linker */
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bool incb_consonant_extended_linker = false;
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/* True if the last character ends a sequence of Indic_Conjunct_Break
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values: consonant {extend|linker}* linker {extend|linker}* */
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bool incb_consonant_extended_linker_extended = false;
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/* True if the last character ends an emoji modifier sequence
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\p{Extended_Pictographic} Extend*. */
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bool emoji_modifier_sequence = false;
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/* True if the last character was immediately preceded by an
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emoji modifier sequence \p{Extended_Pictographic} Extend*. */
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bool emoji_modifier_sequence_before_last_char = false;
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/* Number of consecutive regional indicator (RI) characters seen
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immediately before the current point. */
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size_t ri_count = 0;
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/* Don't break inside multibyte characters. */
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memset (p, 0, 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 (&uc, s, s_end - s);
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int prop = uc_graphemeclusterbreak_property (uc);
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int incb = uc_indic_conjunct_break (uc);
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/* Break at the start of the string (GB1). */
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if (last_char_prop < 0)
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*p = 1;
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else
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{
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/* No break between CR and LF (GB3). */
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if (last_char_prop == GBP_CR && prop == GBP_LF)
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/* *p = 0 */;
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/* Break before and after newlines (GB4, GB5). */
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else if ((last_char_prop == GBP_CR
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|| last_char_prop == GBP_LF
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|| last_char_prop == GBP_CONTROL)
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|| (prop == GBP_CR
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|| prop == GBP_LF
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|| prop == GBP_CONTROL))
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*p = 1;
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/* No break between Hangul syllable sequences (GB6, GB7, GB8). */
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else if ((last_char_prop == GBP_L
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&& (prop == GBP_L
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|| prop == GBP_V
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|| prop == GBP_LV
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|| prop == GBP_LVT))
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|| ((last_char_prop == GBP_LV
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|| last_char_prop == GBP_V)
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&& (prop == GBP_V
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|| prop == GBP_T))
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|| ((last_char_prop == GBP_LVT
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|| last_char_prop == GBP_T)
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&& prop == GBP_T))
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/* *p = 0 */;
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/* No break before extending characters or ZWJ (GB9). */
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else if (prop == GBP_EXTEND || prop == GBP_ZWJ)
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/* *p = 0 */;
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/* No break before SpacingMarks (GB9a). */
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else if (prop == GBP_SPACINGMARK)
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/* *p = 0 */;
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/* No break after Prepend characters (GB9b). */
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else if (last_char_prop == GBP_PREPEND)
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/* *p = 0 */;
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/* No break within certain combinations of Indic_Conjunct_Break
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values: Between
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consonant {extend|linker}* linker {extend|linker}*
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and
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consonant
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(GB9c). */
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else if (incb_consonant_extended_linker_extended
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&& incb == UC_INDIC_CONJUNCT_BREAK_CONSONANT)
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/* *p = 0 */;
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/* No break within emoji modifier sequences or emoji zwj sequences
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(GB11). */
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else if (last_char_prop == GBP_ZWJ
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&& emoji_modifier_sequence_before_last_char
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&& uc_is_property_extended_pictographic (uc))
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/* *p = 0 */;
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/* No break between RI if there is an odd number of RI
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characters before (GB12, GB13). */
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else if (prop == GBP_RI && (ri_count % 2) != 0)
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/* *p = 0 */;
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/* Break everywhere (GB999). */
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else
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*p = 1;
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}
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incb_consonant_extended_linker =
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incb_consonant_extended && incb == UC_INDIC_CONJUNCT_BREAK_LINKER;
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incb_consonant_extended_linker_extended =
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(incb_consonant_extended_linker
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|| (incb_consonant_extended_linker_extended
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&& incb >= UC_INDIC_CONJUNCT_BREAK_LINKER));
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incb_consonant_extended =
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(incb == UC_INDIC_CONJUNCT_BREAK_CONSONANT
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|| (incb_consonant_extended
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&& incb >= UC_INDIC_CONJUNCT_BREAK_LINKER));
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emoji_modifier_sequence_before_last_char = emoji_modifier_sequence;
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emoji_modifier_sequence =
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(emoji_modifier_sequence && prop == GBP_EXTEND)
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|| uc_is_property_extended_pictographic (uc);
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last_char_prop = prop;
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if (prop == GBP_RI)
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ri_count++;
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else
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ri_count = 0;
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s += count;
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p += count;
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}
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}
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}
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