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103 lines
3.4 KiB
C++
103 lines
3.4 KiB
C++
/*
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* Copyright (C) 2003, 2006, 2008, 2009, 2010, 2011 Apple Inc.
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* All rights reserved.
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* Copyright (C) 2008 Holger Hans Peter Freyther
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* Copyright (C) Research In Motion Limited 2011. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library 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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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public License
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* along with this library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*
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*/
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#include "flutter/sky/engine/platform/text/SurrogatePairAwareTextIterator.h"
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#include <unicode/unorm.h>
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using namespace WTF;
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using namespace Unicode;
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namespace blink {
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SurrogatePairAwareTextIterator::SurrogatePairAwareTextIterator(
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const UChar* characters,
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int currentCharacter,
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int lastCharacter,
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int endCharacter)
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: m_characters(characters),
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m_currentCharacter(currentCharacter),
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m_lastCharacter(lastCharacter),
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m_endCharacter(endCharacter) {}
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bool SurrogatePairAwareTextIterator::consumeSlowCase(UChar32& character,
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unsigned& clusterLength) {
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if (character <= 0x30FE) {
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// Deal with Hiragana and Katakana voiced and semi-voiced syllables.
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// Normalize into composed form, and then look for glyph with base +
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// combined mark. Check above for character range to minimize performance
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// impact.
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if (UChar32 normalized = normalizeVoicingMarks()) {
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character = normalized;
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clusterLength = 2;
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}
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return true;
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}
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if (!U16_IS_SURROGATE(character))
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return true;
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// If we have a surrogate pair, make sure it starts with the high part.
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if (!U16_IS_SURROGATE_LEAD(character))
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return false;
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// Do we have a surrogate pair? If so, determine the full Unicode (32 bit)
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// code point before glyph lookup. Make sure we have another character and
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// it's a low surrogate.
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if (m_currentCharacter + 1 >= m_endCharacter)
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return false;
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UChar low = m_characters[1];
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if (!U16_IS_TRAIL(low))
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return false;
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character = U16_GET_SUPPLEMENTARY(character, low);
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clusterLength = 2;
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return true;
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}
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UChar32 SurrogatePairAwareTextIterator::normalizeVoicingMarks() {
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// According to
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// http://www.unicode.org/Public/UNIDATA/UCD.html#Canonical_Combining_Class_Values
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static const uint8_t hiraganaKatakanaVoicingMarksCombiningClass = 8;
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if (m_currentCharacter + 1 >= m_endCharacter)
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return 0;
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if (combiningClass(m_characters[1]) ==
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hiraganaKatakanaVoicingMarksCombiningClass) {
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// Normalize into composed form using 3.2 rules.
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UChar normalizedCharacters[2] = {0, 0};
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UErrorCode uStatus = U_ZERO_ERROR;
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int32_t resultLength =
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unorm_normalize(m_characters, 2, UNORM_NFC, UNORM_UNICODE_3_2,
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&normalizedCharacters[0], 2, &uStatus);
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if (resultLength == 1 && !uStatus)
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return normalizedCharacters[0];
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}
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return 0;
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}
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} // namespace blink
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