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/*
* Copyright (C) 2003-2019 Apple Inc. All rights reserved.
* Copyright (C) 2008 Holger Hans Peter Freyther
* Copyright (C) Research In Motion Limited 2011. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#include "config.h"
#include "SurrogatePairAwareTextIterator.h"
#include <unicode/unorm2.h>
namespace WebCore {
SurrogatePairAwareTextIterator::SurrogatePairAwareTextIterator(const UChar* characters, unsigned currentIndex, unsigned lastIndex, unsigned endIndex)
: m_characters(characters)
, m_currentIndex(currentIndex)
, m_lastIndex(lastIndex)
, m_endIndex(endIndex)
{
}
bool SurrogatePairAwareTextIterator::consumeSlowCase(UChar32& character, unsigned& clusterLength)
{
if (character <= 0x30FE) {
// Deal with Hiragana and Katakana voiced and semi-voiced syllables.
// Normalize into composed form, and then look for glyph with base + combined mark.
// Check above for character range to minimize performance impact.
if (UChar32 normalized = normalizeVoicingMarks()) {
character = normalized;
clusterLength = 2;
}
return true;
}
if (!U16_IS_SURROGATE(character))
return true;
// If we have a surrogate pair, make sure it starts with the high part.
if (!U16_IS_SURROGATE_LEAD(character))
return false;
// Do we have a surrogate pair? If so, determine the full Unicode (32 bit) code point before glyph lookup.
// Make sure we have another character and it's a low surrogate.
if (m_currentIndex + 1 >= m_endIndex)
return false;
UChar low = m_characters[1];
if (!U16_IS_TRAIL(low))
return false;
character = U16_GET_SUPPLEMENTARY(character, low);
clusterLength = 2;
return true;
}
UChar32 SurrogatePairAwareTextIterator::normalizeVoicingMarks()
{
// According to http://www.unicode.org/Public/UNIDATA/UCD.html#Canonical_Combining_Class_Values
static constexpr uint8_t hiraganaKatakanaVoicingMarksCombiningClass = 8;
if (m_currentIndex + 1 >= m_endIndex)
return 0;
if (u_getCombiningClass(m_characters[1]) == hiraganaKatakanaVoicingMarksCombiningClass) {
UErrorCode status = U_ZERO_ERROR;
const UNormalizer2* normalizer = unorm2_getNFCInstance(&status);
ASSERT(U_SUCCESS(status));
auto composedCharacter = unorm2_composePair(normalizer, m_characters[0], m_characters[1]);
if (composedCharacter > 0)
return composedCharacter;
}
return 0;
}
}