mirror of
https://github.com/darlinghq/darling-WebCore.git
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228 lines
11 KiB
C++
228 lines
11 KiB
C++
/*
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* Copyright (C) 2005, 2007, 2010, 2013, 2016 Apple Inc. All rights reserved.
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* Copyright (C) 2011 Google Inc. 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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#pragma once
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#include <unicode/ubrk.h>
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#include <wtf/ASCIICType.h>
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#include <wtf/StdLibExtras.h>
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#include <wtf/text/TextBreakIterator.h>
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#include <wtf/unicode/CharacterNames.h>
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namespace WebCore {
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static const UChar lineBreakTableFirstCharacter = '!';
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static const UChar lineBreakTableLastCharacter = 127;
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static const unsigned lineBreakTableColumnCount = (lineBreakTableLastCharacter - lineBreakTableFirstCharacter) / 8 + 1;
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WEBCORE_EXPORT extern const unsigned char lineBreakTable[][lineBreakTableColumnCount];
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enum class NonBreakingSpaceBehavior {
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IgnoreNonBreakingSpace,
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TreatNonBreakingSpaceAsBreak,
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};
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enum class CanUseShortcut {
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Yes,
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No
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};
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template<NonBreakingSpaceBehavior nonBreakingSpaceBehavior>
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static inline bool isBreakableSpace(UChar character)
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{
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switch (character) {
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case ' ':
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case '\n':
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case '\t':
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return true;
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case noBreakSpace:
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return nonBreakingSpaceBehavior == NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak;
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default:
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return false;
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}
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}
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inline bool shouldBreakAfter(UChar lastCharacter, UChar character, UChar nextCharacter)
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{
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// Don't allow line breaking between '-' and a digit if the '-' may mean a minus sign in the context,
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// while allow breaking in 'ABCD-1234' and '1234-5678' which may be in long URLs.
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if (character == '-' && isASCIIDigit(nextCharacter))
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return isASCIIAlphanumeric(lastCharacter);
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// If both ch and nextCh are ASCII characters, use a lookup table for enhanced speed and for compatibility
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// with other browsers (see comments for asciiLineBreakTable for details).
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if (character >= lineBreakTableFirstCharacter && character <= lineBreakTableLastCharacter && nextCharacter >= lineBreakTableFirstCharacter && nextCharacter <= lineBreakTableLastCharacter) {
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const unsigned char* tableRow = lineBreakTable[character - lineBreakTableFirstCharacter];
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unsigned nextCharacterIndex = nextCharacter - lineBreakTableFirstCharacter;
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return tableRow[nextCharacterIndex / 8] & (1 << (nextCharacterIndex % 8));
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}
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// Otherwise defer to the Unicode algorithm by returning false.
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return false;
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}
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template<NonBreakingSpaceBehavior nonBreakingSpaceBehavior>
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inline bool needsLineBreakIterator(UChar character)
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{
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if (nonBreakingSpaceBehavior == NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak)
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return character > lineBreakTableLastCharacter;
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return character > lineBreakTableLastCharacter && character != noBreakSpace;
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}
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// When in non-loose mode, we can use the ASCII shortcut table.
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template<typename CharacterType, NonBreakingSpaceBehavior nonBreakingSpaceBehavior, CanUseShortcut canUseShortcut>
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inline unsigned nextBreakablePosition(LazyLineBreakIterator& lazyBreakIterator, const CharacterType* string, unsigned length, unsigned startPosition)
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{
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Optional<unsigned> nextBreak;
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CharacterType lastLastCharacter = startPosition > 1 ? string[startPosition - 2] : static_cast<CharacterType>(lazyBreakIterator.secondToLastCharacter());
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CharacterType lastCharacter = startPosition > 0 ? string[startPosition - 1] : static_cast<CharacterType>(lazyBreakIterator.lastCharacter());
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unsigned priorContextLength = lazyBreakIterator.priorContextLength();
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for (unsigned i = startPosition; i < length; i++) {
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CharacterType character = string[i];
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if (isBreakableSpace<nonBreakingSpaceBehavior>(character) || (canUseShortcut == CanUseShortcut::Yes && shouldBreakAfter(lastLastCharacter, lastCharacter, character)))
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return i;
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if (canUseShortcut == CanUseShortcut::No || needsLineBreakIterator<nonBreakingSpaceBehavior>(character) || needsLineBreakIterator<nonBreakingSpaceBehavior>(lastCharacter)) {
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if (!nextBreak || nextBreak.value() < i) {
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// Don't break if positioned at start of primary context and there is no prior context.
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if (i || priorContextLength) {
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UBreakIterator* breakIterator = lazyBreakIterator.get(priorContextLength);
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if (breakIterator) {
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int candidate = ubrk_following(breakIterator, i - 1 + priorContextLength);
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if (candidate == UBRK_DONE)
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nextBreak = WTF::nullopt;
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else {
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unsigned result = candidate;
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ASSERT(result >= priorContextLength);
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nextBreak = result - priorContextLength;
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}
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}
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}
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}
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if (i == nextBreak && !isBreakableSpace<nonBreakingSpaceBehavior>(lastCharacter))
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return i;
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}
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lastLastCharacter = lastCharacter;
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lastCharacter = character;
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}
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return length;
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}
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template<typename CharacterType, NonBreakingSpaceBehavior nonBreakingSpaceBehavior>
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inline unsigned nextBreakablePositionKeepingAllWords(const CharacterType* string, unsigned length, unsigned startPosition)
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{
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for (unsigned i = startPosition; i < length; i++) {
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if (isBreakableSpace<nonBreakingSpaceBehavior>(string[i]))
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return i;
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}
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return length;
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}
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inline unsigned nextBreakablePositionKeepingAllWords(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition)
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{
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auto stringView = lazyBreakIterator.stringView();
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if (stringView.is8Bit())
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return nextBreakablePositionKeepingAllWords<LChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak>(stringView.characters8(), stringView.length(), startPosition);
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return nextBreakablePositionKeepingAllWords<UChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak>(stringView.characters16(), stringView.length(), startPosition);
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}
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inline unsigned nextBreakablePositionKeepingAllWordsIgnoringNBSP(LazyLineBreakIterator& iterator, unsigned startPosition)
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{
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auto stringView = iterator.stringView();
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if (stringView.is8Bit())
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return nextBreakablePositionKeepingAllWords<LChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace>(stringView.characters8(), stringView.length(), startPosition);
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return nextBreakablePositionKeepingAllWords<UChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace>(stringView.characters16(), stringView.length(), startPosition);
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}
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inline unsigned nextBreakablePosition(LazyLineBreakIterator& iterator, unsigned startPosition)
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{
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auto stringView = iterator.stringView();
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if (stringView.is8Bit())
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return nextBreakablePosition<LChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak, CanUseShortcut::Yes>(iterator, stringView.characters8(), stringView.length(), startPosition);
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return nextBreakablePosition<UChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak, CanUseShortcut::Yes>(iterator, stringView.characters16(), stringView.length(), startPosition);
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}
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inline unsigned nextBreakablePositionIgnoringNBSP(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition)
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{
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auto stringView = lazyBreakIterator.stringView();
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if (stringView.is8Bit())
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return nextBreakablePosition<LChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace, CanUseShortcut::Yes>(lazyBreakIterator, stringView.characters8(), stringView.length(), startPosition);
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return nextBreakablePosition<UChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace, CanUseShortcut::Yes>(lazyBreakIterator, stringView.characters16(), stringView.length(), startPosition);
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}
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inline unsigned nextBreakablePositionWithoutShortcut(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition)
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{
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auto stringView = lazyBreakIterator.stringView();
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if (stringView.is8Bit())
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return nextBreakablePosition<LChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak, CanUseShortcut::No>(lazyBreakIterator, stringView.characters8(), stringView.length(), startPosition);
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return nextBreakablePosition<UChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak, CanUseShortcut::No>(lazyBreakIterator, stringView.characters16(), stringView.length(), startPosition);
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}
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inline unsigned nextBreakablePositionIgnoringNBSPWithoutShortcut(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition)
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{
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auto stringView = lazyBreakIterator.stringView();
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if (stringView.is8Bit())
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return nextBreakablePosition<LChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace, CanUseShortcut::No>(lazyBreakIterator, stringView.characters8(), stringView.length(), startPosition);
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return nextBreakablePosition<UChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace, CanUseShortcut::No>(lazyBreakIterator, stringView.characters16(), stringView.length(), startPosition);
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}
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inline unsigned nextBreakablePositionBreakCharacter(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition)
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{
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auto stringView = lazyBreakIterator.stringView();
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ASSERT(startPosition <= stringView.length());
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// FIXME: Can/Should we implement this using a Shared Iterator (performance issue)
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// https://bugs.webkit.org/show_bug.cgi?id=197876
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NonSharedCharacterBreakIterator iterator(stringView);
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Optional<unsigned> next = ubrk_following(iterator, startPosition);
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return next.valueOr(stringView.length());
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}
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inline bool isBreakable(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition, Optional<unsigned>& nextBreakable, bool breakNBSP, bool canUseShortcut, bool keepAllWords, bool breakAnywhere)
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{
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if (nextBreakable && nextBreakable.value() >= startPosition)
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return startPosition == nextBreakable;
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if (breakAnywhere)
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nextBreakable = nextBreakablePositionBreakCharacter(lazyBreakIterator, startPosition);
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else if (keepAllWords) {
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if (breakNBSP)
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nextBreakable = nextBreakablePositionKeepingAllWords(lazyBreakIterator, startPosition);
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else
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nextBreakable = nextBreakablePositionKeepingAllWordsIgnoringNBSP(lazyBreakIterator, startPosition);
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} else if (!canUseShortcut) {
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if (breakNBSP)
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nextBreakable = nextBreakablePositionWithoutShortcut(lazyBreakIterator, startPosition);
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else
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nextBreakable = nextBreakablePositionIgnoringNBSPWithoutShortcut(lazyBreakIterator, startPosition);
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} else {
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if (breakNBSP)
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nextBreakable = nextBreakablePosition(lazyBreakIterator, startPosition);
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else
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nextBreakable = nextBreakablePositionIgnoringNBSP(lazyBreakIterator, startPosition);
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}
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return startPosition == nextBreakable;
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}
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} // namespace WebCore
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