text_break_iterator.h | Explore in Territory

/*
 * Copyright (C) 2006 Lars Knoll <[email protected]>
 * Copyright (C) 2007, 2011, 2012 Apple Inc. 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.
 *
 */

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_TEXT_BREAK_ITERATOR_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_TEXT_BREAK_ITERATOR_H_

#include <unicode/brkiter.h>

#include <memory>
#include <type_traits>

#include "base/check_op.h"
#include "base/containers/span.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/text/character.h"
#include "third_party/blink/renderer/platform/text/layout_locale.h"
#include "third_party/blink/renderer/platform/wtf/text/atomic_string.h"
#include "third_party/blink/renderer/platform/wtf/text/character_names.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_uchar.h"

namespace blink {

TextBreakIterator;

struct PLATFORM_EXPORT ReturnBreakIteratorToPool { … };

//
// LineBreakIterator is stocked in a pool to save the construction time.
// `PooledBreakIterator`, when destructed, returns the instance to the pool
// instead of deleting it.
//
PooledBreakIterator;

//
// Returns a new instance from a pool, or create a new one if the pool is empty.
//
PLATFORM_EXPORT PooledBreakIterator
AcquireLineBreakIterator(StringView, const AtomicString& locale);

// Note: The returned iterator is good only until you get another iterator, with
// the exception of acquireLineBreakIterator.

// This is similar to character break iterator in most cases, but is subject to
// platform UI conventions. One notable example where this can be different
// from character break iterator is Thai prepend characters, see bug 24342.
// Use this for insertion point and selection manipulations.
PLATFORM_EXPORT TextBreakIterator* CursorMovementIterator(
    base::span<const UChar>);
PLATFORM_EXPORT TextBreakIterator* WordBreakIterator(const String&,
                                                     int start,
                                                     int length);
PLATFORM_EXPORT TextBreakIterator* WordBreakIterator(base::span<const UChar>);
PLATFORM_EXPORT TextBreakIterator* SentenceBreakIterator(
    base::span<const UChar>);

// Before calling this, check if the iterator is not at the end. Otherwise,
// it may not work as expected.
// See https://ssl.icu-project.org/trac/ticket/13447 .
PLATFORM_EXPORT bool IsWordTextBreak(TextBreakIterator*);

const int kTextBreakDone = …;

// A Unicode Line Break Word Identifier (key "lw".)
// https://www.unicode.org/reports/tr35/#UnicodeLineBreakWordIdentifier
enum class LineBreakType : uint8_t { … };

// Determines break opportunities around collapsible space characters (space,
// newline, and tabulation characters.)
enum class BreakSpaceType : uint8_t { … };

PLATFORM_EXPORT std::ostream& operator<<(std::ostream&, LineBreakType);
PLATFORM_EXPORT std::ostream& operator<<(std::ostream&, BreakSpaceType);

class PLATFORM_EXPORT LazyLineBreakIterator final { … };

inline const AtomicString& LazyLineBreakIterator::LocaleWithKeyword() const { … }

inline void LazyLineBreakIterator::InvalidateLocaleWithKeyword() { … }

inline void LazyLineBreakIterator::SetBreakType(LineBreakType break_type) { … }

inline void LazyLineBreakIterator::SetStrictness(
    LineBreakStrictness strictness) { … }

// Iterates over "extended grapheme clusters", as defined in UAX #29.
// Note that platform implementations may be less sophisticated - e.g. ICU prior
// to version 4.0 only supports "legacy grapheme clusters".  Use this for
// general text processing, e.g. string truncation.

class PLATFORM_EXPORT NonSharedCharacterBreakIterator final { … };

// Counts the number of grapheme clusters. A surrogate pair or a sequence
// of a non-combining character and following combining characters is
// counted as 1 grapheme cluster.
PLATFORM_EXPORT unsigned NumGraphemeClusters(const String&);

// Returns the number of code units that the next grapheme cluster is made of.
PLATFORM_EXPORT unsigned LengthOfGraphemeCluster(const String&, unsigned = 0);

// Returns a list of graphemes cluster at each character using character break
// rules.
PLATFORM_EXPORT void GraphemesClusterList(const StringView& text,
                                          Vector<unsigned>* graphemes);

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_TEXT_BREAK_ITERATOR_H_
chromium/third_party/blink/renderer/platform/text/text_break_iterator.h
