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// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_TEXT_SEGMENTS_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_TEXT_SEGMENTS_H_
#include "base/optional.h"
#include "third_party/blink/renderer/core/editing/forward.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/forward.h"
namespace blink {
// Provides functions for finding boundary of text segments.
class TextSegments final {
STATIC_ONLY(TextSegments);
public:
// The interface to find boundary of text segment.
class Finder {
public:
class Position final {
STACK_ALLOCATED();
public:
Position();
static Position Before(unsigned offset);
static Position After(unsigned offset);
bool IsAfter() const { return type_ == kAfter; }
bool IsBefore() const { return type_ == kBefore; }
bool IsNone() const { return type_ == kNone; }
unsigned Offset() const;
private:
enum Type { kNone, kBefore, kAfter };
Position(unsigned value, Type type);
const unsigned offset_ = 0;
const Type type_ = kNone;
};
// Returns a text segment boundary position in |text| from |offset|.
// Note: |text| must contains character 16.
// Note: Since implementations can have state, |Find()| function isn't
// marked |const| intentionally.
virtual Position Find(const String text, unsigned offset) = 0;
};
// Returns a boundary position found by |finder| followed by |position|
// (inclusive). |finder| can be stateful or stateless.
static PositionInFlatTree FindBoundaryForward(
const PositionInFlatTree& position,
Finder* finder);
static PositionInFlatTree FindBoundaryBackward(
const PositionInFlatTree& position,
Finder* finder);
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_TEXT_SEGMENTS_H_
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