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// Copyright 2013 The Flutter 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 FLUTTER_SHELL_PLATFORM_COMMON_TEXT_RANGE_H_
#define FLUTTER_SHELL_PLATFORM_COMMON_TEXT_RANGE_H_
#include <algorithm>
#include "flutter/fml/logging.h"
namespace flutter {
// A directional range of text.
//
// A |TextRange| describes a range of text with |base| and |extent| positions.
// In the case where |base| == |extent|, the range is said to be collapsed, and
// when |base| > |extent|, the range is said to be reversed.
class TextRange {
public:
explicit TextRange(size_t position) : base_(position), extent_(position) {}
explicit TextRange(size_t base, size_t extent)
: base_(base), extent_(extent) {}
TextRange(const TextRange&) = default;
TextRange& operator=(const TextRange&) = default;
virtual ~TextRange() = default;
// The base position of the range.
size_t base() const { return base_; }
// Sets the base position of the range.
void set_base(size_t pos) { base_ = pos; }
// The extent position of the range.
size_t extent() const { return extent_; }
// Sets the extent position of the range.
void set_extent(size_t pos) { extent_ = pos; }
// The lesser of the base and extent positions.
size_t start() const { return std::min(base_, extent_); }
// Sets the start position of the range.
void set_start(size_t pos) {
if (base_ <= extent_) {
base_ = pos;
} else {
extent_ = pos;
}
}
// The greater of the base and extent positions.
size_t end() const { return std::max(base_, extent_); }
// Sets the end position of the range.
void set_end(size_t pos) {
if (base_ <= extent_) {
extent_ = pos;
} else {
base_ = pos;
}
}
// The position of a collapsed range.
//
// Asserts that the range is of length 0.
size_t position() const {
FML_DCHECK(base_ == extent_);
return extent_;
}
// The length of the range.
size_t length() const { return end() - start(); }
// Returns true if the range is of length 0.
bool collapsed() const { return base_ == extent_; }
// Returns true if the base is greater than the extent.
bool reversed() const { return base_ > extent_; }
// Returns true if |position| is contained within the range.
bool Contains(size_t position) const {
return position >= start() && position <= end();
}
// Returns true if |range| is contained within the range.
bool Contains(const TextRange& range) const {
return range.start() >= start() && range.end() <= end();
}
bool operator==(const TextRange& other) const {
return base_ == other.base_ && extent_ == other.extent_;
}
private:
size_t base_;
size_t extent_;
};
} // namespace flutter
#endif // FLUTTER_SHELL_PLATFORM_COMMON_TEXT_RANGE_H_