| // 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. |
| |
| #include <algorithm> |
| |
| #include "flutter/fml/logging.h" |
| |
| // 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; |
| |
| // Returns the base position of the range. |
| size_t base() const { return base_; } |
| |
| // Returns the extent position of the range. |
| size_t extent() const { return extent_; } |
| |
| // Returns the lesser of the base and extent positions. |
| size_t start() const { return std::min(base_, extent_); } |
| |
| // Returns the greater of the base and extent positions. |
| size_t end() const { return std::max(base_, extent_); } |
| |
| // Returns the position of a collapsed range. |
| // |
| // Asserts that the range is of length 0. |
| size_t position() const { |
| FML_DCHECK(base_ == extent_); |
| return extent_; |
| } |
| |
| // Returns 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_; } |
| |
| private: |
| size_t base_; |
| size_t extent_; |
| }; |