// Copyright (C) 2020-2021 Primate Labs Inc.
// All rights reserved.
//
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// modification, are permitted provided that the following conditions are
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//
//    * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//    * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
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// this software without specific prior written permission.
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#ifndef LITEHTML_TSTRING_VIEW_H__
#define LITEHTML_TSTRING_VIEW_H__

#include <cstddef>
#include <ostream>

#include "litehtml/os_types.h"

namespace litehtml {

// tstring_view is a string reference type that provides a view into a string
// that is owned elsewhere (e.g., by a std::string object).

// tstring_view implements the same interface as std::base_string_view in the
// standard library.  When litehtml moves to C++17 consider replacing the
// tstring_view implementation with the standard library implementations
// (e.g., via a using statement).

class tstring_view {
 public:
  using value_type = tchar_t;

  using pointer = tchar_t*;

  using const_pointer = const tchar_t*;

  using reference = tchar_t&;

  using const_reference = const tchar_t&;

  using iterator = const_pointer;

  using const_iterator = const_pointer;

  using size_type = size_t;

  using difference_type = std::ptrdiff_t;

 public:
  tstring_view() = default;

  tstring_view(const tstring_view& other) = default;

  tstring_view(const_pointer s, size_type size) : data_(s), size_(size) {}

  constexpr const_iterator begin() const { return data_; }

  constexpr const_iterator cbegin() const { return data_; }

  constexpr const_iterator end() const { return data_ + size_; }

  constexpr const_iterator cend() const { return data_ + size_; }

  constexpr const_reference operator[](size_type offset) const { return *(data_ + offset); }

  constexpr const_pointer data() const { return data_; }

  size_type size() const { return size_; }

  size_type length() const { return size_; }

  bool empty() const { return (size_ == 0); }

 private:
  const_pointer data_ = nullptr;

  size_type size_ = 0;
};

std::basic_ostream<tstring_view::value_type>& operator<<(std::basic_ostream<tstring_view::value_type>&, tstring_view str);

}  // namespace litehtml

#endif  // LITEHTML_TSTRING_VIEW_H__
