core/fxcrt/string_template.h

// Copyright 2024 The PDFium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com

#ifndef CORE_FXCRT_STRING_TEMPLATE_H_
#define CORE_FXCRT_STRING_TEMPLATE_H_

#include <stddef.h>

#include "core/fxcrt/retain_ptr.h"
#include "core/fxcrt/string_data_template.h"
#include "core/fxcrt/string_view_template.h"

namespace fxcrt {

// Base class for a  mutable string with shared buffers using copy-on-write
// semantics that avoids std::string's iterator stability guarantees.
template <typename T>
class StringTemplate {
 public:
  using CharType = T;
  using const_iterator = T*;
  using const_reverse_iterator = std::reverse_iterator<const_iterator>;

  // Holds on to buffer if possible for later re-use. Use assignment
  // to force immediate release if desired.
  void clear();

 protected:
  using StringView = StringViewTemplate<T>;
  using StringData = StringDataTemplate<T>;

  void ReallocBeforeWrite(size_t nNewLen);
  void AllocBeforeWrite(size_t nNewLen);
  void AssignCopy(const T* pSrcData, size_t nSrcLen);
  void Concat(const T* pSrcData, size_t nSrcLen);

  RetainPtr<StringData> m_pData;
};

extern template class StringTemplate<char>;
extern template class StringTemplate<wchar_t>;

}  // namespace fxcrt

#endif  // CORE_FXCRT_STRING_TEMPLATE_H_