StringView.h

// -*- tab-width: 2; indent-tabs-mode: nil; coding: utf-8-with-signature -*-
//-----------------------------------------------------------------------------
// Copyright 2000-2026 CEA (www.cea.fr) IFPEN (www.ifpenergiesnouvelles.com)
// See the top-level COPYRIGHT file for details.
// SPDX-License-Identifier: Apache-2.0
//-----------------------------------------------------------------------------
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/* StringView.h                                                (C) 2000-2025 */
/*                                                                           */
/* View of a UTF-8 character string.                                         */
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#ifndef ARCCORE_BASE_STRINGVIEW_H
#define ARCCORE_BASE_STRINGVIEW_H
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#include "arccore/base/BaseTypes.h"
#include "arccore/base/Span.h"
 
#include <string_view>
 
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namespace Arcane
{
 
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class ARCCORE_BASE_EXPORT StringView
{
 public:

  StringView() = default;
  StringView(const char* str) ARCCORE_NOEXCEPT
  : StringView(str ? std::string_view(str) : std::string_view()) {}

  StringView(std::string_view str) ARCCORE_NOEXCEPT
  : m_v(reinterpret_cast<const Byte*>(str.data()), str.size()) {}

  constexpr StringView(Span<const Byte> str) ARCCORE_NOEXCEPT
  : m_v(str) {}

  constexpr StringView(const StringView& str) = default;
  constexpr StringView& operator=(const StringView& str) = default;
  StringView& operator=(const char* str) ARCCORE_NOEXCEPT
  {
    operator=(str ? std::string_view(str) : std::string_view());
    return (*this);
  }

  StringView& operator=(std::string_view str) ARCCORE_NOEXCEPT
  {
    m_v = Span<const Byte>(reinterpret_cast<const Byte*>(str.data()), str.size());
    return (*this);
  }

  constexpr StringView& operator=(Span<const Byte> str) ARCCORE_NOEXCEPT
  {
    m_v = str;
    return (*this);
  }
 
  ~StringView() = default; 
 
 public:

  constexpr Span<const Byte> bytes() const ARCCORE_NOEXCEPT { return m_v; }

  constexpr Int64 length() const ARCCORE_NOEXCEPT { return m_v.size(); }

  constexpr Int64 size() const ARCCORE_NOEXCEPT { return m_v.size(); }

  constexpr bool empty() const ARCCORE_NOEXCEPT { return size() == 0; }
 
 public:

  std::string_view toStdStringView() const ARCCORE_NOEXCEPT
  {
    return std::string_view(reinterpret_cast<const char*>(m_v.data()), m_v.size());
  }

  friend ARCCORE_BASE_EXPORT std::ostream& operator<<(std::ostream& o, const StringView&);

  friend ARCCORE_BASE_EXPORT bool operator==(const StringView& a, const StringView& b);

  friend inline bool operator!=(const StringView& a, const StringView& b)
  {
    return !operator==(a, b);
  }

  friend ARCCORE_BASE_EXPORT bool operator==(const char* a, const StringView& b);

  friend bool operator!=(const char* a, const StringView& b) { return !operator==(a, b); }

  friend ARCCORE_BASE_EXPORT bool operator==(const StringView& a, const char* b);

  friend inline bool operator!=(const StringView& a, const char* b)
  {
    return !operator==(a, b);
  }

  friend ARCCORE_BASE_EXPORT bool operator<(const StringView& a, const StringView& b);
 
 public:

  void writeBytes(std::ostream& o) const;

  StringView subView(Int64 pos) const;

  StringView subView(Int64 pos, Int64 len) const;
 
 private:
 
  Span<const Byte> m_v;
};
 
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} // namespace Arcane
 
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#endif