ImmutableString.h

#pragma once
 
#include "StringView.h"
 
#include <cstring>
 
namespace Cogs {
 
  class ImmutableString
  {
  public:
 
    constexpr ImmutableString() noexcept = default;
 
    ImmutableString(const ImmutableString&) = delete;
 
    ImmutableString& operator=(const ImmutableString&) = delete;
 
    constexpr ImmutableString(ImmutableString&& other) noexcept { this->swap(other); }
 
    constexpr ImmutableString& operator=(ImmutableString&& other) noexcept { this->swap(other); return *this; }
 
    COGSFOUNDATION_API ImmutableString(const Cogs::StringView& view);
 
    ~ImmutableString() { clear(); }
 
    constexpr operator const char* () const noexcept { return c_str(); }
 
    constexpr operator Cogs::StringView() const noexcept { return asView(); }
 
    constexpr void swap(ImmutableString& other) noexcept { std::swap(ptr, other.ptr); }
 
    constexpr Cogs::StringView asView() const noexcept { return ptr ? Cogs::StringView(ptr + sizeof(size_t), *reinterpret_cast<size_t*>(ptr)) : Cogs::StringView(); }
 
    constexpr bool empty() const noexcept { return ptr == nullptr; }
 
    void clear() { if (ptr) release(); }
 
    constexpr const char* c_str() const noexcept { return ptr ? (ptr + sizeof(size_t)) : nullptr; }
    
    constexpr size_t size() const noexcept { size_t size = 0; if (ptr) { std::memcpy(&size, ptr, sizeof(size)); } return size; }
 
  private:
 
    COGSFOUNDATION_API void release();
 
    char* ptr = nullptr;
  };
  static_assert(sizeof(ImmutableString) == sizeof(char*));
}