BSFixedString.h

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#pragma once
 
#include "RE/B/BSStringPool.h"
#include "RE/C/CRC.h"
 
namespace RE
{
    namespace detail
    {
        template <class CharT>
        class BSFixedString
        {
        public:
            using size_type = std::uint32_t;
            using value_type = CharT;
            using pointer = value_type*;
            using const_pointer = const value_type*;
            using reference = value_type&;
            using const_reference = const value_type&;
 
            constexpr BSFixedString() noexcept = default;
 
            inline BSFixedString(const BSFixedString& a_rhs) :
                _data(a_rhs._data)
            {
                try_acquire();
            }
 
            inline BSFixedString(BSFixedString&& a_rhs) :
                _data(a_rhs._data)
            {
                a_rhs._data = nullptr;
            }
 
            inline BSFixedString(const_pointer a_string)
            {
                if (a_string) {
                    ctor(a_string);
                }
            }
 
            template <
                class T,
                std::enable_if_t<
                    std::conjunction_v<
                        std::is_convertible<const T&, std::basic_string_view<value_type>>,
                        std::negation<
                            std::is_convertible<const T&, const_pointer>>>,
                    int> = 0>
            inline BSFixedString(const T& a_string)
            {
                const auto view = static_cast<std::basic_string_view<value_type>>(a_string);
                if (!view.empty()) {
                    ctor(view.data());
                }
            }
 
            inline ~BSFixedString() { try_release(); }
 
            inline BSFixedString& operator=(const BSFixedString& a_rhs)
            {
                if (this != std::addressof(a_rhs)) {
                    try_release();
                    _data = a_rhs._data;
                    try_acquire();
                }
                return *this;
            }
 
            inline BSFixedString& operator=(BSFixedString&& a_rhs)
            {
                if (this != std::addressof(a_rhs)) {
                    try_release();
                    _data = a_rhs._data;
                    a_rhs._data = nullptr;
                }
                return *this;
            }
 
            inline BSFixedString& operator=(const_pointer a_string)
            {
                try_release();
                if (a_string) {
                    ctor(a_string);
                }
                return *this;
            }
 
            template <
                class T,
                std::enable_if_t<
                    std::conjunction_v<
                        std::is_convertible<const T&, std::basic_string_view<value_type>>,
                        std::negation<
                            std::is_convertible<const T&, const_pointer>>>,
                    int> = 0>
            inline BSFixedString& operator=(const T& a_string)
            {
                const auto view = static_cast<std::basic_string_view<value_type>>(a_string);
                try_release();
                if (!view.empty()) {
                    ctor(view.data());
                }
                return *this;
            }
 
            [[nodiscard]] inline const_reference operator[](size_type a_pos) const noexcept
            {
                assert(a_pos < size());
                return _data[a_pos];
            }
 
            [[nodiscard]] inline const_reference front() const noexcept { return _data[0]; }
            [[nodiscard]] inline const_reference back() const noexcept { return _data[size() - 1]; }
 
            [[nodiscard]] inline const_pointer data() const noexcept
            {
                const auto proxy = get_proxy();
                const auto cstr = proxy ? proxy->template data<value_type>() : nullptr;
                return cstr ? cstr : EMPTY;
            }
 
            [[nodiscard]] inline const_pointer c_str() const noexcept { return data(); }
 
            [[nodiscard]] constexpr operator std::basic_string_view<value_type>() const { return { c_str(), length() }; }
 
            [[nodiscard]] constexpr bool empty() const noexcept { return size() == 0; }
 
            [[nodiscard]] constexpr size_type size() const noexcept
            {
                const auto proxy = get_proxy();
                return proxy ? proxy->size() : 0;
            }
 
            [[nodiscard]] constexpr size_type length() const noexcept { return size(); }
 
            [[nodiscard]] inline friend bool operator==(const BSFixedString& a_lhs, const BSFixedString& a_rhs) noexcept
            {
                return a_lhs._data == a_rhs._data || a_lhs.empty() && a_rhs.empty();
            }
 
            [[nodiscard]] inline friend bool operator!=(const BSFixedString& a_lhs, const BSFixedString& a_rhs) noexcept { return !(a_lhs == a_rhs); }
 
            [[nodiscard]] inline friend bool operator==(const BSFixedString& a_lhs, std::basic_string_view<value_type> a_rhs)
            {
                if (a_lhs.empty() && a_rhs.empty()) {
                    return true;
                } else if (const auto length = a_lhs.length(); length != a_rhs.length()) {
                    return false;
                } else {
                    return strncmp(a_lhs.c_str(), a_rhs.data(), length) == 0;
                }
            }
 
            [[nodiscard]] inline friend bool operator!=(const BSFixedString& a_lhs, std::basic_string_view<value_type> a_rhs) { return !(a_lhs == a_rhs); }
            [[nodiscard]] inline friend bool operator==(std::basic_string_view<value_type> a_lhs, const BSFixedString& a_rhs) { return a_rhs == a_lhs; }
            [[nodiscard]] inline friend bool operator!=(std::basic_string_view<value_type> a_lhs, const BSFixedString& a_rhs) { return !(a_lhs == a_rhs); }
 
            [[nodiscard]] inline friend bool operator==(const BSFixedString& a_lhs, const_pointer a_rhs) { return a_lhs == std::basic_string_view<value_type>(a_rhs ? a_rhs : EMPTY); }
            [[nodiscard]] inline friend bool operator!=(const BSFixedString& a_lhs, const_pointer a_rhs) { return !(a_lhs == a_rhs); }
            [[nodiscard]] inline friend bool operator==(const_pointer a_lhs, const BSFixedString& a_rhs) { return a_rhs == a_lhs; }
            [[nodiscard]] inline friend bool operator!=(const_pointer a_lhs, const BSFixedString& a_rhs) { return !(a_lhs == a_rhs); }
 
        private:
            [[nodiscard]] static inline int strncmp(const char* a_lhs, const char* a_rhs, std::size_t a_length)
            {
                return _strnicmp(a_lhs, a_rhs, a_length);
            }
 
            [[nodiscard]] static inline int strncmp(const wchar_t* a_lhs, const wchar_t* a_rhs, std::size_t a_length)
            {
                return _wcsnicmp(a_lhs, a_rhs, a_length);
            }
 
            inline BSFixedString* ctor(const char* a_data) { return ctor8(a_data); }
            inline BSFixedString* ctor(const wchar_t* a_data) { return ctor16(a_data); }
 
            inline BSFixedString* ctor8(const char* a_data)
            {
                using func_t = decltype(&BSFixedString::ctor8);
                REL::Relocation<func_t> func{ Offset::BSFixedString::Ctor8 };
                return func(this, a_data);
            }
 
            inline BSFixedString* ctor16(const wchar_t* a_data)
            {
                using func_t = decltype(&BSFixedString::ctor16);
                REL::Relocation<func_t> func{ Offset::BSFixedString::Ctor16 };
                return func(this, a_data);
            }
 
            [[nodiscard]] inline BSStringPool::Entry* get_proxy() noexcept
            {
                return _data ?
                           reinterpret_cast<BSStringPool::Entry*>(const_cast<pointer>(_data)) - 1 :
                           nullptr;
            }
 
            [[nodiscard]] inline const BSStringPool::Entry* get_proxy() const noexcept
            {
                return _data ?
                           reinterpret_cast<const BSStringPool::Entry*>(_data) - 1 :
                           nullptr;
            }
 
            inline void try_acquire()
            {
                const auto proxy = get_proxy();
                if (proxy) {
                    proxy->acquire();
                }
            }
 
            inline void try_release() { BSStringPool::Entry::release(_data); }
 
            static constexpr const value_type EMPTY[]{ 0 };
 
            // members
            const_pointer _data{ nullptr };  // 0
        };
 
        extern template class BSFixedString<char>;
        extern template class BSFixedString<wchar_t>;
    }
 
    using BSFixedString = detail::BSFixedString<char>;
    using BSFixedStringCI = BSFixedString;
    using BSFixedStringW = detail::BSFixedString<wchar_t>;
 
    template <class CharT>
    struct BSCRC32_<detail::BSFixedString<CharT>>
    {
    public:
        [[nodiscard]] inline std::uint32_t operator()(const detail::BSFixedString<CharT>& a_key) const noexcept
        {
            return BSCRC32_<const void*>()(a_key.data());
        }
    };
}