index.h

 
#pragma once
 
#include <cstdint>
#include <system/object.h>
#include <system/exceptions.h>
#include <system/details/dereference.h>
#include <system/details/slicing.h>
 
namespace System {
 
class ASPOSECPP_SHARED_CLASS Index : public ::System::Details::BoxableObjectBase
{
    RTTI_INFO_VALUE_TYPE(Index)
 
public:
    constexpr Index() noexcept : m_value(0), m_is_from_end(false) {}
 
    constexpr Index(int32_t value) noexcept : m_value(value), m_is_from_end(false) {}
 
    constexpr Index(int32_t value, bool from_end) noexcept : m_value(value), m_is_from_end(from_end) {}
 
    static constexpr Index FromEnd(int32_t value) noexcept
    {
        return Index(value, true);
    }
 
    static constexpr Index get_Start() noexcept
    {
        return Index(0);
    }
 
    static constexpr Index get_End() noexcept
    {
        return Index(0, true);
    }
 
    constexpr int32_t get_Value() const noexcept
    {
        return m_value;
    }
 
    constexpr bool get_IsFromEnd() const noexcept
    {
        return m_is_from_end;
    }
 
    int32_t GetOffset(int32_t length) const
    {
        return m_is_from_end ? length - m_value : m_value;
    }
 
    bool Equals(const Index& other) const
    {
        return m_value == other.m_value && m_is_from_end == other.m_is_from_end;
    }
 
    int32_t GetHashCode() const
    {
        return m_value;
    }
 
private:
    int32_t m_value;
    bool m_is_from_end;
};
 
template <typename T>
auto& Get(T& collection, const Index& index)
{
    auto& ref = Details::Dereference(collection);
    auto length = Details::GetCollectionSize(ref);
    auto offset = index.GetOffset(length);
    return ref[offset];
}
 
} // namespace System