Normalize.hpp

#pragma once
 
#include <cstddef>
 
#include <stratax/exceptions/Exceptions.hpp>
 
namespace stratax::indexing {
 
using size_type = std::size_t;
using difference_type = std::ptrdiff_t;
 
inline size_type normalize_index(
    difference_type index,
    size_type size)
{
    const size_type magnitude = index < 0
        ? static_cast<size_type>(-(index + 1)) + 1
        : 0;
 
    if ((index >= 0 && static_cast<size_type>(index) >= size) ||
        (index < 0 && magnitude > size))
    {
        throw Exceptions::IndexError("Index is out of bounds.");
    }
 
    return index >= 0 ? static_cast<size_type>(index) : size - magnitude;
}
 
} // namespace stratax::indexing