erasedensevector.cpp

template  size_t handle_map::erase(Id_T handle) 
{ 
    if (!isValid(handle)) { return 0; } 

    m_fragmented = 1;
    Id_T innerId = m_sparseIds[handle.index]; 
    uint32_t innerIndex = innerId.index; 
    
    // push this slot to the back of the freelist 
    innerId.free = 1; 
    ++innerId.generation; 
    
    // increment generation so remaining outer ids go stale 
    innerId.index = 0xFFFFFFFF; 
    
    // max numeric value represents the end of the freelist 
    m_sparseIds[handle.index] = innerId; 
    
    // write outer id changes back to the array 
    if (freeListEmpty()) 
    { 
        // if the freelist was empty, it now starts (and ends) at this index 
        m_freeListFront = handle.index; 
        m_freeListBack = m_freeListFront; 
    } 
    else 
    { 
        m_sparseIds[m_freeListBack].index = handle.index; 
        
        // previous back of the freelist points to new back 
        m_freeListBack = handle.index; 
        
        // new freelist back is stored     
    } 
    
    // remove the component by swapping with the last element, then pop_back 
    if (innerIndex != m_items.size() - 1) 
    { 
        std::swap(m_items.at(innerIndex), m_items.back()); 
        std::swap(m_meta.at(innerIndex), m_meta.back()); 
        
        // fix the ComponentId index of the swapped component 
        m_sparseIds[m_meta.at(innerIndex).denseToSparse].index = innerIndex; 
    } 
    
    m_items.pop_back(); 
    m_meta.pop_back(); 
    return 1; 
}