BitArray.c

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//this class allows for creation and manipulation of arrays which hold unique IDs, and allow for bitwise-like operation over these IDs
//essentially, this extends single INT to any legth when it comes to holding and manipulating individual bits
 
const int BIT_INT_SIZE = 32;
class BitArray
{
  static int IDToIndex(int id)
  {
    int m_NumOfItems = BitArray.IDToNumOfItems(id);
    int index = (id - (m_NumOfItems * BIT_INT_SIZE)) - 1;
    return index;
  }
 
  static int IDToMask(int id)
  {
    int index = BitArray.IDToIndex(id);
    int bit = 1 << index;
    return bit;
  }
  static array<int> CreateMaskArray(int size)
  {
    int m_NumOfItems = BitArray.IDToNumOfItems(size);
    array<int> bit_array = new array<int>;
 
    for (int i = 0; i <= m_NumOfItems; i++)
      bit_array.Insert(0);
 
    return bit_array;
  }
  static int GetBitCount(array<int> bit_array)
  {
    return ((bit_array.Count()) * BIT_INT_SIZE);
  }
 
  static int IDToNumOfItems(int id)
  {
    int m_NumOfItems = id / BIT_INT_SIZE;
    if (id % BIT_INT_SIZE == 0) m_NumOfItems--;
    return m_NumOfItems;
  }
 
  static array<int> CreateArrayWithID(int id)
  {
    int m_NumOfItems = BitArray.IDToNumOfItems(id);//TODO: check for too big id
    int bit = BitArray.IDToMask(id);
 
    array<int> bit_array = new array<int>;
 
    for (int i = 0; i <= m_NumOfItems; i++)
      bit_array.Insert(0);
    bit_array.Set(m_NumOfItems, bit);
    return bit_array;
  }
 
  static bool IsMaskContainID(array<int> bit_array, int id)
  {
    if (BitArray.IDToNumOfItems(id) > bit_array.Count())
      return false;
    else
    {
      int index_mask = BitArray.IDToMask(id);
      int num_of_items = BitArray.IDToNumOfItems(id);
      int array_mask = bit_array.Get(num_of_items);
 
      if (index_mask & array_mask)
        return true;
      else
        return false;
    }
  }
 
  static bool AddIDToMask(array<int> bit_array, int id)
  {
    if (BitArray.IDToNumOfItems(id) > bit_array.Count())
      return false;
    else
    {
      int num_of_items = BitArray.IDToNumOfItems(id);
      int bit = BitArray.IDToMask(id);
      int new_mask = bit_array.Get(num_of_items) | bit;
      bit_array.Set(num_of_items, new_mask);
      return true;
    }
  }
};