IdentifierField.h

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
#ifndef IDENTIFIER_IDENTIFIERFIELD_H
#define IDENTIFIER_IDENTIFIERFIELD_H
 
#include <Identifier/ExpandedIdentifier.h>
#include <vector>
#include <string>
#include <stdexcept>
#include <iostream>
#include <limits>
#include <utility>
#include <variant>
 
class MsgStream;
 
class IdentifierField 
{ 
  public : 
  using element_type = ExpandedIdentifier::element_type ; 
  using size_type = ExpandedIdentifier::size_type; 
  using element_vector = std::vector <element_type>; 
  using index_vector = std::vector <size_type>;
  using BoundedRange = std::pair<element_type, element_type>;
  static constexpr auto minimum_possible = std::numeric_limits<element_type>::min();
  static constexpr auto maximum_possible = std::numeric_limits<element_type>::max();
  static constexpr auto invalidValues = element_vector{};
 
  enum continuation_mode{ 
    none, 
    has_next, 
    has_previous, 
    has_both,
    has_wrap_around
  } ; 

  IdentifierField () = default;

  IdentifierField (element_type value); 

  IdentifierField (element_type minimum, element_type maximum); 
  
  IdentifierField (const element_vector &values); 
 
  //
  inline bool 
  wrap_around() const{ return (has_wrap_around == m_continuation_mode);}  
 
  //
  inline element_type 
  get_minimum() const {return m_minimum;}
  
  //
  inline std::pair<element_type, element_type>
  get_minmax() const {
    return {m_minimum, m_maximum};
  }
  //
  inline element_type 
  get_maximum () const {return m_maximum;} 
  //
  inline const element_vector& 
  get_values() const { 
    if (isBounded()) return invalidValues;
    return std::get<element_vector>(m_data);
  } 

  bool get_previous (element_type current, element_type& previous) const; 
  bool get_next     (element_type current, element_type& next) const; 
  size_type get_indices () const {return m_size;}
  const index_vector& get_indexes () const {return m_indexes;}
  size_type get_bits () const; 
  element_type get_value_at (size_type index) const; 
  size_type get_value_index (element_type value) const; 

  bool match (element_type value) const; 

  bool overlaps_with (const IdentifierField& other) const; 

  void clear (); 
  void set (element_type minimum, element_type maximum); 
  void add_value (element_type value); 
  void set (const element_vector& values); 
  void set (bool wraparound); 
  void set_next (int next);
  void set_previous (int previous);
  void operator |= (const IdentifierField& other); 
 
  operator std::string () const; 
  bool operator == (const IdentifierField& other) const; 
 
  void show(std::ostream & out = std::cout) const;
  void show(MsgStream & out) const;
  
  bool check_for_both_bounded();
    
  void optimize();
  
  inline bool empty() const {return m_empty;}  
  inline bool isBounded() const {return std::holds_alternative<BoundedRange>(m_data);} 
  inline bool isEnumerated() const {return std::holds_alternative<element_vector>(m_data);}
  
private : 
  static constexpr int m_maxNumberOfIndices = 100;
  void set_minimum (element_type value); 
  void set_maximum (element_type value); 

  void create_index_table();
  template <class T>
  T * dataPtr(){return std::get_if<T>(&m_data);}
  //
  element_type m_minimum{}; 
  element_type m_maximum{};
  std::variant<element_vector, BoundedRange> m_data{};
  index_vector m_indexes{}; 
  size_type    m_size{};
  element_type m_previous{}; 
  element_type m_next{}; 
  bool m_empty{true};
  continuation_mode m_continuation_mode{none}; 
}; 
 
inline IdentifierField::element_type 
IdentifierField::get_value_at(size_type index) const { 
  // Only both_bounded and enumerated are valid to calculate the
  // value.
  // both_bounded is the more frequent case and so comes first.
  if (m_empty) return 0;
  if (const auto * p{std::get_if<BoundedRange>(&m_data)}; p) {
    if (index >= (size_type) (p->second - p->first + 1)) {
      throw std::out_of_range("IdentifierField::get_value_at");
    }
    return (p->first + index); 
  }
  return ((std::get<element_vector>(m_data)).at(index)); 
 
} 
 
std::ostream & 
operator << (std::ostream &out, const IdentifierField &c);
std::istream & 
operator >> (std::istream &in, IdentifierField &c);
#endif