/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file sparseArray.h
 * @author drose
 * @date 2007-02-14
 */

#ifndef SPARSEARRAY_H
#define SPARSEARRAY_H

#include "pandabase.h"
#include "ordered_vector.h"

class BitArray;
class BamWriter;
class BamReader;
class Datagram;
class DatagramIterator;

/**
 * This class records a set of integers, where each integer is either present
 * or not present in the set.
 *
 * It is similar in principle and in interface to a BitArray (which can be
 * thought of as a set of integers, one integer corresponding to each
 * different bit position), but the SparseArray is implemented as a list of
 * min/max subrange lists, rather than as a bitmask.
 *
 * This makes it particularly efficient for storing sets which consist of
 * large sections of consecutively included or consecutively excluded
 * elements, with arbitrarily large integers, but particularly inefficient for
 * doing boolean operations such as & or |.
 *
 * Also, unlike BitArray, the SparseArray can store negative integers.
 */
class EXPCL_PANDA_PUTIL SparseArray {
PUBLISHED:
  INLINE SparseArray();
  SparseArray(const BitArray &from);

  INLINE static SparseArray all_on();
  INLINE static SparseArray all_off();
  INLINE static SparseArray lower_on(int on_bits);
  INLINE static SparseArray bit(int index);
  INLINE static SparseArray range(int low_bit, int size);

  INLINE static bool has_max_num_bits();
  INLINE static int get_max_num_bits();

  INLINE int get_num_bits() const;
  INLINE bool get_bit(int index) const;
  INLINE void set_bit(int index);
  INLINE void clear_bit(int index);
  INLINE void set_bit_to(int index, bool value);
  INLINE bool get_highest_bits() const;
  INLINE bool is_zero() const;
  INLINE bool is_all_on() const;

  INLINE bool has_any_of(int low_bit, int size) const;
  INLINE bool has_all_of(int low_bit, int size) const;
  INLINE void set_range(int low_bit, int size);
  INLINE void clear_range(int low_bit, int size);
  INLINE void set_range_to(bool value, int low_bit, int size);

  int get_num_on_bits() const;
  int get_num_off_bits() const;
  int get_lowest_on_bit() const;
  int get_lowest_off_bit() const;
  int get_highest_on_bit() const;
  int get_highest_off_bit() const;
  int get_next_higher_different_bit(int low_bit) const;

  INLINE void invert_in_place();
  bool has_bits_in_common(const SparseArray &other) const;
  INLINE void clear();

  void output(std::ostream &out) const;

  INLINE bool operator == (const SparseArray &other) const;
  INLINE bool operator != (const SparseArray &other) const;
  INLINE bool operator < (const SparseArray &other) const;
  int compare_to(const SparseArray &other) const;

  INLINE SparseArray
  operator & (const SparseArray &other) const;

  INLINE SparseArray
  operator | (const SparseArray &other) const;

  INLINE SparseArray
  operator ^ (const SparseArray &other) const;

  INLINE SparseArray
  operator ~ () const;

  INLINE SparseArray
  operator << (int shift) const;

  INLINE SparseArray
  operator >> (int shift) const;

  void operator &= (const SparseArray &other);
  void operator |= (const SparseArray &other);
  void operator ^= (const SparseArray &other);
  INLINE void operator <<= (int shift);
  INLINE void operator >>= (int shift);

  INLINE bool is_inverse() const;
  INLINE size_t get_num_subranges() const;
  INLINE int get_subrange_begin(size_t n) const;
  INLINE int get_subrange_end(size_t n) const;

private:
  void do_add_range(int begin, int end);
  void do_remove_range(int begin, int end);
  bool do_has_any(int begin, int end) const;
  bool do_has_all(int begin, int end) const;

  void do_intersection(const SparseArray &other);
  void do_union(const SparseArray &other);
  void do_intersection_neg(const SparseArray &other);
  void do_shift(int offset);

  // The SparseArray is implemented as a set of non-overlapping Subranges.
  class Subrange {
  public:
    INLINE Subrange(int begin, int end);
    INLINE bool operator < (const Subrange &other) const;

    int _begin, _end;
  };

  typedef ov_set<Subrange> Subranges;
  Subranges _subranges;
  bool _inverse;

public:
  void write_datagram(BamWriter *manager, Datagram &dg) const;
  void read_datagram(DatagramIterator &scan, BamReader *manager);

public:
  static TypeHandle get_class_type() {
    return _type_handle;
  }
  static void init_type() {
    register_type(_type_handle, "SparseArray");
  }

private:
  static TypeHandle _type_handle;
};

#include "sparseArray.I"

INLINE std::ostream &
operator << (std::ostream &out, const SparseArray &array) {
  array.output(out);
  return out;
}

#endif