/*
 * Copyright (c) 1998
 * Silicon Graphics Computer Systems, Inc.
 *
 * Copyright (c) 1999 
 * Boris Fomitchev
 *
 * This material is provided "as is", with absolutely no warranty expressed
 * or implied. Any use is at your own risk.
 *
 * Permission to use or copy this software for any purpose is hereby granted 
 * without fee, provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is granted,
 * provided the above notices are retained, and a notice that the code was
 * modified is included with the above copyright notice.
 *
 */

#ifndef __SGI_STL_BITSET_H
#define __SGI_STL_BITSET_H

// This implementation of bitset<> has a second template parameter,
// _WordT, which defaults to unsigned long.  *YOU SHOULD NOT USE
// THIS FEATURE*.  It is experimental, and it may be removed in
// future releases.

// A bitset of size N, using words of type _WordT, will have 
// N % (sizeof(_WordT) * CHAR_BIT) unused bits.  (They are the high-
// order bits in the highest word.)  It is a class invariant
// of class bitset<> that those unused bits are always zero.

// Most of the actual code isn't contained in bitset<> itself, but in the 
// base class _Base_bitset.  The base class works with whole words, not with
// individual bits.  This allows us to specialize _Base_bitset for the
// important special case where the bitset is only a single word.

// The C++ standard does not define the precise semantics of operator[].
// In this implementation the const version of operator[] is equivalent
// to test(), except that it does no range checking.  The non-const version
// returns a reference to a bit, again without doing any range checking.

# ifndef __SGI_STL_INTERNAL_ALGOBASE_H
#  include <stl_algobase.h>
# endif

# ifndef __SGI_STL_INTERNAL_ALLOC_H
#  include <stl_alloc.h>
# endif

# ifndef __SGI_STL_INTERNAL_ITERATOR_H
#  include <stl_iterator.h>
# endif

# ifndef __SGI_STL_INTERNAL_UNINITIALIZED_H
#  include <stl_uninitialized.h>
# endif

# ifndef __STLPORT_STRING
#  include <string>
# endif

# ifndef __STLPORT_IOSTREAM
#  include <iostream>
# endif

#define __BITS_PER_WORDT(__wt) (CHAR_BIT*sizeof(__wt))
#define __BITSET_WORDS(__n,__wt) \
 ((__n) < 1 ? 1 : ((__n) + __BITS_PER_WORDT(__wt) - 1)/__BITS_PER_WORDT(__wt))

__STL_BEGIN_NAMESPACE

#if defined(__sgi) && !defined(__GNUC__) && (_MIPS_SIM != _MIPS_SIM_ABI32)
#pragma set woff 1209
#endif

// structure to aid in counting bits
template<bool __dummy> 
struct _Bit_count {
  static unsigned char _S_bit_count[256];
};

// Mapping from 8 bit unsigned integers to the index of the first one
// bit:
template<bool __dummy> 
struct _First_one {
  static unsigned char _S_first_one[256];
};

//
// Base class: general case.
//

template<size_t _Nw, class _WordT>
struct _Base_bitset {
  _WordT _M_w[_Nw];                // 0 is the least significant word.

  _Base_bitset( void ) { _M_do_reset(); }

  _Base_bitset(unsigned long __val);

  static size_t _S_whichword( size_t __pos ) {
    return __pos / __BITS_PER_WORDT(_WordT);
  }
  static size_t _S_whichbyte( size_t __pos ) {
    return (__pos % __BITS_PER_WORDT(_WordT)) / CHAR_BIT;
  }
  static size_t _S_whichbit( size_t __pos ) {
    return __pos % __BITS_PER_WORDT(_WordT);
  }
  static _WordT _S_maskbit( size_t __pos ) {
    return __STATIC_CAST(_WordT,1) << _S_whichbit(__pos);
  }

  _WordT& _M_getword(size_t __pos)       { return _M_w[_S_whichword(__pos)]; }
  _WordT  _M_getword(size_t __pos) const { return _M_w[_S_whichword(__pos)]; }

  _WordT& _M_hiword()       { return _M_w[_Nw - 1]; }
  _WordT  _M_hiword() const { return _M_w[_Nw - 1]; }

  void _M_do_and(const _Base_bitset<_Nw,_WordT>& __x) {
    for ( size_t __i = 0; __i < _Nw; __i++ ) {
      _M_w[__i] &= __x._M_w[__i];
    }
  }

  void _M_do_or(const _Base_bitset<_Nw,_WordT>& __x) {
    for ( size_t __i = 0; __i < _Nw; __i++ ) {
      _M_w[__i] |= __x._M_w[__i];
    }
  }

  void _M_do_xor(const _Base_bitset<_Nw,_WordT>& __x) {
    for ( size_t __i = 0; __i < _Nw; __i++ ) {
      _M_w[__i] ^= __x._M_w[__i];
    }
  }

  void _M_do_left_shift(size_t __shift);

  void _M_do_right_shift(size_t __shift);

  void _M_do_flip() {
    for ( size_t __i = 0; __i < _Nw; __i++ ) {
      _M_w[__i] = ~_M_w[__i];
    }
  }

  void _M_do_set() {
    for ( size_t __i = 0; __i < _Nw; __i++ ) {
      _M_w[__i] = ~__STATIC_CAST(_WordT,0);
    }
  }

  void _M_do_reset() {
    for ( size_t __i = 0; __i < _Nw; __i++ ) {
      _M_w[__i] = 0;
    }
  }

  bool _M_is_equal(const _Base_bitset<_Nw,_WordT>& __x) const {
    for (size_t __i = 0; __i < _Nw; ++__i) {
      if (_M_w[__i] != __x._M_w[__i])
        return false;
    }
    return true;
  }

  bool _M_is_any() const {
    for ( size_t __i = 0; __i < __BITSET_WORDS(_Nw,_WordT); __i++ ) {
      if ( _M_w[__i] != __STATIC_CAST(_WordT,0) )
        return true;
    }
    return false;
  }

  size_t _M_do_count() const {
    size_t __result = 0;
    const unsigned char* __byte_ptr = (const unsigned char*)_M_w;
    const unsigned char* __end_ptr = (const unsigned char*)(_M_w+_Nw);

    while ( __byte_ptr < __end_ptr ) {
      __result += _Bit_count<true>::_S_bit_count[*__byte_ptr];
      __byte_ptr++;
    }
    return __result;
  }

  unsigned long _M_do_to_ulong() const; 

  // find first "on" bit
  size_t _M_do_find_first(size_t __not_found) const;

  // find the next "on" bit that follows "prev"
  size_t _M_do_find_next(size_t __prev, size_t __not_found) const;
};


//
// Base class: specialization for a single word.
//

# if defined (__STL_CLASS_PARTIAL_SPECIALIZATION)
template<class _WordT>
struct _Base_bitset<1, _WordT> {
  _WordT _M_w;

  _Base_bitset( void ) { _M_do_reset(); }

  _Base_bitset(unsigned long __val) {
    _M_do_reset();
    const size_t __n = min(sizeof(unsigned long)*CHAR_BIT,
			   __BITS_PER_WORDT(_WordT));
    for(size_t __i = 0; __i < __n; ++__i, __val >>= 1)
      if ( __val & 0x1 )
	_M_w |= _S_maskbit(__i);
  }
  
  static size_t _S_whichword( size_t __pos ) {
    return __pos / __BITS_PER_WORDT(_WordT);
  }
  static size_t _S_whichbyte( size_t __pos ) {
    return (__pos % __BITS_PER_WORDT(_WordT)) / CHAR_BIT;
  }
  static size_t _S_whichbit( size_t __pos ) {
    return __pos % __BITS_PER_WORDT(_WordT);
  }
  static _WordT _S_maskbit( size_t __pos ) {
    return (__STATIC_CAST(_WordT,1)) << _S_whichbit(__pos);
  }

  _WordT& _M_getword(size_t)       { return _M_w; }
  _WordT  _M_getword(size_t) const { return _M_w; }

  _WordT& _M_hiword()       { return _M_w; }
  _WordT  _M_hiword() const { return _M_w; }

  void _M_do_and(const _Base_bitset<1,_WordT>& __x) { _M_w &= __x._M_w; }
  void _M_do_or(const _Base_bitset<1,_WordT>& __x)  { _M_w |= __x._M_w; }
  void _M_do_xor(const _Base_bitset<1,_WordT>& __x) { _M_w ^= __x._M_w; }
  void _M_do_left_shift(size_t __shift)     { _M_w <<= __shift; }
  void _M_do_right_shift(size_t __shift)    { _M_w >>= __shift; }
  void _M_do_flip()                       { _M_w = ~_M_w; }
  void _M_do_set()                        { _M_w = ~__STATIC_CAST(_WordT,0); }
  void _M_do_reset()                      { _M_w = 0; }

  bool _M_is_equal(const _Base_bitset<1,_WordT>& __x) const {
    return _M_w == __x._M_w;
  }
  bool _M_is_any() const {
    return _M_w != 0;
  }

  size_t _M_do_count() const {
    size_t __result = 0;
    const unsigned char* __byte_ptr = (const unsigned char*)&_M_w;
    const unsigned char* __end_ptr = ((const unsigned char*)&_M_w)+sizeof(_M_w);
    while ( __byte_ptr < __end_ptr ) {
      __result += _Bit_count<true>::_S_bit_count[*__byte_ptr];
      __byte_ptr++;
    }
    return __result;
  }

  unsigned long _M_do_to_ulong() const {
    if (sizeof(_WordT) <= sizeof(unsigned long))
        return __STATIC_CAST(unsigned long,_M_w);
    else {
      const _WordT __mask = __STATIC_CAST(_WordT,__STATIC_CAST(unsigned long,-1));
      if (_M_w & ~__mask) 
        __STL_THROW(overflow_error("bitset"));
      return __STATIC_CAST(unsigned long,_M_w);
    }
  }

  size_t _M_do_find_first(size_t __not_found) const;

  // find the next "on" bit that follows "prev"
  size_t _M_do_find_next(size_t __prev, size_t __not_found) const; 

};


#  if !defined( __STL_MEMBER_SPECIALIZATION_BUG )
//
// One last specialization: _M_do_to_ulong() and the constructor from
// unsigned long are very simple if the bitset consists of a single 
// word of type unsigned long.
//

__STL_TEMPLATE_NULL
inline unsigned long 
_Base_bitset<1, unsigned long>::_M_do_to_ulong() const { return _M_w; }

__STL_TEMPLATE_NULL
inline _Base_bitset<(size_t)1, unsigned long>::_Base_bitset(unsigned long __val) {
  _M_w = __val;
}
#  endif // __STL_MEMBER_SPECIALIZATION_BUG

# endif /* __STL_CLASS_PARTIAL_SPECIALIZATION  */

// ------------------------------------------------------------
// Helper class to zero out the unused high-order bits in the highest word.
# ifdef __STL_CLASS_PARTIAL_SPECIALIZATION
template <class _WordT, size_t _Extrabits> struct _Sanitize {
  static void _M_do_sanitize(_WordT& __val)
    { __val &= ~((~__STATIC_CAST(_WordT,0)) << _Extrabits); }
};

template <class _WordT> struct _Sanitize<_WordT, 0> {
  static void _M_do_sanitize(_WordT) {}
};

#else /* __STL_CLASS_PARTIAL_SPECIALIZATION */

template <class _WordT, size_t _Extrabits> struct _Sanitize {
  static void _M_do_sanitize(_WordT& __val) {
    if (_Extrabits != 0)
      __val &= ~((~__STATIC_CAST(_WordT,0)) << _Extrabits);
  }
};

#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */

// ------------------------------------------------------------
// Class bitset.
//   _Nb may be any nonzero number of type size_t.
//   Type _WordT may be any unsigned integral type.

typedef unsigned long __stl_ulong;

# if defined (__STL_DEFAULT_TYPE_PARAM)
template<size_t _Nb, class _WordT = __stl_ulong>
# else
#  define bitset __bitset
template<size_t _Nb, class _WordT>
# endif
class bitset : public _Base_bitset<__BITSET_WORDS(_Nb,_WordT), _WordT> 
{
private:
  typedef _Base_bitset<__BITSET_WORDS(_Nb,_WordT), _WordT> _Base;

  void _M_do_sanitize() {
    _Sanitize<_WordT,_Nb%__BITS_PER_WORDT(_WordT) >
      ::_M_do_sanitize(_Base_bitset<__BITSET_WORDS(_Nb,_WordT), _WordT>::_M_hiword());
  }

public:
  // bit reference:
  struct reference {
  typedef _Base_bitset<_Nb,_WordT> _Bitset_base;
  typedef bitset<_Nb,_WordT> _Bitset;
    //    friend _Bitset;
    _WordT *_M_wp;
    size_t _M_bpos;

    // should be left undefined
    reference() {}

    reference( _Bitset& __b, size_t __pos ) {
      _M_wp = &__b._M_getword(__pos);
      _M_bpos = _Bitset_base::_S_whichbit(__pos);
    }

  public:
    ~reference() {}

    // for b[i] = __x;
    reference& operator=(bool __x) {
      if ( __x )
        *_M_wp |= _Bitset_base::_S_maskbit(_M_bpos);
      else
        *_M_wp &= ~_Bitset_base::_S_maskbit(_M_bpos);

      return *this;
    }

    // for b[i] = b[__j];
    reference& operator=(const reference& __j) {
      if ( (*(__j._M_wp) & _Bitset_base::_S_maskbit(__j._M_bpos)) )
        *_M_wp |= _Bitset_base::_S_maskbit(_M_bpos);
      else
        *_M_wp &= ~_Bitset_base::_S_maskbit(_M_bpos);

      return *this;
    }

    // flips the bit
    bool operator~() const { return (*(_M_wp) & _Bitset_base::_S_maskbit(_M_bpos)) == 0; }

    // for __x = b[i];
    operator bool() const { return (*(_M_wp) & _Bitset_base::_S_maskbit(_M_bpos)) != 0; }

    // for b[i].flip();
    reference& flip() {
      *_M_wp ^= _Bitset_base::_S_maskbit(_M_bpos);
      return *this;
    }
  };

  friend struct reference;