#include <istream>
#include <ostream>


// [27.7.1] template class basic_stringbuf
/**
 *  @brief  The actual work of input and output (for std::string).
 *
 *  This class associates either or both of its input and output sequences
 *  with a sequence of characters, which can be initialized from, or made
 *  available as, a char_type *.  (Paraphrased from [27.7.1]/1.)
 *
 *  For this class, open modes (of type @c ios_base::openmode) have
 *  @c in set if the input sequence can be read, and @c out set if the
 *  output sequence can be written.
 */
//using namespace std;
using std::ios_base;

template<typename _CharT, typename _Traits, typename _Alloc>
    class basic_arraybuf : public std::basic_streambuf<_CharT, _Traits>
{
 public:
  // Types:
  typedef _CharT 					char_type;
  typedef _Traits 					traits_type;
  // _GLIBCXX_RESOLVE_LIB_DEFECTS
  // 251. basic_stringbuf missing allocator_type
  typedef _Alloc				       	allocator_type;
  typedef typename _Traits::int_type 		int_type;
  typedef typename _Traits::pos_type 		pos_type;
  typedef typename _Traits::off_type 		off_type;
  
  typedef std::basic_streambuf<char_type, traits_type>  	__streambuf_type;
  typedef char_type * 	__array_type;
  typedef typename _Traits::pos_type             		__size_type;
  
 protected:
  /// Place to stash in || out || in | out settings for current arraybuf.
  ios_base::openmode 	_M_mode;
  
  // Data Members:
  __array_type 		_M_array;
  
  __size_type       _M_array_size;
  
 public:
  // Constructors:
  /**
   *  @brief  Starts with an empty array buffer.
   *  @param  mode  Whether the buffer can read, or write, or both.
   *
   *  The default constructor initializes the parent class using its
   *  own default ctor.
   */
  explicit
    basic_arraybuf(ios_base::openmode __mode = ios_base::in | ios_base::out)
    : __streambuf_type(), _M_mode(__mode)
    { 
      _M_array = new char_type[0];
    }
  
  /**
   *  @brief  Starts with an existing array buffer.
   *  @param  str  A array to copy as a starting buffer.
   *  @param  mode  Whether the buffer can read, or write, or both.
   *
   *  This constructor initializes the parent class using its
   *  own default ctor.
   */
  explicit
    basic_arraybuf(const __array_type& __str, const __size_type __strlen,
                   ios_base::openmode __mode = ios_base::in | ios_base::out)
    : __streambuf_type(), _M_mode(), _M_array(__str, __strlen)
    { 
      _M_array = new char_type[__strlen + 1];
      memcpy(_M_array, __str, __strlen);
      _M_arraybuf_init(__mode); 
    }
  
  // Get and set:
  /**
   *  @brief  Copying out the array buffer.
   *  @return  A copy of one of the underlying sequences.
   *
   *  "If the buffer is only created in input mode, the underlying
   *  character sequence is equal to the input sequence; otherwise, it
   *  is equal to the output sequence." [27.7.1.2]/1
   */
  __array_type
    data() {
    return _M_array;
  }
  
  void
    data(const __array_type& __s,
         const __size_type __l)
    { 
      _M_array = __s;
      _M_array_size = __l;
      _M_arraybuf_init(_M_mode);
    }
  
  
  /* 	__array_type __ret; */
  /* 	if (this->pptr()) */
  /* 	  { */
  /* 	    // The current egptr() may not be the actual array end. */
  /* 	    if (this->pptr() > this->egptr()) */
  /* 	      __ret = __array_type(this->pbase(), this->pptr()); */
  /* 	    else */
  /*  	      __ret = __array_type(this->pbase(), this->egptr()); */
  /* 	  } */
  /* 	else */
  /* 	  __ret = _M_array; */
  /* 	return __ret; */
  /*       } */
  
 protected:
  // Common initialization code goes here.
  void
    _M_arraybuf_init(ios_base::openmode __mode)
    {
      _M_mode = __mode;
      __size_type __len = 0;
      if (_M_mode & (ios_base::ate | ios_base::app))
        __len = _M_array_size;
      //_M_sync(const_cast<char_type*>(_M_array), 0, __len);
    }
  
  virtual std::streamsize
    showmanyc()
    { 
      std::streamsize __ret = -1;
      if (_M_mode & ios_base::in)
        {
          _M_update_egptr();
          __ret = this->egptr() - this->gptr();
        }
      return __ret;
    }
  
  virtual int_type
    underflow();
  
  virtual int_type
    pbackfail(int_type __c = traits_type::eof());
  
  virtual int_type
    overflow(int_type __c = traits_type::eof());
  
  /**
   *  @brief  Manipulates the buffer.
   *  @param  s  Pointer to a buffer area.
   *  @param  n  Size of @a s.
   *  @return  @c this
   *
   *  If no buffer has already been created, and both @a s and @a n are
   *  non-zero, then @c s is used as a buffer; see
   *  http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2
   *  for more.
   */
  virtual __streambuf_type*
    setbuf(char_type* __s, std::streamsize __n)
    {
      if (__s && __n >= 0)
        {
          // This is implementation-defined behavior, and assumes
          // that an external char_type array of length __n exists
          // and has been pre-allocated. If this is not the case,
          // things will quickly blow up.
          
          // Step 1: Destroy the current internal array.
          delete _M_array;
          _M_array_size = 0;
          
          // Step 2: Use the external array.
          _M_sync(__s, __n, 0);
        }
      return this;
    }
  
  virtual pos_type
    seekoff(off_type __off, ios_base::seekdir __way,
            ios_base::openmode __mode = ios_base::in | ios_base::out);
  
  virtual pos_type
    seekpos(pos_type __sp,
            ios_base::openmode __mode = ios_base::in | ios_base::out);

  // Internal function for correctly updating the internal buffer
  // for a particular _M_string, due to initialization or re-sizing
  // of an existing _M_string.
  void
    _M_sync(char_type* __base, __size_type __i, __size_type __o);
  
  
  // Internal function for correctly updating egptr() to the actual
  // array end.
  void
    _M_update_egptr()
    {
      const bool __testin = _M_mode & ios_base::in;
      if (this->pptr() && this->pptr() > this->egptr())
        if (__testin)
          this->setg(this->eback(), this->gptr(), this->pptr());
        else
          this->setg(this->pptr(), this->pptr(), this->pptr());
    }
};


// [27.7.2] Template class basic_iarraystream
  /**
   *  @brief  Controlling input for std::array.
   *
   *  This class supports reading from objects of type std::basic_array,
   *  using the inherited functions from std::basic_istream.  To control
   *  the associated sequence, an instance of std::basic_arraybuf is used,
   *  which this page refers to as @c sb.
   */
template<typename _CharT, typename _Traits, typename _Alloc>
    class basic_iarraystream : public std::basic_istream<_CharT, _Traits>
{
 public:
  // Types:
  typedef _CharT 					char_type;
  typedef _Traits 					traits_type;
  // _GLIBCXX_RESOLVE_LIB_DEFECTS
  // 251. basic_arraybuf missing allocator_type
  typedef _Alloc				       	allocator_type;
  typedef typename _Traits::int_type 		int_type;
  typedef typename _Traits::pos_type 		pos_type;
  typedef typename _Traits::off_type 		off_type;
  
  // Non-standard types:
  typedef char_type * 	__array_type;
  typedef basic_arraybuf<_CharT, _Traits, _Alloc> 	__arraybuf_type;
  typedef std::basic_istream<char_type, traits_type>	__istream_type;

  typedef typename _Traits::pos_type             		__size_type;
  
 private:
  __arraybuf_type	_M_arraybuf;
  
 public:
  // Constructors:
  /**
   *  @brief  Default constructor starts with an empty array buffer.
   *  @param  mode  Whether the buffer can read, or write, or both.
   *
   *  @c ios_base::in is automatically included in @a mode.
   *
   *  Initializes @c sb using @c mode|in, and passes @c &sb to the base
   *  class initializer.  Does not allocate any buffer.
   *
   *  That's a lie.  We initialize the base class with NULL, because the
   *  array class does its own memory management.
   */
  explicit
    basic_iarraystream(ios_base::openmode __mode = ios_base::in)
    : __istream_type(), _M_arraybuf(__mode | ios_base::in)
    { this->init(&_M_arraybuf); }
  
  /**
   *  @brief  Starts with an existing array buffer.
   *  @param  str  A array to copy as a starting buffer.
   *  @param  mode  Whether the buffer can read, or write, or both.
   *
   *  @c ios_base::in is automatically included in @a mode.
   *
   *  Initializes @c sb using @a str and @c mode|in, and passes @c &sb
   *  to the base class initializer.
   *
   *  That's a lie.  We initialize the base class with NULL, because the
   *  array class does its own memory management.
   */
  explicit
    basic_iarraystream(const __array_type& __str,
                       const __size_type __strlen,
                       ios_base::openmode __mode = ios_base::in)
    : __istream_type(), _M_arraybuf(__str, __strlen, __mode | ios_base::in)
    { this->init(&_M_arraybuf); }
  
  /**
   *  @brief  The destructor does nothing.
   *
   *  The buffer is deallocated by the arraybuf object, not the
   *  formatting stream.
   */
  ~basic_iarraystream()
    { }
  
  // Members:
  /**
   *  @brief  Accessing the underlying buffer.
   *  @return  The current basic_arraybuf buffer.
   *
   *  This hides both signatures of std::basic_ios::rdbuf().
   */
  __arraybuf_type*
    rdbuf() const
    { return const_cast<__arraybuf_type*>(&_M_arraybuf); }
  
  /**
   *  @brief  Copying out the array buffer.
   *  @return  @c rdbuf()->str()
   */
  __array_type
    data() const
    { return _M_arraybuf.data(); }

  void
    data(const __array_type& __s,
         const __size_type __l)
    {
      return _M_arraybuf.data(__s, __l);
    }

  
};

// [27.7.3] Template class basic_oarraystream
/**
 *  @brief  Controlling output for std::array.
 *
   *  This class supports writing to objects of type std::basic_array,
   *  using the inherited functions from std::basic_ostream.  To control
   *  the associated sequence, an instance of std::basic_arraybuf is used,
   *  which this page refers to as @c sb.
  */
template <typename _CharT, typename _Traits, typename _Alloc>
        class basic_oarraystream : public std::basic_ostream<_CharT, _Traits>
{
 public:
  // Types:
  typedef _CharT 					char_type;
  typedef _Traits 					traits_type;
  // _GLIBCXX_RESOLVE_LIB_DEFECTS
  // 251. basic_arraybuf missing allocator_type
  typedef _Alloc				       	allocator_type;
  typedef typename traits_type::int_type 		int_type;
  typedef typename traits_type::pos_type 		pos_type;
  typedef typename traits_type::off_type 		off_type;
  
  // Non-standard types:
  typedef char_type * 	__array_type;
  typedef basic_arraybuf<_CharT, _Traits, _Alloc> 	__arraybuf_type;
  typedef std::basic_ostream<char_type, traits_type>	__ostream_type;

  typedef typename _Traits::pos_type             		__size_type;

  
 private:
  __arraybuf_type	_M_arraybuf;
  
 public:
  // Constructors/destructor:
  /**
   *  @brief  Default constructor starts with an empty array buffer.
   *  @param  mode  Whether the buffer can read, or write, or both.
   *
   *  @c ios_base::out is automatically included in @a mode.
   *
   *  Initializes @c sb using @c mode|out, and passes @c &sb to the base
   *  class initializer.  Does not allocate any buffer.
   *
   *  That's a lie.  We initialize the base class with NULL, because the
   *  array class does its own memory management.
   */
  explicit
    basic_oarraystream(ios_base::openmode __mode = ios_base::out)
    : __ostream_type(), _M_arraybuf(__mode | ios_base::out)
    { this->init(&_M_arraybuf); }
  
  /**
   *  @brief  Starts with an existing array buffer.
   *  @param  str  A array to copy as a starting buffer.
   *  @param  mode  Whether the buffer can read, or write, or both.
   *
   *  @c ios_base::out is automatically included in @a mode.
   *
   *  Initializes @c sb using @a str and @c mode|out, and passes @c &sb
   *  to the base class initializer.
   *
   *  That's a lie.  We initialize the base class with NULL, because the
   *  array class does its own memory management.
   */
  explicit
    basic_oarraystream(const __array_type& __str,
                       const __size_type __strlen,
                       ios_base::openmode __mode = ios_base::out)
    : __ostream_type(), _M_arraybuf(__str, __strlen, __mode | ios_base::out)
    { this->init(&_M_arraybuf); }
  
  /**
   *  @brief  The destructor does nothing.
   *
   *  The buffer is deallocated by the arraybuf object, not the
   *  formatting stream.
   */
  ~basic_oarraystream()
    { }
  
  // Members:
  /**
   *  @brief  Accessing the underlying buffer.
   *  @return  The current basic_arraybuf buffer.
   *
   *  This hides both signatures of std::basic_ios::rdbuf().
   */
  __arraybuf_type*
    rdbuf() const
    { return const_cast<__arraybuf_type*>(&_M_arraybuf); }
  
  /**
   *  @brief  Copying out the array buffer.
   *  @return  @c rdbuf()->data()
   */
  __array_type
    data() const
    { return _M_arraybuf.data(); }
  
  /**
   *  @brief  Setting a new buffer.
   *  @param  s  The array to use as a new sequence.
   *
   *  Calls @c rdbuf()->str(s).
   */
  void
    data(const __array_type& __s,
         const __size_type __l)
    { _M_arraybuf.data(__s, __l); }
};


// [27.7.4] Template class basic_arraystream
/**
 *  @brief  Controlling input and output for std::array.
 *
 *  This class supports reading from and writing to objects of type
 *  std::basic_array, using the inherited functions from
 *  std::basic_iostream.  To control the associated sequence, an instance
 *  of std::basic_arraybuf is used, which this page refers to as @c sb.
 */
template <typename _CharT, typename _Traits, typename _Alloc>
    class basic_arraystream : public std::basic_iostream<_CharT, _Traits>
{
 public:
  // Types:
  typedef _CharT 					char_type;
  typedef _Traits 					traits_type;
  // _GLIBCXX_RESOLVE_LIB_DEFECTS
  // 251. basic_arraybuf missing allocator_type
  typedef _Alloc				       	allocator_type;
  typedef typename traits_type::int_type 		int_type;
  typedef typename traits_type::pos_type 		pos_type;
  typedef typename traits_type::off_type 		off_type;
  
  // Non-standard Types:
  typedef char_type * 	__array_type;
  typedef basic_arraybuf<_CharT, _Traits, _Alloc> 	__arraybuf_type;
  typedef std::basic_iostream<char_type, traits_type>	__iostream_type;

  typedef typename _Traits::pos_type             		__size_type;
  
 private:
  __arraybuf_type	_M_arraybuf;
  
 public:
  // Constructors/destructors
  /**
   *  @brief  Default constructor starts with an empty array buffer.
   *  @param  mode  Whether the buffer can read, or write, or both.
   *
   *  Initializes @c sb using @c mode, and passes @c &sb to the base
   *  class initializer.  Does not allocate any buffer.
   *
   *  That's a lie.  We initialize the base class with NULL, because the
   *  array class does its own memory management.
   */
  explicit
    basic_arraystream(ios_base::openmode __m = ios_base::out | ios_base::in)
    : __iostream_type(), _M_arraybuf(__m)
    { this->init(&_M_arraybuf); }
  
  /**
   *  @brief  Starts with an existing array buffer.
   *  @param  str  A array to copy as a starting buffer.
   *  @param  mode  Whether the buffer can read, or write, or both.
   *
   *  Initializes @c sb using @a str and @c mode, and passes @c &sb
   *  to the base class initializer.
   *
   *  That's a lie.  We initialize the base class with NULL, because the
   *  array class does its own memory management.
   */
  explicit
    basic_arraystream(const __array_type& __str,
                      const __size_type __strlen,
                      ios_base::openmode __m = ios_base::out | ios_base::in)
    : __iostream_type(), _M_arraybuf(__str, __strlen, __m)
    { this->init(&_M_arraybuf); }
  
  /**
   *  @brief  The destructor does nothing.
   *
   *  The buffer is deallocated by the arraybuf object, not the
   *  formatting stream.
   */
  ~basic_arraystream()
    { }
  
  // Members:
  /**
   *  @brief  Accessing the underlying buffer.
   *  @return  The current basic_arraybuf buffer.
   *
   *  This hides both signatures of std::basic_ios::rdbuf().
   */
  __arraybuf_type*
    rdbuf() const
    { return const_cast<__arraybuf_type*>(&_M_arraybuf); }
  
  /**
   *  @brief  Copying out the array buffer.
   *  @return  @c rdbuf()->data()
   */
  __array_type
    data() const
    { return _M_arraybuf.data(); }
  
  /**
   *  @brief  Setting a new buffer.
   *  @param  s  The array to use as a new sequence.
   *
   *  Calls @c rdbuf()->str(s).
   */
  void
    str(const __array_type& __s,
        const __size_type __l)
    { _M_arraybuf.str(__s, __l); }
};

#include "mstream.tcc"