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// Iostreams base classes -*- C++ -*-

// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006

// Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library is free

// software; you can redistribute it and/or modify it under the

// terms of the GNU General Public License as published by the

// Free Software Foundation; either version 2, or (at your option)

// any later version.

// This library is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along

// with this library; see the file COPYING.  If not, write to the Free

// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,

// USA.

// As a special exception, you may use this file as part of a free software

// library without restriction.  Specifically, if other files instantiate

// templates or use macros or inline functions from this file, or you compile

// this file and link it with other files to produce an executable, this

// file does not by itself cause the resulting executable to be covered by

// the GNU General Public License.  This exception does not however

// invalidate any other reasons why the executable file might be covered by

// the GNU General Public License.

//

// ISO C++ 14882: 27.4  Iostreams base classes

//

/** @file ios_base.h

 *  This is an internal header file, included by other library headers.

 *  You should not attempt to use it directly.

 */

#ifndef _IOS_BASE_H

#define _IOS_BASE_H 1

#pragma GCC system_header

#include <bits/atomicity.h>

#include <bits/localefwd.h>

#include <bits/locale_classes.h>

namespace std

{

  // The following definitions of bitmask types are enums, not ints,

  // as permitted (but not required) in the standard, in order to provide

  // better type safety in iostream calls.  A side effect is that

  // expressions involving them are no longer compile-time constants.

  enum _Ios_Fmtflags

    {

      _S_boolalpha      = 1L << 0,

      _S_dec            = 1L << 1,

      _S_fixed          = 1L << 2,

      _S_hex            = 1L << 3,

      _S_internal       = 1L << 4,

      _S_left           = 1L << 5,

      _S_oct            = 1L << 6,

      _S_right          = 1L << 7,

      _S_scientific     = 1L << 8,

      _S_showbase       = 1L << 9,

      _S_showpoint      = 1L << 10,

      _S_showpos        = 1L << 11,

      _S_skipws         = 1L << 12,

      _S_unitbuf        = 1L << 13,

      _S_uppercase      = 1L << 14,

      _S_adjustfield    = _S_left | _S_right | _S_internal,

      _S_basefield      = _S_dec | _S_oct | _S_hex,

      _S_floatfield     = _S_scientific | _S_fixed,

      _S_ios_fmtflags_end = 1L << 16

    };

  inline _Ios_Fmtflags

  operator&(_Ios_Fmtflags __a, _Ios_Fmtflags __b)

  { return _Ios_Fmtflags(static_cast<int>(__a) & static_cast<int>(__b)); }

  inline _Ios_Fmtflags

  operator|(_Ios_Fmtflags __a, _Ios_Fmtflags __b)

  { return _Ios_Fmtflags(static_cast<int>(__a) | static_cast<int>(__b)); }

  inline _Ios_Fmtflags

  operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b)

  { return _Ios_Fmtflags(static_cast<int>(__a) ^ static_cast<int>(__b)); }

  inline _Ios_Fmtflags&

  operator|=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)

  { return __a = __a | __b; }

  inline _Ios_Fmtflags&

  operator&=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)

  { return __a = __a & __b; }

  inline _Ios_Fmtflags&

  operator^=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)

  { return __a = __a ^ __b; }

  inline _Ios_Fmtflags

  operator~(_Ios_Fmtflags __a)

  { return _Ios_Fmtflags(~static_cast<int>(__a)); }

  enum _Ios_Openmode

    {

      _S_app            = 1L << 0,

      _S_ate            = 1L << 1,

      _S_bin            = 1L << 2,

      _S_in             = 1L << 3,

      _S_out            = 1L << 4,

      _S_trunc          = 1L << 5,

      _S_ios_openmode_end = 1L << 16

    };

  inline _Ios_Openmode

  operator&(_Ios_Openmode __a, _Ios_Openmode __b)

  { return _Ios_Openmode(static_cast<int>(__a) & static_cast<int>(__b)); }

  inline _Ios_Openmode

  operator|(_Ios_Openmode __a, _Ios_Openmode __b)

  { return _Ios_Openmode(static_cast<int>(__a) | static_cast<int>(__b)); }

  inline _Ios_Openmode

  operator^(_Ios_Openmode __a, _Ios_Openmode __b)

  { return _Ios_Openmode(static_cast<int>(__a) ^ static_cast<int>(__b)); }

  inline _Ios_Openmode&

  operator|=(_Ios_Openmode& __a, _Ios_Openmode __b)

  { return __a = __a | __b; }

  inline _Ios_Openmode&

  operator&=(_Ios_Openmode& __a, _Ios_Openmode __b)

  { return __a = __a & __b; }

  inline _Ios_Openmode&

  operator^=(_Ios_Openmode& __a, _Ios_Openmode __b)

  { return __a = __a ^ __b; }

  inline _Ios_Openmode

  operator~(_Ios_Openmode __a)

  { return _Ios_Openmode(~static_cast<int>(__a)); }

  enum _Ios_Iostate

    {

      _S_goodbit                = 0,

      _S_badbit                 = 1L << 0,

      _S_eofbit                 = 1L << 1,

      _S_failbit                = 1L << 2,

      _S_ios_iostate_end = 1L << 16

    };

  inline _Ios_Iostate

  operator&(_Ios_Iostate __a, _Ios_Iostate __b)

  { return _Ios_Iostate(static_cast<int>(__a) & static_cast<int>(__b)); }

  inline _Ios_Iostate

  operator|(_Ios_Iostate __a, _Ios_Iostate __b)

  { return _Ios_Iostate(static_cast<int>(__a) | static_cast<int>(__b)); }

  inline _Ios_Iostate

  operator^(_Ios_Iostate __a, _Ios_Iostate __b)

  { return _Ios_Iostate(static_cast<int>(__a) ^ static_cast<int>(__b)); }

  inline _Ios_Iostate&

  operator|=(_Ios_Iostate& __a, _Ios_Iostate __b)

  { return __a = __a | __b; }

  inline _Ios_Iostate&

  operator&=(_Ios_Iostate& __a, _Ios_Iostate __b)

  { return __a = __a & __b; }

  inline _Ios_Iostate&

  operator^=(_Ios_Iostate& __a, _Ios_Iostate __b)

  { return __a = __a ^ __b; }

  inline _Ios_Iostate

  operator~(_Ios_Iostate __a)

  { return _Ios_Iostate(~static_cast<int>(__a)); }

  enum _Ios_Seekdir

    {

      _S_beg = 0,

      _S_cur = SEEK_CUR,

      _S_end = SEEK_END,

      _S_ios_seekdir_end = 1L << 16

    };

  // 27.4.2  Class ios_base

  /**

   *  @brief  The base of the I/O class hierarchy.

   *

   *  This class defines everything that can be defined about I/O that does

   *  not depend on the type of characters being input or output.  Most

   *  people will only see @c ios_base when they need to specify the full

   *  name of the various I/O flags (e.g., the openmodes).

  */

  class ios_base

  {

  public:

    // 27.4.2.1.1  Class ios_base::failure

    /// These are thrown to indicate problems.  Doc me.

    class failure : public exception

    {

    public:

      // _GLIBCXX_RESOLVE_LIB_DEFECTS

      // 48.  Use of non-existent exception constructor

      explicit

      failure(const string& __str) throw();

      // This declaration is not useless:

      // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118

      virtual

      ~failure() throw();

      virtual const char*

      what() const throw();

    private:

      string _M_msg;

    };

    // 27.4.2.1.2  Type ios_base::fmtflags

    /**

     *  @brief This is a bitmask type.

     *

     *  @c "_Ios_Fmtflags" is implementation-defined, but it is valid to

     *  perform bitwise operations on these values and expect the Right

     *  Thing to happen.  Defined objects of type fmtflags are:

     *  - boolalpha

     *  - dec

     *  - fixed

     *  - hex

     *  - internal

     *  - left

     *  - oct

     *  - right

     *  - scientific

     *  - showbase

     *  - showpoint

     *  - showpos

     *  - skipws

     *  - unitbuf

     *  - uppercase

     *  - adjustfield

     *  - basefield

     *  - floatfield

    */

    typedef _Ios_Fmtflags fmtflags;

    /// Insert/extract @c bool in alphabetic rather than numeric format.

    static const fmtflags boolalpha =   _S_boolalpha;

    /// Converts integer input or generates integer output in decimal base.

    static const fmtflags dec =         _S_dec;

    /// Generate floating-point output in fixed-point notation.

    static const fmtflags fixed =       _S_fixed;

    /// Converts integer input or generates integer output in hexadecimal base.

    static const fmtflags hex =         _S_hex;

    /// Adds fill characters at a designated internal point in certain

    /// generated output, or identical to @c right if no such point is

    /// designated.

    static const fmtflags internal =    _S_internal;

    /// Adds fill characters on the right (final positions) of certain

    /// generated output.  (I.e., the thing you print is flush left.)

    static const fmtflags left =        _S_left;

    /// Converts integer input or generates integer output in octal base.

    static const fmtflags oct =         _S_oct;

    /// Adds fill characters on the left (initial positions) of certain

    /// generated output.  (I.e., the thing you print is flush right.)

    static const fmtflags right =       _S_right;

    /// Generates floating-point output in scientific notation.

    static const fmtflags scientific =  _S_scientific;

    /// Generates a prefix indicating the numeric base of generated integer

    /// output.

    static const fmtflags showbase =    _S_showbase;

    /// Generates a decimal-point character unconditionally in generated

    /// floating-point output.

    static const fmtflags showpoint =   _S_showpoint;

    /// Generates a + sign in non-negative generated numeric output.

    static const fmtflags showpos =     _S_showpos;

    /// Skips leading white space before certain input operations.

    static const fmtflags skipws =      _S_skipws;

    /// Flushes output after each output operation.

    static const fmtflags unitbuf =     _S_unitbuf;

    /// Replaces certain lowercase letters with their uppercase equivalents

    /// in generated output.

    static const fmtflags uppercase =   _S_uppercase;

    /// A mask of left|right|internal.  Useful for the 2-arg form of @c setf.

    static const fmtflags adjustfield = _S_adjustfield;

    /// A mask of dec|oct|hex.  Useful for the 2-arg form of @c setf.

    static const fmtflags basefield =   _S_basefield;

    /// A mask of scientific|fixed.  Useful for the 2-arg form of @c setf.

    static const fmtflags floatfield =  _S_floatfield;

    // 27.4.2.1.3  Type ios_base::iostate

    /**

     *  @brief This is a bitmask type.

     *

     *  @c "_Ios_Iostate" is implementation-defined, but it is valid to

     *  perform bitwise operations on these values and expect the Right

     *  Thing to happen.  Defined objects of type iostate are:

     *  - badbit

     *  - eofbit

     *  - failbit

     *  - goodbit

    */

    typedef _Ios_Iostate iostate;

    /// Indicates a loss of integrity in an input or output sequence (such

    /// as an irrecoverable read error from a file).

    static const iostate badbit =       _S_badbit;

    /// Indicates that an input operation reached the end of an input sequence.

    static const iostate eofbit =       _S_eofbit;

    /// Indicates that an input operation failed to read the expected

    /// characters, or that an output operation failed to generate the

    /// desired characters.

    static const iostate failbit =      _S_failbit;

    /// Indicates all is well.

    static const iostate goodbit =      _S_goodbit;

    // 27.4.2.1.4  Type ios_base::openmode

    /**

     *  @brief This is a bitmask type.

     *

     *  @c "_Ios_Openmode" is implementation-defined, but it is valid to

     *  perform bitwise operations on these values and expect the Right

     *  Thing to happen.  Defined objects of type openmode are:

     *  - app

     *  - ate

     *  - binary

     *  - in

     *  - out

     *  - trunc

    */

    typedef _Ios_Openmode openmode;

    /// Seek to end before each write.

    static const openmode app =         _S_app;

    /// Open and seek to end immediately after opening.

    static const openmode ate =         _S_ate;

    /// Perform input and output in binary mode (as opposed to text mode).

    /// This is probably not what you think it is; see

    /// http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#3 and

    /// http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#7 for more.

    static const openmode binary =      _S_bin;

    /// Open for input.  Default for @c ifstream and fstream.

    static const openmode in =          _S_in;

    /// Open for output.  Default for @c ofstream and fstream.

    static const openmode out =         _S_out;

    /// Open for input.  Default for @c ofstream.

    static const openmode trunc =       _S_trunc;

    // 27.4.2.1.5  Type ios_base::seekdir

    /**

     *  @brief This is an enumerated type.

     *

     *  @c "_Ios_Seekdir" is implementation-defined.  Defined values

     *  of type seekdir are:

     *  - beg

     *  - cur, equivalent to @c SEEK_CUR in the C standard library.

     *  - end, equivalent to @c SEEK_END in the C standard library.

    */

    typedef _Ios_Seekdir seekdir;

    /// Request a seek relative to the beginning of the stream.

    static const seekdir beg =          _S_beg;

    /// Request a seek relative to the current position within the sequence.

    static const seekdir cur =          _S_cur;

    /// Request a seek relative to the current end of the sequence.

    static const seekdir end =          _S_end;

    // Annex D.6

    typedef int io_state;

    typedef int open_mode;

    typedef int seek_dir;

    typedef std::streampos streampos;

    typedef std::streamoff streamoff;

    // Callbacks;

    /**

     *  @brief  The set of events that may be passed to an event callback.

     *

     *  erase_event is used during ~ios() and copyfmt().  imbue_event is used

     *  during imbue().  copyfmt_event is used during copyfmt().

    */

    enum event

    {

      erase_event,

      imbue_event,

      copyfmt_event

    };

    /**

     *  @brief  The type of an event callback function.

     *  @param  event  One of the members of the event enum.

     *  @param  ios_base  Reference to the ios_base object.

     *  @param  int  The integer provided when the callback was registered.

     *

     *  Event callbacks are user defined functions that get called during

     *  several ios_base and basic_ios functions, specifically imbue(),

     *  copyfmt(), and ~ios().

    */

    typedef void (*event_callback) (event, ios_base&, int);

    /**

     *  @brief  Add the callback __fn with parameter __index.

     *  @param  __fn  The function to add.

     *  @param  __index  The integer to pass to the function when invoked.

     *

     *  Registers a function as an event callback with an integer parameter to

     *  be passed to the function when invoked.  Multiple copies of the

     *  function are allowed.  If there are multiple callbacks, they are

     *  invoked in the order they were registered.

    */

    void

    register_callback(event_callback __fn, int __index);

  protected:

    //@{

    /**

     *  @if maint

     *  ios_base data members (doc me)

     *  @endif

    */

    streamsize          _M_precision;

    streamsize          _M_width;

    fmtflags            _M_flags;

    iostate             _M_exception;

    iostate             _M_streambuf_state;

    //@}

    // 27.4.2.6  Members for callbacks

    // 27.4.2.6  ios_base callbacks

    struct _Callback_list

    {

      // Data Members

      _Callback_list*           _M_next;

      ios_base::event_callback  _M_fn;

      int                       _M_index;

      _Atomic_word              _M_refcount;  // 0 means one reference.

      _Callback_list(ios_base::event_callback __fn, int __index,

                     _Callback_list* __cb)

      : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { }

      void

      _M_add_reference() { __gnu_cxx::__atomic_add(&_M_refcount, 1); }

      // 0 => OK to delete.

      int

      _M_remove_reference()

      { return __gnu_cxx::__exchange_and_add(&_M_refcount, -1); }

    };

     _Callback_list*    _M_callbacks;

    void

    _M_call_callbacks(event __ev) throw();

    void

    _M_dispose_callbacks(void);

    // 27.4.2.5  Members for iword/pword storage

    struct _Words

    {

      void*     _M_pword;

      long      _M_iword;

      _Words() : _M_pword(0), _M_iword(0) { }

    };

    // Only for failed iword/pword calls.

    _Words              _M_word_zero;

    // Guaranteed storage.

    // The first 5 iword and pword slots are reserved for internal use.

    enum { _S_local_word_size = 8 };

    _Words              _M_local_word[_S_local_word_size];

    // Allocated storage.

    int                 _M_word_size;

    _Words*             _M_word;

    _Words&

    _M_grow_words(int __index, bool __iword);

    // Members for locale and locale caching.

    locale              _M_ios_locale;

    void

    _M_init();

  public:

    // 27.4.2.1.6  Class ios_base::Init

    // Used to initialize standard streams. In theory, g++ could use

    // -finit-priority to order this stuff correctly without going

    // through these machinations.

    class Init

    {

      friend class ios_base;

    public:

      Init();

      ~Init();

    private:

      static _Atomic_word       _S_refcount;

      static bool               _S_synced_with_stdio;

    };

    // [27.4.2.2] fmtflags state functions

    /**

     *  @brief  Access to format flags.

     *  @return  The format control flags for both input and output.

    */

    inline fmtflags

    flags() const { return _M_flags; }

    /**

     *  @brief  Setting new format flags all at once.

     *  @param  fmtfl  The new flags to set.

     *  @return  The previous format control flags.

     *

     *  This function overwrites all the format flags with @a fmtfl.

    */

    inline fmtflags

    flags(fmtflags __fmtfl)

    {

      fmtflags __old = _M_flags;

      _M_flags = __fmtfl;

      return __old;

    }

    /**

     *  @brief  Setting new format flags.

     *  @param  fmtfl  Additional flags to set.

     *  @return  The previous format control flags.

     *

     *  This function sets additional flags in format control.  Flags that

     *  were previously set remain set.

    */

    inline fmtflags

    setf(fmtflags __fmtfl)

    {

      fmtflags __old = _M_flags;

      _M_flags |= __fmtfl;

      return __old;

    }

    /**

     *  @brief  Setting new format flags.

     *  @param  fmtfl  Additional flags to set.

     *  @param  mask  The flags mask for @a fmtfl.

     *  @return  The previous format control flags.

     *

     *  This function clears @a mask in the format flags, then sets

     *  @a fmtfl @c & @a mask.  An example mask is @c ios_base::adjustfield.

    */

    inline fmtflags

    setf(fmtflags __fmtfl, fmtflags __mask)

    {

      fmtflags __old = _M_flags;

      _M_flags &= ~__mask;

      _M_flags |= (__fmtfl & __mask);

      return __old;

    }

    /**

     *  @brief  Clearing format flags.

     *  @param  mask  The flags to unset.

     *

     *  This function clears @a mask in the format flags.

    */

    inline void

    unsetf(fmtflags __mask) { _M_flags &= ~__mask; }

    /**

     *  @brief  Flags access.

     *  @return  The precision to generate on certain output operations.

     *

     *  @if maint

     *  Be careful if you try to give a definition of "precision" here; see

     *  DR 189.

     *  @endif

    */

    inline streamsize

    precision() const { return _M_precision; }

    /**

     *  @brief  Changing flags.

     *  @param  prec  The new precision value.

     *  @return  The previous value of precision().

    */

    inline streamsize

    precision(streamsize __prec)

    {

      streamsize __old = _M_precision;

      _M_precision = __prec;

      return __old;

    }

    /**

     *  @brief  Flags access.

     *  @return  The minimum field width to generate on output operations.

     *

     *  "Minimum field width" refers to the number of characters.

    */

    inline streamsize

    width() const { return _M_width; }

    /**

     *  @brief  Changing flags.

     *  @param  wide  The new width value.

     *  @return  The previous value of width().

    */

    inline streamsize

    width(streamsize __wide)

    {

      streamsize __old = _M_width;

      _M_width = __wide;

      return __old;

    }

    // [27.4.2.4] ios_base static members

    /**

     *  @brief  Interaction with the standard C I/O objects.

     *  @param  sync  Whether to synchronize or not.

     *  @return  True if the standard streams were previously synchronized.

     *

     *  The synchronization referred to is @e only that between the standard

     *  C facilities (e.g., stdout) and the standard C++ objects (e.g.,

     *  cout).  User-declared streams are unaffected.  See

     *  http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#8 for more.

    */

    static bool

    sync_with_stdio(bool __sync = true);

    // [27.4.2.3] ios_base locale functions

    /**

     *  @brief  Setting a new locale.

     *  @param  loc  The new locale.

     *  @return  The previous locale.

     *

     *  Sets the new locale for this stream, and then invokes each callback

     *  with imbue_event.

    */

    locale

    imbue(const locale& __loc);

    /**

     *  @brief  Locale access

     *  @return  A copy of the current locale.

     *

     *  If @c imbue(loc) has previously been called, then this function

     *  returns @c loc.  Otherwise, it returns a copy of @c std::locale(),

     *  the global C++ locale.

    */

    inline locale

    getloc() const { return _M_ios_locale; }

    /**

     *  @brief  Locale access

     *  @return  A reference to the current locale.

     *

     *  Like getloc above, but returns a reference instead of

     *  generating a copy.

    */

    inline const locale&

    _M_getloc() const { return _M_ios_locale; }

    // [27.4.2.5] ios_base storage functions

    /**

     *  @brief  Access to unique indices.

     *  @return  An integer different from all previous calls.

     *

     *  This function returns a unique integer every time it is called.  It

     *  can be used for any purpose, but is primarily intended to be a unique

     *  index for the iword and pword functions.  The expectation is that an

     *  application calls xalloc in order to obtain an index in the iword and

     *  pword arrays that can be used without fear of conflict.

     *

     *  The implementation maintains a static variable that is incremented and

     *  returned on each invocation.  xalloc is guaranteed to return an index

     *  that is safe to use in the iword and pword arrays.

    */

    static int

    xalloc() throw();

    /**

     *  @brief  Access to integer array.

     *  @param  __ix  Index into the array.

     *  @return  A reference to an integer associated with the index.

     *

     *  The iword function provides access to an array of integers that can be

     *  used for any purpose.  The array grows as required to hold the

     *  supplied index.  All integers in the array are initialized to 0.

     *

     *  The implementation reserves several indices.  You should use xalloc to

     *  obtain an index that is safe to use.  Also note that since the array

     *  can grow dynamically, it is not safe to hold onto the reference.

    */

    inline long&

    iword(int __ix)

    {

      _Words& __word = (__ix < _M_word_size)

                        ? _M_word[__ix] : _M_grow_words(__ix, true);

      return __word._M_iword;

    }

    /**

     *  @brief  Access to void pointer array.

     *  @param  __ix  Index into the array.

     *  @return  A reference to a void* associated with the index.

     *

     *  The pword function provides access to an array of pointers that can be

     *  used for any purpose.  The array grows as required to hold the

     *  supplied index.  All pointers in the array are initialized to 0.

     *

     *  The implementation reserves several indices.  You should use xalloc to

     *  obtain an index that is safe to use.  Also note that since the array

     *  can grow dynamically, it is not safe to hold onto the reference.

    */

    inline void*&

    pword(int __ix)

    {

      _Words& __word = (__ix < _M_word_size)

                        ? _M_word[__ix] : _M_grow_words(__ix, false);

      return __word._M_pword;

    }

    // Destructor

    /**

     *  Invokes each callback with erase_event.  Destroys local storage.

     *

     *  Note that the ios_base object for the standard streams never gets

     *  destroyed.  As a result, any callbacks registered with the standard

     *  streams will not get invoked with erase_event (unless copyfmt is

     *  used).

    */

    virtual ~ios_base();