// Input streams -*- C++ -*-

// Copyright (C) 1997, 1998, 1999, 2001, 2002, 2003

// 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,

// 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: 27.6.1  Input streams

//

/** @file istream

 *  This is a Standard C++ Library header.  You should @c #include this header

 *  in your programs, rather than any of the "st[dl]_*.h" implementation files.

 */

#ifndef _GLIBCXX_ISTREAM

#define _GLIBCXX_ISTREAM 1

#pragma GCC system_header

#include <ios>

#include <limits> // For numeric_limits

namespace std

{

  // [27.6.1.1] Template class basic_istream

  /**

   *  @brief  Controlling input.

   *

   *  This is the base class for all input streams.  It provides text

   *  formatting of all builtin types, and communicates with any class

   *  derived from basic_streambuf to do the actual input.

  */

  template<typename _CharT, typename _Traits>

    class basic_istream : virtual public basic_ios<_CharT, _Traits>

    {

    public:

      // Types (inherited from basic_ios (27.4.4)):

      typedef _CharT                     		char_type;

      typedef typename _Traits::int_type 		int_type;

      typedef typename _Traits::pos_type 		pos_type;

      typedef typename _Traits::off_type 		off_type;

      typedef _Traits                    		traits_type;

      // Non-standard Types:

      typedef basic_streambuf<_CharT, _Traits> 		__streambuf_type;

      typedef basic_ios<_CharT, _Traits>		__ios_type;

      typedef basic_istream<_CharT, _Traits>		__istream_type;

      typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> >        

 							__num_get_type;

      typedef ctype<_CharT>           			__ctype_type;

      template<typename _CharT2, typename _Traits2>

        friend basic_istream<_CharT2, _Traits2>&

        operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2&);

      template<typename _CharT2, typename _Traits2>

        friend basic_istream<_CharT2, _Traits2>&

        operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2*);

    protected:

      // Data Members:

      /**

       *  @if maint

       *  The number of characters extracted in the previous unformatted

       *  function; see gcount().

       *  @endif

      */

      streamsize 		_M_gcount;

    public:

      // [27.6.1.1.1] constructor/destructor

      /**

       *  @brief  Base constructor.

       *

       *  This ctor is almost never called by the user directly, rather from

       *  derived classes' initialization lists, which pass a pointer to

       *  their own stream buffer.

      */

      explicit 

      basic_istream(__streambuf_type* __sb): _M_gcount(streamsize(0))

      { this->init(__sb); }

      /**

       *  @brief  Base destructor.

       *

       *  This does very little apart from providing a virtual base dtor.

      */

      virtual 

      ~basic_istream() 

      { _M_gcount = streamsize(0); }

      // [27.6.1.1.2] prefix/suffix

      class sentry;

      friend class sentry;

      // [27.6.1.2] formatted input

      // [27.6.1.2.3] basic_istream::operator>>

      //@{

      /**

       *  @brief  Interface for manipulators.

       *

       *  Manuipulators such as @c std::ws and @c std::dec use these

       *  functions in constructs like "std::cin >> std::ws".  For more

       *  information, see the iomanip header.

      */

      inline __istream_type&

      operator>>(__istream_type& (*__pf)(__istream_type&));

      inline __istream_type&

      operator>>(__ios_type& (*__pf)(__ios_type&));

      inline __istream_type&

      operator>>(ios_base& (*__pf)(ios_base&));

      //@}

      // [27.6.1.2.2] arithmetic extractors

      /**

       *  @name Arithmetic Extractors

       *

       *  All the @c operator>> functions (aka <em>formatted input

       *  functions</em>) have some common behavior.  Each starts by

       *  constructing a temporary object of type std::basic_istream::sentry

       *  with the second argument (noskipws) set to false.  This has several

       *  effects, concluding with the setting of a status flag; see the

       *  sentry documentation for more.

       *

       *  If the sentry status is good, the function tries to extract

       *  whatever data is appropriate for the type of the argument.

       *

       *  If an exception is thrown during extraction, ios_base::badbit

       *  will be turned on in the stream's error state without causing an

       *  ios_base::failure to be thrown.  The original exception will then

       *  be rethrown.

      */

      //@{

      /**

       *  @brief  Basic arithmetic extractors

       *  @param  A variable of builtin type.

       *  @return  @c *this if successful

       *

       *  These functions use the stream's current locale (specifically, the

       *  @c num_get facet) to parse the input data.

      */

      __istream_type& 

      operator>>(bool& __n);

      __istream_type& 

      operator>>(short& __n);

      __istream_type& 

      operator>>(unsigned short& __n);

      __istream_type& 

      operator>>(int& __n);

      __istream_type& 

      operator>>(unsigned int& __n);

      __istream_type& 

      operator>>(long& __n);

      __istream_type& 

      operator>>(unsigned long& __n);

#ifdef _GLIBCXX_USE_LONG_LONG

      __istream_type& 

      operator>>(long long& __n);

      __istream_type& 

      operator>>(unsigned long long& __n);

#endif

      __istream_type& 

      operator>>(float& __f);

      __istream_type& 

      operator>>(double& __f);

      __istream_type& 

      operator>>(long double& __f);

      __istream_type& 

      operator>>(void*& __p);

      /**

       *  @brief  Extracting into another streambuf.

       *  @param  sb  A pointer to a streambuf

       *

       *  This function behaves like one of the basic arithmetic extractors,

       *  in that it also constructs a sentry object and has the same error

       *  handling behavior.

       *

       *  If @a sb is NULL, the stream will set failbit in its error state.

       *

       *  Characters are extracted from this stream and inserted into the

       *  @a sb streambuf until one of the following occurs:

       *

       *  - the input stream reaches end-of-file,

       *  - insertion into the output buffer fails (in this case, the

       *    character that would have been inserted is not extracted), or

       *  - an exception occurs (and in this case is caught)

       *

       *  If the function inserts no characters, failbit is set.

      */

      __istream_type& 

      operator>>(__streambuf_type* __sb);

      //@}

      // [27.6.1.3] unformatted input

      /**

       *  @brief  Character counting

       *  @return  The number of characters extracted by the previous

       *           unformatted input function dispatched for this stream.

      */

      inline streamsize 

      gcount() const 

      { return _M_gcount; }

      /**

       *  @name Unformatted Input Functions

       *

       *  All the unformatted input functions have some common behavior.

       *  Each starts by constructing a temporary object of type

       *  std::basic_istream::sentry with the second argument (noskipws)

       *  set to true.  This has several effects, concluding with the

       *  setting of a status flag; see the sentry documentation for more.

       *

       *  If the sentry status is good, the function tries to extract

       *  whatever data is appropriate for the type of the argument.

       *

       *  The number of characters extracted is stored for later retrieval

       *  by gcount().

       *

       *  If an exception is thrown during extraction, ios_base::badbit

       *  will be turned on in the stream's error state without causing an

       *  ios_base::failure to be thrown.  The original exception will then

       *  be rethrown.

      */

      //@{

      /**

       *  @brief  Simple extraction.

       *  @return  A character, or eof().

       *

       *  Tries to extract a character.  If none are available, sets failbit

       *  and returns traits::eof().

      */

      int_type 

      get();

      /**

       *  @brief  Simple extraction.

       *  @param  c  The character in which to store data.

       *  @return  *this

       *

       *  Tries to extract a character and store it in @a c.  If none are

       *  available, sets failbit and returns traits::eof().

       *

       *  @note  This function is not overloaded on signed char and

       *         unsigned char.

      */

      __istream_type& 

      get(char_type& __c);

      /**

       *  @brief  Simple multiple-character extraction.

       *  @param  s  Pointer to an array.

       *  @param  n  Maximum number of characters to store in @a s.

       *  @param  delim  A "stop" character.

       *  @return  *this

       *

       *  Characters are extracted and stored into @a s until one of the

       *  following happens:

       *

       *  - @c n-1 characters are stored

       *  - the input sequence reaches EOF

       *  - the next character equals @a delim, in which case the character

       *    is not extracted

       *

       * If no characters are stored, failbit is set in the stream's error

       * state.

       *

       * In any case, a null character is stored into the next location in

       * the array.

       *

       *  @note  This function is not overloaded on signed char and

       *         unsigned char.

      */

      __istream_type& 

      get(char_type* __s, streamsize __n, char_type __delim);

      /**

       *  @brief  Simple multiple-character extraction.

       *  @param  s  Pointer to an array.

       *  @param  n  Maximum number of characters to store in @a s.

       *  @return  *this

       *

       *  Returns @c get(s,n,widen('\n')).

      */

      inline __istream_type& 

      get(char_type* __s, streamsize __n)

      { return this->get(__s, __n, this->widen('\n')); }

      /**

       *  @brief  Extraction into another streambuf.

       *  @param  sb  A streambuf in which to store data.

       *  @param  delim  A "stop" character.

       *  @return  *this

       *

       *  Characters are extracted and inserted into @a sb until one of the

       *  following happens:

       *

       *  - the input sequence reaches EOF

       *  - insertion into the output buffer fails (in this case, the

       *    character that would have been inserted is not extracted)

       *  - the next character equals @a delim (in this case, the character

       *    is not extracted)

       *  - an exception occurs (and in this case is caught)

       *

       * If no characters are stored, failbit is set in the stream's error

       * state.

      */

      __istream_type&

      get(__streambuf_type& __sb, char_type __delim);

      /**

       *  @brief  Extraction into another streambuf.

       *  @param  sb  A streambuf in which to store data.

       *  @return  *this

       *

       *  Returns @c get(sb,widen('\n')).

      */

      inline __istream_type&

      get(__streambuf_type& __sb)

      { return this->get(__sb, this->widen('\n')); }

      /**

       *  @brief  String extraction.

       *  @param  s  A character array in which to store the data.

       *  @param  n  Maximum number of characters to extract.

       *  @param  delim  A "stop" character.

       *  @return  *this

       *

       *  Extracts and stores characters into @a s until one of the

       *  following happens.  Note that these criteria are required to be

       *  tested in the order listed here, to allow an input line to exactly

       *  fill the @a s array without setting failbit.

       *

       *  -# the input sequence reaches end-of-file, in which case eofbit

       *     is set in the stream error state

       *  -# the next character equals @c delim, in which case the character

       *     is extracted (and therefore counted in @c gcount()) but not stored

       *  -# @c n-1 characters are stored, in which case failbit is set

       *     in the stream error state

       *

       *  If no characters are extracted, failbit is set.  (An empty line of

       *  input should therefore not cause failbit to be set.)

       *

       *  In any case, a null character is stored in the next location in

       *  the array.

      */

      __istream_type& 

      getline(char_type* __s, streamsize __n, char_type __delim);

      /**

       *  @brief  String extraction.

       *  @param  s  A character array in which to store the data.

       *  @param  n  Maximum number of characters to extract.

       *  @return  *this

       *

       *  Returns @c getline(s,n,widen('\n')).

      */

      inline __istream_type& 

      getline(char_type* __s, streamsize __n)

      { return this->getline(__s, __n, this->widen('\n')); }

      /**

       *  @brief  Discarding characters

       *  @param  n  Number of characters to discard.

       *  @param  delim  A "stop" character.

       *  @return  *this

       *

       *  Extracts characters and throws them away until one of the

       *  following happens:

       *  - if @a n @c != @c std::numeric_limits<int>::max(), @a n

       *    characters are extracted

       *  - the input sequence reaches end-of-file

       *  - the next character equals @a delim (in this case, the character

       *    is extracted); note that this condition will never occur if

       *    @a delim equals @c traits::eof().

      */

      __istream_type& 

      ignore(streamsize __n = 1, int_type __delim = traits_type::eof());

      /**

       *  @brief  Looking ahead in the stream

       *  @return  The next character, or eof().

       *

       *  If, after constructing the sentry object, @c good() is false,

       *  returns @c traits::eof().  Otherwise reads but does not extract

       *  the next input character.

      */

      int_type 

      peek();

      /**

       *  @brief  Extraction without delimiters.

       *  @param  s  A character array.

       *  @param  n  Maximum number of characters to store.

       *  @return  *this

       *

       *  If the stream state is @c good(), extracts characters and stores

       *  them into @a s until one of the following happens:

       *  - @a n characters are stored

       *  - the input sequence reaches end-of-file, in which case the error

       *    state is set to @c failbit|eofbit.

       *

       *  @note  This function is not overloaded on signed char and

       *         unsigned char.

      */

      __istream_type& 

      read(char_type* __s, streamsize __n);

      /**

       *  @brief  Extraction until the buffer is exhausted, but no more.

       *  @param  s  A character array.

       *  @param  n  Maximum number of characters to store.

       *  @return  The number of characters extracted.

       *

       *  Extracts characters and stores them into @a s depending on the

       *  number of characters remaining in the streambuf's buffer,

       *  @c rdbuf()->in_avail(), called @c A here:

       *  - if @c A @c == @c -1, sets eofbit and extracts no characters

       *  - if @c A @c == @c 0, extracts no characters

       *  - if @c A @c > @c 0, extracts @c min(A,n)

       *

       *  The goal is to empty the current buffer, and to not request any

       *  more from the external input sequence controlled by the streambuf.

      */

      streamsize 

      readsome(char_type* __s, streamsize __n);

      /**

       *  @brief  Unextracting a single character.

       *  @param  c  The character to push back into the input stream.

       *  @return  *this

       *

       *  If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c).

       *

       *  If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in

       *  the error state.

       *

       *  @note  Since no characters are extracted, the next call to

       *         @c gcount() will return 0, as required by DR 60.

      */

      __istream_type& 

      putback(char_type __c);

      /**

       *  @brief  Unextracting the previous character.

       *  @return  *this

       *

       *  If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c).

       *

       *  If @c rdbuf() is null or if @c sungetc() fails, sets badbit in

       *  the error state.

       *

       *  @note  Since no characters are extracted, the next call to

       *         @c gcount() will return 0, as required by DR 60.

      */

      __istream_type& 

      unget();

      /**

       *  @brief  Synchronizing the stream buffer.

       *  @return  0 on success, -1 on failure

       *

       *  If @c rdbuf() is a null pointer, returns -1.

       *

       *  Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,

       *  sets badbit and returns -1.

       *

       *  Otherwise, returns 0.

       *

       *  @note  This function does not count the number of characters

       *         extracted, if any, and therefore does not affect the next

       *         call to @c gcount().

      */

      int 

      sync();

      /**

       *  @brief  Getting the current read position.

       *  @return  A file position object.

       *

       *  If @c fail() is not false, returns @c pos_type(-1) to indicate

       *  failure.  Otherwise returns @c rdbuf()->pubseekoff(0,cur,in).

       *

       *  @note  This function does not count the number of characters

       *         extracted, if any, and therefore does not affect the next

       *         call to @c gcount().

      */

      pos_type 

      tellg();