// Input streams -*- C++ -*-// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,// 2006, 2007, 2008// 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: 27.6.1 Input streams///** @file istream* This is a Standard C++ Library header.*/#ifndef _GLIBCXX_ISTREAM#define _GLIBCXX_ISTREAM 1#pragma GCC system_header#include <ios>#include <ostream>_GLIBCXX_BEGIN_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;protected:// Data Members:/*** The number of characters extracted in the previous unformatted* function; see gcount().*/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.*/explicitbasic_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/suffixclass sentry;friend class sentry;// [27.6.1.2] formatted input// [27.6.1.2.3] basic_istream::operator>>//@{/*** @brief Interface for manipulators.** Manipulators 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.*/__istream_type&operator>>(__istream_type& (*__pf)(__istream_type&)){ return __pf(*this); }__istream_type&operator>>(__ios_type& (*__pf)(__ios_type&)){__pf(*this);return *this;}__istream_type&operator>>(ios_base& (*__pf)(ios_base&)){__pf(*this);return *this;}//@}// [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){ return _M_extract(__n); }__istream_type&operator>>(short& __n);__istream_type&operator>>(unsigned short& __n){ return _M_extract(__n); }__istream_type&operator>>(int& __n);__istream_type&operator>>(unsigned int& __n){ return _M_extract(__n); }__istream_type&operator>>(long& __n){ return _M_extract(__n); }__istream_type&operator>>(unsigned long& __n){ return _M_extract(__n); }#ifdef _GLIBCXX_USE_LONG_LONG__istream_type&operator>>(long long& __n){ return _M_extract(__n); }__istream_type&operator>>(unsigned long long& __n){ return _M_extract(__n); }#endif__istream_type&operator>>(float& __f){ return _M_extract(__f); }__istream_type&operator>>(double& __f){ return _M_extract(__f); }__istream_type&operator>>(long double& __f){ return _M_extract(__f); }__istream_type&operator>>(void*& __p){ return _M_extract(__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.*/streamsizegcount() 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_typeget();/*** @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')).*/__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')).*/__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')).*/__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().** NB: Provide three overloads, instead of the single function* (with defaults) mandated by the Standard: this leads to a* better performing implementation, while still conforming to* the Standard.*/__istream_type&ignore();__istream_type&ignore(streamsize __n);__istream_type&ignore(streamsize __n, int_type __delim);/*** @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_typepeek();/*** @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.*/streamsizereadsome(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().*/intsync();/*** @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_typetellg();/*** @brief Changing the current read position.* @param pos A file position object.* @return *this** If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If* that function fails, sets failbit.** @note This function does not count the number of characters* extracted, if any, and therefore does not affect the next* call to @c gcount().*/__istream_type&seekg(pos_type);/*** @brief Changing the current read position.* @param off A file offset object.* @param dir The direction in which to seek.* @return *this** If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).* If that function fails, sets failbit.** @note This function does not count the number of characters* extracted, if any, and therefore does not affect the next* call to @c gcount().*/__istream_type&seekg(off_type, ios_base::seekdir);//@}protected:basic_istream(): _M_gcount(streamsize(0)){ this->init(0); }template<typename _ValueT>__istream_type&_M_extract(_ValueT& __v);};// Explicit specialization declarations, defined in src/istream.cc.template<>basic_istream<char>&basic_istream<char>::getline(char_type* __s, streamsize __n, char_type __delim);template<>basic_istream<char>&basic_istream<char>::ignore(streamsize __n);template<>basic_istream<char>&basic_istream<char>::ignore(streamsize __n, int_type __delim);#ifdef _GLIBCXX_USE_WCHAR_Ttemplate<>basic_istream<wchar_t>&basic_istream<wchar_t>::getline(char_type* __s, streamsize __n, char_type __delim);template<>basic_istream<wchar_t>&basic_istream<wchar_t>::ignore(streamsize __n);template<>basic_istream<wchar_t>&basic_istream<wchar_t>::ignore(streamsize __n, int_type __delim);#endif/*** @brief Performs setup work for input streams.** Objects of this class are created before all of the standard* extractors are run. It is responsible for "exception-safe prefix and* suffix operations," although only prefix actions are currently required* by the standard.*/template<typename _CharT, typename _Traits>class basic_istream<_CharT, _Traits>::sentry{public:/// Easy access to dependant types.typedef _Traits traits_type;typedef basic_streambuf<_CharT, _Traits> __streambuf_type;typedef basic_istream<_CharT, _Traits> __istream_type;typedef typename __istream_type::__ctype_type __ctype_type;typedef typename _Traits::int_type __int_type;/*** @brief The constructor performs all the work.* @param is The input stream to guard.* @param noskipws Whether to consume whitespace or not.** If the stream state is good (@a is.good() is true), then the* following actions are performed, otherwise the sentry state is* false ("not okay") and failbit is set in the stream state.** The sentry's preparatory actions are:** -# if the stream is tied to an output stream, @c is.tie()->flush()* is called to synchronize the output sequence* -# if @a noskipws is false, and @c ios_base::skipws is set in* @c is.flags(), the sentry extracts and discards whitespace* characters from the stream. The currently imbued locale is* used to determine whether each character is whitespace.** If the stream state is still good, then the sentry state becomes* true ("okay").*/explicitsentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false);/*** @brief Quick status checking.* @return The sentry state.** For ease of use, sentries may be converted to booleans. The* return value is that of the sentry state (true == okay).*/operator bool() const{ return _M_ok; }private:bool _M_ok;};// [27.6.1.2.3] character extraction templates//@{/*** @brief Character extractors* @param in An input stream.* @param c A character reference.* @return in** Behaves like one of the formatted arithmetic extractors described in* std::basic_istream. After constructing a sentry object with good* status, this function extracts a character (if one is available) and* stores it in @a c. Otherwise, sets failbit in the input stream.*/template<typename _CharT, typename _Traits>basic_istream<_CharT, _Traits>&operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c);template<class _Traits>inline basic_istream<char, _Traits>&operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c){ return (__in >> reinterpret_cast<char&>(__c)); }template<class _Traits>inline basic_istream<char, _Traits>&operator>>(basic_istream<char, _Traits>& __in, signed char& __c){ return (__in >> reinterpret_cast<char&>(__c)); }//@}//@{/*** @brief Character string extractors* @param in An input stream.* @param s A pointer to a character array.* @return in** Behaves like one of the formatted arithmetic extractors described in* std::basic_istream. After constructing a sentry object with good* status, this function extracts up to @c n characters and stores them* into the array starting at @a s. @c n is defined as:** - if @c width() is greater than zero, @c n is width()* - otherwise @c n is "the number of elements of the largest array of* @c char_type that can store a terminating @c eos." [27.6.1.2.3]/6** Characters are extracted and stored until one of the following happens:* - @c n-1 characters are stored* - EOF is reached* - the next character is whitespace according to the current locale* - the next character is a null byte (i.e., @c charT() )** @c width(0) is then called for the input stream.** If no characters are extracted, sets failbit.*/template<typename _CharT, typename _Traits>basic_istream<_CharT, _Traits>&operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s);// Explicit specialization declaration, defined in src/istream.cc.template<>basic_istream<char>&operator>>(basic_istream<char>& __in, char* __s);template<class _Traits>inline basic_istream<char, _Traits>&operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s){ return (__in >> reinterpret_cast<char*>(__s)); }template<class _Traits>inline basic_istream<char, _Traits>&operator>>(basic_istream<char, _Traits>& __in, signed char* __s){ return (__in >> reinterpret_cast<char*>(__s)); }//@}// 27.6.1.5 Template class basic_iostream/*** @brief Merging istream and ostream capabilities.** This class multiply inherits from the input and output stream classes* simply to provide a single interface.*/template<typename _CharT, typename _Traits>class basic_iostream: public basic_istream<_CharT, _Traits>,public basic_ostream<_CharT, _Traits>{public:// _GLIBCXX_RESOLVE_LIB_DEFECTS// 271. basic_iostream missing typedefs// Types (inherited):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_istream<_CharT, _Traits> __istream_type;typedef basic_ostream<_CharT, _Traits> __ostream_type;/*** @brief Constructor does nothing.** Both of the parent classes are initialized with the same* streambuf pointer passed to this constructor.*/explicitbasic_iostream(basic_streambuf<_CharT, _Traits>* __sb): __istream_type(__sb), __ostream_type(__sb) { }/*** @brief Destructor does nothing.*/virtual~basic_iostream() { }protected:basic_iostream(): __istream_type(), __ostream_type() { }};// [27.6.1.4] standard basic_istream manipulators/*** @brief Quick and easy way to eat whitespace** This manipulator extracts whitespace characters, stopping when the* next character is non-whitespace, or when the input sequence is empty.* If the sequence is empty, @c eofbit is set in the stream, but not* @c failbit.** The current locale is used to distinguish whitespace characters.** Example:* @code* MyClass mc;** std::cin >> std::ws >> mc;* @endcode* will skip leading whitespace before calling operator>> on cin and your* object. Note that the same effect can be achieved by creating a* std::basic_istream::sentry inside your definition of operator>>.*/template<typename _CharT, typename _Traits>basic_istream<_CharT, _Traits>&ws(basic_istream<_CharT, _Traits>& __is);_GLIBCXX_END_NAMESPACE#ifndef _GLIBCXX_EXPORT_TEMPLATE# include <bits/istream.tcc>#endif#endif /* _GLIBCXX_ISTREAM */