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Diffstat (limited to 'libstdc++-v3/include/std/istream')
| -rw-r--r-- | libstdc++-v3/include/std/istream | 861 |
1 files changed, 861 insertions, 0 deletions
diff --git a/libstdc++-v3/include/std/istream b/libstdc++-v3/include/std/istream new file mode 100644 index 000000000..fb393921f --- /dev/null +++ b/libstdc++-v3/include/std/istream @@ -0,0 +1,861 @@ +// Input streams -*- C++ -*- + +// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, +// 2006, 2007, 2008, 2009, 2010, 2011 +// 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 3, 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. + +// Under Section 7 of GPL version 3, you are granted additional +// permissions described in the GCC Runtime Library Exception, version +// 3.1, as published by the Free Software Foundation. + +// You should have received a copy of the GNU General Public License and +// a copy of the GCC Runtime Library Exception along with this program; +// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +// <http://www.gnu.org/licenses/>. + +// +// ISO C++ 14882: 27.6.1 Input streams +// + +/** @file include/istream + * This is a Standard C++ Library header. + */ + +#ifndef _GLIBCXX_ISTREAM +#define _GLIBCXX_ISTREAM 1 + +#pragma GCC system_header + +#include <ios> +#include <ostream> + +namespace std _GLIBCXX_VISIBILITY(default) +{ +_GLIBCXX_BEGIN_NAMESPACE_VERSION + + // [27.6.1.1] Template class basic_istream + /** + * @brief Controlling input. + * @ingroup io + * + * 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. + */ + 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. + * + * Manipulators such as @c std::ws and @c std::dec use these + * functions in constructs like + * <code>std::cin >> std::ws</code>. + * 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. + */ + 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')). + */ + __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_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 This function first clears eofbit. 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 This function first clears eofbit. 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(). At variance with putback, unget and + * seekg, eofbit is not cleared first. + */ + pos_type + tellg(); + + /** + * @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 first clears eofbit. It 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 first clears eofbit. It 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_T + template<> + 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 <em>exception-safe + * prefix and suffix operations,</em> although only prefix actions + * are currently required by the standard. + */ + template<typename _CharT, typename _Traits> + class basic_istream<_CharT, _Traits>::sentry + { + // Data Members. + bool _M_ok; + + 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 (<em>not okay</em>) 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 (@a okay). + */ + explicit + sentry(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). + */ +#ifdef __GXX_EXPERIMENTAL_CXX0X__ + explicit +#endif + operator bool() const + { return _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 <em>the number of elements of the largest array of * + * - @c char_type that can store a terminating @c eos.</em> + * - [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. + * @ingroup io + * + * 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. + */ + explicit + basic_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); + +#ifdef __GXX_EXPERIMENTAL_CXX0X__ + // [27.7.1.6] Rvalue stream extraction + /** + * @brief Generic extractor for rvalue stream + * @param is An input stream. + * @param x A reference to the extraction target. + * @return is + * + * This is just a forwarding function to allow extraction from + * rvalue streams since they won't bind to the extractor functions + * that take an lvalue reference. + */ + template<typename _CharT, typename _Traits, typename _Tp> + inline basic_istream<_CharT, _Traits>& + operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x) + { return (__is >> __x); } +#endif // __GXX_EXPERIMENTAL_CXX0X__ + +_GLIBCXX_END_NAMESPACE_VERSION +} // namespace + +#include <bits/istream.tcc> + +#endif /* _GLIBCXX_ISTREAM */ |