| // Stream buffer classes -*- C++ -*- |
| |
| // Copyright (C) 1997-2014 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/>. |
| |
| /** @file include/streambuf |
| * This is a Standard C++ Library header. |
| */ |
| |
| // |
| // ISO C++ 14882: 27.5 Stream buffers |
| // |
| |
| #ifndef _GLIBXX_STREAMBUF |
| #define _GLIBXX_STREAMBUF 1 |
| |
| #pragma GCC system_header |
| |
| #include <bits/c++config.h> |
| #include <iosfwd> |
| #include <bits/localefwd.h> |
| #include <bits/ios_base.h> |
| #include <bits/cpp_type_traits.h> |
| #include <ext/type_traits.h> |
| |
| namespace std _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| template<typename _CharT, typename _Traits> |
| streamsize |
| __copy_streambufs_eof(basic_streambuf<_CharT, _Traits>*, |
| basic_streambuf<_CharT, _Traits>*, bool&); |
| |
| /** |
| * @brief The actual work of input and output (interface). |
| * @ingroup io |
| * |
| * @tparam _CharT Type of character stream. |
| * @tparam _Traits Traits for character type, defaults to |
| * char_traits<_CharT>. |
| * |
| * This is a base class. Derived stream buffers each control a |
| * pair of character sequences: one for input, and one for output. |
| * |
| * Section [27.5.1] of the standard describes the requirements and |
| * behavior of stream buffer classes. That section (three paragraphs) |
| * is reproduced here, for simplicity and accuracy. |
| * |
| * -# Stream buffers can impose various constraints on the sequences |
| * they control. Some constraints are: |
| * - The controlled input sequence can be not readable. |
| * - The controlled output sequence can be not writable. |
| * - The controlled sequences can be associated with the contents of |
| * other representations for character sequences, such as external |
| * files. |
| * - The controlled sequences can support operations @e directly to or |
| * from associated sequences. |
| * - The controlled sequences can impose limitations on how the |
| * program can read characters from a sequence, write characters to |
| * a sequence, put characters back into an input sequence, or alter |
| * the stream position. |
| * . |
| * -# Each sequence is characterized by three pointers which, if non-null, |
| * all point into the same @c charT array object. The array object |
| * represents, at any moment, a (sub)sequence of characters from the |
| * sequence. Operations performed on a sequence alter the values |
| * stored in these pointers, perform reads and writes directly to or |
| * from associated sequences, and alter <em>the stream position</em> and |
| * conversion state as needed to maintain this subsequence relationship. |
| * The three pointers are: |
| * - the <em>beginning pointer</em>, or lowest element address in the |
| * array (called @e xbeg here); |
| * - the <em>next pointer</em>, or next element address that is a |
| * current candidate for reading or writing (called @e xnext here); |
| * - the <em>end pointer</em>, or first element address beyond the |
| * end of the array (called @e xend here). |
| * . |
| * -# The following semantic constraints shall always apply for any set |
| * of three pointers for a sequence, using the pointer names given |
| * immediately above: |
| * - If @e xnext is not a null pointer, then @e xbeg and @e xend shall |
| * also be non-null pointers into the same @c charT array, as |
| * described above; otherwise, @e xbeg and @e xend shall also be null. |
| * - If @e xnext is not a null pointer and @e xnext < @e xend for an |
| * output sequence, then a <em>write position</em> is available. |
| * In this case, @e *xnext shall be assignable as the next element |
| * to write (to put, or to store a character value, into the sequence). |
| * - If @e xnext is not a null pointer and @e xbeg < @e xnext for an |
| * input sequence, then a <em>putback position</em> is available. |
| * In this case, @e xnext[-1] shall have a defined value and is the |
| * next (preceding) element to store a character that is put back |
| * into the input sequence. |
| * - If @e xnext is not a null pointer and @e xnext< @e xend for an |
| * input sequence, then a <em>read position</em> is available. |
| * In this case, @e *xnext shall have a defined value and is the |
| * next element to read (to get, or to obtain a character value, |
| * from the sequence). |
| */ |
| template<typename _CharT, typename _Traits> |
| class basic_streambuf |
| { |
| public: |
| //@{ |
| /** |
| * These are standard types. They permit a standardized way of |
| * referring to names of (or names dependent on) the template |
| * parameters, which are specific to the implementation. |
| */ |
| typedef _CharT char_type; |
| typedef _Traits traits_type; |
| typedef typename traits_type::int_type int_type; |
| typedef typename traits_type::pos_type pos_type; |
| typedef typename traits_type::off_type off_type; |
| //@} |
| |
| //@{ |
| /// This is a non-standard type. |
| typedef basic_streambuf<char_type, traits_type> __streambuf_type; |
| //@} |
| |
| friend class basic_ios<char_type, traits_type>; |
| friend class basic_istream<char_type, traits_type>; |
| friend class basic_ostream<char_type, traits_type>; |
| friend class istreambuf_iterator<char_type, traits_type>; |
| friend class ostreambuf_iterator<char_type, traits_type>; |
| |
| friend streamsize |
| __copy_streambufs_eof<>(basic_streambuf*, basic_streambuf*, bool&); |
| |
| template<bool _IsMove, typename _CharT2> |
| friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, |
| _CharT2*>::__type |
| __copy_move_a2(istreambuf_iterator<_CharT2>, |
| istreambuf_iterator<_CharT2>, _CharT2*); |
| |
| template<typename _CharT2> |
| friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, |
| istreambuf_iterator<_CharT2> >::__type |
| find(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>, |
| const _CharT2&); |
| |
| template<typename _CharT2, typename _Traits2> |
| friend basic_istream<_CharT2, _Traits2>& |
| operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2*); |
| |
| template<typename _CharT2, typename _Traits2, typename _Alloc> |
| friend basic_istream<_CharT2, _Traits2>& |
| operator>>(basic_istream<_CharT2, _Traits2>&, |
| basic_string<_CharT2, _Traits2, _Alloc>&); |
| |
| template<typename _CharT2, typename _Traits2, typename _Alloc> |
| friend basic_istream<_CharT2, _Traits2>& |
| getline(basic_istream<_CharT2, _Traits2>&, |
| basic_string<_CharT2, _Traits2, _Alloc>&, _CharT2); |
| |
| protected: |
| /* |
| * This is based on _IO_FILE, just reordered to be more consistent, |
| * and is intended to be the most minimal abstraction for an |
| * internal buffer. |
| * - get == input == read |
| * - put == output == write |
| */ |
| char_type* _M_in_beg; ///< Start of get area. |
| char_type* _M_in_cur; ///< Current read area. |
| char_type* _M_in_end; ///< End of get area. |
| char_type* _M_out_beg; ///< Start of put area. |
| char_type* _M_out_cur; ///< Current put area. |
| char_type* _M_out_end; ///< End of put area. |
| |
| /// Current locale setting. |
| locale _M_buf_locale; |
| |
| public: |
| /// Destructor deallocates no buffer space. |
| virtual |
| ~basic_streambuf() |
| { } |
| |
| // [27.5.2.2.1] locales |
| /** |
| * @brief Entry point for imbue(). |
| * @param __loc The new locale. |
| * @return The previous locale. |
| * |
| * Calls the derived imbue(__loc). |
| */ |
| locale |
| pubimbue(const locale& __loc) |
| { |
| locale __tmp(this->getloc()); |
| this->imbue(__loc); |
| _M_buf_locale = __loc; |
| return __tmp; |
| } |
| |
| /** |
| * @brief Locale access. |
| * @return The current locale in effect. |
| * |
| * If pubimbue(loc) has been called, then the most recent @c loc |
| * is returned. Otherwise the global locale in effect at the time |
| * of construction is returned. |
| */ |
| locale |
| getloc() const |
| { return _M_buf_locale; } |
| |
| // [27.5.2.2.2] buffer management and positioning |
| //@{ |
| /** |
| * @brief Entry points for derived buffer functions. |
| * |
| * The public versions of @c pubfoo dispatch to the protected |
| * derived @c foo member functions, passing the arguments (if any) |
| * and returning the result unchanged. |
| */ |
| basic_streambuf* |
| pubsetbuf(char_type* __s, streamsize __n) |
| { return this->setbuf(__s, __n); } |
| |
| /** |
| * @brief Alters the stream position. |
| * @param __off Offset. |
| * @param __way Value for ios_base::seekdir. |
| * @param __mode Value for ios_base::openmode. |
| * |
| * Calls virtual seekoff function. |
| */ |
| pos_type |
| pubseekoff(off_type __off, ios_base::seekdir __way, |
| ios_base::openmode __mode = ios_base::in | ios_base::out) |
| { return this->seekoff(__off, __way, __mode); } |
| |
| /** |
| * @brief Alters the stream position. |
| * @param __sp Position |
| * @param __mode Value for ios_base::openmode. |
| * |
| * Calls virtual seekpos function. |
| */ |
| pos_type |
| pubseekpos(pos_type __sp, |
| ios_base::openmode __mode = ios_base::in | ios_base::out) |
| { return this->seekpos(__sp, __mode); } |
| |
| /** |
| * @brief Calls virtual sync function. |
| */ |
| int |
| pubsync() { return this->sync(); } |
| //@} |
| |
| // [27.5.2.2.3] get area |
| /** |
| * @brief Looking ahead into the stream. |
| * @return The number of characters available. |
| * |
| * If a read position is available, returns the number of characters |
| * available for reading before the buffer must be refilled. |
| * Otherwise returns the derived @c showmanyc(). |
| */ |
| streamsize |
| in_avail() |
| { |
| const streamsize __ret = this->egptr() - this->gptr(); |
| return __ret ? __ret : this->showmanyc(); |
| } |
| |
| /** |
| * @brief Getting the next character. |
| * @return The next character, or eof. |
| * |
| * Calls @c sbumpc(), and if that function returns |
| * @c traits::eof(), so does this function. Otherwise, @c sgetc(). |
| */ |
| int_type |
| snextc() |
| { |
| int_type __ret = traits_type::eof(); |
| if (__builtin_expect(!traits_type::eq_int_type(this->sbumpc(), |
| __ret), true)) |
| __ret = this->sgetc(); |
| return __ret; |
| } |
| |
| /** |
| * @brief Getting the next character. |
| * @return The next character, or eof. |
| * |
| * If the input read position is available, returns that character |
| * and increments the read pointer, otherwise calls and returns |
| * @c uflow(). |
| */ |
| int_type |
| sbumpc() |
| { |
| int_type __ret; |
| if (__builtin_expect(this->gptr() < this->egptr(), true)) |
| { |
| __ret = traits_type::to_int_type(*this->gptr()); |
| this->gbump(1); |
| } |
| else |
| __ret = this->uflow(); |
| return __ret; |
| } |
| |
| /** |
| * @brief Getting the next character. |
| * @return The next character, or eof. |
| * |
| * If the input read position is available, returns that character, |
| * otherwise calls and returns @c underflow(). Does not move the |
| * read position after fetching the character. |
| */ |
| int_type |
| sgetc() |
| { |
| int_type __ret; |
| if (__builtin_expect(this->gptr() < this->egptr(), true)) |
| __ret = traits_type::to_int_type(*this->gptr()); |
| else |
| __ret = this->underflow(); |
| return __ret; |
| } |
| |
| /** |
| * @brief Entry point for xsgetn. |
| * @param __s A buffer area. |
| * @param __n A count. |
| * |
| * Returns xsgetn(__s,__n). The effect is to fill @a __s[0] through |
| * @a __s[__n-1] with characters from the input sequence, if possible. |
| */ |
| streamsize |
| sgetn(char_type* __s, streamsize __n) |
| { return this->xsgetn(__s, __n); } |
| |
| // [27.5.2.2.4] putback |
| /** |
| * @brief Pushing characters back into the input stream. |
| * @param __c The character to push back. |
| * @return The previous character, if possible. |
| * |
| * Similar to sungetc(), but @a __c is pushed onto the stream |
| * instead of <em>the previous character.</em> If successful, |
| * the next character fetched from the input stream will be @a |
| * __c. |
| */ |
| int_type |
| sputbackc(char_type __c) |
| { |
| int_type __ret; |
| const bool __testpos = this->eback() < this->gptr(); |
| if (__builtin_expect(!__testpos || |
| !traits_type::eq(__c, this->gptr()[-1]), false)) |
| __ret = this->pbackfail(traits_type::to_int_type(__c)); |
| else |
| { |
| this->gbump(-1); |
| __ret = traits_type::to_int_type(*this->gptr()); |
| } |
| return __ret; |
| } |
| |
| /** |
| * @brief Moving backwards in the input stream. |
| * @return The previous character, if possible. |
| * |
| * If a putback position is available, this function decrements |
| * the input pointer and returns that character. Otherwise, |
| * calls and returns pbackfail(). The effect is to @a unget |
| * the last character @a gotten. |
| */ |
| int_type |
| sungetc() |
| { |
| int_type __ret; |
| if (__builtin_expect(this->eback() < this->gptr(), true)) |
| { |
| this->gbump(-1); |
| __ret = traits_type::to_int_type(*this->gptr()); |
| } |
| else |
| __ret = this->pbackfail(); |
| return __ret; |
| } |
| |
| // [27.5.2.2.5] put area |
| /** |
| * @brief Entry point for all single-character output functions. |
| * @param __c A character to output. |
| * @return @a __c, if possible. |
| * |
| * One of two public output functions. |
| * |
| * If a write position is available for the output sequence (i.e., |
| * the buffer is not full), stores @a __c in that position, increments |
| * the position, and returns @c traits::to_int_type(__c). If a write |
| * position is not available, returns @c overflow(__c). |
| */ |
| int_type |
| sputc(char_type __c) |
| { |
| int_type __ret; |
| if (__builtin_expect(this->pptr() < this->epptr(), true)) |
| { |
| *this->pptr() = __c; |
| this->pbump(1); |
| __ret = traits_type::to_int_type(__c); |
| } |
| else |
| __ret = this->overflow(traits_type::to_int_type(__c)); |
| return __ret; |
| } |
| |
| /** |
| * @brief Entry point for all single-character output functions. |
| * @param __s A buffer read area. |
| * @param __n A count. |
| * |
| * One of two public output functions. |
| * |
| * |
| * Returns xsputn(__s,__n). The effect is to write @a __s[0] through |
| * @a __s[__n-1] to the output sequence, if possible. |
| */ |
| streamsize |
| sputn(const char_type* __s, streamsize __n) |
| { return this->xsputn(__s, __n); } |
| |
| protected: |
| /** |
| * @brief Base constructor. |
| * |
| * Only called from derived constructors, and sets up all the |
| * buffer data to zero, including the pointers described in the |
| * basic_streambuf class description. Note that, as a result, |
| * - the class starts with no read nor write positions available, |
| * - this is not an error |
| */ |
| basic_streambuf() |
| : _M_in_beg(0), _M_in_cur(0), _M_in_end(0), |
| _M_out_beg(0), _M_out_cur(0), _M_out_end(0), |
| _M_buf_locale(locale()) |
| { } |
| |
| // [27.5.2.3.1] get area access |
| //@{ |
| /** |
| * @brief Access to the get area. |
| * |
| * These functions are only available to other protected functions, |
| * including derived classes. |
| * |
| * - eback() returns the beginning pointer for the input sequence |
| * - gptr() returns the next pointer for the input sequence |
| * - egptr() returns the end pointer for the input sequence |
| */ |
| char_type* |
| eback() const { return _M_in_beg; } |
| |
| char_type* |
| gptr() const { return _M_in_cur; } |
| |
| char_type* |
| egptr() const { return _M_in_end; } |
| //@} |
| |
| /** |
| * @brief Moving the read position. |
| * @param __n The delta by which to move. |
| * |
| * This just advances the read position without returning any data. |
| */ |
| void |
| gbump(int __n) { _M_in_cur += __n; } |
| |
| /** |
| * @brief Setting the three read area pointers. |
| * @param __gbeg A pointer. |
| * @param __gnext A pointer. |
| * @param __gend A pointer. |
| * @post @a __gbeg == @c eback(), @a __gnext == @c gptr(), and |
| * @a __gend == @c egptr() |
| */ |
| void |
| setg(char_type* __gbeg, char_type* __gnext, char_type* __gend) |
| { |
| _M_in_beg = __gbeg; |
| _M_in_cur = __gnext; |
| _M_in_end = __gend; |
| } |
| |
| // [27.5.2.3.2] put area access |
| //@{ |
| /** |
| * @brief Access to the put area. |
| * |
| * These functions are only available to other protected functions, |
| * including derived classes. |
| * |
| * - pbase() returns the beginning pointer for the output sequence |
| * - pptr() returns the next pointer for the output sequence |
| * - epptr() returns the end pointer for the output sequence |
| */ |
| char_type* |
| pbase() const { return _M_out_beg; } |
| |
| char_type* |
| pptr() const { return _M_out_cur; } |
| |
| char_type* |
| epptr() const { return _M_out_end; } |
| //@} |
| |
| /** |
| * @brief Moving the write position. |
| * @param __n The delta by which to move. |
| * |
| * This just advances the write position without returning any data. |
| */ |
| void |
| pbump(int __n) { _M_out_cur += __n; } |
| |
| /** |
| * @brief Setting the three write area pointers. |
| * @param __pbeg A pointer. |
| * @param __pend A pointer. |
| * @post @a __pbeg == @c pbase(), @a __pbeg == @c pptr(), and |
| * @a __pend == @c epptr() |
| */ |
| void |
| setp(char_type* __pbeg, char_type* __pend) |
| { |
| _M_out_beg = _M_out_cur = __pbeg; |
| _M_out_end = __pend; |
| } |
| |
| // [27.5.2.4] virtual functions |
| // [27.5.2.4.1] locales |
| /** |
| * @brief Changes translations. |
| * @param __loc A new locale. |
| * |
| * Translations done during I/O which depend on the current |
| * locale are changed by this call. The standard adds, |
| * <em>Between invocations of this function a class derived |
| * from streambuf can safely cache results of calls to locale |
| * functions and to members of facets so obtained.</em> |
| * |
| * @note Base class version does nothing. |
| */ |
| virtual void |
| imbue(const locale& __loc) |
| { } |
| |
| // [27.5.2.4.2] buffer management and positioning |
| /** |
| * @brief Manipulates the buffer. |
| * |
| * Each derived class provides its own appropriate behavior. See |
| * the next-to-last paragraph of |
| * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html |
| * for more on this function. |
| * |
| * @note Base class version does nothing, returns @c this. |
| */ |
| virtual basic_streambuf<char_type,_Traits>* |
| setbuf(char_type*, streamsize) |
| { return this; } |
| |
| /** |
| * @brief Alters the stream positions. |
| * |
| * Each derived class provides its own appropriate behavior. |
| * @note Base class version does nothing, returns a @c pos_type |
| * that represents an invalid stream position. |
| */ |
| virtual pos_type |
| seekoff(off_type, ios_base::seekdir, |
| ios_base::openmode /*__mode*/ = ios_base::in | ios_base::out) |
| { return pos_type(off_type(-1)); } |
| |
| /** |
| * @brief Alters the stream positions. |
| * |
| * Each derived class provides its own appropriate behavior. |
| * @note Base class version does nothing, returns a @c pos_type |
| * that represents an invalid stream position. |
| */ |
| virtual pos_type |
| seekpos(pos_type, |
| ios_base::openmode /*__mode*/ = ios_base::in | ios_base::out) |
| { return pos_type(off_type(-1)); } |
| |
| /** |
| * @brief Synchronizes the buffer arrays with the controlled sequences. |
| * @return -1 on failure. |
| * |
| * Each derived class provides its own appropriate behavior, |
| * including the definition of @a failure. |
| * @note Base class version does nothing, returns zero. |
| */ |
| virtual int |
| sync() { return 0; } |
| |
| // [27.5.2.4.3] get area |
| /** |
| * @brief Investigating the data available. |
| * @return An estimate of the number of characters available in the |
| * input sequence, or -1. |
| * |
| * <em>If it returns a positive value, then successive calls to |
| * @c underflow() will not return @c traits::eof() until at |
| * least that number of characters have been supplied. If @c |
| * showmanyc() returns -1, then calls to @c underflow() or @c |
| * uflow() will fail.</em> [27.5.2.4.3]/1 |
| * |
| * @note Base class version does nothing, returns zero. |
| * @note The standard adds that <em>the intention is not only that the |
| * calls [to underflow or uflow] will not return @c eof() but |
| * that they will return immediately.</em> |
| * @note The standard adds that <em>the morphemes of @c showmanyc are |
| * @b es-how-many-see, not @b show-manic.</em> |
| */ |
| virtual streamsize |
| showmanyc() { return 0; } |
| |
| /** |
| * @brief Multiple character extraction. |
| * @param __s A buffer area. |
| * @param __n Maximum number of characters to assign. |
| * @return The number of characters assigned. |
| * |
| * Fills @a __s[0] through @a __s[__n-1] with characters from the input |
| * sequence, as if by @c sbumpc(). Stops when either @a __n characters |
| * have been copied, or when @c traits::eof() would be copied. |
| * |
| * It is expected that derived classes provide a more efficient |
| * implementation by overriding this definition. |
| */ |
| virtual streamsize |
| xsgetn(char_type* __s, streamsize __n); |
| |
| /** |
| * @brief Fetches more data from the controlled sequence. |
| * @return The first character from the <em>pending sequence</em>. |
| * |
| * Informally, this function is called when the input buffer is |
| * exhausted (or does not exist, as buffering need not actually be |
| * done). If a buffer exists, it is @a refilled. In either case, the |
| * next available character is returned, or @c traits::eof() to |
| * indicate a null pending sequence. |
| * |
| * For a formal definition of the pending sequence, see a good text |
| * such as Langer & Kreft, or [27.5.2.4.3]/7-14. |
| * |
| * A functioning input streambuf can be created by overriding only |
| * this function (no buffer area will be used). For an example, see |
| * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25.html |
| * |
| * @note Base class version does nothing, returns eof(). |
| */ |
| virtual int_type |
| underflow() |
| { return traits_type::eof(); } |
| |
| /** |
| * @brief Fetches more data from the controlled sequence. |
| * @return The first character from the <em>pending sequence</em>. |
| * |
| * Informally, this function does the same thing as @c underflow(), |
| * and in fact is required to call that function. It also returns |
| * the new character, like @c underflow() does. However, this |
| * function also moves the read position forward by one. |
| */ |
| virtual int_type |
| uflow() |
| { |
| int_type __ret = traits_type::eof(); |
| const bool __testeof = traits_type::eq_int_type(this->underflow(), |
| __ret); |
| if (!__testeof) |
| { |
| __ret = traits_type::to_int_type(*this->gptr()); |
| this->gbump(1); |
| } |
| return __ret; |
| } |
| |
| // [27.5.2.4.4] putback |
| /** |
| * @brief Tries to back up the input sequence. |
| * @param __c The character to be inserted back into the sequence. |
| * @return eof() on failure, <em>some other value</em> on success |
| * @post The constraints of @c gptr(), @c eback(), and @c pptr() |
| * are the same as for @c underflow(). |
| * |
| * @note Base class version does nothing, returns eof(). |
| */ |
| virtual int_type |
| pbackfail(int_type __c = traits_type::eof()) |
| { return traits_type::eof(); } |
| |
| // Put area: |
| /** |
| * @brief Multiple character insertion. |
| * @param __s A buffer area. |
| * @param __n Maximum number of characters to write. |
| * @return The number of characters written. |
| * |
| * Writes @a __s[0] through @a __s[__n-1] to the output sequence, as if |
| * by @c sputc(). Stops when either @a n characters have been |
| * copied, or when @c sputc() would return @c traits::eof(). |
| * |
| * It is expected that derived classes provide a more efficient |
| * implementation by overriding this definition. |
| */ |
| virtual streamsize |
| xsputn(const char_type* __s, streamsize __n); |
| |
| /** |
| * @brief Consumes data from the buffer; writes to the |
| * controlled sequence. |
| * @param __c An additional character to consume. |
| * @return eof() to indicate failure, something else (usually |
| * @a __c, or not_eof()) |
| * |
| * Informally, this function is called when the output buffer |
| * is full (or does not exist, as buffering need not actually |
| * be done). If a buffer exists, it is @a consumed, with |
| * <em>some effect</em> on the controlled sequence. |
| * (Typically, the buffer is written out to the sequence |
| * verbatim.) In either case, the character @a c is also |
| * written out, if @a __c is not @c eof(). |
| * |
| * For a formal definition of this function, see a good text |
| * such as Langer & Kreft, or [27.5.2.4.5]/3-7. |
| * |
| * A functioning output streambuf can be created by overriding only |
| * this function (no buffer area will be used). |
| * |
| * @note Base class version does nothing, returns eof(). |
| */ |
| virtual int_type |
| overflow(int_type __c = traits_type::eof()) |
| { return traits_type::eof(); } |
| |
| #if _GLIBCXX_USE_DEPRECATED |
| // Annex D.6 |
| public: |
| /** |
| * @brief Tosses a character. |
| * |
| * Advances the read pointer, ignoring the character that would have |
| * been read. |
| * |
| * See http://gcc.gnu.org/ml/libstdc++/2002-05/msg00168.html |
| */ |
| void |
| stossc() |
| { |
| if (this->gptr() < this->egptr()) |
| this->gbump(1); |
| else |
| this->uflow(); |
| } |
| #endif |
| |
| // Also used by specializations for char and wchar_t in src. |
| void |
| __safe_gbump(streamsize __n) { _M_in_cur += __n; } |
| |
| void |
| __safe_pbump(streamsize __n) { _M_out_cur += __n; } |
| |
| private: |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // Side effect of DR 50. |
| basic_streambuf(const basic_streambuf& __sb) |
| : _M_in_beg(__sb._M_in_beg), _M_in_cur(__sb._M_in_cur), |
| _M_in_end(__sb._M_in_end), _M_out_beg(__sb._M_out_beg), |
| _M_out_cur(__sb._M_out_cur), _M_out_end(__sb._M_out_cur), |
| _M_buf_locale(__sb._M_buf_locale) |
| { } |
| |
| basic_streambuf& |
| operator=(const basic_streambuf&) { return *this; }; |
| }; |
| |
| // Explicit specialization declarations, defined in src/streambuf.cc. |
| template<> |
| streamsize |
| __copy_streambufs_eof(basic_streambuf<char>* __sbin, |
| basic_streambuf<char>* __sbout, bool& __ineof); |
| #ifdef _GLIBCXX_USE_WCHAR_T |
| template<> |
| streamsize |
| __copy_streambufs_eof(basic_streambuf<wchar_t>* __sbin, |
| basic_streambuf<wchar_t>* __sbout, bool& __ineof); |
| #endif |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace |
| |
| #include <bits/streambuf.tcc> |
| |
| #endif /* _GLIBCXX_STREAMBUF */ |
