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authorbkoz <bkoz@138bc75d-0d04-0410-961f-82ee72b054a4>2006-12-07 09:35:57 +0000
committerbkoz <bkoz@138bc75d-0d04-0410-961f-82ee72b054a4>2006-12-07 09:35:57 +0000
commit0fe3068e3b47285bb5c21d6b19cf76ededffc68f (patch)
tree076de9fd1585847daacdaac6c30b78058cce3aa0 /libstdc++-v3/include/std/streambuf
parent2f603cf0eb135bf67ff0bb570452df725a43c9ce (diff)
downloadppe42-gcc-0fe3068e3b47285bb5c21d6b19cf76ededffc68f.tar.gz
ppe42-gcc-0fe3068e3b47285bb5c21d6b19cf76ededffc68f.zip
2006-12-06 Benjamin Kosnik <bkoz@redhat.com>
* include/Makefile.am (std_headers_rename): Remove. (c_base_headers_rename): Remove. (std_headers): Adjust to true names. (c_base_headers): Adjust to true names. (stamp-c_base, stamp_std, stamp_c_base_extra): Adjust. * configure: Regenerate. * include/Makefile.in: Regenerate. * include/std/std_algorithm.h: To... * include/std/std_bitset.h: To... * include/std/std_complex.h: To... * include/std/std_deque.h: To... * include/std/std_fstream.h: To... * include/std/std_functional.h: To... * include/std/std_iomanip.h: To... * include/std/std_iosfwd.h: To... * include/std/std_ios.h: To... * include/std/std_iostream.h: To... * include/std/std_istream.h: To... * include/std/std_iterator.h: To... * include/std/std_limits.h: To... * include/std/std_list.h: To... * include/std/std_locale.h: To... * include/std/std_map.h: To... * include/std/std_memory.h: To... * include/std/std_numeric.h: To... * include/std/std_ostream.h: To... * include/std/std_queue.h: To... * include/std/std_set.h: To... * include/std/std_sstream.h: To... * include/std/std_stack.h: To... * include/std/std_stdexcept.h: To... * include/std/std_streambuf.h: To... * include/std/std_string.h: To... * include/std/std_utility.h: To... * include/std/std_valarray.h: To... * include/std/std_vector.h: To... * include/std/algorithm: ...this. * include/std/bitset: ...this. * include/std/complex: ...this. * include/std/deque: ...this. * include/std/fstream: ...this. * include/std/functional: ...this. * include/std/iomanip: ...this. * include/std/iosfwd: ...this. * include/std/ios: ...this. * include/std/iostream: ...this. * include/std/istream: ...this. * include/std/iterator: ...this. * include/std/limits: ...this. * include/std/list: ...this. * include/std/locale: ...this. * include/std/map: ...this. * include/std/memory: ...this. * include/std/numeric: ...this. * include/std/ostream: ...this. * include/std/queue: ...this. * include/std/set: ...this. * include/std/sstream: ...this. * include/std/stack: ...this. * include/std/stdexcept: ...this. * include/std/streambuf: ...this. * include/std/string: ...this. * include/std/utility: ...this. * include/std/valarray: ...this. * include/std/vector: ...this. * include/c_std/std_cassert.h: To... * include/c_std/std_cctype.h: To... * include/c_std/std_cerrno.h: To... * include/c_std/std_cfloat.h: To... * include/c_std/std_ciso646.h: To... * include/c_std/std_climits.h: To... * include/c_std/std_clocale.h: To... * include/c_std/std_cmath.h: To... * include/c_std/std_csetjmp.h: To... * include/c_std/std_csignal.h: To... * include/c_std/std_cstdarg.h: To... * include/c_std/std_cstddef.h: To... * include/c_std/std_cstdio.h: To... * include/c_std/std_cstdlib.h: To... * include/c_std/std_cstring.h: To... * include/c_std/std_ctime.h: To... * include/c_std/std_cwchar.h: To... * include/c_std/std_cwctype.h: To... * include/c_std/cassert: ...this. * include/c_std/cctype: ...this. * include/c_std/cerrno: ...this. * include/c_std/cfloat: ...this. * include/c_std/ciso646: ...this. * include/c_std/climits: ...this. * include/c_std/clocale: ...this. * include/c_std/cmath: ...this. * include/c_std/csetjmp: ...this. * include/c_std/csignal: ...this. * include/c_std/cstdarg: ...this. * include/c_std/cstddef: ...this. * include/c_std/cstdio: ...this. * include/c_std/cstdlib: ...this. * include/c_std/cstring: ...this. * include/c_std/ctime: ...this. * include/c_std/cwchar: ...this. * include/c_std/cwctype: ...this. * include/c/std_cassert.h: To... * include/c/std_cctype.h: To... * include/c/std_cerrno.h: To... * include/c/std_cfloat.h: To... * include/c/std_ciso646.h: To... * include/c/std_climits.h: To... * include/c/std_clocale.h: To... * include/c/std_cmath.h: To... * include/c/std_csetjmp.h: To... * include/c/std_csignal.h: To... * include/c/std_cstdarg.h: To... * include/c/std_cstddef.h: To... * include/c/std_cstdio.h: To... * include/c/std_cstdlib.h: To... * include/c/std_cstring.h: To... * include/c/std_ctime.h: To... * include/c/std_cwchar.h: To... * include/c/std_cwctype.h: To... * include/c/cassert: ...this. * include/c/cctype: ...this. * include/c/cerrno: ...this. * include/c/cfloat: ...this. * include/c/ciso646: ...this. * include/c/climits: ...this. * include/c/clocale: ...this. * include/c/cmath: ...this. * include/c/csetjmp: ...this. * include/c/csignal: ...this. * include/c/cstdarg: ...this. * include/c/cstddef: ...this. * include/c/cstdio: ...this. * include/c/cstdlib: ...this. * include/c/cstring: ...this. * include/c/ctime: ...this. * include/c/cwchar: ...this. * include/c/cwctype: ...this. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@119611 138bc75d-0d04-0410-961f-82ee72b054a4
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+// Stream buffer classes -*- C++ -*-
+
+// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
+// Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 2, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING. If not, write to the Free
+// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+// USA.
+
+// As a special exception, you may use this file as part of a free software
+// library without restriction. Specifically, if other files instantiate
+// templates or use macros or inline functions from this file, or you compile
+// this file and link it with other files to produce an executable, this
+// file does not by itself cause the resulting executable to be covered by
+// the GNU General Public License. This exception does not however
+// invalidate any other reasons why the executable file might be covered by
+// the GNU General Public License.
+
+/** @file 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>
+
+_GLIBCXX_BEGIN_NAMESPACE(std)
+
+ /**
+ * @if maint
+ * Does stuff.
+ * @endif
+ */
+ 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).
+ *
+ * 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 "the stream position" 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 dependant 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;
+ //@}
+
+ //@{
+ /**
+ * @if maint
+ * This is a non-standard type.
+ * @endif
+ */
+ 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<>(__streambuf_type*, __streambuf_type*, bool&);
+
+ template<typename _CharT2>
+ friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
+ _CharT2*>::__type
+ __copy_aux(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:
+ //@{
+ /**
+ * @if maint
+ * 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
+ * @endif
+ */
+ 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.
+
+ /**
+ * @if maint
+ * Current locale setting.
+ * @endif
+ */
+ 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.
+ */
+ __streambuf_type*
+ pubsetbuf(char_type* __s, streamsize __n)
+ { return this->setbuf(__s, __n); }
+
+ 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); }
+
+ pos_type
+ pubseekpos(pos_type __sp,
+ ios_base::openmode __mode = ios_base::in | ios_base::out)
+ { return this->seekpos(__sp, __mode); }
+
+ 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 "the previous character". 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 "unget" the last character
+ * "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, "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."
+ *
+ * @note Base class version does nothing.
+ */
+ virtual void
+ imbue(const locale&)
+ { }
+
+ // [27.5.2.4.2] buffer management and positioning
+ /**
+ * @brief Maniuplates the buffer.
+ *
+ * Each derived class provides its own appropriate behavior. See
+ * the next-to-last paragraph of
+ * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 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 "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.
+ *
+ * "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."
+ * [27.5.2.4.3]/1
+ *
+ * @note Base class version does nothing, returns zero.
+ * @note The standard adds that "the intention is not only that the
+ * calls [to underflow or uflow] will not return @c eof() but
+ * that they will return "immediately".
+ * @note The standard adds that "the morphemes of @c showmanyc are
+ * "es-how-many-see", not "show-manic".
+ */
+ 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 "refilled". In either case, the
+ * next available character is returned, or @c traits::eof() to
+ * indicate a null pending sequence.
+ *
+ * For a formal definiton 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++/27_io/howto.html#6
+ *
+ * @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, "some other value" 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 "consumed", with "some effect" 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 definiton 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(); }
+
+#ifdef _GLIBCXX_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
+ *
+ * @note This function has been deprecated by the standard. You
+ * must define @c _GLIBCXX_DEPRECATED to make this visible; see
+ * c++config.h.
+ */
+ void
+ stossc()
+ {
+ if (this->gptr() < this->egptr())
+ this->gbump(1);
+ else
+ this->uflow();
+ }
+#endif
+
+ private:
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // Side effect of DR 50.
+ basic_streambuf(const __streambuf_type& __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)
+ { }
+
+ __streambuf_type&
+ operator=(const __streambuf_type&) { 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
+
+#ifndef _GLIBCXX_EXPORT_TEMPLATE
+# include <bits/streambuf.tcc>
+#endif
+
+#endif /* _GLIBCXX_STREAMBUF */
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