Ask associated streambuf for character when needed instead of accumulate it in istreambuf_iterator object.
Benefits from this: - minus one class member in istreambuf_iterator - trivial synchronization of states of istreambuf_iterator and associated streambuf --- libstdc++-v3/include/bits/streambuf_iterator.h | 34 ++++++++++++-------------- 1 file changed, 15 insertions(+), 19 deletions(-) diff --git a/libstdc++-v3/include/bits/streambuf_iterator.h b/libstdc++-v3/include/bits/streambuf_iterator.h index 08fb13b..203da9d 100644 --- a/libstdc++-v3/include/bits/streambuf_iterator.h +++ b/libstdc++-v3/include/bits/streambuf_iterator.h @@ -95,19 +95,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // NB: This implementation assumes the "end of stream" value // is EOF, or -1. mutable streambuf_type* _M_sbuf; - mutable int_type _M_c; public: class proxy { friend class istreambuf_iterator; private: - proxy(int_type c, streambuf_type* sbuf_) : + proxy(int_type c, streambuf_type* sbuf_) : _M_c(c), _M_sbuf(sbuf_) { } int_type _M_c; - streambuf_type* _M_sbuf; + streambuf_type* _M_sbuf; public: char_type @@ -118,7 +117,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION public: /// Construct end of input stream iterator. _GLIBCXX_CONSTEXPR istreambuf_iterator() _GLIBCXX_USE_NOEXCEPT - : _M_sbuf(0), _M_c(traits_type::eof()) { } + : _M_sbuf(0) { } #if __cplusplus >= 201103L istreambuf_iterator(const istreambuf_iterator&) noexcept = default; @@ -128,15 +127,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION /// Construct start of input stream iterator. istreambuf_iterator(istream_type& __s) _GLIBCXX_USE_NOEXCEPT - : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { } + : _M_sbuf(__s.rdbuf()) { } /// Construct start of streambuf iterator. istreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT - : _M_sbuf(__s), _M_c(traits_type::eof()) { } + : _M_sbuf(__s) { } /// Construct start of istreambuf iterator. istreambuf_iterator(const proxy& __p) _GLIBCXX_USE_NOEXCEPT - : _M_sbuf(__p._M_sbuf), _M_c(traits_type::eof()) { } + : _M_sbuf(__p._M_sbuf) { } /// Return the current character pointed to by iterator. This returns /// streambuf.sgetc(). It cannot be assigned. NB: The result of @@ -147,11 +146,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION #ifdef _GLIBCXX_DEBUG_PEDANTIC // Dereferencing a past-the-end istreambuf_iterator is a // libstdc++ extension - __glibcxx_requires_cond(!_M_at_eof(), + int_type __tmp = _M_get(); + __glibcxx_requires_cond(!traits_type::eq_int_type(__tmp,traits_type::eof()), _M_message(__gnu_debug::__msg_deref_istreambuf) ._M_iterator(*this)); -#endif + return traits_type::to_char_type(__tmp); +#else return traits_type::to_char_type(_M_get()); +#endif } /// Advance the iterator. Calls streambuf.sbumpc(). @@ -172,7 +174,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION _M_message(__gnu_debug::__msg_inc_istreambuf) ._M_iterator(*this)); #endif - _M_c = traits_type::eof(); } return *this; } @@ -181,17 +182,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION proxy operator++(int) { - _M_get(); - __glibcxx_requires_cond(_M_sbuf - && !traits_type::eq_int_type(_M_c,traits_type::eof()), + int_type c = _M_get(); + __glibcxx_requires_cond(!traits_type::eq_int_type(c,traits_type::eof()), _M_message(__gnu_debug::__msg_inc_istreambuf) ._M_iterator(*this)); - proxy __old(_M_c, _M_sbuf); + proxy __old(c, _M_sbuf); if (_M_sbuf) { _M_sbuf->sbumpc(); - _M_c = traits_type::eof(); } return __old; } @@ -209,9 +208,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION _M_get() const { const int_type __eof = traits_type::eof(); - if (_M_sbuf && traits_type::eq_int_type(_M_c, __eof)) - _M_c = _M_sbuf->sgetc(); - return _M_c; + return _M_sbuf ? _M_sbuf->sgetc() : __eof; } bool @@ -418,7 +415,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION else __c = __sb->snextc(); } - __first._M_c = __c; } return __first; } -- 2.10.1