[PATCH 1/4] Revert "2017-10-04 Petr Ovtchenkov "

[Petr Ovtchenkov]

This reverts commit 0dfbafdf338cc6899d146add5161e52efb02c067
(svn r253417).
---
 libstdc++-v3/include/bits/streambuf_iterator.h | 59 ++++++++++++++------------
 1 file changed, 33 insertions(+), 26 deletions(-)

diff --git a/libstdc++-v3/include/bits/streambuf_iterator.h 
b/libstdc++-v3/include/bits/streambuf_iterator.h
index 081afe5..69ee013 100644
--- a/libstdc++-v3/include/bits/streambuf_iterator.h
+++ b/libstdc++-v3/include/bits/streambuf_iterator.h
@@ -95,7 +95,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       // NB: This implementation assumes the "end of stream" value
       // is EOF, or -1.
       mutable streambuf_type*  _M_sbuf;
-      int_type                 _M_c;
+      mutable int_type         _M_c;
 
     public:
       ///  Construct end of input stream iterator.
@@ -122,29 +122,28 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       char_type
       operator*() const
       {
-       int_type __c = _M_get();
-
 #ifdef _GLIBCXX_DEBUG_PEDANTIC
        // Dereferencing a past-the-end istreambuf_iterator is a
        // libstdc++ extension
-       __glibcxx_requires_cond(!_S_is_eof(__c),
+       __glibcxx_requires_cond(!_M_at_eof(),
                                _M_message(__gnu_debug::__msg_deref_istreambuf)
                                ._M_iterator(*this));
 #endif
-       return traits_type::to_char_type(__c);
+       return traits_type::to_char_type(_M_get());
       }
 
       /// Advance the iterator.  Calls streambuf.sbumpc().
       istreambuf_iterator&
       operator++()
       {
-       __glibcxx_requires_cond(_M_sbuf &&
-                               (!_S_is_eof(_M_c) || 
!_S_is_eof(_M_sbuf->sgetc())),
+       __glibcxx_requires_cond(!_M_at_eof(),
                                _M_message(__gnu_debug::__msg_inc_istreambuf)
                                ._M_iterator(*this));
-
-       _M_sbuf->sbumpc();
-       _M_c = traits_type::eof();
+       if (_M_sbuf)
+         {
+           _M_sbuf->sbumpc();
+           _M_c = traits_type::eof();
+         }
        return *this;
       }
 
@@ -152,14 +151,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       istreambuf_iterator
       operator++(int)
       {
-       __glibcxx_requires_cond(_M_sbuf &&
-                               (!_S_is_eof(_M_c) || 
!_S_is_eof(_M_sbuf->sgetc())),
+       __glibcxx_requires_cond(!_M_at_eof(),
                                _M_message(__gnu_debug::__msg_inc_istreambuf)
                                ._M_iterator(*this));
 
        istreambuf_iterator __old = *this;
-       __old._M_c = _M_sbuf->sbumpc();
-       _M_c = traits_type::eof();
+       if (_M_sbuf)
+         {
+           __old._M_c = _M_sbuf->sbumpc();
+           _M_c = traits_type::eof();
+         }
        return __old;
       }
 
@@ -175,21 +176,26 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       int_type
       _M_get() const
       {
-       int_type __ret = _M_c;
-       if (_M_sbuf && _S_is_eof(__ret) && _S_is_eof(__ret = _M_sbuf->sgetc()))
-         _M_sbuf = 0;
+       const int_type __eof = traits_type::eof();
+       int_type __ret = __eof;
+       if (_M_sbuf)
+         {
+           if (!traits_type::eq_int_type(_M_c, __eof))
+             __ret = _M_c;
+           else if (!traits_type::eq_int_type((__ret = _M_sbuf->sgetc()),
+                                              __eof))
+             _M_c = __ret;
+           else
+             _M_sbuf = 0;
+         }
        return __ret;
       }
 
       bool
       _M_at_eof() const
-      { return _S_is_eof(_M_get()); }
-
-      static bool
-      _S_is_eof(int_type __c)
       {
        const int_type __eof = traits_type::eof();
-       return traits_type::eq_int_type(__c, __eof);
+       return traits_type::eq_int_type(_M_get(), __eof);
       }
     };
 
@@ -367,14 +373,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       typedef typename __is_iterator_type::traits_type     traits_type;
       typedef typename __is_iterator_type::streambuf_type  streambuf_type;
       typedef typename traits_type::int_type               int_type;
-      const int_type __eof = traits_type::eof();
 
       if (__first._M_sbuf && !__last._M_sbuf)
        {
          const int_type __ival = traits_type::to_int_type(__val);
          streambuf_type* __sb = __first._M_sbuf;
          int_type __c = __sb->sgetc();
-         while (!traits_type::eq_int_type(__c, __eof)
+         while (!traits_type::eq_int_type(__c, traits_type::eof())
                 && !traits_type::eq_int_type(__c, __ival))
            {
              streamsize __n = __sb->egptr() - __sb->gptr();
@@ -391,9 +396,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
                __c = __sb->snextc();
            }
 
-         __first._M_c = __eof;
+         if (!traits_type::eq_int_type(__c, traits_type::eof()))
+           __first._M_c = __c;
+         else
+           __first._M_sbuf = 0;
        }
-
       return __first;
     }
 
-- 
2.10.1