[PATCH] streambuf_iterator: avoid debug-dependent behaviour

[Petr Ovtchenkov]

Explicit do sgetc from associated streambuf. Avoid debug-dependent
sgetc (within _M_at_eof()):

       __glibcxx_requires_cond(!_M_at_eof(),
                               _M_message(__gnu_debug::__msg_inc_istreambuf)
                               ._M_iterator(*this));

Increment operators not require not-eof precoditions.

Don't unlink associated streambuf if eof detected (in _M_get).

Clean logic in postfix increment operator.
---
 libstdc++-v3/include/bits/streambuf_iterator.h | 24 +++++-------------------
 1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/libstdc++-v3/include/bits/streambuf_iterator.h 
b/libstdc++-v3/include/bits/streambuf_iterator.h
index 2230e94..cff3b69 100644
--- a/libstdc++-v3/include/bits/streambuf_iterator.h
+++ b/libstdc++-v3/include/bits/streambuf_iterator.h
@@ -136,9 +136,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       istreambuf_iterator&
       operator++()
       {
-       __glibcxx_requires_cond(!_M_at_eof(),
-                               _M_message(__gnu_debug::__msg_inc_istreambuf)
-                               ._M_iterator(*this));
        if (_M_sbuf)
          {
            _M_sbuf->sbumpc();
@@ -151,14 +148,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       istreambuf_iterator
       operator++(int)
       {
-       __glibcxx_requires_cond(!_M_at_eof(),
-                               _M_message(__gnu_debug::__msg_inc_istreambuf)
-                               ._M_iterator(*this));
+        _M_get();
 
        istreambuf_iterator __old = *this;
        if (_M_sbuf)
          {
-           __old._M_c = _M_sbuf->sbumpc();
+           _M_sbuf->sbumpc();
            _M_c = traits_type::eof();
          }
        return __old;
@@ -177,18 +172,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _M_get() const
       {
        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;
+       if (_M_sbuf && traits_type::eq_int_type(_M_c, __eof))
+          _M_c = _M_sbuf->sgetc();
+       return _M_c;
       }
 
       bool
-- 
2.10.1