re PR libstdc++/12593 (Resolution of DR 91 (WP) still unimplemented)

2003-11-22  Paolo Carlini  <pcarlini@suse.de>

	PR libstdc++/12593
	* include/bits/istream.tcc (operator>>(basic_string<>&),
	getline(basic_string<>&)): Implement resolution of DR 91 [WP];
	fix some minor issues with the exit conditions.
	* docs/html/ext/howto.html: Add an entry for DR 91.

From-SVN: r73835

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 6f9fab4..22c9b0c 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,11 @@
+2003-11-22  Paolo Carlini  <pcarlini@suse.de>
+
+       PR libstdc++/12593
+       * include/bits/istream.tcc (operator>>(basic_string<>&),
+       getline(basic_string<>&)): Implement resolution of DR 91 [WP];
+       fix some minor issues with the exit conditions.
+       * docs/html/ext/howto.html: Add an entry for DR 91.
+
 2003-11-21  Paolo Carlini  <pcarlini@suse.de>
 
        * config/locale/gnu/monetary_members.cc

diff --git a/libstdc++-v3/docs/html/ext/howto.html b/libstdc++-v3/docs/html/ext/howto.html
index 336abd7..82930a8 100644 (file)
--- a/libstdc++-v3/docs/html/ext/howto.html
+++ b/libstdc++-v3/docs/html/ext/howto.html
@@ -526,6 +526,15 @@
         replaced by <code>isspace(c,is.getloc())</code>.
     </dd>
 
+    <dt><a href="lwg-defects.html#91">91</a>:
+        <em>Description of operator&gt;&gt; and getline() for string&lt;&gt;
+           might cause endless loop</em>
+    </dt>
+    <dd>They behave as a formatted input function and as an unformatted
+        input function, respectively (except that <code>getline</code> is
+       not required to set <code>gcount</code>).
+    </dd>
+
     <dt><a href="lwg-defects.html#109">109</a>:
         <em>Missing binders for non-const sequence elements</em>
     </dt>

diff --git a/libstdc++-v3/include/bits/istream.tcc b/libstdc++-v3/include/bits/istream.tcc
index c455200..40acf11 100644 (file)
--- a/libstdc++-v3/include/bits/istream.tcc
+++ b/libstdc++-v3/include/bits/istream.tcc
@@ -1102,32 +1102,46 @@ namespace std
       typedef typename __istream_type::__ctype_type    __ctype_type;
       typedef basic_string<_CharT, _Traits, _Alloc>    __string_type;
       typedef typename __string_type::size_type                __size_type;
-      __size_type __extracted = 0;
 
+      __size_type __extracted = 0;
       typename __istream_type::sentry __cerb(__in, false);
       if (__cerb) 
        {
-         __str.erase();
-         streamsize __w = __in.width();
-         __size_type __n;
-         __n = __w > 0 ? static_cast<__size_type>(__w) : __str.max_size();
-
-         const __ctype_type& __ct = use_facet<__ctype_type>(__in.getloc());
-         const __int_type __eof = _Traits::eof();
-         __streambuf_type* __sb = __in.rdbuf();
-         __int_type __c = __sb->sgetc();
-         
-         while (__extracted < __n 
-                && !_Traits::eq_int_type(__c, __eof)
-                && !__ct.is(ctype_base::space, _Traits::to_char_type(__c)))
+         try
            {
-             __str += _Traits::to_char_type(__c);
-             ++__extracted;
-             __c = __sb->snextc();
+             __str.erase();
+             streamsize __w = __in.width();
+             __size_type __n;
+             __n = __w > 0 ? static_cast<__size_type>(__w) : __str.max_size();
+             
+             const __ctype_type& __ct = use_facet<__ctype_type>(__in.getloc());
+             const __int_type __eof = _Traits::eof();
+             __streambuf_type* __sb = __in.rdbuf();
+             __int_type __c = __sb->sgetc();
+             
+             while (__extracted < __n 
+                    && !_Traits::eq_int_type(__c, __eof)
+                    && !__ct.is(ctype_base::space, _Traits::to_char_type(__c)))
+               {
+                 __str += _Traits::to_char_type(__c);
+                 ++__extracted;
+                 __c = __sb->snextc();
+               }
+             if (_Traits::eq_int_type(__c, __eof))
+               __in.setstate(ios_base::eofbit);
+             __in.width(0);
+           }
+         catch(...)
+           {
+             // _GLIBCXX_RESOLVE_LIB_DEFECTS
+             // 91. Description of operator>> and getline() for string<>
+             // might cause endless loop
+             // 27.6.1.2.1 Common requirements.
+             // Turn this on without causing an ios::failure to be thrown.
+             __in.setstate(ios_base::badbit);
+             if ((__in.exceptions() & ios_base::badbit) != 0)
+               __throw_exception_again;
            }
-         if (_Traits::eq_int_type(__c, __eof))
-           __in.setstate(ios_base::eofbit);
-         __in.width(0);
        }
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 211.  operator>>(istream&, string&) doesn't set failbit
@@ -1149,31 +1163,44 @@ namespace std
       typedef typename __string_type::size_type                __size_type;
 
       __size_type __extracted = 0;
+      const __size_type __n = __str.max_size();
       bool __testdelim = false;
       typename __istream_type::sentry __cerb(__in, true);
       if (__cerb) 
        {
-         __str.erase();
-         __size_type __n = __str.max_size();
-
-         __int_type __idelim = _Traits::to_int_type(__delim);
-         __streambuf_type* __sb = __in.rdbuf();
-         __int_type __c = __sb->sbumpc();
-         const __int_type __eof = _Traits::eof();
-         __testdelim = _Traits::eq_int_type(__c, __idelim);
-
-         while (__extracted <= __n && !_Traits::eq_int_type(__c, __eof)
-                && !__testdelim)
+         try
            {
-             __str += _Traits::to_char_type(__c);
-             ++__extracted;
-             __c = __sb->sbumpc();
+             __str.erase();
+             __int_type __idelim = _Traits::to_int_type(__delim);
+             __streambuf_type* __sb = __in.rdbuf();
+             __int_type __c = __sb->sbumpc();
+             const __int_type __eof = _Traits::eof();
              __testdelim = _Traits::eq_int_type(__c, __idelim);
+             
+             while (!_Traits::eq_int_type(__c, __eof) && !__testdelim
+                    && __extracted < __n)
+               {
+                 __str += _Traits::to_char_type(__c);
+                 ++__extracted;
+                 __c = __sb->sbumpc();
+                 __testdelim = _Traits::eq_int_type(__c, __idelim);
+               }
+             if (_Traits::eq_int_type(__c, __eof))
+               __in.setstate(ios_base::eofbit);
+           }
+         catch(...)
+           {
+             // _GLIBCXX_RESOLVE_LIB_DEFECTS
+             // 91. Description of operator>> and getline() for string<>
+             // might cause endless loop
+             // 27.6.1.2.1 Common requirements.
+             // Turn this on without causing an ios::failure to be thrown.
+             __in.setstate(ios_base::badbit);
+             if ((__in.exceptions() & ios_base::badbit) != 0)
+               __throw_exception_again;
            }
-         if (_Traits::eq_int_type(__c, __eof))
-           __in.setstate(ios_base::eofbit);
        }
-      if (!__extracted && !__testdelim)
+      if ((!__extracted && !__testdelim) || __extracted == __n)
        __in.setstate(ios_base::failbit);
       return __in;
     }