[libstdc++] Partial implementation of DR 60.

[Phil Edwards]

DR 60 makes changes to which functions affect, or do not affect, subsequent
calls to gcount().  Easily implemented as below.  I'd actually noticed
these back when doxygenating the I/O library, but never checked them in.  (?)

DR 60 also changes other things, not done here.

Tested on athlon_mp/linux, no regressions.

Should this go in 3.3?  *shrug*



2003-04-20  Phil Edwards  <pme@gcc.gnu.org>

	* docs/html/ext/howto.html ('LWG Issues'):  Add issue 60, partial
	implementation only.
	* include/bits/istream.tcc (putback, unget, sync, seekg):  Comment
	and change to comply with DR 60 and the effect on gcount().
	* include/std/std_istream.h:  Update comments.


Index: docs/html/ext/howto.html
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/docs/html/ext/howto.html,v
retrieving revision 1.27
diff -u -3 -p -r1.27 howto.html
--- docs/html/ext/howto.html	20 Apr 2003 22:18:49 -0000	1.27
+++ docs/html/ext/howto.html	20 Apr 2003 22:55:15 -0000
@@ -464,6 +464,13 @@
         "copying stream state" was deemed too complicated.
     </dd>
 
+    <dt><a href="lwg-defects.html#60">60</a>:
+        <em>What is a formatted input function?</em>
+    </dt>
+    <dd>This DR made many widespread changes to <code>basic_istream</code>,
+        not all of which have been implemented.
+    </dd>
+
     <dt><a href="lwg-defects.html#68">68</a>:
         <em>Extractors for char* should store null at end</em>
     </dt>
Index: include/bits/istream.tcc
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/include/bits/istream.tcc,v
retrieving revision 1.43
diff -u -3 -p -r1.43 istream.tcc
--- include/bits/istream.tcc	18 Apr 2003 03:46:43 -0000	1.43
+++ include/bits/istream.tcc	20 Apr 2003 22:55:15 -0000
@@ -841,7 +841,10 @@ namespace std 
     basic_istream<_CharT, _Traits>::
     putback(char_type __c)
     {
+#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
+// 60. What is a formatted input function?
       _M_gcount = 0;
+#endif
       sentry __cerb(*this, true);
       if (__cerb) 
 	{
@@ -872,7 +875,10 @@ namespace std 
     basic_istream<_CharT, _Traits>::
     unget(void)
     {
+#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
+// 60. What is a formatted input function?
       _M_gcount = 0;
+#endif
       sentry __cerb(*this, true);
       if (__cerb) 
 	{
@@ -903,8 +909,8 @@ namespace std 
     basic_istream<_CharT, _Traits>::
     sync(void)
     {
+      // DR60.  Do not change _M_gcount.
       int __ret = -1;
-      _M_gcount = 0;
       sentry __cerb(*this, true);
       if (__cerb) 
 	{
@@ -948,7 +954,7 @@ namespace std 
     basic_istream<_CharT, _Traits>::
     seekg(pos_type __pos)
     {
-      _M_gcount = 0;
+      // DR60.  Do not change _M_gcount.
       if (!this->fail())
 	{
 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
@@ -968,7 +974,7 @@ namespace std 
     basic_istream<_CharT, _Traits>::
     seekg(off_type __off, ios_base::seekdir __dir)
     {
-      _M_gcount = 0;
+      // DR60.  Do not change _M_gcount.
       if (!this->fail())
 	{
 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
Index: include/std/std_istream.h
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/include/std/std_istream.h,v
retrieving revision 1.8
diff -u -3 -p -r1.8 std_istream.h
--- include/std/std_istream.h	28 Mar 2003 19:45:44 -0000	1.8
+++ include/std/std_istream.h	20 Apr 2003 22:55:15 -0000
@@ -476,10 +476,6 @@ namespace std
        *
        *  @note  Since no characters are extracted, the next call to
        *         @c gcount() will return 0, as required by DR 60.
-       *
-       *  @if maint
-       *  FIXME We don't comply with DR 60 here, _M_gcount is untouched.
-       *  @endif
       */
       __istream_type& 
       putback(char_type __c);
@@ -513,9 +509,6 @@ namespace std
        *  @note  This function does not count the number of characters
        *         extracted, if any, and therefore does not affect the next
        *         call to @c gcount().
-       *  @if maint
-       *  FIXME We don't comply with DR 60 here, _M_gcount is zeroed.
-       *  @endif
       */
       int 
       sync();
@@ -545,9 +538,6 @@ namespace std
        *  @note  This function does not count the number of characters
        *         extracted, if any, and therefore does not affect the next
        *         call to @c gcount().
-       *  @if maint
-       *  FIXME We don't comply with DR 60 here, _M_gcount is zeroed.
-       *  @endif
       */
       __istream_type& 
       seekg(pos_type);
@@ -564,9 +554,6 @@ namespace std
        *  @note  This function does not count the number of characters
        *         extracted, if any, and therefore does not affect the next
        *         call to @c gcount().
-       *  @if maint
-       *  FIXME We don't comply with DR 60 here, _M_gcount is zeroed.
-       *  @endif
       */
       __istream_type& 
       seekg(off_type, ios_base::seekdir);