rc_string_base.h (__rc_string_base::_S_max_size): Adjust, take into account rounding...

2006-07-03  Paolo Carlini  <pcarlini@suse.de>

	* include/ext/rc_string_base.h (__rc_string_base::_S_max_size):
	Adjust, take into account rounding in _M_create.
	(__rc_string_base::_M_create): Add early _S_max_size check.

From-SVN: r115158

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 01868aaabcbe9aa314f2289e834518639c43e094..5e4c01ef4dd1fa1c661f043c6790bec479bd2598 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,9 @@
+2006-07-03  Paolo Carlini  <pcarlini@suse.de>
+
+       * include/ext/rc_string_base.h (__rc_string_base::_S_max_size):
+       Adjust, take into account rounding in _M_create.
+       (__rc_string_base::_M_create): Add early _S_max_size check.
+
 2006-07-03  Ian Lance Taylor  <ian@airs.com>
            Paolo Carlini  <pcarlini@suse.de>
 

diff --git a/libstdc++-v3/include/ext/rc_string_base.h b/libstdc++-v3/include/ext/rc_string_base.h
index 9470db74fe34ac1937d653af7a4831d78866f1c4..eec6f2dcf0d1a2c2e571e749f176c87861834577 100644 (file)
--- a/libstdc++-v3/include/ext/rc_string_base.h
+++ b/libstdc++-v3/include/ext/rc_string_base.h
@@ -175,11 +175,13 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
       // with a terminating character and m _CharT elements, it'd
       // look like this:
       // npos = sizeof(_Rep) + (m * sizeof(_CharT)) + sizeof(_CharT)
+      //        + sizeof(_Rep) - 1
+      // (NB: last two terms for rounding reasons, see _M_create below)
       // Solving for m:
-      // m = ((npos - sizeof(_Rep)) / sizeof(_CharT)) - 1
+      // m = ((npos - 2 * sizeof(_Rep) + 1) / sizeof(_CharT)) - 1
       // In addition, this implementation halfs this amount.
-      enum { _S_max_size = (((static_cast<size_type>(-1) - sizeof(_Rep))
-                            / sizeof(_CharT)) - 1) / 2 };
+      enum { _S_max_size = (((static_cast<size_type>(-1) - 2 * sizeof(_Rep)
+                             + 1) / sizeof(_CharT)) - 1) / 2 };
 
       // Data Member (private):
       mutable typename _Util_Base::template _Alloc_hider<_Alloc>  _M_dataplus;
@@ -386,7 +388,12 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
       // meet amortized linear time requirements of the library: see
       // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html.
       if (__capacity > __old_capacity && __capacity < 2 * __old_capacity)
-       __capacity = 2 * __old_capacity;
+       {
+         __capacity = 2 * __old_capacity;
+         // Never allocate a string bigger than _S_max_size.
+         if (__capacity > size_type(_S_max_size))
+           __capacity = size_type(_S_max_size);
+       }
 
       // NB: Need an array of char_type[__capacity], plus a terminating
       // null char_type() element, plus enough for the _Rep data structure,
@@ -401,7 +408,6 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
        {
          const size_type __extra = __pagesize - __adj_size % __pagesize;
          __capacity += __extra / sizeof(_CharT);
-         // Never allocate a string bigger than _S_max_size.
          if (__capacity > size_type(_S_max_size))
            __capacity = size_type(_S_max_size);
          __size = (__capacity + 1) * sizeof(_CharT) + 2 * sizeof(_Rep) - 1;