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

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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
This commit is contained in:
Paolo Carlini 2006-07-03 19:27:55 +00:00 committed by Paolo Carlini
parent 7aa6ba766c
commit 2da7ea252a
2 changed files with 17 additions and 5 deletions
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6
libstdc++-v3/ChangeLog
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@ -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>

16
libstdc++-v3/include/ext/rc_string_base.h
View File

@ -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;