Martin Sebor wrote:
>
>Travis Vitek wrote:
>>
>> If that is the case, then why would we possibly need this
>> same code in any of the other methods that are used to extend
>> the original string?
>
>I don't think we do, really. I suspect the main reason why the
>code is in all other (out-of-line) modifiers is so we can throw
>the exception from function that is called directly by program
>rather than from the one that happens to be called from it to
>do the real work (all roads lead to replace()).
>
The problem I see is this...
// if you do this calculation without checking for overflow
// you may be surprised when __size becomes smaller than
// capacity. [240 + 20 = 6]
//
const size_type __size = size () + __n;
// if we get here and capacity () is 240, but __size is 6
// replace() won't be called.
if ( capacity () <= __size
|| size_type (1) < size_type (_C_pref ()->_C_get_ref ()))
return replace (size (), size_type (), __s, __n);
// and we will copy past the end of _C_data
traits_type::copy (_C_data + size (), __s, __n);
// then throw a null terminator down
traits_type::assign (_C_data [__size], value_type ());
// and record the wrong size
_C_pref ()->_C_size._C_size = __size;
With the default std::string/wstring, there isn't really a problem
because the allocator fails before size_type will overflow, but that
doesn't mean it isn't a problem.
Travis
>
>I think the test case has some problems but I just saw your
>update so I'll follow up on it there.
>
>Martin
>
