[Boost-users] Question regarding circular buffer usage

Subject: [Boost-users] Question regarding circular buffer usage
From: Salivar.William (William.Salivar_at_[hidden])
Date: 2013-02-01 16:59:50

I am using the circular buffer container to hold up to 10000 std string objects.  I am finding that once the buffer has reached max capacity, memory continues to be consumed as I push new strings in.  Is there something I'm missing?  I stepped into the boost code and it does make a copy of the string using the std string operator so I would think it handles the string copy properly.  The size of the strings are variable but I would expect the memory usage to be fairly stable when the buffer is full but that is not the case.

Here's basic usage

Definition:

      boost::circular_buffer<std::string> m_message_buffer;

Initialization:

      m_message_buffer.set_capacity (10000);

Usage:

void myClass::writeToBuffer (const char *message)
{
      m_message_buffer.push_back (string (message));
}

Boost code:

    void push_back(param_value_type item = value_type()) {
        if (full()) {
            if (empty())
                return;
            replace(m_last, item);
            increment(m_last);
            m_first = m_last;
        } else {
            m_alloc.construct(m_last, item);
            increment(m_last);
            ++m_size;
        }
    }

    void replace(pointer pos, param_value_type item) {
        *pos = item;
#if BOOST_CB_ENABLE_DEBUG
        invalidate_iterators(iterator(this, pos));
#endif
    }