Meaning of _used member in Poco::Buffer

[DBarzo]

Hi,

If I have not misunderstood, the _used member in Poco::Buffer should contains the number of 'valid' data into the buffer.
But, if so, I have some doubts.
In some situation, it has the same meaning of 'capacity'...

For example, in the constructor:

Poco::Buffer<UINT8> _buffer(100); // _used is initialized to 100
bool is_empty = _buffer.empty();  // Return FALSE!

or using the clear() method:

Poco::Buffer<UINT8> _buffer(100);
_buffer.append(_data);
_buffer.clear();   // _used is not cleared
bool is_empty = _buffer.empty();  // Return FALSE!

Is this the desired behavior?

Of course I could have a buffer with all "valid" '0' but, in this case I will use the ctor:

Buffer(T* pMem, std::size_t length)

where _used is correctly valorized.

Daniele.

[aleks-f]

When empty() is true, it means the size of used data in buffer is zero. _used is the valid (used) size, see Buffer::size(). Calling clear() zeroes the used memory but does not empty the buffer. There may be a difference between used and capacity because, after the buffer is shrunk to smaller capacity, unused memory is not deallocated, see resize() and setCapacity()

[DBarzo]

Hi Alex,
thanks for the reply.
I change my code from my_buffer.clear() to my_buffer.resize(0) to 'destroy' (or 'invalidate') the buffer, I don't have found another way to do it 😄