Re: [boost] [gil::io] Feedback for scanline_read_iterator

Subject: Re: [boost] [gil::io] Feedback for scanline_read_iterator
From: Michael Marcin (mike.marcin_at_[hidden])
Date: 2013-02-25 00:22:22

Jeffrey Lee Hellrung, Jr. wrote:
> On Sun, Feb 24, 2013 at 1:07 PM, Christian Henning <chhenning_at_[hidden]>wrote:
>
>> Hi Michael,
>>
>>>> I moved the buffer creation internally.
>>>>
>>>
>>> I think this might be even worse unfortunately, if the iterator is
>> copied, such
>>> as with (*i++) it's going to make a full copy of the buffer. Now that
>> readers
>>> have a begin and end maybe the reader could own the buffer?
>>
>> I see two ways, apart from moving the buffer into the reader. I could
>> use a shared ptr or the user has to pass the buffer into the
>> constructor. I lean towards the shared pointer. Do you have an
>> opinion?
>>
>
> Does that mean all copies of an iterator share the same buffer? Won't that
> screw things up if iterators which share the same buffer are dereferenced
> from different positions in the image?
>

I don't think that is a valid use case for an InputIterator.