There are two different questions:
- expressiveness
- efficiency
Real efficiency of transfer (without any intermediate copy) is only
guaranteed in very rare cases
(if the target collection of write stream is same species as source
collection of read stream, and there are no transform in any of the
intermediate wrapper streams, then a direct bulk transfer of the form
targetCollection replaceFrom:to:with: sourceCollection startingAt: is
possible)
I'm not at all convinced that we should focus too much on such optimization.
The fact that we have at least two choices, let the readStream drive the
operation, or let the writeStream do it, is a smell.
It sounds like we could provide the two:
aReadStream writeContentsTo: aWriteStream.
aWriteStream readContentsFrom: aReadStream.
... and then let the programmer decide (maybe there is a more optimal path).
... or provide a way to negotiate the transfer (size of chunked buffers,
etc...)
Unless there is a more symetrical solution.
It's a long time since I did not check Xtreams, but wasn't there a reified
Buffer that could/would be the effective actor of such transfer?
Nicolas
2018-03-29 15:02 GMT+02:00 Denis Kudriashov <[email protected]>:
> 2018-03-29 14:40 GMT+02:00 Sven Van Caekenberghe <[email protected]>:
>
>>
>>
>> > On 29 Mar 2018, at 14:34, Denis Kudriashov <[email protected]>
>> wrote:
>> >
>> >
>> > 2018-03-29 11:45 GMT+02:00 Sven Van Caekenberghe <[email protected]>:
>> > ZnUtils class>>#streamFrom:to: ?
>> >
>> > Yes, it gives feature which I want. But it's too Java style.
>> > What you think to move it to stream itself? And with what message name?
>>
>> This was written in a specific context, to be efficient. I don't know if
>> it is general enough for broad use. Yes it could be more OO to not make it
>> a utility method, but on the other hand, where would you put it ?
>
>
> In read streams we already have:
>
>
> readInto: aCollection startingAt: startIndex count: n
>
>
> So I would put new method in ReadStream (#readIntoStream: ?).
>
>
>> I am hesitant to make the Stream API bigger ;-)
>>
>
> We already have this method in Utils class. So it is here but in strange
> hidden place.
>
>
>> > > On 29 Mar 2018, at 11:22, Denis Kudriashov <[email protected]>
>> wrote:
>> > >
>> > > Hi.
>> > >
>> > > Do we have simple method to write data between streams?
>> > >
>> > > I want something like:
>> > >
>> > > writeStream nextPutAllFrom: readStream
>> > >
>> > > I always used loop for this. But maybe we have something suitable.
>> Otherwise lets introduce it.
>> > >
>> > > Best regards,
>> > > Denis
>> >
>> >
>> >
>>
>>
>>
>
