I use writeStream nextPutAll: readStream contents but it is quite silly...to convert stream -> string -> stream On Thu, Mar 29, 2018 at 11:45 AM, Sven Van Caekenberghe <sven@stfx.eu> wrote:

ZnUtils class>>#streamFrom:to: ?

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On 29 Mar 2018, at 11:22, Denis Kudriashov <dionisiydk@gmail.com> 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

On 29 Mar 2018, at 14:34, Denis Kudriashov <dionisiydk@gmail.com> wrote:

2018-03-29 11:45 GMT+02:00 Sven Van Caekenberghe <sven@stfx.eu>: 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 ? I am hesitant to make the Stream API bigger ;-)

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On 29 Mar 2018, at 11:22, Denis Kudriashov <dionisiydk@gmail.com> 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

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 <dionisiydk@gmail.com>:

2018-03-29 14:40 GMT+02:00 Sven Van Caekenberghe <sven@stfx.eu>:

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On 29 Mar 2018, at 14:34, Denis Kudriashov <dionisiydk@gmail.com> wrote:

2018-03-29 11:45 GMT+02:00 Sven Van Caekenberghe <sven@stfx.eu>: 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: ?).

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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.

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On 29 Mar 2018, at 11:22, Denis Kudriashov <dionisiydk@gmail.com> 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

Hi Nicolas 2018-03-29 17:44 GMT+02:00 Nicolas Cellier < nicolas.cellier.aka.nice@gmail.com>:

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...)

I like this idea.

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?

Xtreams provides nice API to "pipe" multiple streams. But as I remember the Buffer was internal detail hidden from your. Idea was to reuse internal stream arrays to minimize garbage (or something like this).

Nicolas

2018-03-29 15:02 GMT+02:00 Denis Kudriashov <dionisiydk@gmail.com>:

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2018-03-29 14:40 GMT+02:00 Sven Van Caekenberghe <sven@stfx.eu>:

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On 29 Mar 2018, at 14:34, Denis Kudriashov <dionisiydk@gmail.com> wrote:

2018-03-29 11:45 GMT+02:00 Sven Van Caekenberghe <sven@stfx.eu>: 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.

...

...

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On 29 Mar 2018, at 11:22, Denis Kudriashov <dionisiydk@gmail.com> 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

On 29 Mar 2018, at 15:02, Denis Kudriashov <dionisiydk@gmail.com> wrote:

2018-03-29 14:40 GMT+02:00 Sven Van Caekenberghe <sven@stfx.eu>:

...

On 29 Mar 2018, at 14:34, Denis Kudriashov <dionisiydk@gmail.com> wrote:

2018-03-29 11:45 GMT+02:00 Sven Van Caekenberghe <sven@stfx.eu>: 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.

Not all streams inherit from ReadStream, far from it. So if you add it there, you add it to 'the stream API' that every other stream-like class has to implement. Hence it is a burden, for limited gain. I also do not specifically like Util classes, but this is a more special case. The operation belongs to both parties involved. You could define a StreamCopier to do the job. The way it is implemented now, it does not extend the stream API, that is worth something too. Anyway, we are just discussing ideas.

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On 29 Mar 2018, at 11:22, Denis Kudriashov <dionisiydk@gmail.com> 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