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RE: [EXI] Precompression needs more clarity

From: Taki Kamiya <tkamiya@us.fujitsu.com>
Date: Thu, 19 Jun 2008 16:51:39 -0700
To: <santhana@huawei.com>, <public-exi@w3.org>
Message-ID: <73CC4B948319433F862AE909CBFD92C0@catarojp>

Hi Santhanakrishnan,

Sorry for the belated response.

As far as reading an EXI stream, a block can be read with only
a single pass. The first thing you encounter in a block is the structure
channel which is followed by value channels. You can read them
continuously in one pass.

However, you would need to buffer the whole event sequence that
you get from reading the structure channel, so that values can then
be interpolated into the structure, only after that you get the complete
set of data corresponding to the block.

Hope it helps,

-taki


-----Original Message-----
From: public-exi-request@w3.org [mailto:public-exi-request@w3.org] On Behalf Of santhanakrishnan
Sent: Tuesday, May 27, 2008 7:01 AM
To: 'Taki Kamiya'; public-exi@w3.org
Subject: RE: [EXI] Precompression needs more clarity


Hi Taki
	Sorry for the delayed follow up. As per this structure of channels
we will have to go about more than one pass of the exi block to get the
information present in one block.
First pass can only read structure channel (event code and qnames). Only
after this we will be able to read all the values. Then in one more pass we
will be able to construct the XML stream for the content present in this
block.
Am I correct ?
Regards
Santhanakrishnan

-----Original Message-----
From: Taki Kamiya [mailto:tkamiya@us.fujitsu.com]
Sent: Friday, May 02, 2008 4:44 AM
To: santhana@huawei.com; public-exi@w3.org
Subject: RE: [EXI] Precompression needs more clarity

Hi Santhanakrishnan,

The boundaries between channels are implicit.
By reading the structure channel, one can know how many value channels there
are in the block, in what order, which channels are combined in what order,
as well as the number of values contained in each channels. Because you
know the number of values in the channel, you can decode each value using
its associated datatype. When you've finished decoding one channel, it's
the start of next channel when there are more channels subsequently,
otherwise it's the end of the block.

Hope it helps,

-taki


________________________________

From: public-exi-request@w3.org [mailto:public-exi-request@w3.org] On Behalf
Of santhanakrishnan
Sent: Wednesday, April 30, 2008 11:21 PM
To: public-exi@w3.org
Subject: [EXI] Precompression needs more clarity



Hi

       I feel the pre-compression explained in the specification needs some
clarity. It does not deal with the demarcation of
different value channels that are combined together. Some example
pre-compression steps would be useful in better understanding.

Regards

Santhanakrishnan
Received on Thursday, 19 June 2008 23:52:24 GMT

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