H.245 OCTET STRINGs

[Mike Nilsson]

Jim,

I think it is just a matter of compiler options.

We are using the OSS tools. If no options are set, there are many such
warnings, and the resulting H.245 structure is about 32 Mbytes. This
seems to be because by default all parts of the structure (except object
IDs) are included, as specified, in a union.

To eliminate the warnings and reduce the structure size to something
manageable we have used the options
--<LINKED SET OF, SEQUENCE OF , OCTET STRING>--

This causes the compiler to create a structure with pointers to objects
rather than a structure with the objects included directly.

Best regards

Mike

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* Mike Nilsson                     Tel:   +44 1473 645413              *
* Video Processing Unit            Fax:   +44 1473 643791              *
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>----------
>From:  Jim Toga[SMTP:jtoga at jf.intel.com]
>Sent:  17 February 1998 21:44
>To:    itu-sg16 at mailbag.jf.intel.com
>Cc:    mike.nilsson at BT-SYS.BT.CO.UK; dskran at ascend.com;
>mreid at videoserver.com
>Subject:       H.245 OCTET STRINGs
>
>It has come to my attention that there are a number of OCTET STRINGS
>defined in H.245 along the lines of
>
>       "h235Key                OCTET STRING (SIZE(1..65535))"
>
>       "value          OCTET STRING (SIZE(1..65535))"
>
>               "certificateResponse            OCTET STRING (SIZE(1..65535))
>OPTIONAL"
>
>The problem with these difinitions is that with the terminating NULL (
>I
>think...) the lentgh goes over by one byte, a 64k block of data.   The
>OSS
>compiler generates the following warning, which goes away if we change
>the
>lenth to '65534'....
>
>
>"h245.asn", line 1941 (MULTIMEDIA-SYSTEM-CONTROL): C0470W: The size of
>the
>generated C structure for the SET OF or SEQUENCE OF exceeds 64K bytes
>and may
>adversely affect CPU and memory performance.  Consider use of the
>LINKED or
>UNBOUNDED directive.
>
>
>Comments?....fixes?......
>
>jimt.
>
>
>
>
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