Hi All/Wei,
I built a few prototypes trying to work out a design. Here's what I
found.
1) A Source can be modified so that it presents data on a channel
other than DEFAULT_CHANNEL. In my case, I simply built a ChannelSource
(...) modeled after StringSource:
ChannelSource(const char *string, ..., const std::string& channel="")
: SourceTemplate<StringStore>(attachment)
{
SourceInitialize(pumpAll, MakeParameters("InputBuffer",
ConstByteArrayParameter(string)));
TransferAllTo2( *AttachedTransformation(), channel );
};
2) Filters are problematic. A filter assumes that data is meant for
the default channel, unless PutChannel(...) or other non-default
channel methods are called. What we need is a filter with 'forwarding'
behavior where appropriate. That is, if a filter's PutChannel is
called and the filter does not have the channel, it should perform its
transformation and on the data in the specified channel. Two examples
would be a HexEncoder and Redirector - transform the data (as
required) and pass the data down.
3) Some filters, such as AuthenticatedDecryptionFilter, should not be
a forwarder. If a channel does not exist, a non-forwarding filter
should return the appropriate error.
Wei: Is this correct or did I miss something in the big picture?
Jeff
On Mar 12, 8:57 pm, Jeffrey Walton <[email protected]> wrote:
> Hi All/Wei,
>
> What I want to achieve is similar to below. StringSource does not have
> it, and neither does Redirector. Both would be good candidates, but I
> think Redirector would probably trump due to its behavior. Or should I
> look at rolling ChannelSource(...)?
>
> Using a ChannelSwitch is like using a Filter's PutChannel - it's not
> quite as elegant as Crypto++.
>
> Jeff
>
> AuthenticatedDecryptionFilter df( d, ... );
>
> ArraySource( (const byte*)adata.data(),
> adata.size(), true,
> new Redirector( df ),
> "AAD"
> ); // ArraySource
>
> ArraySource( (const byte*)enc.data(),
> enc.size(), true,
> new Redirector( df ),
> DEFAULT_CHANNEL
> ); // ArraySource
>
> ArraySource( (const byte*)tag.data(),
> tag.size(), true,
> new Redirector( df ),
> "MAC"
> ); // ArraySource
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