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27 weeks 6 days ago - wtVcFo Got it! Thanks a lot
45 weeks 4 days ago - How to detect start and end
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Table of contents
When decoding a FAST message, we need to determine the template ID, retrieve the template, and combine the message content with the template definitions and operators, reproduce the original message.
Picture 3.1 - "FAST Message Decoding Process"
FAST decoder decodes each message using the following algorithms:
Picture 3.2 - "Message decoding algorithm"
Picture 3.3 - "Field decoding algorithm"
To summarize, we follow these steps to decode FAST messages:
- Extract Presence Map
- Determine Message Template ID
- Decode each message field
How to detect start and end
How to detect start and end of FAST message?
The only way to determine the
The only way to determine the size of a FAST message from the data itself is by decoding the message.
There are basically two scenarios when dealing with FAST.
1) You are reading whole messages from a UDP packet or from a store. In this case, you should be able to compute the size based on the packet size.
2) You are reading from an input stream with no message boundaries (like TCP). If you run out of bytes while decoding, you need to wait for more bytes to arrive on the incoming stream.
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