Decoding Sequence
This section provides a detailed example of the process for decoding a FAST message. You should thoroughly test your application to determine that you have properly decoded a message.
Note: This decoding example is a generic description of the basic decoding process; it does not reflect the structure of the reference code.
FAST message decoding consists of three major steps:
Step 1: Transfer Decoding
• Identify Template ID and Pmap bit value for each given field. Pmap values are 0, 1.
• Decode FAST 7-bit binary values to identify data present in the message.
Step 2: Field Decoding
• Apply field operators to extracted binary values.
• Determine state of field to be decoded.
Step 3: Build FIX Message
• Apply FIX or internal structure to the decoded message.
The decoding sequence in the example used throughout this section uses a FAST message containing a header, trade, and two new bids.
