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Swapped receive and replicate flags #73

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Swapped receive and replicate flags #73

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Expand Up @@ -1153,7 +1153,7 @@ <h4 id="vector-clocks">Vector Clocks</h4>
<p>The value in each key-value pair of a vector clock encodes a maximum of three data points: a replicate flag, a receive flag and a sequence number. A negative value (usually -1) signals that the responder does not wish to replicate the associated feed, neither sending nor receiving messages. In this scenario, the replicate flag is set to false and both the receive flag and sequence number are irrelevant.</p>
<p>A positive value signals that the responder wishes to replicate the associated feed. If the value is positive it should be decoded as follows. First, the JSON number is parsed and converted to a signed integer. Then, the rightmost (lowest order) bit of the number is interpreted as a binary flag with 0 equal to true and 1 equal to false. This flag is referred to as the receive flag. Next, a sign-extending right shift (also called arithmetic right shift) by 1 bit is performed on the binary number, therefore discarding the rightmost (lowest order) bit. The remaining number is then interpreted as a sequence number for the associated feed.</p>
<p>If the receive flag is set to true, the peer who sent the vector clock wishes to receive messages for the associated feed. The decoded sequence number defines the latest message held by the peer for that feed.</p>
<p>Encoding of a vector clock value involves reversing the steps outlined above. If the peer does not wish to replicate a feed, the value is simply set to -1. Otherwise, the latest sequence number of the associated feed is stored as a signed integer and an arithmetic left shift is performed. The rightmost (lowest order) bit is then set according to the replicate flag as described previously.</p>
<p>Encoding of a vector clock value involves reversing the steps outlined above. If the peer does not wish to replicate a feed, the value is simply set to -1. Otherwise, the latest sequence number of the associated feed is stored as a signed integer and an arithmetic left shift is performed. The rightmost (lowest order) bit is then set according to the receive flag as described previously.</p>
<table class="clock-values">
<thead>
<tr>
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