1. Craig McQueen
  2. cobs-c

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Consistent Overhead Byte Stuffing—Reduced (COBS/R)

This COBS C implementation includes code for a variant on COBS, which I am calling "Consistent Overhead Byte Stuffing—Reduced" (COBS/R).

COBS/R is a small modification of the COBS encoding algorithm, which can often avoid the +1 byte overhead that occurs in COBS. Thus it decreases the average encoding overhead, especially when encoding many small packets.

The COBS/R encoding is never larger than the COBS encoding; often the COBS/R encoded data can be the same size as the original data, thus being 1 byte smaller than the COBS encoding. It does not increase the worst-case encoding overhead compared to COBS.

COBS/R was originally developed in the cobs module for the Python language. The Python cobs module documentation contains a more detailed explanation of the COBS/R encoding variation, including a mathematical analysis of the expected reduction in encoding overhead.

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