Ability to rewind while sending

[xloem]

If you hit advance by accident, or mis-scan a code, there is no way to adjust where you are in the stream (go back to the previous code).

This is mostly only useful so long as codes are still manually advanced.

[mofosyne]

This would be more useful if there is a way to tell if you missed a sequence.

Wonder if CRC running sum is an approach. Where the manifest tells you what the crc should look like at each scan, and let you know if the current scan indicates a missed barcode.

e.g. crc4=34b3r;md5=swef3 indicating 5 barcodes and it's expected crc (4bit represented by a single hex char) in the correct sequence. After each sequences of barcodes, you check it against a truncated (read from right side) md5 hash to check if correct)