The code is incomplete cause a match could span two chunks.

You need to seek back the longest possible match (here 8) before reading the next chunk.

Actually the correct number is something like min ( p ,m )

With p = chunksize - pos

and m = length of longest possible match

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!

In reply to Re^2: How to optimize a regex on a large file read line by line ? by LanX
in thread How to optimize a regex on a large file read line by line ? by John FENDER

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