I would like to understand the lz77 module in detail as it is present in the diagram but no such module exists.

[PoojaR07]

This is the the diagram

Can you please share the code for this module lz77?

[WangXuan95]

LZ77 is not an independent module here, but is implemented in the code. The code is messy and I don't have time to sort it out now (although it has no known bugs). To understand the LZ77 algorithm, you can refer to some other code implementations (e.g. search "Simple Deflate") instead of this code.