What is the compression algorithm?

Question

Data compression

Help on a format of a data stream to define a data compression method.
The data stream contains a series of blocks (1 flag bit and data).
Block starts with flag
1 - block will contain raw data (8 bits)
0 - block will refer to existing blocks with offset and block length (12 bits for offset and 4 bits for length)
Sample data flow with flag 1
1 // flag
01001110 N // data
1 // flag
01100001 a // data
1 // flag
01101101 m // data
1 // flag
01100101 e // data Data
flow example with flag 0
0 // flag
000000000111 // offset
0000 // length

Answer 1

It's a very simple algorithm. Similar to LZ77
https://ru.m.wikipedia.org/wiki/LZ77