There are some confusions in the process of reading the source code

[spemed]

    b.gen++
    if b.gen&((1<<genSizeBits)-1) == 0 {
    b.gen++
    }

Hello the developers of fastcache. I am learning how this library running by read the source code.
And i have some confuses when reading the code of function Get() in fastcache.go, line 341.

In my opinion, the field gen in bucket means the reset rounds that the chunk had experienced.
And if gen reach the maximum 1<<genSizeBits it should be reset to 1 and not be gen++.

Is my understanding correct?