Can't seem to understand what this function is doing...

This is in pool.go. Originally I was trying to understand how pool.get worked. It brought me down a rabbit hole and I ran into this

func indexLocal(l unsafe.Pointer, i int) *poolLocal {
return &(*[1000000]poolLocal)(l)[i]
}

What is it doing? initializing an array of size 1000000 of poolLocal. and then ... ?

Someone correct me but if I read that correctly it:


"cast" l to a pointer to an array of 1000000 pool local (I guess since it's an unsafe pointer the compiler is OK with that)

returns the address of the pool local item at index i

The large array size is to avoid tripping whatever boundary check the compiler is inserting I assume. There's no actual array of that size. 

ty!

You nailed it. One thing to note, this code is changing very soon. If you check tip, they recently improved pool performance.