One-to-one integer mapping function

Question

We are using MySQL and developing an application where we\'d like the ID sequence not to be publicly visible... the IDs are hardly top secret and there is no significant iss

Answer 1

For our application, we use bit shuffle to generate the ID. It is very easy to reverse back to the original ID.

func (m Meeting) MeetingCode() uint {
    hashed := (m.ID + 10000000) & 0x00FFFFFF
    chunks := [24]uint{}
    for i := 0; i < 24; i++ {
        chunks[i] = hashed >> i & 0x1
    }
    shuffle := [24]uint{14, 1, 15, 21, 0, 6, 5, 10, 4, 3, 20, 22, 2, 23, 8, 13, 19, 9, 18, 12, 7, 11, 16, 17}
    result := uint(0)
    for i := 0; i < 24; i++ {
        result = result | (chunks[shuffle[i]] << i)
    }
    return result
}