func NewHashTableSomeStructFileBacked(initialSize uint64, filepath string) (*HashTableSomeStruct, error) {
// fresh
initialSize = util.UpperPowerOfTwo(initialSize)
h := allocHashTableSomeStructFileBacked(initialSize, filepath)
h.MagicNumber = MAGIC_NUMBERSomeStruct
h.ArraySize = initialSize
h.Population = 0
return h, nil
}
func TestGrowth(t *testing.T) {
h := NewHashTableSomeStruct(2)
Convey("Given a size 2 table, inserting 0 and 1 should retain and recall the 0 and the 1 keys", t, func() {
So(h.Population, ShouldEqual, 0)
for i := 0; i < 2; i++ {
_, ok := h.Insert(uint64(i))
So(ok, ShouldEqual, true)
}
So(h.Population, ShouldEqual, 2)
So(h.ArraySize, ShouldEqual, 4)
})
h.Clear()
Convey("inserting more than the current size should automatically grow the table", t, func() {
N := uint64(100)
So(h.Population, ShouldEqual, 0)
for i := uint64(0); i < N; i++ {
_, ok := h.Insert(i)
So(ok, ShouldEqual, true)
}
So(h.Population, ShouldEqual, N)
So(h.ArraySize, ShouldEqual, util.UpperPowerOfTwo(uint64(float64(N)*4.0/3.0)))
cell := h.Lookup(0)
So(cell, ShouldNotEqual, nil)
So(cell.unHashedKey, ShouldEqual, 1)
for i := uint64(1); i < N; i++ {
cell := h.Lookup(i)
So(cell, ShouldNotEqual, nil)
So(cell.unHashedKey, ShouldEqual, i)
}
cell = h.Lookup(N + 1)
So(cell, ShouldEqual, nil)
})
}
// Compact will compress the hashtable so that it is at most
// 75% full.
func (t *HashTableSomeStruct) Compact() {
t.Repopulate(util.UpperPowerOfTwo((t.Population*4 + 3) / 3))
}