func (b *bitmapIndexedHmnode) assoc2(shift uint32, hash uint32, key interface{}, val interface{}) (hmnode, bool) {
bit := bitpos(hash, shift)
idx := b.index(bit)
if (b.bitmap & bit) != 0 {
keyOrNil := b.array[2*idx]
valOrNode := b.array[2*idx+1]
if keyOrNil == nil {
n, ok := valOrNode.(hmnode)
if !ok {
panic("Unexpected node type")
}
n, addedLeaf := n.assoc2(shift+5, hash, key, val)
if n == valOrNode {
return b, false
}
return &bitmapIndexedHmnode{b.bitmap, cloneAndSetObjectSlice(b.array, 2*idx+1, n)}, addedLeaf
}
if sequtil.Equiv(key, keyOrNil) {
if val == valOrNode {
return b, false
}
return &bitmapIndexedHmnode{b.bitmap, cloneAndSetObjectSlice(b.array, 2*idx+1, val)}, false
}
return &bitmapIndexedHmnode{b.bitmap, cloneAndSetObjectSlice2(b.array, 2*idx, nil, 2*idx+1, createNode(shift+5, keyOrNil, valOrNode, hash, key, val))}, true
}
n := sequtil.BitCountU32(b.bitmap)
if n >= 16 {
nodes := make([]hmnode, 32)
jdx := imask(hash, shift)
nodes[jdx] = emptyBitmapIndexedHmnode.assoc(shift+5, hash, key, val)
for i, j := 0, 0; i < 32; i++ {
if ((b.bitmap >> uint(i)) & 1) != 0 {
if b.array[j] == nil {
if nn, ok := b.array[j+1].(hmnode); ok {
nodes[i] = nn
} else {
panic("Unexpected node type")
}
} else {
nodes[i] = emptyBitmapIndexedHmnode.assoc(shift+5, Hash(b.array[j]), b.array[j], b.array[j+1])
}
j += 2
}
}
return &arrayHmnode{n + 1, nodes}, true
}
newArray := make([]interface{}, 2*(n+1))
copy(newArray, b.array[0:2*idx])
newArray[2*idx] = key
newArray[2*idx+1] = val
copy(newArray[2*(idx+1):], b.array[2*idx:])
return &bitmapIndexedHmnode{b.bitmap | bit, newArray}, true
}
func (b *bitmapIndexedHmnode) index(bit uint32) int {
return sequtil.BitCountU32(b.bitmap & (bit - 1))
}