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package test_core_container
import rb "core:container/rbtree"
import "core:math/rand"
import "core:testing"
import "base:intrinsics"
import "core:slice"
import "core:log"
test_rbtree_integer :: proc(t: ^testing.T, $Key: typeid, $Value: typeid) {
log.infof("Testing Red-Black Tree($Key=%v,$Value=%v) using random seed %v.", type_info_of(Key), type_info_of(Value), t.seed)
tree: rb.Tree(Key, Value)
rb.init(&tree)
testing.expect(t, rb.len(tree) == 0, "empty: len should be 0")
testing.expect(t, rb.first(&tree) == nil, "empty: first should be nil")
testing.expect(t, rb.last(&tree) == nil, "empty: last should be nil")
iter := rb.iterator(&tree, .Forward)
testing.expect(t, rb.iterator_get(&iter) == nil, "empty/iterator: first node should be nil")
// Test insertion.
NR_INSERTS :: 32 + 1 // Ensure at least 1 collision.
inserted_map := make(map[Key]^rb.Node(Key, Value))
min_key := max(Key)
max_key := min(Key)
for i := 0; i < NR_INSERTS; i += 1 {
k := Key(rand.uint32()) & 0x1f
min_key = min(min_key, k); max_key = max(max_key, k)
v := Value(rand.uint32())
existing_node, in_map := inserted_map[k]
n, inserted, _ := rb.find_or_insert(&tree, k, v)
testing.expect(t, in_map != inserted, "insert: inserted should match inverse of map lookup")
if inserted {
inserted_map[k] = n
} else {
testing.expect(t, existing_node == n, "insert: expecting existing node")
}
}
entry_count := len(inserted_map)
testing.expect(t, rb.len(tree) == entry_count, "insert: len after")
validate_rbtree(t, &tree)
first := rb.first(&tree)
last := rb.last(&tree)
testing.expectf(t, first != nil && first.key == min_key, "insert: first should be present with key %v", min_key)
testing.expectf(t, last != nil && last.key == max_key, "insert: last should be present with key %v", max_key)
// Ensure that all entries can be found.
for k, v in inserted_map {
testing.expect(t, v == rb.find(tree, k), "Find(): Node")
testing.expect(t, k == v.key, "Find(): Node key")
}
// Test the forward/backward iterators.
inserted_keys: [dynamic]Key
for k in inserted_map {
append(&inserted_keys, k)
}
slice.sort(inserted_keys[:])
iter = rb.iterator(&tree, rb.Direction.Forward)
visited: int
for node in rb.iterator_next(&iter) {
k, idx := node.key, visited
testing.expect(t, inserted_keys[idx] == k, "iterator/forward: key")
testing.expect(t, node == rb.iterator_get(&iter), "iterator/forward: get")
visited += 1
}
testing.expect(t, visited == entry_count, "iterator/forward: visited")
slice.reverse(inserted_keys[:])
iter = rb.iterator(&tree, rb.Direction.Backward)
visited = 0
for node in rb.iterator_next(&iter) {
k, idx := node.key, visited
testing.expect(t, inserted_keys[idx] == k, "iterator/backward: key")
visited += 1
}
testing.expect(t, visited == entry_count, "iterator/backward: visited")
// Test removal (and on_remove callback)
rand.shuffle(inserted_keys[:])
callback_count := entry_count
tree.user_data = &callback_count
tree.on_remove = proc(key: Key, value: Value, user_data: rawptr) {
(^int)(user_data)^ -= 1
}
for k, i in inserted_keys {
node := rb.find(tree, k)
testing.expect(t, node != nil, "remove: find (pre)")
ok := rb.remove(&tree, k)
testing.expect(t, ok, "remove: succeeds")
testing.expect(t, entry_count - (i + 1) == rb.len(tree), "remove: len (post)")
validate_rbtree(t, &tree)
testing.expect(t, nil == rb.find(tree, k), "remove: find (post")
}
testing.expect(t, rb.len(tree) == 0, "remove: len should be 0")
testing.expectf(t, callback_count == 0, "remove: on_remove should've been called %v times, it was %v", entry_count, callback_count)
testing.expect(t, rb.first(&tree) == nil, "remove: first should be nil")
testing.expect(t, rb.last(&tree) == nil, "remove: last should be nil")
// Refill the tree.
for k in inserted_keys {
rb.find_or_insert(&tree, k, 42)
}
// Test that removing the node doesn't break the iterator.
callback_count = entry_count
iter = rb.iterator(&tree, rb.Direction.Forward)
if node := rb.iterator_get(&iter); node != nil {
k := node.key
ok := rb.iterator_remove(&iter)
testing.expect(t, ok, "iterator/remove: success")
ok = rb.iterator_remove(&iter)
testing.expect(t, !ok, "iterator/remove: redundant removes should fail")
testing.expect(t, rb.find(tree, k) == nil, "iterator/remove: node should be gone")
testing.expect(t, rb.iterator_get(&iter) == nil, "iterator/remove: get should return nil")
// Ensure that iterator_next still works.
node, ok = rb.iterator_next(&iter)
testing.expect(t, ok == (rb.len(tree) > 0), "iterator/remove: next should return false")
testing.expect(t, node == rb.first(&tree), "iterator/remove: next should return first")
validate_rbtree(t, &tree)
}
testing.expect(t, rb.len(tree) == entry_count - 1, "iterator/remove: len should drop by 1")
rb.destroy(&tree)
testing.expect(t, rb.len(tree) == 0, "destroy: len should be 0")
testing.expectf(t, callback_count == 0, "remove: on_remove should've been called %v times, it was %v", entry_count, callback_count)
// print_tree_node(tree._root)
delete(inserted_map)
delete(inserted_keys)
}
@(test)
test_rbtree :: proc(t: ^testing.T) {
test_rbtree_integer(t, u16, u16)
}
print_tree_node :: proc(n: ^$N/rb.Node($Key, $Value), indent := 0) {
if n == nil {
fmt.println("<empty tree>")
return
}
if n.right != nil {
print_tree_node(n.right, indent + 1)
}
for _ in 0..<indent {
fmt.printf("\t")
}
if n.color == .Black {
fmt.printfln("%v", n.key)
} else {
fmt.printfln("<%v>", n.key)
}
if n.left != nil {
print_tree_node(n.left, indent + 1)
}
}
validate_rbtree :: proc(t: ^testing.T, tree: ^$T/rb.Tree($Key, $Value)) {
verify_rbtree_propery_1(t, tree._root)
verify_rbtree_propery_2(t, tree._root)
/* Property 3 is implicit */
verify_rbtree_propery_4(t, tree._root)
verify_rbtree_propery_5(t, tree._root)
}
verify_rbtree_propery_1 :: proc(t: ^testing.T, n: ^$N/rb.Node($Key, $Value)) {
testing.expect(t, rb.node_color(n) == .Black || rb.node_color(n) == .Red, "Property #1: Each node is either red or black.")
if n == nil {
return
}
verify_rbtree_propery_1(t, n._left)
verify_rbtree_propery_1(t, n._right)
}
verify_rbtree_propery_2 :: proc(t: ^testing.T, root: ^$N/rb.Node($Key, $Value)) {
testing.expect(t, rb.node_color(root) == .Black, "Property #2: Root node should be black.")
}
verify_rbtree_propery_4 :: proc(t: ^testing.T, n: ^$N/rb.Node($Key, $Value)) {
if rb.node_color(n) == .Red {
// A red node's left, right and parent should be black
all_black := rb.node_color(n._left) == .Black && rb.node_color(n._right) == .Black && rb.node_color(n._parent) == .Black
testing.expect(t, all_black, "Property #3: Red node's children + parent must be black.")
}
if n == nil {
return
}
verify_rbtree_propery_4(t, n._left)
verify_rbtree_propery_4(t, n._right)
}
verify_rbtree_propery_5 :: proc(t: ^testing.T, root: ^$N/rb.Node($Key, $Value)) {
black_count_path := -1
verify_rbtree_propery_5_helper(t, root, 0, &black_count_path)
}
verify_rbtree_propery_5_helper :: proc(t: ^testing.T, n: ^$N/rb.Node($Key, $Value), black_count: int, path_black_count: ^int) {
black_count := black_count
if rb.node_color(n) == .Black {
black_count += 1
}
if n == nil {
if path_black_count^ == -1 {
path_black_count^ = black_count
} else {
testing.expect(t, black_count == path_black_count^, "Property #5: Paths from a node to its leaves contain same black count.")
}
return
}
verify_rbtree_propery_5_helper(t, n._left, black_count, path_black_count)
verify_rbtree_propery_5_helper(t, n._right, black_count, path_black_count)
}
// Properties 4 and 5 together guarantee that no path in the tree is more than about twice as long as any other path,
// which guarantees that it has O(log n) height.
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