source: src/tests/avltree/avl3.c@ e4d3ceb

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors ctor deferred_resn demangler enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox memory new-ast new-ast-unique-expr new-env no_list persistent-indexer pthread-emulation qualifiedEnum resolv-new with_gc
Last change on this file since e4d3ceb was 3dcd347a, checked in by Thierry Delisle <tdelisle@…>, 9 years ago

moved some more tests to new test folder
  • Property mode set to 100644
File size: 2.9 KB
Line 
1#include "avl.h"
2#include "avl-private.h"
3
4// from stdlib
5forall(otype T)
6void swap(T *, T *);
7
8// swaps the data within two tree nodes
9forall(otype K | Comparable(K), otype V)
10void node_swap(tree(K, V) * t, tree(K, V) * t2){
11 swap(&t->key, &t2->key);
12 swap(&t->value, &t2->value);
13}
14
15// go left as deep as possible from within the right subtree
16forall(otype K | Comparable(K), otype V)
17tree(K, V) * find_successor(tree(K, V) * t){
18 tree(K, V) * find_successor_helper(tree(K, V) * t){
19 // go left as deep as possible, return the last node
20 if (empty(t->left)){
21 return t;
22 } else {
23 return find_successor_helper(t->left);
24 }
25 }
26 return find_successor_helper(t->right);
27}
28
29// cleanup - don't want to deep delete, so set children to NULL first.
30forall(otype K | Comparable(K), otype V)
31void deleteSingleNode(tree(K, V) * t) {
32 t->left = NULL;
33 t->right = NULL;
34 deleteSingleNode(t);
35}
36
37// does the actual remove operation once we've found the node in question
38forall(otype K | Comparable(K), otype V)
39tree(K, V) * remove_node(tree(K, V) * t){
40 // is the node a leaf?
41 if (empty(t->left) && empty(t->right)){
42 // yes, just delete this node
43 delete(t);
44 return NULL;
45 } else if (empty(t->left)){
46 // if the left is empty, there is only one child -> move right up
47 node_swap(t, t->right);
48 tree(K, V) * tmp = t->right;
49
50 // relink tree
51 t->left = tmp->left;
52 t->right = tmp->right;
53
54 setParent(t->left, t);
55 setParent(t->right, t);
56 deleteSingleNode(tmp);
57 return t;
58 } else if (empty(t->right)){
59 // if the right is empty, there is only one child -> move left up
60 node_swap(t, t->left);
61 tree(K, V) * tmp = t->left;
62
63 // relink tree
64 t->left = tmp->left;
65 t->right = tmp->right;
66
67 setParent(t->left, t);
68 setParent(t->right, t);
69 deleteSingleNode(tmp);
70 return t;
71 } else {
72 // swap with the successor
73 tree(K, V) * s = find_successor(t);
74 tree(K, V) * parent = s->parent;
75
76 if (parent->left == s){
77 parent->left = s->right;
78 } else {
79 assert(parent->right == s);
80 parent->right = s->right;
81 }
82 setParent(s->right, parent);
83 node_swap(t, s);
84 deleteSingleNode(s);
85 return t;
86 }
87}
88
89// finds the node that needs to be removed
90forall(otype K | Comparable(K), otype V)
91tree(K, V) * remove_helper(tree(K, V) * t, K key, int * worked){
92 if (empty(t)){
93 // did not work because key was not found
94 // set the status variable and return
95 *worked = 1;
96 } else if (t->key == key) {
97 t = remove_node(t);
98 } else if (t->key < key){
99 t->right = remove_helper(t->right, key, worked);
100 } else {
101 // t->key > key
102 t->left = remove_helper(t->left, key, worked);
103 }
104 // try to fix after deleting
105 if (! empty(t)) {
106 t = tryFix(t);
107 }
108 return t;
109}
110
111forall(otype K | Comparable(K), otype V)
112int remove(tree(K, V) ** t, K key){
113 int worked = 0;
114 tree(K, V) * newTree = remove_helper(*t, key, &worked);
115 *t = newTree;
116 return worked;
117}
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