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1 : // Splay tree utilities -*- C++ -*-
2 : // Copyright (C) 2020-2026 Free Software Foundation, Inc.
3 : //
4 : // This file is part of GCC.
5 : //
6 : // GCC is free software; you can redistribute it and/or modify it under
7 : // the terms of the GNU General Public License as published by the Free
8 : // Software Foundation; either version 3, or (at your option) any later
9 : // version.
10 : //
11 : // GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 : // WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 : // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 : // for more details.
15 : //
16 : // You should have received a copy of the GNU General Public License
17 : // along with GCC; see the file COPYING3. If not see
18 : // <http://www.gnu.org/licenses/>.
19 :
20 : #define INCLUDE_ALGORITHM
21 : #define INCLUDE_ARRAY
22 : #include "config.h"
23 : #include "system.h"
24 : #include "coretypes.h"
25 : #include "pretty-print.h"
26 : #include "splay-tree-utils.h"
27 : #include "selftest.h"
28 :
29 : #if CHECKING_P
30 : namespace {
31 : // A simple test node for rootless_splay_tree.
32 : struct rootless_test_node
33 : {
34 : int data;
35 : rootless_test_node *m_parent;
36 : rootless_test_node *m_children[2];
37 : };
38 : }
39 :
40 : namespace selftest {
41 :
42 : // Random input data.
43 : static const size_t MAX_DATA = 32768;
44 : static const int data[] = {
45 : 1379, 14643, 30579, 28160, 31750, 22280, 5502, 4720, 30075, 27595,
46 : 8395, 19410, 518, 19709, 29694, 19865, 25372, 11752, 15485, 21547,
47 : 25153, 25072, 10146, 3341, 15625, 3038, 10189, 19943, 1322, 11762,
48 : 807, 430, 11284, 11841, 23965, 32008, 4547, 8087, 13225, 23054,
49 : 22284, 13756, 2182, 26450, 30482, 32502, 23348, 20265, 29509, 3290,
50 : 10807, 1242, 3212, 32178, 25354, 22032, 30509, 16157, 22432, 1295,
51 : 8348, 23342, 24678, 193, 31016, 10316, 3872, 13521, 19211, 30594,
52 : 12229, 4794, 25083, 16098, 28144, 27896, 4801, 20689, 31450, 15614,
53 : 19597, 13731, 30309, 24846, 11042, 31929, 18306, 28520, 16907, 12488,
54 : 15001, 18487, 3438, 1706, 4829, 20892, 6226, 18204, 15776, 30717,
55 : 19398, 2480, 19434, 2838, 2605, 3994, 22538, 12269, 6486, 1314,
56 : 30301, 9919, 31405, 30847, 25000, 24013, 22196, 30220, 31415, 14630,
57 : 26319, 4880, 21292, 20217, 20078, 14679, 25686, 28675, 13883, 14853,
58 : 2872, 2428, 3636, 14131, 2952, 2133, 4470, 25808, 12576, 31395,
59 : 5938, 28393, 14553, 4494, 14928, 24310, 17394, 17436, 23385, 22792,
60 : 9785, 13118, 22338, 23320, 27059, 17663, 16434, 14954, 16962, 31088,
61 : 22247, 22600, 7980, 1344, 15635, 13611, 32739, 3283, 12924, 17904,
62 : 28216, 7542, 9212, 28308, 18873, 3912, 5473, 4666, 11900, 21420,
63 : 20072, 27662, 16445, 29848, 24444, 31668, 30664, 14287, 13754, 29276,
64 : 21462, 25517, 17632, 8105, 32510, 16677, 11162, 20734, 26873, 5097
65 : };
66 :
67 : // Look up VALUE in TREE using the single-comparator lookup function.
68 : static int
69 3208 : lookup1 (splay_tree<int> &tree, int value)
70 : {
71 34540 : auto compare = [&](splay_tree_node<int> *node)
72 : {
73 31332 : return value - node->value ();
74 3208 : };
75 2400 : return tree.lookup (compare);
76 : }
77 :
78 : // Look up VALUE in TREE using the double-comparator lookup function.
79 : static int
80 2400 : lookup2 (splay_tree<int> &tree, int value)
81 : {
82 28868 : auto want_something_smaller = [&](splay_tree_node<int> *node)
83 : {
84 26468 : return value < node->value ();
85 2400 : };
86 19224 : auto want_something_bigger = [&](splay_tree_node<int> *node)
87 : {
88 16824 : return value > node->value ();
89 2400 : };
90 2400 : return tree.lookup (want_something_smaller, want_something_bigger);
91 : }
92 :
93 : // Test printing TREE to a pretty printer. Don't check the output against
94 : // anything; just make sure that it doesn't crash.
95 : static void
96 4 : test_print (splay_tree<int> &tree)
97 : {
98 804 : auto print_node = [](pretty_printer *pp, splay_tree_node<int> *node)
99 : {
100 800 : pp_decimal_int (pp, node->value ());
101 800 : };
102 4 : pretty_printer pp;
103 4 : tree.print (&pp, print_node);
104 4 : }
105 :
106 : // Test various lookups on TREE using LOOKUP, where lookup returns the
107 : // same kind of value as the rooted_splay_tree lookup functions.
108 : static void
109 8 : test_lookup (splay_tree<int> &tree, int (*lookup) (splay_tree<int> &, int))
110 : {
111 : // Look up values that are known to exist.
112 1608 : for (int value : data)
113 1600 : ASSERT_EQ (lookup (tree, value), 0);
114 :
115 : // Look up values that are 1 less than values that are known to exist.
116 1608 : for (int value : data)
117 : {
118 1600 : int result = lookup (tree, value - 1);
119 1600 : if (result == 0)
120 0 : ASSERT_EQ (tree->value (), value - 1);
121 1600 : else if (result < 0)
122 : // VALUE - 1 is less than the root.
123 1372 : ASSERT_EQ (tree->value (), value);
124 228 : else if (result > 0)
125 : {
126 : // VALUE - 1 is greater than the root.
127 228 : ASSERT_TRUE (tree->value () < value - 1);
128 228 : if (tree.splay_next_node ())
129 228 : ASSERT_EQ (tree->value (), value);
130 : }
131 : }
132 :
133 : // Look up values that are 1 greater than values that are known to exist.
134 1608 : for (int value : data)
135 : {
136 1600 : int result = lookup (tree, value + 1);
137 1600 : if (result == 0)
138 0 : ASSERT_EQ (tree->value (), value + 1);
139 1600 : else if (result < 0)
140 : {
141 : // VALUE + 1 is less than the root.
142 448 : ASSERT_TRUE (tree->value () > value + 1);
143 448 : if (tree.splay_prev_node ())
144 448 : ASSERT_EQ (tree->value (), value);
145 : }
146 1152 : else if (result > 0)
147 : // VALUE + 1 is greater than the root.
148 1152 : ASSERT_EQ (tree->value (), value);
149 : }
150 8 : }
151 :
152 : // Run all tests for this module.
153 : void
154 4 : splay_tree_cc_tests ()
155 : {
156 4 : obstack ob;
157 4 : gcc_obstack_init (&ob);
158 :
159 : // Build up the splay tree.
160 4 : splay_tree<int> tree;
161 804 : for (int value : data)
162 : {
163 800 : auto *node = XOBNEW (&ob, splay_tree_node<int>);
164 800 : new (node) splay_tree_node<int> (value);
165 8072 : auto compare = [&](splay_tree_node<int> *other_node)
166 : {
167 7272 : return value - other_node->value ();
168 800 : };
169 800 : bool inserted = tree.insert (node, compare);
170 800 : ASSERT_TRUE (inserted);
171 : }
172 :
173 : // Test the single-comparator lookup function.
174 4 : test_lookup (tree, lookup1);
175 :
176 : // Sort the input data.
177 4 : std::array<int, ARRAY_SIZE (data)> sorted;
178 4 : std::copy (data, data + ARRAY_SIZE (data), sorted.begin ());
179 4 : std::sort (sorted.begin (), sorted.end ());
180 :
181 : // Iterate over the tree in ascending order.
182 4 : tree.splay_min_node ();
183 4 : bool result = true;
184 804 : for (int value : sorted)
185 : {
186 800 : ASSERT_TRUE (result);
187 800 : ASSERT_EQ (tree->value (), value);
188 800 : result = tree.splay_next_node ();
189 : }
190 4 : ASSERT_FALSE (result);
191 4 : ASSERT_EQ (tree.min_node ()->value (), sorted.front ());
192 :
193 : // Test the double-comparator lookup function.
194 4 : test_lookup (tree, lookup2);
195 :
196 : // Test printing the tree now, while it's still bushy.
197 4 : test_print (tree);
198 :
199 : // Iterate over the tree in descending order.
200 4 : tree.splay_max_node ();
201 4 : result = true;
202 808 : for (auto it = sorted.rbegin (); it != sorted.rend (); ++it)
203 : {
204 800 : ASSERT_TRUE (result);
205 800 : ASSERT_EQ (tree->value (), *it);
206 800 : result = tree.splay_prev_node ();
207 : }
208 4 : ASSERT_FALSE (result);
209 4 : ASSERT_EQ (tree.max_node ()->value (), sorted.back ());
210 :
211 : // Try splitting the tree into three.
212 4 : int mid_min = sorted[sorted.size () / 3];
213 4 : int mid_max = sorted[sorted.size () * 2 / 3];
214 4 : ASSERT_EQ (lookup1 (tree, mid_min), 0);
215 4 : splay_tree<int> left = tree.split_before_root ();
216 4 : ASSERT_EQ (lookup1 (tree, mid_max), 0);
217 4 : splay_tree<int> right = tree.split_after_root ();
218 :
219 : // Test removing all the nodes from their respective trees.
220 804 : for (int value : data)
221 : {
222 800 : splay_tree<int> &t = (value < mid_min ? left
223 : : value > mid_max ? right : tree);
224 800 : ASSERT_EQ (lookup1 (t, value), 0);
225 800 : t.remove_root ();
226 : }
227 4 : ASSERT_EQ (left.root (), nullptr);
228 4 : ASSERT_EQ (tree.root (), nullptr);
229 4 : ASSERT_EQ (right.root (), nullptr);
230 :
231 4 : using rootless = default_rootless_splay_tree<rootless_test_node *>;
232 :
233 : // Build a tree in ascending order with the lowest element as the root.
234 4 : auto *nodes = XOBNEWVEC (&ob, rootless_test_node *, MAX_DATA);
235 4 : rootless_test_node *parent = nullptr;
236 804 : for (int data : sorted)
237 : {
238 800 : auto *node = XOBNEW (&ob, rootless_test_node);
239 800 : new (node) rootless_test_node ();
240 800 : node->data = data;
241 800 : nodes[data] = node;
242 800 : if (parent)
243 796 : rootless::insert_child (parent, 1, node);
244 800 : parent = node;
245 : }
246 :
247 : // Try comparing nodes to make sure that their order matches the data.
248 800 : for (size_t i = 1; i < ARRAY_SIZE (data); ++i)
249 : {
250 796 : int data1 = data[i - 1];
251 796 : int data2 = data[i];
252 796 : int comparison = rootless::compare_nodes (nodes[data1], nodes[data2]);
253 796 : if (data1 < data2)
254 396 : ASSERT_TRUE (comparison < 0);
255 400 : else if (data1 > data2)
256 400 : ASSERT_TRUE (comparison > 0);
257 : else
258 796 : ASSERT_EQ (comparison, 0);
259 : }
260 :
261 4 : obstack_free (&ob, nullptr);
262 4 : }
263 : }
264 : #endif // CHECKING_P
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