1// Splay tree utilities -*- C++ -*-
2// Copyright (C) 2020-2023 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
30namespace {
31// A simple test node for rootless_splay_tree.
32struct rootless_test_node
33{
34 int data;
35 rootless_test_node *m_parent;
36 rootless_test_node *m_children[2];
37};
38}
39
40namespace selftest {
41
42// Random input data.
43static const size_t MAX_DATA = 32768;
44static 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.
68static int
69lookup1 (splay_tree<int> &tree, int value)
70{
71 auto compare = [&](splay_tree_node<int> *node)
72 {
73 return value - node->value ();
74 };
75 return tree.lookup (compare);
76}
77
78// Look up VALUE in TREE using the double-comparator lookup function.
79static int
80lookup2 (splay_tree<int> &tree, int value)
81{
82 auto want_something_smaller = [&](splay_tree_node<int> *node)
83 {
84 return value < node->value ();
85 };
86 auto want_something_bigger = [&](splay_tree_node<int> *node)
87 {
88 return value > node->value ();
89 };
90 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.
95static void
96test_print (splay_tree<int> &tree)
97{
98 auto print_node = [](pretty_printer *pp, splay_tree_node<int> *node)
99 {
100 pp_decimal_int (pp, node->value ());
101 };
102 pretty_printer pp;
103 tree.print (pp: &pp, printer: print_node);
104}
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.
108static void
109test_lookup (splay_tree<int> &tree, int (*lookup) (splay_tree<int> &, int))
110{
111 // Look up values that are known to exist.
112 for (int value : data)
113 ASSERT_EQ (lookup (tree, value), 0);
114
115 // Look up values that are 1 less than values that are known to exist.
116 for (int value : data)
117 {
118 int result = lookup (tree, value - 1);
119 if (result == 0)
120 ASSERT_EQ (tree->value (), value - 1);
121 else if (result < 0)
122 // VALUE - 1 is less than the root.
123 ASSERT_EQ (tree->value (), value);
124 else if (result > 0)
125 {
126 // VALUE - 1 is greater than the root.
127 ASSERT_TRUE (tree->value () < value - 1);
128 if (tree.splay_next_node ())
129 ASSERT_EQ (tree->value (), value);
130 }
131 }
132
133 // Look up values that are 1 greater than values that are known to exist.
134 for (int value : data)
135 {
136 int result = lookup (tree, value + 1);
137 if (result == 0)
138 ASSERT_EQ (tree->value (), value + 1);
139 else if (result < 0)
140 {
141 // VALUE + 1 is less than the root.
142 ASSERT_TRUE (tree->value () > value + 1);
143 if (tree.splay_prev_node ())
144 ASSERT_EQ (tree->value (), value);
145 }
146 else if (result > 0)
147 // VALUE + 1 is greater than the root.
148 ASSERT_EQ (tree->value (), value);
149 }
150}
151
152// Run all tests for this module.
153void
154splay_tree_cc_tests ()
155{
156 obstack ob;
157 gcc_obstack_init (&ob);
158
159 // Build up the splay tree.
160 splay_tree<int> tree;
161 for (int value : data)
162 {
163 auto *node = XOBNEW (&ob, splay_tree_node<int>);
164 new (node) splay_tree_node<int> (value);
165 auto compare = [&](splay_tree_node<int> *other_node)
166 {
167 return value - other_node->value ();
168 };
169 bool inserted = tree.insert (new_node: node, compare);
170 ASSERT_TRUE (inserted);
171 }
172
173 // Test the single-comparator lookup function.
174 test_lookup (tree, lookup: lookup1);
175
176 // Sort the input data.
177 std::array<int, ARRAY_SIZE (data)> sorted;
178 std::copy (first: data, last: data + ARRAY_SIZE (data), result: sorted.begin ());
179 std::sort (first: sorted.begin (), last: sorted.end ());
180
181 // Iterate over the tree in ascending order.
182 tree.splay_min_node ();
183 bool result = true;
184 for (int value : sorted)
185 {
186 ASSERT_TRUE (result);
187 ASSERT_EQ (tree->value (), value);
188 result = tree.splay_next_node ();
189 }
190 ASSERT_FALSE (result);
191 ASSERT_EQ (tree.min_node ()->value (), sorted.front ());
192
193 // Test the double-comparator lookup function.
194 test_lookup (tree, lookup: lookup2);
195
196 // Test printing the tree now, while it's still bushy.
197 test_print (tree);
198
199 // Iterate over the tree in descending order.
200 tree.splay_max_node ();
201 result = true;
202 for (auto it = sorted.rbegin (); it != sorted.rend (); ++it)
203 {
204 ASSERT_TRUE (result);
205 ASSERT_EQ (tree->value (), *it);
206 result = tree.splay_prev_node ();
207 }
208 ASSERT_FALSE (result);
209 ASSERT_EQ (tree.max_node ()->value (), sorted.back ());
210
211 // Try splitting the tree into three.
212 int mid_min = sorted[sorted.size () / 3];
213 int mid_max = sorted[sorted.size () * 2 / 3];
214 ASSERT_EQ (lookup1 (tree, mid_min), 0);
215 splay_tree<int> left = tree.split_before_root ();
216 ASSERT_EQ (lookup1 (tree, mid_max), 0);
217 splay_tree<int> right = tree.split_after_root ();
218
219 // Test removing all the nodes from their respective trees.
220 for (int value : data)
221 {
222 splay_tree<int> &t = (value < mid_min ? left
223 : value > mid_max ? right : tree);
224 ASSERT_EQ (lookup1 (t, value), 0);
225 t.remove_root ();
226 }
227 ASSERT_EQ (left.root (), nullptr);
228 ASSERT_EQ (tree.root (), nullptr);
229 ASSERT_EQ (right.root (), nullptr);
230
231 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 auto *nodes = XOBNEWVEC (&ob, rootless_test_node *, MAX_DATA);
235 rootless_test_node *parent = nullptr;
236 for (int data : sorted)
237 {
238 auto *node = XOBNEW (&ob, rootless_test_node);
239 new (node) rootless_test_node ();
240 node->data = data;
241 nodes[data] = node;
242 if (parent)
243 rootless::insert_child (node: parent, index: 1, child: node);
244 parent = node;
245 }
246
247 // Try comparing nodes to make sure that their order matches the data.
248 for (size_t i = 1; i < ARRAY_SIZE (data); ++i)
249 {
250 int data1 = data[i - 1];
251 int data2 = data[i];
252 int comparison = rootless::compare_nodes (node1: nodes[data1], node2: nodes[data2]);
253 if (data1 < data2)
254 ASSERT_TRUE (comparison < 0);
255 else if (data1 > data2)
256 ASSERT_TRUE (comparison > 0);
257 else
258 ASSERT_EQ (comparison, 0);
259 }
260
261 obstack_free (&ob, nullptr);
262}
263}
264#endif // CHECKING_P
265

source code of gcc/splay-tree-utils.cc