1// Copyright (C) 2001 Free Software Foundation, Inc.
2//
3// This file is part of the GNU ISO C++ Library.  This library is free
4// software; you can redistribute it and/or modify it under the
5// terms of the GNU General Public License as published by the
6// Free Software Foundation; either version 2, or (at your option)
7// any later version.
8
9// This library is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13
14// You should have received a copy of the GNU General Public License along
15// with this library; see the file COPYING.  If not, write to the Free
16// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
17// USA.
18
19// 25.3.1 algorithms, sort()
20
21#include <algorithm>
22#include <testsuite_hooks.h>
23
24bool test __attribute__((unused)) = true;
25
26const int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20};
27const int B[] = {10, 20, 1, 11, 2, 12, 3, 13, 4, 14, 5, 15, 6, 16, 7, 17, 8, 18, 9, 19};
28const int C[] = {20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
29const int N = sizeof(A) / sizeof(int);
30const int logN = 3; // ln(N) rounded up
31const int P = 7;
32
33// comparison predicate for stable_sort: order by rightmost digit
34struct CompLast
35{
36    bool
37    operator()(const int x, const int y)
38    { return x % 10 < y % 10; }
39};
40
41// This functor has the equivalent functionality of std::geater<>,
42// but there is no dependency on <functional> and it also tracks the
43// number of invocations since creation.
44class Gt
45{
46public:
47    static int count() { return itsCount; }
48    static void reset() { itsCount = 0; }
49
50    bool
51    operator()(const int& x, const int& y)
52    {
53        ++itsCount;
54        return x > y;
55    }
56
57private:
58    static int itsCount;
59};
60
61int Gt::itsCount = 0;
62
63
64// 25.3.1.1 sort()
65void
66test01()
67{
68    int s1[N];
69    std::copy(B, B + N, s1);
70    VERIFY(std::equal(s1, s1 + N, B));
71
72    std::sort(s1, s1 + N);
73    VERIFY(std::equal(s1, s1 + N, A));
74
75    Gt gt;
76    gt.reset();
77    std::sort(s1, s1 + N, gt);
78    VERIFY(std::equal(s1, s1 + N, C));
79}
80
81// 25.3.1.2 stable_sort()
82void
83test02()
84{
85    int s1[N];
86    std::copy(A, A + N, s1);
87    VERIFY(std::equal(s1, s1 + N, A));
88
89    std::stable_sort(s1, s1 + N, CompLast());
90    VERIFY(std::equal(s1, s1 + N, B));
91
92    std::stable_sort(s1, s1 + N);
93    VERIFY(std::equal(s1, s1 + N, A));
94
95    Gt gt;
96    gt.reset();
97    std::stable_sort(s1, s1 + N, gt);
98    VERIFY(std::equal(s1, s1 + N, C));
99    VERIFY(gt.count() <= N * logN * logN);
100}
101
102// 25.3.1.3 partial_sort()
103void
104test03()
105{
106    int s1[N];
107    std::copy(B, B + N, s1);
108    VERIFY(std::equal(s1, s1 + N, B));
109
110    std::partial_sort(s1, s1 + P, s1 + N);
111    VERIFY(std::equal(s1, s1 + P, A));
112
113    Gt gt;
114    gt.reset();
115    std::partial_sort(s1, s1 + P, s1 + N, gt);
116    VERIFY(std::equal(s1, s1 + P, C));
117}
118
119// 25.3.1.4 partial_sort_copy()
120void
121test04()
122{
123    using std::partial_sort_copy;
124
125    int s1[N];
126    std::copy(B, B + N, s1);
127    VERIFY(std::equal(s1, s1 + N, B));
128
129    int s2[2*N];
130
131    partial_sort_copy(s1, s1 + N, s2, s2 + P);
132    VERIFY(std::equal(s2, s2 + P, A));
133
134    Gt gt;
135    gt.reset();
136    partial_sort_copy(s1, s1 + N, s2, s2 + P, gt);
137    VERIFY(std::equal(s2, s2 + P, C));
138
139    VERIFY(std::equal(s2, partial_sort_copy(s1, s1 + N, s2, s2 + 2*N), A));
140}
141
142// 25.3.2 nth_element()
143void
144test05()
145{
146    using std::nth_element;
147
148    int s1[N];
149    std::copy(B, B + N, s1);
150    VERIFY(std::equal(s1, s1 + N, B));
151
152    int* pn = s1 + (N / 2) - 1;
153    nth_element(s1, pn, s1 + N);
154    for (const int* i = pn; i < s1 + N; ++i) VERIFY(!(*i < *pn));
155
156    CompLast pred;
157    nth_element(s1, pn, s1 + N, pred);
158    for (const int* i = pn; i < s1 + N; ++i) VERIFY(!pred(*i, *pn));
159}
160
161int
162main()
163{
164  test01();
165  test02();
166  test03();
167  test04();
168  test05();
169
170  return 0;
171}
172