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// Copyright (C) 2001 Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library is free

// software; you can redistribute it and/or modify it under the

// terms of the GNU General Public License as published by the

// Free Software Foundation; either version 2, or (at your option)

// any later version.

// This library is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along

// with this library; see the file COPYING.  If not, write to the Free

// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,

// USA.

// 25.3.1 algorithms, sort()

#include <algorithm>

#include <testsuite_hooks.h>

bool test __attribute__((unused)) = true;

const int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20};

const int B[] = {10, 20, 1, 11, 2, 12, 3, 13, 4, 14, 5, 15, 6, 16, 7, 17, 8, 18, 9, 19};

const int C[] = {20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1};

const int N = sizeof(A) / sizeof(int);

const int logN = 3; // ln(N) rounded up

const int P = 7;

// comparison predicate for stable_sort: order by rightmost digit

struct CompLast

{

    bool

    operator()(const int x, const int y)

    { return x % 10 < y % 10; }

};

// This functor has the equivalent functionality of std::geater<>,

// but there is no dependency on <functional> and it also tracks the

// number of invocations since creation.

class Gt

{

public:

    static int count() { return itsCount; }

    static void reset() { itsCount = 0; }

    bool

    operator()(const int& x, const int& y)

    {

        ++itsCount;

        return x > y;

    }

private:

    static int itsCount;

};

int Gt::itsCount = 0;

// 25.3.1.1 sort()

void

test01()

{

    int s1[N];

    std::copy(B, B + N, s1);

    VERIFY(std::equal(s1, s1 + N, B));

    std::sort(s1, s1 + N);

    VERIFY(std::equal(s1, s1 + N, A));

    Gt gt;

    gt.reset();

    std::sort(s1, s1 + N, gt);

    VERIFY(std::equal(s1, s1 + N, C));

}

// 25.3.1.2 stable_sort()

void

test02()

{

    int s1[N];

    std::copy(A, A + N, s1);

    VERIFY(std::equal(s1, s1 + N, A));

    std::stable_sort(s1, s1 + N, CompLast());

    VERIFY(std::equal(s1, s1 + N, B));

    std::stable_sort(s1, s1 + N);

    VERIFY(std::equal(s1, s1 + N, A));

    Gt gt;

    gt.reset();

    std::stable_sort(s1, s1 + N, gt);

    VERIFY(std::equal(s1, s1 + N, C));

    VERIFY(gt.count() <= N * logN * logN);

}

// 25.3.1.3 partial_sort()

void

test03()

{

    int s1[N];

    std::copy(B, B + N, s1);

    VERIFY(std::equal(s1, s1 + N, B));

    std::partial_sort(s1, s1 + P, s1 + N);

    VERIFY(std::equal(s1, s1 + P, A));

    Gt gt;

    gt.reset();

    std::partial_sort(s1, s1 + P, s1 + N, gt);

    VERIFY(std::equal(s1, s1 + P, C));

}

// 25.3.1.4 partial_sort_copy()

void

test04()

{

    using std::partial_sort_copy;

    int s1[N];

    std::copy(B, B + N, s1);

    VERIFY(std::equal(s1, s1 + N, B));

    int s2[2*N];

    partial_sort_copy(s1, s1 + N, s2, s2 + P);

    VERIFY(std::equal(s2, s2 + P, A));

    Gt gt;

    gt.reset();

    partial_sort_copy(s1, s1 + N, s2, s2 + P, gt);

    VERIFY(std::equal(s2, s2 + P, C));

    VERIFY(std::equal(s2, partial_sort_copy(s1, s1 + N, s2, s2 + 2*N), A));

}

// 25.3.2 nth_element()

void

test05()

{

    using std::nth_element;

    int s1[N];

    std::copy(B, B + N, s1);

    VERIFY(std::equal(s1, s1 + N, B));

    int* pn = s1 + (N / 2) - 1;

    nth_element(s1, pn, s1 + N);

    for (const int* i = pn; i < s1 + N; ++i) VERIFY(!(*i < *pn));

    CompLast pred;

    nth_element(s1, pn, s1 + N, pred);

    for (const int* i = pn; i < s1 + N; ++i) VERIFY(!pred(*i, *pn));

}

int

main()

{

  test01();

  test02();

  test03();

  test04();

  test05();

  return 0;

}