```/***************************************************************************
*  algo/test_sort.cpp
*
*  Part of the STXXL. See http://stxxl.sourceforge.net
*
*  Copyright (C) 2002 Roman Dementiev <dementiev@mpi-sb.mpg.de>
*  Copyright (C) 2010 Andreas Beckmann <beckmann@cs.uni-frankfurt.de>
*
*  Distributed under the Boost Software License, Version 1.0.
*  (See accompanying file LICENSE_1_0.txt or copy at
*  http://www.boost.org/LICENSE_1_0.txt)
**************************************************************************/

//! \example algo/test_sort.cpp
//! This is an example of how to use \c stxxl::sort() algorithm

#include <stxxl/mng>
#include <stxxl/sort>
#include <stxxl/vector>

#define RECORD_SIZE 8

struct my_type
{
typedef unsigned key_type;

key_type _key;
char _data[RECORD_SIZE - sizeof(key_type)];
key_type key() const
{
return _key;
}

my_type() { }
my_type(key_type __key) : _key(__key) { }

static my_type min_value()
{
return my_type((std::numeric_limits<key_type>::min)());
}
static my_type max_value()
{
return my_type((std::numeric_limits<key_type>::max)());
}

~my_type() { }
};

std::ostream & operator << (std::ostream & o, const my_type & obj)
{
o << obj._key;
return o;
}

bool operator < (const my_type & a, const my_type & b)
{
return a.key() < b.key();
}

bool operator == (const my_type & a, const my_type & b)
{
return a.key() == b.key();
}

bool operator != (const my_type & a, const my_type & b)
{
return a.key() != b.key();
}

struct cmp : public std::less<my_type>
{
my_type min_value() const
{
return my_type::min_value();
}
my_type max_value() const
{
return my_type::max_value();
}
};

int main()
{
#if STXXL_PARALLEL_MULTIWAY_MERGE
STXXL_MSG("STXXL_PARALLEL_MULTIWAY_MERGE");
#endif
unsigned memory_to_use = 128 * 1024 * 1024;
typedef stxxl::vector<my_type> vector_type;

{
// test small vector that can be sorted internally
vector_type v(3);
v[0] = 42;
v[1] = 0;
v[2] = 23;
STXXL_MSG("small vector unsorted " << v[0] << " " << v[1] << " " << v[2]);
//stxxl::sort(v.begin(), v.end(), cmp(), memory_to_use);
stxxl::stl_in_memory_sort(v.begin(), v.end(), cmp());
STXXL_MSG("small vector sorted   " << v[0] << " " << v[1] << " " << v[2]);
assert(stxxl::is_sorted(v.begin(), v.end(), cmp()));
}

const stxxl::int64 n_records =
stxxl::int64(384) * stxxl::int64(1024 * 1024) / sizeof(my_type);
vector_type v(n_records);

stxxl::random_number32 rnd;
STXXL_MSG("Filling vector..., input size = " << v.size() << " elements (" << ((v.size() * sizeof(my_type)) >> 20) << " MiB)");
for (vector_type::size_type i = 0; i < v.size(); i++)
v[i]._key = 1 + (rnd() % 0xfffffff);

STXXL_MSG("Checking order...");
STXXL_MSG(((stxxl::is_sorted(v.begin(), v.end(), cmp())) ? "OK" : "WRONG"));

STXXL_MSG("Sorting (using " << (memory_to_use >> 20) << " MiB of memory)...");
stxxl::sort(v.begin(), v.end(), cmp(), memory_to_use);

STXXL_MSG("Checking order...");
STXXL_MSG(((stxxl::is_sorted(v.begin(), v.end(), cmp())) ? "OK" : "WRONG"));

STXXL_MSG("Done, output size=" << v.size());

return 0;
}

// vim: et:ts=4:sw=4
```