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/***************************************************************************
* tests/containers/test_sorter.cpp
*
* Part of the STXXL. See http://stxxl.sourceforge.net
*
* Copyright (C) 2012 Timo Bingmann <tb@panthema.net>
*
* 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 containers/test_sorter.cpp
//! This is an example of how to use \c stxxl::sorter() container
#include <limits>
#include <stxxl/sorter>
#define RECORD_SIZE 16
struct my_type
{
typedef unsigned key_type;
key_type m_key;
char m_data[RECORD_SIZE - sizeof(key_type)];
key_type key() const
{
return m_key;
}
my_type() { }
my_type(key_type k)
: m_key(k)
{
#if STXXL_WITH_VALGRIND
memset(m_data, 0, sizeof(m_data));
#endif
}
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.m_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();
}
struct Comparator : public std::less<my_type>
{
inline bool operator () (const my_type& a, const my_type& b) const
{
return a.key() < b.key();
}
my_type min_value() const
{
return my_type::min_value();
}
my_type max_value() const
{
return my_type::max_value();
}
};
// forced instantiation
template class stxxl::sorter<my_type, Comparator, 8192>;
int main()
{
#if STXXL_PARALLEL_MULTIWAY_MERGE
STXXL_MSG("STXXL_PARALLEL_MULTIWAY_MERGE");
#endif
unsigned memory_to_use = 128 * 1024 * 1024;
enum { block_size = 8192 };
// comparator object used for sorters
Comparator cmp;
// construct sorter type: stxxl::sorter<ValueType, ComparatorType, BlockSize>
typedef stxxl::sorter<my_type, Comparator, block_size> sorter_type;
{
// test small number of items that can be sorted internally
sorter_type s(cmp, memory_to_use);
// put in some items
s.push(42);
s.push(0);
s.push(23);
// finish input, switch to sorting stage.
s.sort();
STXXL_CHECK(*s == 0);
++s;
STXXL_CHECK(*s == 23);
++s;
STXXL_CHECK(*s == 42);
++s;
STXXL_CHECK(s.empty());
}
{
// large test with 384 MiB items
const stxxl::uint64 n_records = stxxl::int64(384) * stxxl::int64(1024 * 1024) / sizeof(my_type);
sorter_type s(cmp, memory_to_use);
stxxl::random_number32 rnd;
STXXL_MSG("Filling sorter..., input size = " << n_records << " elements (" << ((n_records * sizeof(my_type)) >> 20) << " MiB)");
for (stxxl::uint64 i = 0; i < n_records; i++)
{
STXXL_CHECK(s.size() == i);
s.push(1 + (rnd() % 0xfffffff));
}
// finish input, switch to sorting stage.
s.sort();
STXXL_MSG("Checking order...");
STXXL_CHECK(!s.empty());
STXXL_CHECK(s.size() == n_records);
my_type prev = *s; // get first item
++s;
stxxl::uint64 count = n_records - 1;
while (!s.empty())
{
STXXL_CHECK(s.size() == count);
if (!(prev <= *s)) STXXL_MSG("WRONG");
STXXL_CHECK(prev <= *s);
++s;
--count;
}
STXXL_MSG("OK");
// rewind and read output again
s.rewind();
STXXL_MSG("Checking order again...");
STXXL_CHECK(!s.empty());
STXXL_CHECK(s.size() == n_records);
prev = *s; // get first item
++s;
while (!s.empty())
{
if (!(prev <= *s)) STXXL_MSG("WRONG");
STXXL_CHECK(prev <= *s);
++s;
}
STXXL_MSG("OK");
STXXL_CHECK(s.size() == 0);
STXXL_MSG("Done");
}
return 0;
}
// vim: et:ts=4:sw=4
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