Pull the point examples out into test files - fixing a few bugs in the process.

[SVN r41996]
This commit is contained in:
Daniel James 2007-12-13 00:31:55 +00:00
parent f6dcb589f8
commit 27e055b228
3 changed files with 95 additions and 44 deletions

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@ -34,59 +34,21 @@ case-insensitive dictionary:
[case_insensitive_functions]
[case_insensitive_dictionary]
A more generic version is available at:
This is a simplified version of the example at:
[@../../libs/unordered/examples/case_insensitive.hpp /libs/unordered/examples/case_insensitive.hpp]
which supports other locales and string types.
[h2 Custom Types]
Similarly, a custom hash function can be used for custom types:
struct point {
int x;
int y;
};
bool operator==(point const& p1, point const& p2)
{
return p1.x == p2.x && p1.y == p2.y;
}
struct point_hash
: std::unary_function<point, std::size_t>
{
std::size_t operator()(point const& p) const
{
std::size_t seed = 0;
boost::hash_combine(seed, p.x);
boost::hash_combine(seed, p.y);
return seed;
}
}
boost::unordered_multiset<point, std::equal_to<point>, point_hash>
points;
[import src_code/point1.cpp]
[point_example1]
Although, customising Boost.Hash is probably a better solution:
struct point {
int x;
int y;
};
bool operator==(point const& p1, point const& p2)
{
return p1.x == p2.x && p1.y == p2.y;
}
std::size_t hash_value(point const& x) {
std::size_t seed = 0;
boost::hash_combine(seed, p.x);
boost::hash_combine(seed, p.y);
return seed;
}
// Now the default functions work.
boost::unordered_multiset<point> points;
[import src_code/point2.cpp]
[point_example2]
See the Boost.Hash documentation for more detail on how to do this. Remember
that it relies on extensions to the draft standard - so it won't work on other

46
doc/src_code/point1.cpp Normal file
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@ -0,0 +1,46 @@
// Copyright 2006-2007 Daniel James.
// 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)
#include <boost/unordered_set.hpp>
#include <boost/detail/lightweight_test.hpp>
//[point_example1
struct point {
int x;
int y;
};
bool operator==(point const& p1, point const& p2)
{
return p1.x == p2.x && p1.y == p2.y;
}
struct point_hash
: std::unary_function<point, std::size_t>
{
std::size_t operator()(point const& p) const
{
std::size_t seed = 0;
boost::hash_combine(seed, p.x);
boost::hash_combine(seed, p.y);
return seed;
}
};
boost::unordered_multiset<point, point_hash, std::equal_to<point> >
points;
//]
int main() {
point x[] = {{1,2}, {3,4}, {1,5}, {1,2}};
for(int i = 0; i < sizeof(x) / sizeof(point); ++i)
points.insert(x[i]);
BOOST_TEST(points.count(x[0]) == 2);
BOOST_TEST(points.count(x[1]) == 1);
point y = {10, 2};
BOOST_TEST(points.count(y) == 0);
return boost::report_errors();
}

43
doc/src_code/point2.cpp Normal file
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@ -0,0 +1,43 @@
// Copyright 2006-2007 Daniel James.
// 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)
#include <boost/unordered_set.hpp>
#include <boost/functional/hash.hpp>
#include <boost/detail/lightweight_test.hpp>
//[point_example2
struct point {
int x;
int y;
};
bool operator==(point const& p1, point const& p2)
{
return p1.x == p2.x && p1.y == p2.y;
}
std::size_t hash_value(point const& p) {
std::size_t seed = 0;
boost::hash_combine(seed, p.x);
boost::hash_combine(seed, p.y);
return seed;
}
// Now the default functions work.
boost::unordered_multiset<point> points;
//]
int main() {
point x[] = {{1,2}, {3,4}, {1,5}, {1,2}};
for(int i = 0; i < sizeof(x) / sizeof(point); ++i)
points.insert(x[i]);
BOOST_TEST(points.count(x[0]) == 2);
BOOST_TEST(points.count(x[1]) == 1);
point y = {10, 2};
BOOST_TEST(points.count(y) == 0);
return boost::report_errors();
}