Merge pull request #43 from timblechmann/topic/unary-irange

irange: introduce one-parameter variant of irange
This commit is contained in:
neilgroves
2017-11-15 19:48:19 +00:00
committed by GitHub
3 changed files with 59 additions and 11 deletions

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@ -10,7 +10,11 @@
``
template<class Integer>
iterator_range< range_detail::integer_iterator<Integer> >
irange(Integer first, Integer last);
irange(Integer last);
template<class Integer>
iterator_range< range_detail::integer_iterator<Integer> >
irange(Integer first, Integer last);
template<class Integer, class StepSize>
iterator_range< range_detail::integer_iterator_with_step<Integer, StepSize> >
@ -37,4 +41,3 @@ Defined in the header file `boost/range/irange.hpp`
Constant. Since this function generates a new range the most significant performance cost is incurred through the iteration of the generated range.
[endsect]

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@ -217,7 +217,7 @@ namespace boost
{
BOOST_ASSERT( step_size != 0 );
BOOST_ASSERT( (step_size > 0) ? (last >= first) : (last <= first) );
typedef typename range_detail::integer_iterator_with_step<Integer> iterator_t;
const std::ptrdiff_t sz = static_cast<std::ptrdiff_t>(step_size >= 0 ? step_size : -step_size);
@ -225,12 +225,19 @@ namespace boost
const Integer f = step_size >= 0 ? first : last;
const std::ptrdiff_t num_steps = (l - f) / sz + ((l - f) % sz ? 1 : 0);
BOOST_ASSERT(num_steps >= 0);
return strided_integer_range<Integer>(
iterator_t(first, 0, step_size),
iterator_t(first, num_steps, step_size));
}
template<typename Integer>
integer_range<Integer>
irange(Integer last)
{
return integer_range<Integer>(static_cast<Integer>(0), last);
}
} // namespace boost
#endif // include guard

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@ -18,6 +18,23 @@
namespace boost
{
// Test an integer range with a step size of 1.
template<typename Integer>
void test_irange_impl(Integer last)
{
std::vector<Integer> reference;
for (Integer i = static_cast<Integer>(0); i < last; ++i)
{
reference.push_back(i);
}
std::vector<Integer> test;
boost::push_back(test, boost::irange(last));
BOOST_CHECK_EQUAL_COLLECTIONS( test.begin(), test.end(),
reference.begin(), reference.end() );
}
// Test an integer range with a step size of 1.
template<typename Integer>
void test_irange_impl(Integer first, Integer last)
@ -34,36 +51,52 @@ namespace boost
BOOST_CHECK_EQUAL_COLLECTIONS( test.begin(), test.end(),
reference.begin(), reference.end() );
}
// Test an integer range with a runtime specified step size.
template<typename Integer, typename IntegerInput>
void test_irange_impl(IntegerInput first, IntegerInput last, int step)
{
BOOST_ASSERT( step != 0 );
// Skip tests that have negative values if the type is
// unsigned
if ((static_cast<IntegerInput>(static_cast<Integer>(first)) != first)
|| (static_cast<IntegerInput>(static_cast<Integer>(last)) != last))
return;
std::vector<Integer> reference;
const std::ptrdiff_t first_p = static_cast<std::ptrdiff_t>(first);
const std::ptrdiff_t last_p = static_cast<std::ptrdiff_t>(last);
const std::ptrdiff_t step_p = static_cast<std::ptrdiff_t>(step);
for (std::ptrdiff_t current_value = first_p;
for (std::ptrdiff_t current_value = first_p;
step_p >= 0 ? current_value < last_p : current_value > last_p;
current_value += step_p)
reference.push_back(current_value);
std::vector<Integer> test;
boost::push_back(test, boost::irange(first, last, step));
BOOST_CHECK_EQUAL_COLLECTIONS( test.begin(), test.end(),
reference.begin(), reference.end() );
}
// Test driver function that for an integer range [first, last)
// drives the test implementation through various integer
// types.
void test_irange(int last)
{
test_irange_impl<signed char>(last);
test_irange_impl<unsigned char>(last);
test_irange_impl<signed short>(last);
test_irange_impl<unsigned short>(last);
test_irange_impl<signed int>(last);
test_irange_impl<unsigned int>(last);
test_irange_impl<signed long>(last);
test_irange_impl<unsigned long>(last);
}
// Test driver function that for an integer range [first, last)
// drives the test implementation through various integer
// types.
@ -102,6 +135,11 @@ namespace boost
// number of implementation branches.
void irange_unit_test()
{
// Test the single-step version of irange(last)
test_irange(0);
test_irange(1);
test_irange(10);
// Test the single-step version of irange(first, last)
test_irange(0, 0);
test_irange(0, 1);
@ -124,14 +162,14 @@ namespace boost
test_irange(9, -9, -2);
test_irange(10, 20, 5);
test_irange(20, 10, -5);
test_irange(0, 0, 3);
test_irange(0, 1, 3);
test_irange(0, 2, 3);
test_irange(0, 3, 3);
test_irange(0, 4, 3);
test_irange(0, 10, 3);
test_irange(0, 0, -3);
test_irange(0, -1, -3);
test_irange(0, -2, -3);