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[range] Fix off-by-one error in implementation of irange() (refs #7731).

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[SVN r84701]
This commit is contained in:
Nathan Ridge
2013-06-08 20:41:43 +00:00
parent 1eb5554da9
commit 8be23dd1aa
2 changed files with 7 additions and 13 deletions
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2
include/boost/range/irange.hpp
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@ -217,7 +217,7 @@ namespace boost
const std::ptrdiff_t sz = static_cast<std::ptrdiff_t>(step_size >= 0 ? step_size : -step_size);
const Integer l = step_size >= 0 ? last : first;
const Integer f = step_size >= 0 ? first : last;
const std::ptrdiff_t num_steps = (l + ((l-f) % sz) - f) / sz;
const std::ptrdiff_t num_steps = (l - f) / sz + ((l - f) % sz ? 1 : 0);
BOOST_ASSERT(num_steps >= 0);
return strided_integer_range<Integer>(

18
test/irange.cpp
View File

@ -35,15 +35,6 @@ namespace boost
reference.begin(), reference.end() );
}
template<typename Integer>
std::ptrdiff_t test_irange_calculate_num_steps(Integer first, Integer last, int step)
{
const std::ptrdiff_t sz = static_cast<std::ptrdiff_t>(step >= 0 ? step : -step);
const std::ptrdiff_t l = static_cast<std::ptrdiff_t>(step >= 0 ? last : first);
const std::ptrdiff_t f = static_cast<std::ptrdiff_t>(step >= 0 ? first : last);
return (l + ((l-f) % sz) - f) / sz;
}
// 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)
@ -58,9 +49,12 @@ namespace boost
std::vector<Integer> reference;
const std::ptrdiff_t num_steps = test_irange_calculate_num_steps(first, last, step);
Integer current_value = first;
for (std::ptrdiff_t i = 0; i < num_steps; ++i, current_value += step)
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;
step_p >= 0 ? current_value < last_p : current_value > last_p;
current_value += step_p)
reference.push_back(current_value);
std::vector<Integer> test;