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- //Templated Spreadsort-based implementation of integer_sort
- // Copyright Steven J. Ross 2001 - 2014.
- // 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)
- // See http://www.boost.org/libs/sort/ for library home page.
- /*
- Some improvements suggested by:
- Phil Endecott and Frank Gennari
- Doxygen comments by Paul A. Bristow Jan 2015
- */
- #ifndef BOOST_INTEGER_SORT_HPP
- #define BOOST_INTEGER_SORT_HPP
- #include <algorithm>
- #include <vector>
- #include <cstring>
- #include <limits>
- #include <boost/static_assert.hpp>
- #include <boost/sort/spreadsort/detail/constants.hpp>
- #include <boost/sort/spreadsort/detail/integer_sort.hpp>
- #include <boost/range/begin.hpp>
- #include <boost/range/end.hpp>
- namespace boost {
- namespace sort {
- namespace spreadsort {
- //Top-level sorting call for integers.
- /*! \brief Integer sort algorithm using random access iterators.
- (All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
- \details @c integer_sort is a fast templated in-place hybrid radix/comparison algorithm,
- which in testing tends to be roughly 50% to 2X faster than @c std::sort for large tests (>=100kB).\n
- Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
- so @c integer_sort is asymptotically faster
- than pure comparison-based algorithms. @c s is @c max_splits, which defaults to 11,
- so its worst-case with default settings for 32-bit integers is
- <em> O(N * ((32/11) </em> slow radix-based iterations fast comparison-based iterations).\n\n
- Some performance plots of runtime vs. n and log(range) are provided:\n
- <a href="../../doc/graph/windows_integer_sort.htm"> windows_integer_sort</a>
- \n
- <a href="../../doc/graph/osx_integer_sort.htm"> osx_integer_sort</a>
- \param[in] first Iterator pointer to first element.
- \param[in] last Iterator pointing to one beyond the end of data.
- \pre [@c first, @c last) is a valid range.
- \pre @c RandomAccessIter @c value_type is mutable.
- \pre @c RandomAccessIter @c value_type is <a href="http://en.cppreference.com/w/cpp/concept/LessThanComparable">LessThanComparable</a>
- \pre @c RandomAccessIter @c value_type supports the @c operator>>,
- which returns an integer-type right-shifted a specified number of bits.
- \post The elements in the range [@c first, @c last) are sorted in ascending order.
- \throws std::exception Propagates exceptions if any of the element comparisons, the element swaps (or moves),
- the right shift, subtraction of right-shifted elements, functors, or any operations on iterators throw.
- \warning Throwing an exception may cause data loss. This will also throw if a small vector resize throws, in which case there will be no data loss.
- \warning Invalid arguments cause undefined behaviour.
- \note @c spreadsort function provides a wrapper that calls the fastest sorting algorithm available for a data type,
- enabling faster generic-programming.
- \remark The lesser of <em> O(N*log(N)) </em> comparisons and <em> O(N*log(K/S + S)) </em>operations worst-case, where:
- \remark * N is @c last - @c first,
- \remark * K is the log of the range in bits (32 for 32-bit integers using their full range),
- \remark * S is a constant called max_splits, defaulting to 11 (except for strings where it is the log of the character size).
- */
- template <class RandomAccessIter>
- inline void integer_sort(RandomAccessIter first, RandomAccessIter last)
- {
- // Don't sort if it's too small to optimize.
- if (last - first < detail::min_sort_size)
- boost::sort::pdqsort(first, last);
- else
- detail::integer_sort(first, last, *first >> 0);
- }
- /*! \brief Integer sort algorithm using range.
- (All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
- \details @c integer_sort is a fast templated in-place hybrid radix/comparison algorithm,
- which in testing tends to be roughly 50% to 2X faster than @c std::sort for large tests (>=100kB).\n
- Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
- so @c integer_sort is asymptotically faster
- than pure comparison-based algorithms. @c s is @c max_splits, which defaults to 11,
- so its worst-case with default settings for 32-bit integers is
- <em> O(N * ((32/11) </em> slow radix-based iterations fast comparison-based iterations).\n\n
- Some performance plots of runtime vs. n and log(range) are provided:\n
- <a href="../../doc/graph/windows_integer_sort.htm"> windows_integer_sort</a>
- \n
- <a href="../../doc/graph/osx_integer_sort.htm"> osx_integer_sort</a>
- \param[in] range Range [first, last) for sorting.
- \pre [@c first, @c last) is a valid range.
- \post The elements in the range [@c first, @c last) are sorted in ascending order.
- \throws std::exception Propagates exceptions if any of the element comparisons, the element swaps (or moves),
- the right shift, subtraction of right-shifted elements, functors, or any operations on iterators throw.
- \warning Throwing an exception may cause data loss. This will also throw if a small vector resize throws, in which case there will be no data loss.
- \warning Invalid arguments cause undefined behaviour.
- \note @c spreadsort function provides a wrapper that calls the fastest sorting algorithm available for a data type,
- enabling faster generic-programming.
- \remark The lesser of <em> O(N*log(N)) </em> comparisons and <em> O(N*log(K/S + S)) </em>operations worst-case, where:
- \remark * N is @c last - @c first,
- \remark * K is the log of the range in bits (32 for 32-bit integers using their full range),
- \remark * S is a constant called max_splits, defaulting to 11 (except for strings where it is the log of the character size).
- */
- template <class Range>
- inline void integer_sort(Range& range)
- {
- integer_sort(boost::begin(range), boost::end(range));
- }
- /*! \brief Integer sort algorithm using random access iterators with both right-shift and user-defined comparison operator.
- (All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
- \details @c integer_sort is a fast templated in-place hybrid radix/comparison algorithm,
- which in testing tends to be roughly 50% to 2X faster than @c std::sort for large tests (>=100kB).\n
- Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
- so @c integer_sort is asymptotically faster
- than pure comparison-based algorithms. @c s is @c max_splits, which defaults to 11,
- so its worst-case with default settings for 32-bit integers is
- <em> O(N * ((32/11) </em> slow radix-based iterations fast comparison-based iterations).\n\n
- Some performance plots of runtime vs. n and log(range) are provided:\n
- <a href="../../doc/graph/windows_integer_sort.htm"> windows_integer_sort</a>
- \n
- <a href="../../doc/graph/osx_integer_sort.htm"> osx_integer_sort</a>
- \param[in] first Iterator pointer to first element.
- \param[in] last Iterator pointing to one beyond the end of data.
- \param[in] shift Functor that returns the result of shifting the value_type right a specified number of bits.
- \param[in] comp A binary functor that returns whether the first element passed to it should go before the second in order.
- \pre [@c first, @c last) is a valid range.
- \pre @c RandomAccessIter @c value_type is mutable.
- \post The elements in the range [@c first, @c last) are sorted in ascending order.
- \return @c void.
- \throws std::exception Propagates exceptions if any of the element comparisons, the element swaps (or moves),
- the right shift, subtraction of right-shifted elements, functors,
- or any operations on iterators throw.
- \warning Throwing an exception may cause data loss. This will also throw if a small vector resize throws, in which case there will be no data loss.
- \warning Invalid arguments cause undefined behaviour.
- \note @c spreadsort function provides a wrapper that calls the fastest sorting algorithm available for a data type,
- enabling faster generic-programming.
- \remark The lesser of <em> O(N*log(N)) </em> comparisons and <em> O(N*log(K/S + S)) </em>operations worst-case, where:
- \remark * N is @c last - @c first,
- \remark * K is the log of the range in bits (32 for 32-bit integers using their full range),
- \remark * S is a constant called max_splits, defaulting to 11 (except for strings where it is the log of the character size).
- */
- template <class RandomAccessIter, class Right_shift, class Compare>
- inline void integer_sort(RandomAccessIter first, RandomAccessIter last,
- Right_shift shift, Compare comp) {
- if (last - first < detail::min_sort_size)
- boost::sort::pdqsort(first, last, comp);
- else
- detail::integer_sort(first, last, shift(*first, 0), shift, comp);
- }
- /*! \brief Integer sort algorithm using range with both right-shift and user-defined comparison operator.
- (All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
- \details @c integer_sort is a fast templated in-place hybrid radix/comparison algorithm,
- which in testing tends to be roughly 50% to 2X faster than @c std::sort for large tests (>=100kB).\n
- Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
- so @c integer_sort is asymptotically faster
- than pure comparison-based algorithms. @c s is @c max_splits, which defaults to 11,
- so its worst-case with default settings for 32-bit integers is
- <em> O(N * ((32/11) </em> slow radix-based iterations fast comparison-based iterations).\n\n
- Some performance plots of runtime vs. n and log(range) are provided:\n
- <a href="../../doc/graph/windows_integer_sort.htm"> windows_integer_sort</a>
- \n
- <a href="../../doc/graph/osx_integer_sort.htm"> osx_integer_sort</a>
- \param[in] range Range [first, last) for sorting.
- \param[in] shift Functor that returns the result of shifting the value_type right a specified number of bits.
- \param[in] comp A binary functor that returns whether the first element passed to it should go before the second in order.
- \pre [@c first, @c last) is a valid range.
- \post The elements in the range [@c first, @c last) are sorted in ascending order.
- \return @c void.
- \throws std::exception Propagates exceptions if any of the element comparisons, the element swaps (or moves),
- the right shift, subtraction of right-shifted elements, functors,
- or any operations on iterators throw.
- \warning Throwing an exception may cause data loss. This will also throw if a small vector resize throws, in which case there will be no data loss.
- \warning Invalid arguments cause undefined behaviour.
- \note @c spreadsort function provides a wrapper that calls the fastest sorting algorithm available for a data type,
- enabling faster generic-programming.
- \remark The lesser of <em> O(N*log(N)) </em> comparisons and <em> O(N*log(K/S + S)) </em>operations worst-case, where:
- \remark * N is @c last - @c first,
- \remark * K is the log of the range in bits (32 for 32-bit integers using their full range),
- \remark * S is a constant called max_splits, defaulting to 11 (except for strings where it is the log of the character size).
- */
- template <class Range, class Right_shift, class Compare>
- inline void integer_sort(Range& range, Right_shift shift, Compare comp)
- {
- integer_sort(boost::begin(range), boost::end(range), shift, comp);
- }
- /*! \brief Integer sort algorithm using random access iterators with just right-shift functor.
- (All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
- \details @c integer_sort is a fast templated in-place hybrid radix/comparison algorithm,
- which in testing tends to be roughly 50% to 2X faster than @c std::sort for large tests (>=100kB).\n
- \par Performance:
- Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
- so @c integer_sort is asymptotically faster
- than pure comparison-based algorithms. @c s is @c max_splits, which defaults to 11,
- so its worst-case with default settings for 32-bit integers is
- <em> O(N * ((32/11) </em> slow radix-based iterations fast comparison-based iterations).\n\n
- Some performance plots of runtime vs. n and log(range) are provided:\n
- * <a href="../../doc/graph/windows_integer_sort.htm"> windows_integer_sort</a>\n
- * <a href="../../doc/graph/osx_integer_sort.htm"> osx_integer_sort</a>
- \param[in] first Iterator pointer to first element.
- \param[in] last Iterator pointing to one beyond the end of data.
- \param[in] shift A functor that returns the result of shifting the value_type right a specified number of bits.
- \pre [@c first, @c last) is a valid range.
- \pre @c RandomAccessIter @c value_type is mutable.
- \pre @c RandomAccessIter @c value_type is <a href="http://en.cppreference.com/w/cpp/concept/LessThanComparable">LessThanComparable</a>
- \post The elements in the range [@c first, @c last) are sorted in ascending order.
- \throws std::exception Propagates exceptions if any of the element comparisons, the element swaps (or moves),
- the right shift, subtraction of right-shifted elements, functors,
- or any operations on iterators throw.
- \warning Throwing an exception may cause data loss. This will also throw if a small vector resize throws, in which case there will be no data loss.
- \warning Invalid arguments cause undefined behaviour.
- \note @c spreadsort function provides a wrapper that calls the fastest sorting algorithm available for a data type,
- enabling faster generic-programming.
- \remark The lesser of <em> O(N*log(N)) </em> comparisons and <em> O(N*log(K/S + S)) </em>operations worst-case, where:
- \remark * N is @c last - @c first,
- \remark * K is the log of the range in bits (32 for 32-bit integers using their full range),
- \remark * S is a constant called max_splits, defaulting to 11 (except for strings where it is the log of the character size).
- */
- template <class RandomAccessIter, class Right_shift>
- inline void integer_sort(RandomAccessIter first, RandomAccessIter last,
- Right_shift shift) {
- if (last - first < detail::min_sort_size)
- boost::sort::pdqsort(first, last);
- else
- detail::integer_sort(first, last, shift(*first, 0), shift);
- }
- /*! \brief Integer sort algorithm using range with just right-shift functor.
- (All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
- \details @c integer_sort is a fast templated in-place hybrid radix/comparison algorithm,
- which in testing tends to be roughly 50% to 2X faster than @c std::sort for large tests (>=100kB).\n
- \par Performance:
- Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
- so @c integer_sort is asymptotically faster
- than pure comparison-based algorithms. @c s is @c max_splits, which defaults to 11,
- so its worst-case with default settings for 32-bit integers is
- <em> O(N * ((32/11) </em> slow radix-based iterations fast comparison-based iterations).\n\n
- Some performance plots of runtime vs. n and log(range) are provided:\n
- * <a href="../../doc/graph/windows_integer_sort.htm"> windows_integer_sort</a>\n
- * <a href="../../doc/graph/osx_integer_sort.htm"> osx_integer_sort</a>
- \param[in] range Range [first, last) for sorting.
- \param[in] shift A functor that returns the result of shifting the value_type right a specified number of bits.
- \pre [@c first, @c last) is a valid range.
- \post The elements in the range [@c first, @c last) are sorted in ascending order.
- \throws std::exception Propagates exceptions if any of the element comparisons, the element swaps (or moves),
- the right shift, subtraction of right-shifted elements, functors,
- or any operations on iterators throw.
- \warning Throwing an exception may cause data loss. This will also throw if a small vector resize throws, in which case there will be no data loss.
- \warning Invalid arguments cause undefined behaviour.
- \note @c spreadsort function provides a wrapper that calls the fastest sorting algorithm available for a data type,
- enabling faster generic-programming.
- \remark The lesser of <em> O(N*log(N)) </em> comparisons and <em> O(N*log(K/S + S)) </em>operations worst-case, where:
- \remark * N is @c last - @c first,
- \remark * K is the log of the range in bits (32 for 32-bit integers using their full range),
- \remark * S is a constant called max_splits, defaulting to 11 (except for strings where it is the log of the character size).
- */
- template <class Range, class Right_shift>
- inline void integer_sort(Range& range, Right_shift shift)
- {
- integer_sort(boost::begin(range), boost::end(range), shift);
- }
- }
- }
- }
- #endif
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