boost/sort/spreadsort/string_sort.hpp
//Templated hybrid string_sort
// Copyright Steven J. Ross 2001 - 2009.
// 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
*/
#ifndef BOOST_STRING_SORT_HPP
#define BOOST_STRING_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/string_sort.hpp>
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
namespace boost {
namespace sort {
namespace spreadsort {
/*! \brief String sort algorithm using random access iterators, allowing character-type overloads.\n
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
\details @c string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\tparam RandomAccessIter <a href="http://www.cplusplus.com/reference/iterator/RandomAccessIterator/">Random access iterator</a>
\tparam Unsigned_char_type Unsigned character type used for string.
\param[in] first Iterator pointer to first element.
\param[in] last Iterator pointing to one beyond the end of data.
\param[in] unused value with the same type as the result of the [] operator, defining the Unsigned_char_type. The actual value is unused.
\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, class Unsigned_char_type>
inline void string_sort(RandomAccessIter first, RandomAccessIter last,
Unsigned_char_type unused)
{
//Don't sort if it's too small to optimize
if (last - first < detail::min_sort_size)
boost::sort::pdqsort(first, last);
else
detail::string_sort(first, last, unused);
}
/*! \brief String sort algorithm using range, allowing character-type overloads.\n
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
\details @c string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\tparam Unsigned_char_type Unsigned character type used for string.
\param[in] range Range [first, last) for sorting.
\param[in] unused value with the same type as the result of the [] operator, defining the Unsigned_char_type. The actual value is unused.
\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 Unsigned_char_type>
inline void string_sort(Range& range, Unsigned_char_type unused)
{
string_sort(boost::begin(range), boost::end(range), unused);
}
/*! \brief String sort algorithm using random access iterators, wraps using default of unsigned char.
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
\details @c string_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 string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>
\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_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 string_sort(RandomAccessIter first, RandomAccessIter last)
{
unsigned char unused = '\0';
string_sort(first, last, unused);
}
/*! \brief String sort algorithm using range, wraps using default of unsigned char.
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
\details @c string_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 string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>
\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_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 string_sort(Range& range)
{
string_sort(boost::begin(range), boost::end(range));
}
/*! \brief String sort algorithm using random access iterators, allowing character-type overloads.
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < detail::min_sort_size).
\details @c string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\tparam RandomAccessIter <a href="http://www.cplusplus.com/reference/iterator/RandomAccessIterator/">Random access iterator</a>
\tparam Comp Functor type to use for comparison.
\tparam Unsigned_char_type Unsigned character type used for string.
\param[in] first Iterator pointer to first element.
\param[in] last Iterator pointing to one beyond the end of data.
\param[in] comp A binary functor that returns whether the first element passed to it should go before the second in order.
\param[in] unused value with the same type as the result of the [] operator, defining the Unsigned_char_type. The actual value is unused.
\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.
\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 Compare, class Unsigned_char_type>
inline void reverse_string_sort(RandomAccessIter first,
RandomAccessIter last, Compare comp, Unsigned_char_type unused)
{
//Don't sort if it's too small to optimize.
if (last - first < detail::min_sort_size)
boost::sort::pdqsort(first, last, comp);
else
detail::reverse_string_sort(first, last, unused);
}
/*! \brief String sort algorithm using range, allowing character-type overloads.
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < detail::min_sort_size).
\details @c string_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 string_sort is asymptotically faster
than pure comparison-based algorithms. \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>
\tparam Comp Functor type to use for comparison.
\tparam Unsigned_char_type Unsigned character type used for string.
\param[in] range Range [first, last) for sorting.
\param[in] comp A binary functor that returns whether the first element passed to it should go before the second in order.
\param[in] unused value with the same type as the result of the [] operator, defining the Unsigned_char_type. The actual value is unused.
\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 Compare, class Unsigned_char_type>
inline void reverse_string_sort(Range& range, Compare comp, Unsigned_char_type unused)
{
reverse_string_sort(boost::begin(range), boost::end(range), comp, unused);
}
/*! \brief String sort algorithm using random access iterators, wraps using default of @c unsigned char.
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
\details @c string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms.\n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\param[in] first Iterator pointer to first element.
\param[in] last Iterator pointing to one beyond the end of data.
\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.
\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.
\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 Compare>
inline void reverse_string_sort(RandomAccessIter first,
RandomAccessIter last, Compare comp)
{
unsigned char unused = '\0';
reverse_string_sort(first, last, comp, unused);
}
/*! \brief String sort algorithm using range, wraps using default of @c unsigned char.
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
\details @c string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\param[in] range Range [first, last) for sorting.
\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 Compare>
inline void reverse_string_sort(Range& range, Compare comp)
{
reverse_string_sort(boost::begin(range), boost::end(range), comp);
}
/*! \brief String sort algorithm using random access iterators, wraps using default of @c unsigned char.
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
\details @c string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\param[in] first Iterator pointer to first element.
\param[in] last Iterator pointing to one beyond the end of data.
\param[in] get_character Bracket functor equivalent to @c operator[], taking a number corresponding to the character offset.
\param[in] length Functor to get the length of the string in characters.
\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.
\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 Get_char, class Get_length>
inline void string_sort(RandomAccessIter first, RandomAccessIter last,
Get_char get_character, Get_length length)
{
//Don't sort if it's too small to optimize
if (last - first < detail::min_sort_size)
boost::sort::pdqsort(first, last);
else {
//skipping past empties, which allows us to get the character type
//.empty() is not used so as not to require a user declaration of it
while (!length(*first)) {
if (++first == last)
return;
}
detail::string_sort(first, last, get_character, length, get_character((*first), 0));
}
}
/*! \brief String sort algorithm using range, wraps using default of @c unsigned char.
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
\details @c string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\param[in] range Range [first, last) for sorting.
\param[in] get_character Bracket functor equivalent to @c operator[], taking a number corresponding to the character offset.
\param[in] length Functor to get the length of the string in characters.
\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 Get_char, class Get_length>
inline void string_sort(Range& range, Get_char get_character, Get_length length)
{
string_sort(boost::begin(range), boost::end(range), get_character, length);
}
/*! \brief String sort algorithm using random access iterators, wraps using default of @c unsigned char.
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
\details @c string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\param[in] first Iterator pointer to first element.
\param[in] last Iterator pointing to one beyond the end of data.
\param[in] get_character Bracket functor equivalent to @c operator[], taking a number corresponding to the character offset.
\param[in] length Functor to get the length of the string in characters.
\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.
\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.
\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 Get_char, class Get_length,
class Compare>
inline void string_sort(RandomAccessIter first, RandomAccessIter last,
Get_char get_character, Get_length length, Compare comp)
{
//Don't sort if it's too small to optimize
if (last - first < detail::min_sort_size)
boost::sort::pdqsort(first, last, comp);
else {
//skipping past empties, which allows us to get the character type
//.empty() is not used so as not to require a user declaration of it
while (!length(*first)) {
if (++first == last)
return;
}
detail::string_sort(first, last, get_character, length, comp,
get_character((*first), 0));
}
}
/*! \brief String sort algorithm using range, wraps using default of @c unsigned char.
(All variants fall back to @c boost::sort::pdqsort if the data size is too small, < @c detail::min_sort_size).
\details @c string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\param[in] range Range [first, last) for sorting.
\param[in] get_character Bracket functor equivalent to @c operator[], taking a number corresponding to the character offset.
\param[in] length Functor to get the length of the string in characters.
\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 Get_char, class Get_length, class Compare>
inline void string_sort(Range& range,
Get_char get_character, Get_length length, Compare comp)
{
string_sort(boost::begin(range), boost::end(range), get_character, length, comp);
}
/*! \brief Reverse String 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 string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\param[in] first Iterator pointer to first element.
\param[in] last Iterator pointing to one beyond the end of data.
\param[in] get_character Bracket functor equivalent to @c operator[], taking a number corresponding to the character offset.
\param[in] length Functor to get the length of the string in characters.
\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.
\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.
\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 Get_char, class Get_length,
class Compare>
inline void reverse_string_sort(RandomAccessIter first,
RandomAccessIter last, Get_char get_character, Get_length length, Compare comp)
{
//Don't sort if it's too small to optimize
if (last - first < detail::min_sort_size)
boost::sort::pdqsort(first, last, comp);
else {
//skipping past empties, which allows us to get the character type
//.empty() is not used so as not to require a user declaration of it
while (!length(*(--last))) {
//If there is just one non-empty at the beginning, this is sorted
if (first == last)
return;
}
//making last just after the end of the non-empty part of the array
detail::reverse_string_sort(first, last + 1, get_character, length, comp,
get_character((*last), 0));
}
}
/*! \brief Reverse String 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 string_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
Worst-case performance is <em> O(N * (lg(range)/s + s)) </em>,
so @c string_sort is asymptotically faster
than pure comparison-based algorithms. \n\n
Some performance plots of runtime vs. n and log(range) are provided:\n
<a href="../../doc/graph/windows_string_sort.htm"> windows_string_sort</a>\n
<a href="../../doc/graph/osx_string_sort.htm"> osx_string_sort</a>
\param[in] range Range [first, last) for sorting.
\param[in] get_character Bracket functor equivalent to @c operator[], taking a number corresponding to the character offset.
\param[in] length Functor to get the length of the string in characters.
\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 Get_char, class Get_length,
class Compare>
inline void reverse_string_sort(Range& range, Get_char get_character, Get_length length, Compare comp)
{
reverse_string_sort(boost::begin(range), boost::end(range), get_character, length, comp);
}
}
}
}
#endif