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+//---------------------------------------------------------------------------//
+// Copyright (c) 2016 Jakub Szuppe <j.szuppe@gmail.com>
+//
+// 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://boostorg.github.com/compute for more information.
+//---------------------------------------------------------------------------//
+
+#ifndef BOOST_COMPUTE_ALGORITHM_STABLE_SORT_BY_KEY_HPP
+#define BOOST_COMPUTE_ALGORITHM_STABLE_SORT_BY_KEY_HPP
+
+#include <iterator>
+
+#include <boost/compute/system.hpp>
+#include <boost/compute/command_queue.hpp>
+#include <boost/compute/algorithm/sort_by_key.hpp>
+#include <boost/compute/detail/iterator_range_size.hpp>
+
+namespace boost {
+namespace compute {
+
+namespace detail {
+
+template<class KeyIterator, class ValueIterator>
+inline void
+dispatch_gpu_ssort_by_key(KeyIterator keys_first,
+                          KeyIterator keys_last,
+                          ValueIterator values_first,
+                          less<typename std::iterator_traits<KeyIterator>::value_type> compare,
+                          command_queue &queue,
+                          typename boost::enable_if_c<
+                              is_radix_sortable<
+                                  typename std::iterator_traits<KeyIterator>::value_type
+                              >::value
+                          >::type* = 0)
+{
+    size_t count = detail::iterator_range_size(keys_first, keys_last);
+
+    if(count < 32){
+        detail::serial_insertion_sort_by_key(
+            keys_first, keys_last, values_first, compare, queue
+        );
+    }
+    else {
+        detail::radix_sort_by_key(
+            keys_first, keys_last, values_first, queue
+        );
+    }
+}
+
+template<class KeyIterator, class ValueIterator>
+inline void
+dispatch_gpu_ssort_by_key(KeyIterator keys_first,
+                          KeyIterator keys_last,
+                          ValueIterator values_first,
+                          greater<typename std::iterator_traits<KeyIterator>::value_type> compare,
+                          command_queue &queue,
+                          typename boost::enable_if_c<
+                              is_radix_sortable<
+                                  typename std::iterator_traits<KeyIterator>::value_type
+                              >::value
+                          >::type* = 0)
+{
+    size_t count = detail::iterator_range_size(keys_first, keys_last);
+
+    if(count < 32){
+        detail::serial_insertion_sort_by_key(
+            keys_first, keys_last, values_first, compare, queue
+        );
+    }
+    else {
+        // radix sorts in descending order
+        detail::radix_sort_by_key(
+            keys_first, keys_last, values_first, false, queue
+        );
+    }
+}
+
+template<class KeyIterator, class ValueIterator, class Compare>
+inline void dispatch_gpu_ssort_by_key(KeyIterator keys_first,
+                                      KeyIterator keys_last,
+                                      ValueIterator values_first,
+                                      Compare compare,
+                                      command_queue &queue)
+{
+    size_t count = detail::iterator_range_size(keys_first, keys_last);
+
+    if(count < 32){
+        detail::serial_insertion_sort_by_key(
+            keys_first, keys_last, values_first,
+            compare, queue
+        );
+    } else {
+        detail::merge_sort_by_key_on_gpu(
+            keys_first, keys_last, values_first,
+            compare, true /* stable */, queue
+        );
+    }
+}
+
+template<class KeyIterator, class ValueIterator, class Compare>
+inline void dispatch_ssort_by_key(KeyIterator keys_first,
+                                  KeyIterator keys_last,
+                                  ValueIterator values_first,
+                                  Compare compare,
+                                  command_queue &queue)
+{
+    if(queue.get_device().type() & device::gpu) {
+        dispatch_gpu_ssort_by_key(
+            keys_first, keys_last, values_first, compare, queue
+        );
+        return;
+    }
+    ::boost::compute::detail::merge_sort_by_key_on_cpu(
+        keys_first, keys_last, values_first, compare, queue
+    );
+}
+
+} // end detail namespace
+
+/// Performs a key-value stable sort using the keys in the range [\p keys_first,
+/// \p keys_last) on the values in the range [\p values_first,
+/// \p values_first \c + (\p keys_last \c - \p keys_first)) using \p compare.
+///
+/// If no compare function is specified, \c less is used.
+///
+/// \see sort()
+template<class KeyIterator, class ValueIterator, class Compare>
+inline void stable_sort_by_key(KeyIterator keys_first,
+                               KeyIterator keys_last,
+                               ValueIterator values_first,
+                               Compare compare,
+                               command_queue &queue = system::default_queue())
+{
+    ::boost::compute::detail::dispatch_ssort_by_key(
+        keys_first, keys_last, values_first, compare, queue
+    );
+}
+
+/// \overload
+template<class KeyIterator, class ValueIterator>
+inline void stable_sort_by_key(KeyIterator keys_first,
+                               KeyIterator keys_last,
+                               ValueIterator values_first,
+                               command_queue &queue = system::default_queue())
+{
+    typedef typename std::iterator_traits<KeyIterator>::value_type key_type;
+
+    ::boost::compute::stable_sort_by_key(
+        keys_first, keys_last, values_first, less<key_type>(), queue
+    );
+}
+
+} // end compute namespace
+} // end boost namespace
+
+#endif // BOOST_COMPUTE_ALGORITHM_STABLE_SORT_BY_KEY_HPP