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diff --git a/boost/fiber/detail/context_spinlock_queue.hpp b/boost/fiber/detail/context_spinlock_queue.hpp
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+++ b/boost/fiber/detail/context_spinlock_queue.hpp
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+
+//          Copyright Oliver Kowalke 2015.
+// 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)
+//
+
+#ifndef BOOST_FIBERS_DETAIL_SPINLOCK_QUEUE_H
+#define BOOST_FIBERS_DETAIL_SPINLOCK_QUEUE_H
+
+#include <cstddef>
+#include <cstring>
+#include <mutex>
+
+#include <boost/config.hpp>
+
+#include <boost/fiber/context.hpp>
+#include <boost/fiber/detail/config.hpp>
+#include <boost/fiber/detail/spinlock.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace fibers {
+namespace detail {
+
+class context_spinlock_queue {
+private:
+	typedef context *   slot_type;
+
+    alignas(cache_alignment) mutable spinlock   splk_{};
+	std::size_t                                 pidx_{ 0 };
+	std::size_t                                 cidx_{ 0 };
+	std::size_t                                 capacity_;
+	slot_type                               *   slots_;
+
+	void resize_() {
+		slot_type * old_slots = slots_;
+		slots_ = new slot_type[2*capacity_];
+		std::size_t offset = capacity_ - cidx_;
+		std::memcpy( slots_, old_slots + cidx_, offset * sizeof( slot_type) );
+		if ( 0 < cidx_) {
+			std::memcpy( slots_ + offset, old_slots, pidx_ * sizeof( slot_type) );
+		}
+		cidx_ = 0;
+		pidx_ = capacity_ - 1;
+		capacity_ *= 2;
+		delete [] old_slots;
+	}
+
+	bool is_full_() const noexcept {
+		return cidx_ == ((pidx_ + 1) % capacity_);
+	}
+
+	bool is_empty_() const noexcept {
+		return cidx_ == pidx_;
+	}
+
+public:
+	context_spinlock_queue( std::size_t capacity = 4096) :
+			capacity_{ capacity } {
+		slots_ = new slot_type[capacity_];
+	}
+
+	~context_spinlock_queue() {
+		delete [] slots_;
+	}
+
+    context_spinlock_queue( context_spinlock_queue const&) = delete;
+    context_spinlock_queue & operator=( context_spinlock_queue const&) = delete;
+
+	bool empty() const noexcept {
+        spinlock_lock lk{ splk_ };
+		return is_empty_();
+	}
+
+	void push( context * c) {
+        spinlock_lock lk{ splk_ };
+		if ( is_full_() ) {
+			resize_();
+		}
+		slots_[pidx_] = c;
+		pidx_ = (pidx_ + 1) % capacity_;
+	}
+
+	context * pop() {
+        spinlock_lock lk{ splk_ };
+		context * c = nullptr;
+		if ( ! is_empty_() ) {
+			c = slots_[cidx_];
+			cidx_ = (cidx_ + 1) % capacity_;
+		}
+		return c;
+	}
+
+	context * steal() {
+        spinlock_lock lk{ splk_ };
+		context * c = nullptr;
+		if ( ! is_empty_() ) {
+			c = slots_[cidx_];
+            if ( c->is_context( type::pinned_context) ) {
+                return nullptr;
+            }
+			cidx_ = (cidx_ + 1) % capacity_;
+		}
+		return c;
+	}
+};
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_FIBERS_DETAIL_SPINLOCK_QUEUE_H