Initial Commit

.svn/pristine/5e/5e32061e6ad34bea5b185a6516d54edffff497dc.svn-base

@@ -0,0 +1,44 @@
+//---------------------------------------------------------------------------//
+// Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@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_DETAIL_ITERATOR_RANGE_SIZE_H
+#define BOOST_COMPUTE_DETAIL_ITERATOR_RANGE_SIZE_H
+
+#include <cstddef>
+#include <algorithm>
+#include <iterator>
+
+namespace boost {
+namespace compute {
+namespace detail {
+
+// This is a convenience function which returns the size of a range
+// bounded by two iterators. This function has two differences from
+// the std::distance() function: 1) the return type (size_t) is
+// unsigned, and 2) the return value is always positive.
+template<class Iterator>
+inline size_t iterator_range_size(Iterator first, Iterator last)
+{
+    typedef typename
+        std::iterator_traits<Iterator>::difference_type
+        difference_type;
+
+    difference_type difference = std::distance(first, last);
+
+    return static_cast<size_t>(
+        (std::max)(difference, static_cast<difference_type>(0))
+    );
+}
+
+} // end detail namespace
+} // end compute namespace
+} // end boost namespace
+
+#endif // BOOST_COMPUTE_DETAIL_ITERATOR_RANGE_SIZE_H