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+// Boost.Geometry (aka GGL, Generic Geometry Library)
+// This file is manually converted from PROJ4
+
+// Copyright (c) 2008-2012 Barend Gehrels, Amsterdam, the Netherlands.
+
+// This file was modified by Oracle on 2017.
+// Modifications copyright (c) 2017, Oracle and/or its affiliates.
+// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
+
+// Use, modification and distribution is subject to 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)
+
+// This file is converted from PROJ4, http://trac.osgeo.org/proj
+// PROJ4 is originally written by Gerald Evenden (then of the USGS)
+// PROJ4 is maintained by Frank Warmerdam
+// PROJ4 is converted to Geometry Library by Barend Gehrels (Geodan, Amsterdam)
+
+// Original copyright notice:
+
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+#ifndef BOOST_GEOMETRY_PROJECTIONS_PJ_QSFN_HPP
+#define BOOST_GEOMETRY_PROJECTIONS_PJ_QSFN_HPP
+
+
+namespace boost { namespace geometry { namespace projections
+{
+
+namespace detail {
+
+/* determine small q */
+template <typename T>
+inline T pj_qsfn(T const& sinphi, T const& e, T const& one_es)
+{
+ static const T EPSILON = 1.0e-7;
+
+ if (e >= EPSILON)
+ {
+ T con = e * sinphi;
+ return (one_es * (sinphi / (1. - con * con) -
+ (.5 / e) * log ((1. - con) / (1. + con))));
+ } else
+ return (sinphi + sinphi);
+}
+
+
+static const int MAX_C = 9;
+
+template <typename T>
+struct AUTHALIC
+{
+ T C[MAX_C], CP[MAX_C], CQ[MAX_C];
+};
+
+/**
+ * @brief determine authalic latitude
+ * @param[in] phi geographic latitude
+ * @param[in] a initialized structure pointer
+ * @return authalic latitude
+ */
+template <typename T>
+inline T proj_qsfn(T const& phi, AUTHALIC<T> const& a)
+{
+ T s, s2, sum;
+ int i = MAX_C;
+
+ s = sin(phi);
+ s2 = s * s;
+ sum = a.CQ[MAX_C - 1];
+ while (--i) sum = a.CQ[i] + s2 * sum;
+ return(s * sum);
+}
+
+} // namespace detail
+
+}}} // namespace boost::geometry::projections
+
+#endif