add cast.hpp from osmium

ThirdParty/osmium/util/cast.hpp

@@ -0,0 +1,72 @@
+#ifndef OSMIUM_UTIL_CAST_HPP
+#define OSMIUM_UTIL_CAST_HPP
+
+/*
+
+This file is part of Osmium (http://osmcode.org/libosmium).
+
+Copyright 2013,2014 Jochen Topf <jochen@topf.org> and others (see README).
+
+Boost Software License - Version 1.0 - August 17th, 2003
+
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+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, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+
+*/
+
+#include <cassert>
+#include <limits>
+#include <type_traits>
+
+namespace osmium {
+
+    template <typename T, typename F, typename std::enable_if<std::is_integral<T>::value && std::is_integral<F>::value && std::is_signed<T>::value && std::is_signed<F>::value, int>::type = 0>
+    inline T static_cast_with_assert(const F value) {
+        static_assert(sizeof(T) < sizeof(F), "unnecessary static_cast_with_assert when casting into type of equal or larger size");
+        assert(value >= std::numeric_limits<T>::min() && value <= std::numeric_limits<T>::max());
+        return static_cast<T>(value);
+    } 
+
+    template <typename T, typename F, typename std::enable_if<std::is_integral<T>::value && std::is_integral<F>::value && std::is_unsigned<T>::value && std::is_signed<F>::value, int>::type = 0>
+    inline T static_cast_with_assert(const F value) {
+        static_assert(sizeof(T) <= sizeof(F), "unnecessary static_cast_with_assert when casting into type of larger size");
+        assert(value >= 0 && static_cast<typename std::make_unsigned<F>::type>(value) <= std::numeric_limits<T>::max());
+        return static_cast<T>(value);
+    }
+
+    template <typename T, typename F, typename std::enable_if<std::is_integral<T>::value && std::is_integral<F>::value && std::is_unsigned<T>::value && std::is_unsigned<F>::value, int>::type = 0>
+    inline T static_cast_with_assert(const F value) {
+        static_assert(sizeof(T) < sizeof(F), "unnecessary static_cast_with_assert when casting into type of equal or larger size");
+        assert(value <= std::numeric_limits<T>::max());
+        return static_cast<T>(value);
+    }
+
+    template <typename T, typename F, typename std::enable_if<std::is_integral<T>::value && std::is_integral<F>::value && std::is_signed<T>::value && std::is_unsigned<F>::value, int>::type = 0>
+    inline T static_cast_with_assert(const F value) {
+        static_assert(sizeof(T) <= sizeof(F), "unnecessary static_cast_with_assert when casting into type of larger size");
+        assert(value <= std::numeric_limits<T>::max());
+        return static_cast<T>(value);
+    } 
+
+} // namespace osmium
+
+#endif // OSMIUM_UTIL_CAST_HPP