104 lines
4.8 KiB
C++
104 lines
4.8 KiB
C++
#ifndef OSMIUM_UTIL_CAST_HPP
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#define OSMIUM_UTIL_CAST_HPP
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/*
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This file is part of Osmium (http://osmcode.org/libosmium).
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Copyright 2013-2017 Jochen Topf <jochen@topf.org> and others (see README).
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Boost Software License - Version 1.0 - August 17th, 2003
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Permission is hereby granted, free of charge, to any person or organization
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obtaining a copy of the software and accompanying documentation covered by
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this license (the "Software") to use, reproduce, display, distribute,
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execute, and transmit the Software, and to prepare derivative works of the
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Software, and to permit third-parties to whom the Software is furnished to
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do so, all subject to the following:
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The copyright notices in the Software and this entire statement, including
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the above license grant, this restriction and the following disclaimer,
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must be included in all copies of the Software, in whole or in part, and
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all derivative works of the Software, unless such copies or derivative
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works are solely in the form of machine-executable object code generated by
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a source language processor.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
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SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
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ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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DEALINGS IN THE SOFTWARE.
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*/
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#ifndef assert
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# include <cassert>
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#endif
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#include <cstdint>
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#include <limits>
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#include <type_traits>
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namespace osmium {
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// These functions are wrappers around static_cast<>() that call assert()
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// to check that there is no integer overflow happening before doing the
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// cast. There are several versions of this templated function here
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// depending on the types of the input and output. In any case, both input
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// and output have to be integral types. If the cast can't overflow, no
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// check is done.
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template <typename A, typename B>
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struct are_real_integers :
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std::integral_constant<bool,
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std::is_integral<A>::value &&
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std::is_integral<B>::value &&
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!std::is_same<A, bool>::value &&
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!std::is_same<B, bool>::value> {
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};
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template <typename T, typename F, typename std::enable_if<are_real_integers<T, F>::value && std::is_same<T, F>::value, int>::type = 0>
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inline T static_cast_with_assert(const F value) {
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return value;
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}
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template <typename T, typename F, typename std::enable_if<are_real_integers<T, F>::value && !std::is_same<T, F>::value && (sizeof(T) > sizeof(F)), int>::type = 0>
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inline T static_cast_with_assert(const F value) {
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return static_cast<T>(value);
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}
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template <typename T, typename F, typename std::enable_if<are_real_integers<T, F>::value && !std::is_same<T, F>::value && std::is_signed<T>::value == std::is_signed<F>::value && (sizeof(T) == sizeof(F)), int>::type = 0>
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inline T static_cast_with_assert(const F value) {
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return static_cast<T>(value);
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}
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template <typename T, typename F, typename std::enable_if<are_real_integers<T, F>::value && !std::is_same<T, F>::value && (sizeof(T) < sizeof(F)) && std::is_signed<T>::value && std::is_signed<F>::value, int>::type = 0>
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inline T static_cast_with_assert(const F value) {
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assert(value >= std::numeric_limits<T>::min() && value <= std::numeric_limits<T>::max());
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return static_cast<T>(value);
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}
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template <typename T, typename F, typename std::enable_if<are_real_integers<T, F>::value && !std::is_same<T, F>::value && (sizeof(T) <= sizeof(F)) && std::is_unsigned<T>::value && std::is_signed<F>::value, int>::type = 0>
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inline T static_cast_with_assert(const F value) {
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assert(value >= 0 && static_cast<typename std::make_unsigned<F>::type>(value) <= std::numeric_limits<T>::max());
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return static_cast<T>(value);
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}
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template <typename T, typename F, typename std::enable_if<are_real_integers<T, F>::value && !std::is_same<T, F>::value && (sizeof(T) < sizeof(F)) && std::is_unsigned<T>::value && std::is_unsigned<F>::value, int>::type = 0>
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inline T static_cast_with_assert(const F value) {
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assert(value <= std::numeric_limits<T>::max());
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return static_cast<T>(value);
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}
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template <typename T, typename F, typename std::enable_if<are_real_integers<T, F>::value && !std::is_same<T, F>::value && (sizeof(T) <= sizeof(F)) && std::is_signed<T>::value && std::is_unsigned<F>::value, int>::type = 0>
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inline T static_cast_with_assert(const F value) {
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assert(static_cast<int64_t>(value) <= static_cast<int64_t>(std::numeric_limits<T>::max()));
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return static_cast<T>(value);
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}
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} // namespace osmium
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#endif // OSMIUM_UTIL_CAST_HPP
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