| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you under the Apache License, Version 2.0 (the |
| // "License"); you may not use this file except in compliance |
| // with the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, |
| // software distributed under the License is distributed on an |
| // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| // KIND, either express or implied. See the License for the |
| // specific language governing permissions and limitations |
| // under the License. |
| |
| #ifndef IMPALA_UTIL_TEMPLATE_UTIL_H |
| #define IMPALA_UTIL_TEMPLATE_UTIL_H |
| |
| #include <boost/type_traits/is_arithmetic.hpp> |
| #include <boost/type_traits/is_integral.hpp> |
| #include <boost/type_traits/is_float.hpp> |
| #include <boost/utility/enable_if.hpp> |
| |
| /// The ENABLE_IF_* macros are used to 'enable' - i.e. to make available to the compiler - |
| /// a method only if a type parameter belongs to the set described by each macro. Each |
| /// macro takes the return type of the method as an argument (a requirement of the |
| /// underlying type trait template that implements this logic). |
| /// Usage: |
| /// template <typename T> ENABLE_IF_ARITHMETIC(T, T) foo(T arg) { return arg + 2; } |
| |
| /// Enables a method only if 'type_param' is arithmetic, that is an integral type or a |
| /// floating-point type |
| #define ENABLE_IF_ARITHMETIC(type_param, return_type) \ |
| typename boost::enable_if_c<boost::is_arithmetic<type_param>::value, return_type>::type |
| |
| /// Enables a method only if 'type_param' is not arithmetic, that is neither an integral |
| /// type or a floating-point type |
| #define ENABLE_IF_NOT_ARITHMETIC(type_param, return_type) \ |
| typename boost::enable_if_c<!boost::is_arithmetic<type_param>::value, return_type>::type |
| |
| /// Enables a method only if 'type_param' is integral, i.e. some variant of int or long |
| #define ENABLE_IF_INTEGRAL(type_param, return_type) \ |
| typename boost::enable_if_c<boost::is_integral<type_param>::value, return_type>::type |
| |
| /// Enables a method only if 'type_param' is a floating point type, i.e. some variant of |
| /// float or double. |
| #define ENABLE_IF_FLOAT(type_param, return_type) \ |
| typename boost::enable_if_c<!boost::is_integral<type_param>::value, return_type>::type |
| |
| #endif |