Algorithm: Use decltype(auto)

Avoids some code duplication. Available with C++14 / GCC>=4.9.

Change-Id: Iae90466ec9620ffc84b7a45a55490f5fbc8c5b74
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>
This commit is contained in:
Eike Ziller
2017-01-12 09:43:51 +01:00
parent 63f66f28ac
commit af8812b248

View File

@@ -140,8 +140,7 @@ typename T::value_type findOrDefault(const T &container, R (S::*function)() cons
// find helpers
//////////////////
template<typename R, typename S, typename T>
auto equal(R (S::*function)() const, T value)
-> decltype(std::bind<bool>(std::equal_to<T>(), value, std::bind(function, std::placeholders::_1)))
decltype(auto) equal(R (S::*function)() const, T value)
{
// This should use std::equal_to<> instead of std::eqaul_to<T>,
// but that's not supported everywhere yet, since it is C++14
@@ -149,8 +148,7 @@ auto equal(R (S::*function)() const, T value)
}
template<typename R, typename S, typename T>
auto equal(R S::*member, T value)
-> decltype(std::bind<bool>(std::equal_to<T>(), value, std::bind(member, std::placeholders::_1)))
decltype(auto) equal(R S::*member, T value)
{
return std::bind<bool>(std::equal_to<T>(), value, std::bind(member, std::placeholders::_1));
}
@@ -262,8 +260,7 @@ struct TransformImpl {
template<typename C, // container
typename F>
Q_REQUIRED_RESULT
auto transform(const C &container, F function)
-> typename ContainerType<C>::template ResultOfTransform<F>
decltype(auto) transform(const C &container, F function)
{
return TransformImpl<
typename ContainerType<C>::template ResultOfTransform<F>,
@@ -276,8 +273,7 @@ template<typename C,
typename R,
typename S>
Q_REQUIRED_RESULT
auto transform(const C &container, R (S::*p)() const)
->typename ContainerType<C>::template ResultOfTransformPMF<R>
decltype(auto) transform(const C &container, R (S::*p)() const)
{
return TransformImpl<
typename ContainerType<C>::template ResultOfTransformPMF<R>,
@@ -290,8 +286,7 @@ template<template<typename> class C, // result container type
typename SC, // input container type
typename F> // function type
Q_REQUIRED_RESULT
auto transform(const SC &container, F function)
-> typename ContainerType<SC>::template ResultOfTransform<F, C>
decltype(auto) transform(const SC &container, F function)
{
return TransformImpl<
typename ContainerType<SC>::template ResultOfTransform<F, C>,
@@ -306,8 +301,7 @@ template<template<typename> class C, // result container type
typename R,
typename S>
Q_REQUIRED_RESULT
auto transform(const SC &container, R (S::*p)() const)
-> C<std::decay_t<R>>
decltype(auto) transform(const SC &container, R (S::*p)() const)
{
return TransformImpl<
C<std::decay_t<R>>,