summaryrefslogtreecommitdiff
path: root/zen/optional.h
diff options
context:
space:
mode:
authorB Stack <bgstack15@gmail.com>2018-09-09 18:53:23 -0400
committerB Stack <bgstack15@gmail.com>2018-09-09 18:53:23 -0400
commiteb5d3e5df99de2c3d8da2e8bc7b12ed427465dba (patch)
tree0f0441755ff0e6d65e12222d4502c648bffd6a7c /zen/optional.h
parent10.3 (diff)
downloadFreeFileSync-eb5d3e5df99de2c3d8da2e8bc7b12ed427465dba.tar.gz
FreeFileSync-eb5d3e5df99de2c3d8da2e8bc7b12ed427465dba.tar.bz2
FreeFileSync-eb5d3e5df99de2c3d8da2e8bc7b12ed427465dba.zip
pull in latest 10.4 from upstream
Diffstat (limited to 'zen/optional.h')
-rwxr-xr-xzen/optional.h114
1 files changed, 0 insertions, 114 deletions
diff --git a/zen/optional.h b/zen/optional.h
deleted file mode 100755
index e4605c5f..00000000
--- a/zen/optional.h
+++ /dev/null
@@ -1,114 +0,0 @@
-// *****************************************************************************
-// * This file is part of the FreeFileSync project. It is distributed under *
-// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0 *
-// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
-// *****************************************************************************
-
-#ifndef OPTIONAL_H_2857428578342203589
-#define OPTIONAL_H_2857428578342203589
-
-#include <type_traits>
-
-
-namespace zen
-{
-/*
-Optional return value without heap memory allocation!
- -> interface like a pointer, performance like a value
-
- Usage:
- ------
- Opt<MyEnum> someFunction();
-{
- if (allIsWell)
- return enumVal;
- else
- return NoValue();
-}
-
- Opt<MyEnum> optValue = someFunction();
- if (optValue)
- ... use *optValue ...
-*/
-
-struct NoValue {};
-
-template <class T>
-class Opt
-{
-public:
- Opt() {}
- Opt(NoValue) {}
- Opt(const T& val) : valid_(true) { new (&rawMem_) T(val); } //throw X
- Opt( T&& tmp) : valid_(true) { new (&rawMem_) T(std::move(tmp)); }
-
- Opt(const Opt& other) : valid_(other.valid_)
- {
- if (const T* val = other.get())
- new (&rawMem_) T(*val); //throw X
- }
-
- ~Opt() { if (T* val = get()) val->~T(); }
-
- Opt& operator=(const Opt& other) //strong exception-safety iff T::operator=() is strongly exception-safe
- {
- if (T* val = get())
- {
- if (const T* valOther = other.get())
- *val = *valOther; //throw X
- else
- {
- valid_ = false;
- val->~T();
- }
- }
- else if (const T* valOther = other.get())
- {
- new (&rawMem_) T(*valOther); //throw X
- valid_ = true;
- }
- return *this;
- }
-
- Opt& operator=(NoValue) //support assignment to Opt<const T>
- {
- if (T* val = get())
- {
- valid_ = false;
- val->~T();
- }
- return *this;
- }
-
- explicit operator bool() const { return valid_; } //thank you, C++11!!!
-
- const T* get() const { return valid_ ? reinterpret_cast<const T*>(&rawMem_) : nullptr; }
- T* get() { return valid_ ? reinterpret_cast< T*>(&rawMem_) : nullptr; }
-
- const T& operator*() const { return *get(); }
- /**/ T& operator*() { return *get(); }
-
- const T* operator->() const { return get(); }
- /**/ T* operator->() { return get(); }
-
-private:
- std::aligned_storage_t<sizeof(T), alignof(T)> rawMem_; //don't require T to be default-constructible!
- bool valid_ = false;
-};
-
-
-template <class T> inline
-bool operator==(const Opt<T>& lhs, const Opt<T>& rhs)
-{
- if (static_cast<bool>(lhs) != static_cast<bool>(rhs))
- return false;
- if (!lhs)
- return true;
- return *lhs == *rhs;
-}
-template <class T> inline
-bool operator!=(const Opt<T>& lhs, const Opt<T>& rhs) { return !(lhs == rhs); }
-
-}
-
-#endif //OPTIONAL_H_2857428578342203589
bgstack15