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//
// Copyright (c) ZeroC, Inc. All rights reserved.
//
#ifndef ICE_UTIL_OPTIONAL_H
#define ICE_UTIL_OPTIONAL_H
#ifndef ICE_CPP11_MAPPING
#include <IceUtil/Config.h>
namespace IceUtilInternal
{
struct NoneType
{
};
}
namespace IceUtil
{
/** A sentinel value used to indicate that no optional value was provided. */
const IceUtilInternal::NoneType None = {};
/** Encapsulates an optional value, which may or may not be present. */
template<typename T>
class Optional
{
public:
typedef T element_type;
/**
* Constructs an empty optional with no value.
*/
Optional() : _isSet(false)
{
}
/**
* Constructs an empty optional with no value.
*/
Optional(IceUtilInternal::NoneType) : _isSet(false)
{
}
/**
* Constructs an optional as a copy of the given optional.
* @param r The source optional.
*/
Optional(const Optional& r) : _value(r._value), _isSet(r._isSet)
{
}
/**
* Constructs an optional with the given value.
* @param p The initial value.
*/
template<typename Y>
Optional(Y p) : _value(p), _isSet(true)
{
}
/**
* Constructs an optional as a copy of the given optional.
* @param r The source optional.
*/
template<typename Y>
Optional(const Optional<Y>& r) : _value(r._value), _isSet(r._isSet)
{
}
~Optional()
{
}
/**
* Resets this optional to have no value.
*/
Optional& operator=(IceUtilInternal::NoneType)
{
_value = T();
_isSet = false;
return *this;
}
/**
* Resets this optional to have the given value.
* @param p The new value.
*/
template<typename Y>
Optional& operator=(Y p)
{
_value = p;
_isSet = true;
return *this;
}
/**
* Resets this optional to be a copy of the given optional.
* @param r The source optional.
*/
template<typename Y>
Optional& operator=(const Optional<Y>& r)
{
_value = r._value;
_isSet = r._isSet;
return *this;
}
/**
* Resets this optional to be a copy of the given optional.
* @param r The source optional.
*/
Optional& operator=(const Optional& r)
{
_value = r._value;
_isSet = r._isSet;
return *this;
}
/**
* Obtains the current value.
* @return The current value.
* @throws OptionalNotSetException if this optional has no value.
*/
const T& value() const
{
checkIsSet();
return _value;
}
/**
* Obtains the current value.
* @return The current value.
* @throws OptionalNotSetException if this optional has no value.
*/
T& value()
{
checkIsSet();
return _value;
}
/**
* Obtains the current value.
* @return The current value.
* @throws OptionalNotSetException if this optional has no value.
*/
const T& get() const
{
return value();
}
/**
* Obtains the current value.
* @return The current value.
* @throws OptionalNotSetException if this optional has no value.
*/
T& get()
{
return value();
}
/**
* Obtains a pointer to the current value.
* @return A pointer to the current value.
* @throws OptionalNotSetException if this optional has no value.
*/
const T* operator->() const
{
return &value();
}
/**
* Obtains a pointer to the current value.
* @return A pointer to the current value.
* @throws OptionalNotSetException if this optional has no value.
*/
T* operator->()
{
return &value();
}
/**
* Obtains the current value.
* @return The current value.
* @throws OptionalNotSetException if this optional has no value.
*/
const T& operator*() const
{
return value();
}
/**
* Obtains the current value.
* @return The current value.
* @throws OptionalNotSetException if this optional has no value.
*/
T& operator*()
{
return value();
}
/**
* Determines whether this optional has a value.
* @return True if the optional has a value, false otherwise.
*/
operator bool() const
{
return _isSet;
}
/**
* Determines whether this optional has a value.
* @return True if the optional does not have a value, false otherwise.
*/
bool operator!() const
{
return !_isSet;
}
/**
* Exchanges the state of this optional with another one.
* @param other The optional value with which to swap.
*/
void swap(Optional& other)
{
std::swap(_isSet, other._isSet);
std::swap(_value, other._value);
}
/// \cond INTERNAL
void __setIsSet()
{
_isSet = true;
}
/// \endcond
private:
void checkIsSet() const
{
if(!_isSet)
{
throwOptionalNotSetException(__FILE__, __LINE__);
}
}
void throwOptionalNotSetException(const char *, int) const;
T _value;
bool _isSet;
};
/**
* Constructs an optional from the given value.
* @param v The optional's initial value.
* @return A new optional object.
*/
template<class T> inline Optional<T>
makeOptional(const T& v)
{
return Optional<T>(v);
}
/// \cond INTERNAL
template<typename T> inline void
Optional<T>::throwOptionalNotSetException(const char* file, int line) const
{
throw OptionalNotSetException(file, line);
}
/// \endcond
template<typename T, typename U>
inline bool operator==(const Optional<T>& lhs, const Optional<U>& rhs)
{
if(lhs && rhs)
{
return *lhs == *rhs;
}
else
{
return !lhs && !rhs;
}
}
template<typename T, typename U>
inline bool operator!=(const Optional<T>& lhs, const Optional<U>& rhs)
{
return !operator==(lhs, rhs);
}
template<typename T, typename U>
inline bool operator<(const Optional<T>& lhs, const Optional<U>& rhs)
{
if(lhs && rhs)
{
return *lhs < *rhs;
}
else
{
return !lhs && rhs;
}
}
template<typename T, typename U>
inline bool operator<=(const Optional<T>& lhs, const Optional<U>& rhs)
{
return lhs < rhs || lhs == rhs;
}
template<typename T, typename U>
inline bool operator>(const Optional<T>& lhs, const Optional<U>& rhs)
{
return !(lhs < rhs || lhs == rhs);
}
template<typename T, typename U>
inline bool operator>=(const Optional<T>& lhs, const Optional<U>& rhs)
{
return !(lhs < rhs);
}
// Optional<T> vs Y
template<typename T, typename Y>
inline bool operator==(const Optional<T>& lhs, const Y& rhs)
{
if(!lhs)
{
return false;
}
else
{
return *lhs == rhs;
}
}
template<typename T, typename Y>
inline bool operator!=(const Optional<T>& lhs, const Y& rhs)
{
return !operator==(lhs, rhs);
}
template<typename T, typename Y>
inline bool operator<(const Optional<T>& lhs, const Y& rhs)
{
if(lhs)
{
return *lhs < rhs;
}
else
{
return true;
}
}
template<typename T, typename Y>
inline bool operator<=(const Optional<T>& lhs, const Y& rhs)
{
return lhs < rhs || lhs == rhs;
}
template<typename T, typename Y>
inline bool operator>(const Optional<T>& lhs, const Y& rhs)
{
return !(lhs < rhs || lhs == rhs);
}
template<typename T, typename Y>
inline bool operator>=(const Optional<T>& lhs, const Y& rhs)
{
return !(lhs < rhs);
}
// Y vs Optional<T>
template<typename T, typename Y>
inline bool operator==(const Y& lhs, const Optional<T>& rhs)
{
if(!rhs)
{
return false;
}
else
{
return lhs == *rhs;
}
}
template<typename T, typename Y>
inline bool operator!=(const Y& lhs, const Optional<T>& rhs)
{
return !operator==(lhs, rhs);
}
template<typename T, typename Y>
inline bool operator<(const Y& lhs, const Optional<T>& rhs)
{
if(rhs)
{
return lhs < *rhs;
}
else
{
return false;
}
}
template<typename T, typename Y>
inline bool operator<=(const Y& lhs, const Optional<T>& rhs)
{
return lhs < rhs || lhs == rhs;
}
template<typename T, typename Y>
inline bool operator>(const Y& lhs, const Optional<T>& rhs)
{
return !(lhs < rhs || lhs == rhs);
}
template<typename T, typename Y>
inline bool operator>=(const Y& lhs, const Optional<T>& rhs)
{
return !(lhs < rhs);
}
}
#endif
#endif
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