topical media & game development
lib-of-vs-libs-Poco-include-Poco-Any.h / h
//
// Any.h
//
//
//
// Library: Foundation
// Package: Core
// Module: Any
//
// Copyright Kevlin Henney, 2000, 2001, 2002. All rights reserved.
// Extracted from Boost 1.33.1 lib and adapted for poco: Peter Schojer/AppliedInformatics 2006-02-02
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
//
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
ifndef Foundation_Any_INCLUDED
define Foundation_Any_INCLUDED
include "Poco/Exception.h"
include <algorithm>
include <typeinfo>
namespace Poco {
class Any
An Any class represents a general type and is capable of storing any type, supporting type-safe extraction
of the internally stored data.
Code taken from the Boost 1.33.1 library. Original copyright by Kevlin Henney. Modified for Poco
by Applied Informatics.
{
public:
Any():
_content(0)
Creates an empty any type.
{
}
template <typename ValueType>
Any(const ValueType& value):
_content(new Holder<ValueType>(value))
Creates an any which stores the init parameter inside.
Example:
Any a(13);
Any a(string("12345"));
{
}
Any(const Any& other):
_content(other._content ? other._content->clone() : 0)
Copy constructor, works with empty Anys and initialized Any values.
{
}
~Any()
{
delete _content;
}
Any& swap(Any& rhs)
Swaps the content of the two Anys.
{
std::swap(_content, rhs._content);
return *this;
}
template <typename ValueType>
Any& operator = (const ValueType& rhs)
Assignment operator for all types != Any.
Example:
Any a = 13;
Any a = string("12345");
{
Any(rhs).swap(*this);
return *this;
}
Any& operator = (const Any& rhs)
Assignment operator for Any.
{
Any(rhs).swap(*this);
return *this;
}
bool empty() const
returns true if the Any is empty
{
return !_content;
}
const std::type_info& type() const
Returns the type information of the stored content.
If the Any is empty typeid(void) is returned.
It is suggested to always query an Any for its type info before trying to extract
data via an AnyCast/RefAnyCast.
{
return _content ? _content->type() : typeid(void);
}
private:
class Placeholder
{
public:
virtual ~Placeholder()
{
}
virtual const std::type_info& type() const = 0;
virtual Placeholder* clone() const = 0;
};
template <typename ValueType>
class Holder: public Placeholder
{
public:
Holder(const ValueType& value):
_held(value)
{
}
virtual const std::type_info& type() const
{
return typeid(ValueType);
}
virtual Placeholder* clone() const
{
return new Holder(_held);
}
ValueType _held;
};
private:
template <typename ValueType>
friend ValueType* AnyCast(Any*);
template <typename ValueType>
friend ValueType* UnsafeAnyCast(Any*);
Placeholder* _content;
};
template <typename ValueType>
ValueType* AnyCast(Any* operand)
AnyCast operator used to extract the ValueType from an Any*. Will return a pointer
to the stored value.
Example Usage:
MyType* pTmp = AnyCast<MyType*>(pAny).
Will return NULL if the cast fails, i.e. types don't match.
{
return operand && operand->type() == typeid(ValueType)
? &static_cast<Any::Holder<ValueType>*>(operand->_content)->_held
: 0;
}
template <typename ValueType>
const ValueType* AnyCast(const Any* operand)
AnyCast operator used to extract a const ValueType pointer from an const Any*. Will return a const pointer
to the stored value.
Example Usage:
const MyType* pTmp = AnyCast<MyType*>(pAny).
Will return NULL if the cast fails, i.e. types don't match.
{
return AnyCast<ValueType>(const_cast<Any*>(operand));
}
template <typename ValueType>
ValueType AnyCast(const Any& operand)
AnyCast operator used to extract a copy of the ValueType from an const Any&.
Example Usage:
MyType tmp = AnyCast<MyType>(anAny).
Will throw a BadCastException if the cast fails.
Dont use an AnyCast in combination with references, i.e. MyType& tmp = ... or const MyType& = ...
Some compilers will accept this code although a copy is returned. Use the RefAnyCast in
these cases.
{
ValueType* result = AnyCast<ValueType>(const_cast<Any*>(&operand));
if (!result) throw BadCastException("Failed to convert between const Any types");
return *result;
}
template <typename ValueType>
ValueType AnyCast(Any& operand)
AnyCast operator used to extract a copy of the ValueType from an Any&.
Example Usage:
MyType tmp = AnyCast<MyType>(anAny).
Will throw a BadCastException if the cast fails.
Dont use an AnyCast in combination with references, i.e. MyType& tmp = ... or const MyType& tmp = ...
Some compilers will accept this code although a copy is returned. Use the RefAnyCast in
these cases.
{
ValueType* result = AnyCast<ValueType>(&operand);
if (!result) throw BadCastException("Failed to convert between Any types");
return *result;
}
template <typename ValueType>
const ValueType& RefAnyCast(const Any & operand)
AnyCast operator used to return a const reference to the internal data.
Example Usage:
const MyType& tmp = RefAnyCast<MyType>(anAny);
{
ValueType* result = AnyCast<ValueType>(const_cast<Any*>(&operand));
if (!result) throw BadCastException("RefAnyCast: Failed to convert between const Any types");
return *result;
}
template <typename ValueType>
ValueType& RefAnyCast(Any& operand)
AnyCast operator used to return a reference to the internal data.
Example Usage:
MyType& tmp = RefAnyCast<MyType>(anAny);
{
ValueType* result = AnyCast<ValueType>(&operand);
if (!result) throw BadCastException("RefAnyCast: Failed to convert between Any types");
return *result;
}
template <typename ValueType>
ValueType* UnsafeAnyCast(Any* operand)
The "unsafe" versions of AnyCast are not part of the
public interface and may be removed at any time. They are
required where we know what type is stored in the any and can't
use typeid() comparison, e.g., when our types may travel across
different shared libraries.
{
return &static_cast<Any::Holder<ValueType>*>(operand->_content)->_held;
}
template <typename ValueType>
const ValueType* UnsafeAnyCast(const Any* operand)
The "unsafe" versions of AnyCast are not part of the
public interface and may be removed at any time. They are
required where we know what type is stored in the any and can't
use typeid() comparison, e.g., when our types may travel across
different shared libraries.
{
return AnyCast<ValueType>(const_cast<Any*>(operand));
}
} // namespace Poco
endif
(C) Æliens
04/09/2009
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