opencv/modules/flann/include/opencv2/flann/any.h
2012-06-20 17:57:26 +00:00

303 lines
7.3 KiB
C++

#ifndef OPENCV_FLANN_ANY_H_
#define OPENCV_FLANN_ANY_H_
/*
* (C) Copyright Christopher Diggins 2005-2011
* (C) Copyright Pablo Aguilar 2005
* (C) Copyright Kevlin Henney 2001
*
* Distributed under the Boost Software License, Version 1.0. (See
* accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt
*
* Adapted for FLANN by Marius Muja
*/
#include "defines.h"
#include <stdexcept>
#include <ostream>
#include <typeinfo>
namespace cvflann
{
namespace anyimpl
{
struct bad_any_cast
{
};
struct empty_any
{
};
inline std::ostream& operator <<(std::ostream& out, const empty_any&)
{
out << "[empty_any]";
return out;
}
struct base_any_policy
{
virtual void static_delete(void** x) = 0;
virtual void copy_from_value(void const* src, void** dest) = 0;
virtual void clone(void* const* src, void** dest) = 0;
virtual void move(void* const* src, void** dest) = 0;
virtual void* get_value(void** src) = 0;
virtual ::size_t get_size() = 0;
virtual const std::type_info& type() = 0;
virtual void print(std::ostream& out, void* const* src) = 0;
virtual ~base_any_policy() {}
};
template<typename T>
struct typed_base_any_policy : base_any_policy
{
virtual ::size_t get_size() { return sizeof(T); }
virtual const std::type_info& type() { return typeid(T); }
};
template<typename T>
struct small_any_policy : typed_base_any_policy<T>
{
virtual void static_delete(void**) { }
virtual void copy_from_value(void const* src, void** dest)
{
new (dest) T(* reinterpret_cast<T const*>(src));
}
virtual void clone(void* const* src, void** dest) { *dest = *src; }
virtual void move(void* const* src, void** dest) { *dest = *src; }
virtual void* get_value(void** src) { return reinterpret_cast<void*>(src); }
virtual void print(std::ostream& out, void* const* src) { out << *reinterpret_cast<T const*>(src); }
};
template<typename T>
struct big_any_policy : typed_base_any_policy<T>
{
virtual void static_delete(void** x)
{
if (* x) delete (* reinterpret_cast<T**>(x)); *x = NULL;
}
virtual void copy_from_value(void const* src, void** dest)
{
*dest = new T(*reinterpret_cast<T const*>(src));
}
virtual void clone(void* const* src, void** dest)
{
*dest = new T(**reinterpret_cast<T* const*>(src));
}
virtual void move(void* const* src, void** dest)
{
(*reinterpret_cast<T**>(dest))->~T();
**reinterpret_cast<T**>(dest) = **reinterpret_cast<T* const*>(src);
}
virtual void* get_value(void** src) { return *src; }
virtual void print(std::ostream& out, void* const* src) { out << *reinterpret_cast<T const*>(*src); }
};
template<> inline void big_any_policy<flann_centers_init_t>::print(std::ostream& out, void* const* src)
{
out << int(*reinterpret_cast<flann_centers_init_t const*>(*src));
}
template<> inline void big_any_policy<flann_algorithm_t>::print(std::ostream& out, void* const* src)
{
out << int(*reinterpret_cast<flann_algorithm_t const*>(*src));
}
template<typename T>
struct choose_policy
{
typedef big_any_policy<T> type;
};
template<typename T>
struct choose_policy<T*>
{
typedef small_any_policy<T*> type;
};
struct any;
/// Choosing the policy for an any type is illegal, but should never happen.
/// This is designed to throw a compiler error.
template<>
struct choose_policy<any>
{
typedef void type;
};
/// Specializations for small types.
#define SMALL_POLICY(TYPE) \
template<> \
struct choose_policy<TYPE> { typedef small_any_policy<TYPE> type; \
}
SMALL_POLICY(signed char);
SMALL_POLICY(unsigned char);
SMALL_POLICY(signed short);
SMALL_POLICY(unsigned short);
SMALL_POLICY(signed int);
SMALL_POLICY(unsigned int);
SMALL_POLICY(signed long);
SMALL_POLICY(unsigned long);
SMALL_POLICY(float);
SMALL_POLICY(bool);
#undef SMALL_POLICY
/// This function will return a different policy for each type.
template<typename T>
base_any_policy* get_policy()
{
static typename choose_policy<T>::type policy;
return &policy;
}
} // namespace anyimpl
struct any
{
private:
// fields
anyimpl::base_any_policy* policy;
void* object;
public:
/// Initializing constructor.
template <typename T>
any(const T& x)
: policy(anyimpl::get_policy<anyimpl::empty_any>()), object(NULL)
{
assign(x);
}
/// Empty constructor.
any()
: policy(anyimpl::get_policy<anyimpl::empty_any>()), object(NULL)
{ }
/// Special initializing constructor for string literals.
any(const char* x)
: policy(anyimpl::get_policy<anyimpl::empty_any>()), object(NULL)
{
assign(x);
}
/// Copy constructor.
any(const any& x)
: policy(anyimpl::get_policy<anyimpl::empty_any>()), object(NULL)
{
assign(x);
}
/// Destructor.
~any()
{
policy->static_delete(&object);
}
/// Assignment function from another any.
any& assign(const any& x)
{
reset();
policy = x.policy;
policy->clone(&x.object, &object);
return *this;
}
/// Assignment function.
template <typename T>
any& assign(const T& x)
{
reset();
policy = anyimpl::get_policy<T>();
policy->copy_from_value(&x, &object);
return *this;
}
/// Assignment operator.
template<typename T>
any& operator=(const T& x)
{
return assign(x);
}
/// Assignment operator, specialed for literal strings.
/// They have types like const char [6] which don't work as expected.
any& operator=(const char* x)
{
return assign(x);
}
/// Utility functions
any& swap(any& x)
{
std::swap(policy, x.policy);
std::swap(object, x.object);
return *this;
}
/// Cast operator. You can only cast to the original type.
template<typename T>
T& cast()
{
if (policy->type() != typeid(T)) throw anyimpl::bad_any_cast();
T* r = reinterpret_cast<T*>(policy->get_value(&object));
return *r;
}
/// Cast operator. You can only cast to the original type.
template<typename T>
const T& cast() const
{
if (policy->type() != typeid(T)) throw anyimpl::bad_any_cast();
void* obj = const_cast<void*>(object);
T* r = reinterpret_cast<T*>(policy->get_value(&obj));
return *r;
}
/// Returns true if the any contains no value.
bool empty() const
{
return policy->type() == typeid(anyimpl::empty_any);
}
/// Frees any allocated memory, and sets the value to NULL.
void reset()
{
policy->static_delete(&object);
policy = anyimpl::get_policy<anyimpl::empty_any>();
}
/// Returns true if the two types are the same.
bool compatible(const any& x) const
{
return policy->type() == x.policy->type();
}
/// Returns if the type is compatible with the policy
template<typename T>
bool has_type()
{
return policy->type() == typeid(T);
}
const std::type_info& type() const
{
return policy->type();
}
friend std::ostream& operator <<(std::ostream& out, const any& any_val);
};
inline std::ostream& operator <<(std::ostream& out, const any& any_val)
{
any_val.policy->print(out,&any_val.object);
return out;
}
}
#endif // OPENCV_FLANN_ANY_H_