/*
 * Copyright 2012, Alex Smith, alex@alex-smith.me.uk.
 * Distributed under the terms of the MIT License.
 */
#ifndef KERNEL_UTIL_FIXED_WIDTH_POINTER_H
#define KERNEL_UTIL_FIXED_WIDTH_POINTER_H


#include <SupportDefs.h>


/*!
        \class FixedWidthPointer
        \brief Pointer class with fixed size (64-bit) storage.

        This class is a pointer-like class that uses a fixed size 64-bit storage.
        This is used to make kernel_args compatible (i.e. the same size) for both
        32-bit and 64-bit kernels.
*/
template<typename Type>
class FixedWidthPointer {
public:
        Type * Pointer() const
        {
                return (Type*)(addr_t)fValue;
        }

        operator Type*() const
        {
                return Pointer();
        }

        Type& operator*() const
        {
                return *Pointer();
        }

        Type* operator->() const
        {
                return Pointer();
        }

        Type& operator[](size_t i) const
        {
                return Pointer()[i];
        }

        FixedWidthPointer& operator=(const FixedWidthPointer& p)
        {
                fValue = p.fValue;
                return *this;
        }

        FixedWidthPointer& operator=(Type* p)
        {
                fValue = (addr_t)p;
                return *this;
        }

        /*!
                Get the 64-bit pointer value.
                \return Pointer address.
        */
        uint64 Get() const
        {
                return fValue;
        }

        /*!
                Set the 64-bit pointer value.
                \param addr New address for the pointer.
        */
        void SetTo(uint64 addr)
        {
                fValue = addr;
        }

private:
        uint64 fValue;
} _PACKED;


// Specialization for void pointers, can be converted to another pointer type.
template<>
class FixedWidthPointer<void> {
public:
        void * Pointer() const
        {
                return (void*)(addr_t)fValue;
        }

        operator void*() const
        {
                return Pointer();
        }

        FixedWidthPointer& operator=(const FixedWidthPointer& p)
        {
                fValue = p.fValue;
                return *this;
        }

        FixedWidthPointer& operator=(void* p)
        {
                fValue = (addr_t)p;
                return *this;
        }

        uint64 Get() const
        {
                return fValue;
        }

        void SetTo(uint64 addr)
        {
                fValue = addr;
        }

private:
        uint64 fValue;
} _PACKED;


template<typename Type>
inline bool
operator==(const FixedWidthPointer<Type>& a, const Type* b)
{
        return a.Get() == (addr_t)b;
}


template<typename Type>
inline bool
operator!=(const FixedWidthPointer<Type>& a, const Type* b)
{
        return a.Get() != (addr_t)b;
}


template<typename Type>
inline bool
operator==(const FixedWidthPointer<Type>& a, Type* b)
{
        return a.Get() == (addr_t)b;
}


template<typename Type>
inline bool
operator!=(const FixedWidthPointer<Type>& a, Type* b)
{
        return a.Get() != (addr_t)b;
}


#endif  /* KERNEL_UTIL_FIXED_WIDTH_POINTER_H */