haiku/headers/private/kernel/util/FixedWidthPointer.h

130 lines
2.1 KiB
C++

/*
* 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:
operator Type*() const
{
return (Type *)(addr_t)fValue;
}
Type& operator*() const
{
return *(Type *)*this;
}
Type* operator->() const
{
return *this;
}
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:
operator void*() const
{
return (void*)(addr_t)fValue;
}
template<typename OtherType>
operator OtherType*() const
{
return (OtherType*)(addr_t)fValue;
}
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, void* b)
{
return a.Get() == (addr_t)b;
}
template<typename Type>
inline bool
operator!=(const FixedWidthPointer<Type>& a, void* b)
{
return a.Get() != (addr_t)b;
}
#endif /* KERNEL_UTIL_FIXED_WIDTH_POINTER_H */