xref: /xnu-8792.81.2/iokit/DriverKit/bounded_array.h (revision 19c3b8c28c31cb8130e034cfb5df6bf9ba342d90)

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#ifndef XNU_LIBKERN_LIBKERN_CXX_BOUNDED_ARRAY_H
#define XNU_LIBKERN_LIBKERN_CXX_BOUNDED_ARRAY_H

#if !TAPI

#if DRIVERKIT_FRAMEWORK_INCLUDE
#include <DriverKit/bounded_ptr.h>
#else
#include <libkern/c++/bounded_ptr.h>
#endif /* DRIVERKIT_FRAMEWORK_INCLUDE */
#include <stddef.h>
#include <os/base.h>

namespace libkern {
// `bounded_array` is a simple abstraction for a C-style array.
//
// Unlike C-style arrays, however, it ensures that the array is not accessed
// outside of its bounds. Furthermore, the iterators of the `bounded_array`
// are `bounded_ptr`, which track the range they're allowed to access.
//
// TODO:
// - Should we provide deep comparison operators?
// - Document individual methods
template <typename T, size_t N, typename TrappingPolicy>
struct bounded_array {
	// DO NOT USE THIS MEMBER DIRECTLY OR WE WILL BREAK YOUR CODE IN THE FUTURE.
	// THIS HAS TO BE PUBLIC FOR THIS TYPE TO SUPPORT AGGREGATE-INITIALIZATION.
	T data_[N];

	using iterator = bounded_ptr<T, TrappingPolicy>;
	using const_iterator = bounded_ptr<T const, TrappingPolicy>;

	iterator
	begin() noexcept
	{
		return iterator(data_, data_, data_ + N);
	}
	const_iterator
	begin() const noexcept
	{
		return const_iterator(data_, data_, data_ + N);
	}
	iterator
	end() noexcept
	{
		return iterator(data_ + N, data_, data_ + N);
	}
	const_iterator
	end() const noexcept
	{
		return const_iterator(data_ + N, data_, data_ + N);
	}
	constexpr size_t
	size() const noexcept
	{
		return N;
	}
	constexpr size_t
	length() const noexcept
	{
		return N;
	}
	constexpr T*
	data() noexcept
	{
		return data_;
	}
	constexpr T const*
	data() const noexcept
	{
		return data_;
	}
	OS_ALWAYS_INLINE T&
	operator[](ptrdiff_t n)
	{
		return begin()[n];
	}
	OS_ALWAYS_INLINE T const&
	operator[](ptrdiff_t n) const
	{
		return begin()[n];
	}
};
} // end namespace libkern

#endif /* !TAPI */

#endif // !XNU_LIBKERN_LIBKERN_CXX_BOUNDED_ARRAY_H