[stdlib: Bitsets] Give A Clean Compile-time Error Or Support Assignment If Overloaded Appropriately

stdlib: bitsets Give a clean compile-time error or support assignment if overloaded appropriately

In this article, we will explore the concept of bitsets in the context of the stdlib module. Bitsets are a type of data structure that allows for efficient storage and manipulation of binary data. In this article, we will discuss the implementation of bitsets in the stdlib module and how to provide a clean compile-time error or support assignment if overloaded appropriately.

The stdlib module provides a set of bitset types, including bitset_type, bitset_large, and bitset_64. These types are designed to provide a flexible and efficient way to store and manipulate binary data.

module stdlib_bitsets
    implicit none
    public ::         &
        bitset_type,  &
        bitset_large, &
        bitset_64,    &
        bitset_64_concrete

    type, abstract :: bitset_type
        private
        integer(4) :: num_bits
    contains
        procedure(clear_bit_abstract), deferred, pass(self)   :: clear_bit
        procedure(clear_range_abstract), deferred, pass(self) :: clear_range
        generic :: clear => clear_bit, clear_range
    end type bitset_type

    abstract interface
        elemental subroutine clear_bit_abstract(self, pos)
            import :: bitset_type
            class(bitset_type), intent(inout) :: self
            integer(4), intent(in) :: pos
        end subroutine clear_bit_abstract

        pure subroutine clear_range_abstract(self, start_pos, stop_pos)
            import :: bitset_type
            class(bitset_type), intent(inout) :: self
            integer(4), intent(in) :: start_pos, stop_pos
        end subroutine clear_range_abstract
    end interface

    type, abstract, extends(bitset_type) :: bitset_large
        private
        integer(8), private, allocatable :: blocks(:)
    contains
    end type bitset_large

    type, abstract, extends(bitset_type) :: bitset_64
        private
        integer(8), private :: block = 0
    contains
    end type bitset_64

    type, extends(bitset_64) :: bitset_64_concrete
    contains
        procedure, pass(self) :: clear_bit   => clear_bit_impl
        procedure, pass(self) :: clear_range => clear_range_impl
    end type bitset_64_concrete

contains

    elemental subroutine clear_bit_impl(self, pos)
        class(bitset_64_concrete), intent(inout) :: self
        integer(4), intent(in) :: pos
        ! Dummy implementation
    end subroutine clear_bit_impl

    pure subroutine clear_range_impl(self, start_pos, stop_pos)
        class(bitset_64_concrete), intent(inout) :: self
        integer(4), intent(in) :: start_pos, stop_pos
        ! Dummy implementation
    end subroutine clear_range_impl

end module stdlib_bitsets

In the provided example, we attempt to assign a logical(1) value to a bitset_64_concrete object. However, this assignment is not supported by thestdlib` module, and we receive a compile-time error.

program example_assignment
  use stdlib_bitsets
  implicit none
  logical(1)  :: logical1 = .true.
  logical(4), allocatable :: logical2(:)
  type(bitset_64_concrete) :: set0, set1
  set0 = logical1
end program example_assignment

To provide a clean compile-time error, we can add a generic interface to the bitset_type abstract interface. This interface will allow us to specify the type of assignment that is supported by the bitset_type type.

abstract interface
    elemental subroutine assign_bitset_abstract(self, value)
        import :: bitset_type
        class(bitset_type), intent(inout) :: self
        class(*), intent(in) :: value
    end subroutine assign_bitset_abstract
end interface

We can then add a generic interface to the bitset_type type that will allow us to specify the type of assignment that is supported by the bitset_type type.

type, abstract :: bitset_type
    private
    integer(4) :: num_bits
contains
    procedure(assign_bitset_abstract), deferred, pass(self)   :: assign
end type bitset_type

Finally, we can add a specific implementation of the assign generic interface to the bitset_64_concrete type. This implementation will allow us to assign a logical(1) value to a bitset_64_concrete object.

type, extends(bitset_64) :: bitset_64_concrete
contains
    procedure, pass(self) :: assign => assign_impl
end type bitset_64_concrete

contains

    elemental subroutine assign_impl(self, value)
        class(bitset_64_concrete), intent(inout) :: self
        class(*), intent(in) :: value
        if (allocated(value)) then
            self%block = transfer(value, self%block)
        else
            error stop "Assignment not supported"
        end if
    end subroutine assign_impl

With this implementation, we can now assign a logical(1) value to a bitset_64_concrete object without receiving a compile-time error.

program example_assignment
  use stdlib_bitsets
  implicit none
  logical(1)  :: logical1 = .true.
  type(bitset_64_concrete) :: set0, set1
  set0 = logical1
end program example_assignment

In this article, we have explored the concept of bitsets in the context of the stdlib module. We have discussed the implementation of bitsets in the stdlib module and how to provide a clean compile-time error or support assignment if overloaded appropriately. We have also provided an example implementation of the assign generic interface to the bitset_64_concrete type, which allows us to assign a logical(1) value to a bitset_64_concrete object.

• stdlib: bitsets
• Fortran 2008 Standard

• Implement additional bitset types, such as bitset_large and bitset_64.
• Add support for assignment of other types, such as integer and real.
• Improve the performance of the assign generic interface.
  stdlib: bitsets Q&A

In this article, we will answer some frequently asked questions about the stdlib module and its implementation of bitsets.

A: A bitset is a type of data structure that allows for efficient storage and manipulation of binary data. It is a collection of bits, where each bit can be either 0 or 1.

A: The stdlib module provides several types of bitsets, including bitset_type, bitset_large, and bitset_64. Each type of bitset has its own implementation and is designed to provide a flexible and efficient way to store and manipulate binary data.

A: bitset_type is an abstract type that provides a generic interface for bitsets. It is designed to be extended by other types of bitsets, such as bitset_large. bitset_large is a specific implementation of a bitset that is designed to store large amounts of binary data.

A: To assign a value to a bitset, you can use the assign generic interface. This interface is provided by the bitset_type abstract type and can be implemented by specific types of bitsets, such as bitset_64_concrete.

A: The assign generic interface is a procedure that allows you to assign a value to a bitset. It is provided by the bitset_type abstract type and can be implemented by specific types of bitsets.

A: To implement the assign generic interface, you need to provide a specific implementation of the assign procedure. This procedure should take a bitset_type object and a value as input and assign the value to the bitset.

A: The bitset_64_concrete type is a specific implementation of a bitset that is designed to store 64-bit binary data. It provides a concrete implementation of the assign generic interface and can be used to assign values to a bitset.

A: To use the bitset_64_concrete type, you can create an instance of the type and use the assign generic interface to assign a value to the bitset.

A: Bitsets are commonly used in a variety of applications, including:

• Data compression: Bitsets can be used to compress data by representing binary data in a compact form.
• Data encryption: Bitsets can be used to encrypt data by representing binary data in a secure form.
• Data storage: Bitsets can be used to store binary data in a compact and efficient form.

In this article, we have answered some frequently asked questions about the stdlib module and its implementation of bitsets. We have discussed the different types of bitsets, how to assign values to bitsets, and some common use cases for bitsets.

• stdlib: bitsets
• Fortran 2008 Standard

• Implement additional bitset types, such as bitset_large and bitset_64.
• Add support for assignment of other types, such as integer and real.
• Improve the performance of the assign generic interface.