bitfields operations on bitfields of arbitrary length More...

Detailed Description

bitfields operations on bitfields of arbitrary length

Note: Code taken mostly from Stackoverflow, User Christoph

Author: Oliver Hahm olive.nosp@m.r.ha.nosp@m.hm@in.nosp@m.ria..nosp@m.fr

Definition in file bitfield.h.

#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>
#include <string.h>
#include "irq.h"

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Go to the source code of this file.

#define	BITFIELD(NAME, SIZE) uint8_t NAME[((SIZE) + 7) / 8]
	Declare a bitfield of a given size.

static void	bf_set (uint8_t field[], size_t idx)
	Set the bit to 1.

static void	bf_set_atomic (uint8_t field[], size_t idx)
	Atomically set the bit to 1.

static void	bf_unset (uint8_t field[], size_t idx)
	Clear the bit.

static void	bf_unset_atomic (uint8_t field[], size_t idx)
	Atomically clear the bit.

static void	bf_toggle (uint8_t field[], size_t idx)
	Toggle the bit.

static void	bf_toggle_atomic (uint8_t field[], size_t idx)
	Atomically toggle the bit.

static bool	bf_isset (const uint8_t field[], size_t idx)
	Check if the bet is set.

static void	bf_or (uint8_t out[], const uint8_t a[], const uint8_t b[], size_t len)
	Perform a bitwise OR operation on two bitfields `out = a \| b`

static void	bf_or_atomic (uint8_t out[], const uint8_t a[], const uint8_t b[], size_t len)
	Atomically perform a bitwise OR operation on two bitfields `out = a \| b`

static void	bf_and (uint8_t out[], const uint8_t a[], const uint8_t b[], size_t len)
	Perform a bitwise AND operation on two bitfields `out = a & b`

static void	bf_and_atomic (uint8_t out[], const uint8_t a[], const uint8_t b[], size_t len)
	Atomically perform a bitwise AND operation on two bitfields `out = a & b`

static void	bf_xor (uint8_t out[], const uint8_t a[], const uint8_t b[], size_t len)
	Perform a bitwise XOR operation on two bitfields `out = a ^ b`

static void	bf_xor_atomic (uint8_t out[], const uint8_t a[], const uint8_t b[], size_t len)
	Atomically perform a bitwise XOR operation on two bitfields `out = a ^ b`

static void	bf_inv (uint8_t out[], const uint8_t a[], size_t len)
	Perform a bitwise NOT operation on a bitfield `out = ~a`

static void	bf_inv_atomic (uint8_t out[], const uint8_t a[], size_t len)
	Atomically perform a bitwise NOT operation on a bitfield `out = ~a`

int	bf_get_unset (uint8_t field[], size_t len)
	Atomically get the number of an unset bit and set it.

int	bf_find_first_set (const uint8_t field[], size_t size)
	Get the index of the first set bit in the field.

int	bf_find_first_unset (const uint8_t field[], size_t size)
	Get the index of the zero bit in the field.

void	bf_set_all (uint8_t field[], size_t size)
	Set all bits in the bitfield to 1.

static void	bf_set_all_atomic (uint8_t field[], size_t size)
	Atomically set all bits in the bitfield to 1.

void	bf_clear_all (uint8_t field[], size_t size)
	Clear all bits in the bitfield to 0.

static void	bf_clear_all_atomic (uint8_t field[], size_t size)
	Atomically clear all bits in the bitfield to 0.

unsigned	bf_popcnt (const uint8_t field[], size_t size)
	Count set bits in the bitfield.

Macro Definition Documentation

◆ BITFIELD

#define BITFIELD	(	NAME,
		SIZE
	)	uint8_t NAME[((SIZE) + 7) / 8]

Declare a bitfield of a given size.

Note: SIZE should be a constant expression. This avoids variable length arrays.

Definition at line 48 of file bitfield.h.

Function Documentation

◆ bf_and()

static void bf_and	(	uint8_t	out[],
		const uint8_t	a[],
		const uint8_t	b[],
		size_t	len
	)

inlinestatic

Perform a bitwise AND operation on two bitfields out = a & b

Precondition: The size of a, b and out must be at least len bits

Note: This operation will also affect unused bits of the bytes that make up the bitfield.

Parameters

[out]	out	The resulting bitfield
[in]	a	The first bitfield
[in]	b	The second bitfield
[in]	len	The number of bits in the bitfields

Definition at line 191 of file bitfield.h.

◆ bf_and_atomic()

static void bf_and_atomic	(	uint8_t	out[],
		const uint8_t	a[],
		const uint8_t	b[],
		size_t	len
	)

inlinestatic

Atomically perform a bitwise AND operation on two bitfields out = a & b

Precondition: The size of a, b and out must be at least len bits

Note: This operation will also affect unused bits of the bytes that make up the bitfield.

Parameters

[out]	out	The resulting bitfield
[in]	a	The first bitfield
[in]	b	The second bitfield
[in]	len	The number of bits in the bitfields

Definition at line 213 of file bitfield.h.

◆ bf_clear_all()

void bf_clear_all	(	uint8_t	field[],
		size_t	size
	)

Clear all bits in the bitfield to 0.

Parameters

[in]	field	The bitfield
[in]	size	The number of bits in the bitfield

◆ bf_clear_all_atomic()

static void bf_clear_all_atomic	(	uint8_t	field[],
		size_t	size
	)

inlinestatic

Atomically clear all bits in the bitfield to 0.

Parameters

[in]	field	The bitfield
[in]	size	The number of bits in the bitfield

Definition at line 376 of file bitfield.h.

◆ bf_find_first_set()

int bf_find_first_set	(	const uint8_t	field[],
		size_t	size
	)

Get the index of the first set bit in the field.

Parameters

[in]	field	The bitfield
[in]	size	The number of bits in the bitfield

Returns: number of the first set bit; -1 if no bit is set

◆ bf_find_first_unset()

int bf_find_first_unset	(	const uint8_t	field[],
		size_t	size
	)

Get the index of the zero bit in the field.

Parameters

[in]	field	The bitfield
[in]	size	The number of bits in the bitfield

Returns: number of the first unset bit; -1 if all bits are set

◆ bf_get_unset()

int bf_get_unset	(	uint8_t	field[],
		size_t	len
	)

Atomically get the number of an unset bit and set it.

This function can be used to record e.g., empty entries in an array.

Parameters

[in,out]	field	The bitfield
[in]	len	The number of bits in the bitfield to consider

Returns: number of bit that was set; -1 if no bit was unset

◆ bf_inv()

static void bf_inv	(	uint8_t	out[],
		const uint8_t	a[],
		size_t	len
	)

inlinestatic

Perform a bitwise NOT operation on a bitfield out = ~a

Precondition: The size of a and out must be at least len bits

Note: This operation will also affect unused bits of the bytes that make up the bitfield.

Parameters

[out]	out	The resulting bitfield
[in]	a	The bitfield to invert
[in]	len	The number of bits in the bitfield

Definition at line 278 of file bitfield.h.

◆ bf_inv_atomic()

static void bf_inv_atomic	(	uint8_t	out[],
		const uint8_t	a[],
		size_t	len
	)

inlinestatic

Atomically perform a bitwise NOT operation on a bitfield out = ~a

Precondition: The size of a and out must be at least len bits

Note: This operation will also affect unused bits of the bytes that make up the bitfield.

Parameters

[out]	out	The resulting bitfield
[in]	a	The bitfield to invert
[in]	len	The number of bits in the bitfield

Definition at line 299 of file bitfield.h.

◆ bf_isset()

static bool bf_isset	(	const uint8_t	field[],
		size_t	idx
	)

inlinestatic

Check if the bet is set.

Parameters

[in,out]	field	The bitfield
[in]	idx	The number of the bit to check

Definition at line 128 of file bitfield.h.

◆ bf_or()

static void bf_or	(	uint8_t	out[],
		const uint8_t	a[],
		const uint8_t	b[],
		size_t	len
	)

inlinestatic

Perform a bitwise OR operation on two bitfields out = a | b

Precondition: The size of a, b and out must be at least len bits

Note: This operation will also affect unused bits of the bytes that make up the bitfield.

Parameters

[out]	out	The resulting bitfield
[in]	a	The first bitfield
[in]	b	The second bitfield
[in]	len	The number of bits in the bitfields

Definition at line 147 of file bitfield.h.

◆ bf_or_atomic()

static void bf_or_atomic	(	uint8_t	out[],
		const uint8_t	a[],
		const uint8_t	b[],
		size_t	len
	)

inlinestatic

Atomically perform a bitwise OR operation on two bitfields out = a | b

Precondition: The size of a, b and out must be at least len bits

Note: This operation will also affect unused bits of the bytes that make up the bitfield.

Parameters

[out]	out	The resulting bitfield
[in]	a	The first bitfield
[in]	b	The second bitfield
[in]	len	The number of bits in the bitfields

Definition at line 169 of file bitfield.h.

◆ bf_popcnt()

unsigned bf_popcnt	(	const uint8_t	field[],
		size_t	size
	)

Count set bits in the bitfield.

Parameters

[in]	field	The bitfield
[in]	size	The number of bits in the bitfield

Returns: number of '1' bits in the bitfield

◆ bf_set()

static void bf_set	(	uint8_t	field[],
		size_t	idx
	)

inlinestatic

Set the bit to 1.

Parameters

[in,out]	field	The bitfield
[in]	idx	The number of the bit to set

Definition at line 56 of file bitfield.h.

◆ bf_set_all()

void bf_set_all	(	uint8_t	field[],
		size_t	size
	)

Set all bits in the bitfield to 1.

Parameters

[in]	field	The bitfield
[in]	size	The number of bits in the bitfield

◆ bf_set_all_atomic()

static void bf_set_all_atomic	(	uint8_t	field[],
		size_t	size
	)

inlinestatic

Atomically set all bits in the bitfield to 1.

Parameters

[in]	field	The bitfield
[in]	size	The number of bits in the bitfield

Definition at line 355 of file bitfield.h.

◆ bf_set_atomic()

static void bf_set_atomic	(	uint8_t	field[],
		size_t	idx
	)

inlinestatic

Atomically set the bit to 1.

Parameters

[in,out]	field	The bitfield
[in]	idx	The number of the bit to set

Definition at line 67 of file bitfield.h.

◆ bf_toggle()

static void bf_toggle	(	uint8_t	field[],
		size_t	idx
	)

inlinestatic

Toggle the bit.

Parameters

[in,out]	field	The bitfield
[in]	idx	The number of the bit to toggle

Definition at line 104 of file bitfield.h.

◆ bf_toggle_atomic()

static void bf_toggle_atomic	(	uint8_t	field[],
		size_t	idx
	)

inlinestatic

Atomically toggle the bit.

Parameters

[in,out]	field	The bitfield
[in]	idx	The number of the bit to toggle

Definition at line 115 of file bitfield.h.

◆ bf_unset()

static void bf_unset	(	uint8_t	field[],
		size_t	idx
	)

inlinestatic

Clear the bit.

Parameters

[in,out]	field	The bitfield
[in]	idx	The number of the bit to clear

Definition at line 80 of file bitfield.h.

◆ bf_unset_atomic()

static void bf_unset_atomic	(	uint8_t	field[],
		size_t	idx
	)

inlinestatic

Atomically clear the bit.

Parameters

[in,out]	field	The bitfield
[in]	idx	The number of the bit to clear

Definition at line 91 of file bitfield.h.

◆ bf_xor()

static void bf_xor	(	uint8_t	out[],
		const uint8_t	a[],
		const uint8_t	b[],
		size_t	len
	)

inlinestatic

Perform a bitwise XOR operation on two bitfields out = a ^ b

Precondition: The size of a, b and out must be at least len bits

Note: This operation will also affect unused bits of the bytes that make up the bitfield.

Parameters

[out]	out	The resulting bitfield
[in]	a	The first bitfield
[in]	b	The second bitfield
[in]	len	The number of bits in the bitfields

Definition at line 235 of file bitfield.h.

◆ bf_xor_atomic()

static void bf_xor_atomic	(	uint8_t	out[],
		const uint8_t	a[],
		const uint8_t	b[],
		size_t	len
	)

inlinestatic

Atomically perform a bitwise XOR operation on two bitfields out = a ^ b

Precondition: The size of a, b and out must be at least len bits

Note: This operation will also affect unused bits of the bytes that make up the bitfield.

Parameters

[out]	out	The resulting bitfield
[in]	a	The first bitfield
[in]	b	The second bitfield
[in]	len	The number of bits in the bitfields

Definition at line 257 of file bitfield.h.