usual/bits.h File Reference

Bit arithmetics. More...

Functions
static bool	is_power_of_2 (unsigned int n)
	Checks if integer has only one bit set.
static uint16_t	rol16 (uint16_t v, int s)
	Rotate 16-bit int to left.
static uint32_t	rol32 (uint32_t v, int s)
	Rotate 32-bit int to left.
static uint64_t	rol64 (uint64_t v, int s)
	Rotate 64-bit int to left.
static uint16_t	ror16 (uint16_t v, int s)
	Rotate 16-bit int to right.
static uint32_t	ror32 (uint32_t v, int s)
	Rotate 32-bit int to right.
static uint64_t	ror64 (uint64_t v, int s)
	Rotate 64-bit int to right.
static int	fls (int x)
	Find last (highest) set bit, 1-based offset, 0 if arg == 0.
static int	flsl (long x)
	Find last (highest) set bit, 1-based offset, 0 if arg == 0.
static int	flsll (long long x)
	Find last (highest) set bit, 1-based offset, 0 if arg == 0.
static int	ffs (int x)
	Find first (lowest) set bit, 1-based ofs, 0 if arg == 0.
static int	ffsl (long x)
	Find first (lowest) set bit, 1-based ofs, 0 if arg == 0.
static int	ffsll (long long x)
	Find first (lowest) set bit, 1-based ofs, 0 if arg == 0.
static bool	safe_mul_uint (unsigned int *res_p, unsigned int a, unsigned int b)
	Multiply with overflow check for 'unsigned int'.
static bool	safe_mul_ulong (unsigned long *res_p, unsigned long a, unsigned long b)
	Multiply with overflow check for 'unsigned long'.
static bool	safe_mul_uint8 (uint8_t *res_p, uint8_t a, uint8_t b)
	Multiply with overflow check for 'uint8_t'.
static bool	safe_mul_uint16 (uint16_t *res_p, uint16_t a, uint16_t b)
	Multiply with overflow check for 'uint16_t'.
static bool	safe_mul_uint32 (uint32_t *res_p, uint32_t a, uint32_t b)
	Multiply with overflow check for 'uint32_t'.
static bool	safe_mul_uint64 (uint64_t *res_p, uint64_t a, uint64_t b)
	Multiply with overflow check for 'uint64_t'.
static bool	safe_mul_size (size_t *res_p, size_t a, size_t b)
	Multiply with overflow check for 'size_t'.

---

Detailed Description

Bit arithmetics.

• is_power_of_2
• ffs, ffsl, ffsll
• fls, flsl, flsll
• rol16, rol32, rol64
• ror16, ror32, ror64

---

Function Documentation

static bool is_power_of_2

(

unsigned int

n

)

[inline, static]

Checks if integer has only one bit set.

static uint16_t rol16	(	uint16_t	v,
		int	s
	)		[inline, static]

Rotate 16-bit int to left.

Referenced by ror16().

static uint32_t rol32	(	uint32_t	v,
		int	s
	)		[inline, static]

Rotate 32-bit int to left.

Referenced by ror32().

static uint64_t rol64	(	uint64_t	v,
		int	s
	)		[inline, static]

Rotate 64-bit int to left.

Referenced by ror64().

static uint16_t ror16	(	uint16_t	v,
		int	s
	)		[inline, static]

Rotate 16-bit int to right.

References rol16().

static uint32_t ror32	(	uint32_t	v,
		int	s
	)		[inline, static]

Rotate 32-bit int to right.

References rol32().

static uint64_t ror64	(	uint64_t	v,
		int	s
	)		[inline, static]

Rotate 64-bit int to right.

References rol64().

static int fls

(

int

x

)

[inline, static]

Find last (highest) set bit, 1-based offset, 0 if arg == 0.

static int flsl

(

long

x

)

[inline, static]

Find last (highest) set bit, 1-based offset, 0 if arg == 0.

static int flsll

(

long long

x

)

[inline, static]

Find last (highest) set bit, 1-based offset, 0 if arg == 0.

static int ffs

(

int

x

)

[inline, static]

Find first (lowest) set bit, 1-based ofs, 0 if arg == 0.

static int ffsl

(

long

x

)

[inline, static]

Find first (lowest) set bit, 1-based ofs, 0 if arg == 0.

static int ffsll

(

long long

x

)

[inline, static]

Find first (lowest) set bit, 1-based ofs, 0 if arg == 0.

static bool safe_mul_uint	(	unsigned int *	res_p,
		unsigned int	a,
		unsigned int	b
	)		[inline, static]

Multiply with overflow check for 'unsigned int'.

static bool safe_mul_ulong	(	unsigned long *	res_p,
		unsigned long	a,
		unsigned long	b
	)		[inline, static]

Multiply with overflow check for 'unsigned long'.

static bool safe_mul_uint8	(	uint8_t *	res_p,
		uint8_t	a,
		uint8_t	b
	)		[inline, static]

Multiply with overflow check for 'uint8_t'.

static bool safe_mul_uint16	(	uint16_t *	res_p,
		uint16_t	a,
		uint16_t	b
	)		[inline, static]

Multiply with overflow check for 'uint16_t'.

static bool safe_mul_uint32	(	uint32_t *	res_p,
		uint32_t	a,
		uint32_t	b
	)		[inline, static]

Multiply with overflow check for 'uint32_t'.

static bool safe_mul_uint64	(	uint64_t *	res_p,
		uint64_t	a,
		uint64_t	b
	)		[inline, static]

Multiply with overflow check for 'uint64_t'.

static bool safe_mul_size	(	size_t *	res_p,
		size_t	a,
		size_t	b
	)		[inline, static]

Multiply with overflow check for 'size_t'.