Bit operations

Collaboration diagram for Bit operations:

Macros
#define	VLC_INT_FUNC(basename)
#define	VLC_INT_FUNC_TYPE(basename, type, suffix)
#define	VLC_INT_GENERIC(func, x)
#define	clz(x)
	Count leading zeroes. More...
#define	ctz(x)   VLC_INT_GENERIC(vlc_ctz, x)
	Count trailing zeroes. More...
#define	parity(x)   VLC_INT_GENERIC(vlc_parity, x)
	Parity. More...
#define	vlc_popcount(x)
	Bit weight / population count. More...

Functions
static int	vlc_clzll (unsigned long long x)
static int	vlc_clzl (unsigned long x)
static int	vlc_clz (unsigned x)
static int	vlc_ctz_generic (unsigned long long x)
static int	vlc_parity_generic (unsigned long long x)
static int	vlc_popcount_generic (unsigned long long x)
static int	vlc_ctz (unsigned x)
static int	vlc_ctzl (unsigned long x)
static int	vlc_ctzll (unsigned long long x)
static int	vlc_parity (unsigned x)
static int	vlc_parityl (unsigned long x)
static int	vlc_parityll (unsigned long long x)
static int	vlc_popcount (unsigned x)
static int	vlc_popcountl (unsigned long x)
static int	vlc_popcountll (unsigned long long x)
static uint16_t	vlc_bswap16 (uint16_t x)
	Byte swap (16 bits) More...
static uint32_t	vlc_bswap32 (uint32_t x)
	Byte swap (32 bits) More...
static uint64_t	vlc_bswap64 (uint64_t x)
	Byte swap (64 bits) More...

Detailed Description

Macro Definition Documentation

clz

#define clz

(

x

)

Value:

    _Generic((x), \
        unsigned char: (vlc_clz(x) - (sizeof (unsigned) - 1) * 8), \
        unsigned short: (vlc_clz(x) \
        - (sizeof (unsigned) - sizeof (unsigned short)) * 8), \
        unsigned: vlc_clz(x), \
        unsigned long: vlc_clzl(x), \
        unsigned long long: vlc_clzll(x))

Count leading zeroes.

This function counts the number of consecutive zero (clear) bits down from the highest order bit in an unsigned integer.

Parameters

x	a non-zero integer

Note

This macro assumes that CHAR_BIT equals 8.

Warning

By definition, the result depends on the (width of the) type of x.

Returns

The number of leading zero bits in x.

ctz

#define ctz

(

x

)

VLC_INT_GENERIC(vlc_ctz, x)

Count trailing zeroes.

This function counts the number of consecutive zero bits up from the lowest order bit in an unsigned integer.

Parameters

x	a non-zero integer

Note

This function assumes that CHAR_BIT equals 8.

Returns

The number of trailing zero bits in x.

parity

#define parity

(

x

)

VLC_INT_GENERIC(vlc_parity, x)

Parity.

This function determines the parity of an integer.

Return values

0	if x has an even number of set bits.
1	if x has an odd number of set bits.

VLC_INT_FUNC

#define VLC_INT_FUNC

(

basename

)

Value:

        VLC_INT_FUNC_TYPE(basename, unsigned, ) \
        VLC_INT_FUNC_TYPE(basename, unsigned long, l) \
        VLC_INT_FUNC_TYPE(basename, unsigned long long, ll)

VLC_INT_FUNC_TYPE

#define VLC_INT_FUNC_TYPE	(		basename,
			type,
			suffix
	)

Value:

VLC_USED static inline int vlc_##basename##suffix(type x) \
{ \
    return vlc_##basename##_generic(x); \
}

VLC_INT_GENERIC

#define VLC_INT_GENERIC	(		func,
			x
	)

Value:

    _Generic((x), \
        unsigned char:      func(x), \
          signed char:      func(x), \
        unsigned short:     func(x), \
          signed short:     func(x), \
        unsigned int:       func(x), \
          signed int:       func(x), \
        unsigned long:      func##l(x), \
          signed long:      func##l(x), \
        unsigned long long: func##ll(x), \
          signed long long: func##ll(x))

vlc_popcount

#define vlc_popcount

(

x

)

Value:

    _Generic((x), \
        signed char:  vlc_popcount((unsigned char)(x)), \
        signed short: vlc_popcount((unsigned short)(x)), \
        default: VLC_INT_GENERIC(vlc_popcount ,x))

Bit weight / population count.

This function counts the number of non-zero bits in an integer.

Returns

The count of non-zero bits.

Function Documentation

vlc_bswap16()

static uint16_t vlc_bswap16 ( uint16_t  x )

inlinestatic

Byte swap (16 bits)

Referenced by GetWLE(), and SetWLE().

vlc_bswap32()

static uint32_t vlc_bswap32 ( uint32_t  x )

inlinestatic

Byte swap (32 bits)

Referenced by GetDWLE(), and SetDWLE().

vlc_bswap64()

static uint64_t vlc_bswap64 ( uint64_t  x )

inlinestatic

Byte swap (64 bits)

Referenced by GetQWLE(), and SetQWLE().

vlc_clz()

static int vlc_clz ( unsigned  x )

inlinestatic

References vlc_clzll().

vlc_clzl()

static int vlc_clzl ( unsigned long  x )

inlinestatic

References vlc_clzll().

vlc_clzll()

static int vlc_clzll ( unsigned long long  x )

inlinestatic

Referenced by vlc_clz(), and vlc_clzl().

vlc_ctz()

static int vlc_ctz ( unsigned  x )

inlinestatic

vlc_ctz_generic()

static int vlc_ctz_generic ( unsigned long long  x )

inlinestatic

vlc_ctzl()

static int vlc_ctzl ( unsigned long  x )

inlinestatic

vlc_ctzll()

static int vlc_ctzll ( unsigned long long  x )

inlinestatic

vlc_parity()

static int vlc_parity ( unsigned  x )

inlinestatic

vlc_parity_generic()

static int vlc_parity_generic ( unsigned long long  x )

inlinestatic

vlc_parityl()

static int vlc_parityl ( unsigned long  x )

inlinestatic

vlc_parityll()

static int vlc_parityll ( unsigned long long  x )

inlinestatic

vlc_popcount()

static int vlc_popcount ( unsigned  x )

inlinestatic

vlc_popcount_generic()

static int vlc_popcount_generic ( unsigned long long  x )

inlinestatic

References count.

vlc_popcountl()

static int vlc_popcountl ( unsigned long  x )

inlinestatic

vlc_popcountll()

static int vlc_popcountll ( unsigned long long  x )

inlinestatic