Bitmap management functions

Data Structures
struct	wget_bitmap_st

Macros
#define	bitmap_type   uint64_t
#define	bitmap_bits   (sizeof(bitmap_type) * 8)
#define	bitmap_shift   6
#define	map(n)
#define	bit(n)

Functions
void	wget_bitmap_set (wget_bitmap *b, unsigned n)
void	wget_bitmap_clear (wget_bitmap *b, unsigned n)
bool	wget_bitmap_get (const wget_bitmap *b, unsigned n)
int	wget_bitmap_init (wget_bitmap **b, unsigned bits)
void	wget_bitmap_free (wget_bitmap **b)

Detailed Description

Bitmap (bit array) implementation.

This is useful when you need a bitmap with more than 64 bits. Up to 64 bits you can use the C99 uint64_t as a standard C bitfield.

As a usage example, Wget2 uses bitmaps for options with lists of HTTP status codes, which have values of 100-699.

Macro Definition Documentation

map

#define map

(

n

)

Value:

(((wget_bitmap *)b)->map[(n) >> bitmap_shift])

bit

#define bit

(

n

)

Value:

(((bitmap_type) 1) << ((n) & (bitmap_bits - 1)))

Function Documentation

wget_bitmap_set()

void wget_bitmap_set	(	wget_bitmap *	b,
		unsigned	n )

Parameters

b	Bitmap to act on
n	Number of the bit to set (0-...)

Set the bit n in the bitmap b.

wget_bitmap_clear()

void wget_bitmap_clear	(	wget_bitmap *	b,
		unsigned	n )

Parameters

b	Bitmap to act on
n	Number of the bit to clear (0-...)

Clear the bit n in the bitmap b.

wget_bitmap_get()

bool wget_bitmap_get	(	const wget_bitmap *	b,
		unsigned	n )

Parameters

[in]	b	Bitmap to read from
[in]	n	Number of the bit of interest (0-...)

Returns

0 if bit n is cleared or if n is out of range 1 if bit is set

Returns whether the bit n is set or not.

wget_bitmap_init()

int wget_bitmap_init	(	wget_bitmap **	b,
		unsigned	bits )

Parameters

[out]	b	Pointer to the allocated bitmap
[in]	bits	Number of bits

Returns

A wget_error value

Allocates a bitmap with a capacity of bits. It must be freed by wget_bitmap_free() after usage.

wget_bitmap_free()

void wget_bitmap_free

(

wget_bitmap **

b

)

Parameters

[in]

b

Pointer to bitmap to free

Frees and clears the bitmap pointed to by b.