libwget-bitmap(3) Introduction to Library Functions libwget-bitmap(3)

NAME

libwget-bitmap - Bitmap management functions

SYNOPSIS

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) (((wget_bitmap *)b)->map[(n) >> bitmap_shift])
#define bit(n) (((bitmap_type) 1) << ((n) & (bitmap_bits - 1)))

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.

Function Documentation
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.

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.

bool wget_bitmap_get (const wget_bitmap * b, unsigned n)
Parameters
b Bitmap to read from
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.

int wget_bitmap_init (wget_bitmap ** b, unsigned bits)
Parameters
b Pointer to the allocated bitmap
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.

void wget_bitmap_free (wget_bitmap ** b)
Parameters
b Pointer to bitmap to free

Frees and clears the bitmap pointed to by b.

Author
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wget2 Version 2.2.0 libwget-bitmap(3)