Struct BitmapVec

Source

pub struct BitmapVec { /* private fields */ }

Expand description

Represents an owned bitmap.

Wraps underlying C bitmap API. See Bitmap for available methods.

§Examples

Basic usage

use kernel::alloc::flags::GFP_KERNEL;
use kernel::bitmap::BitmapVec;

let mut b = BitmapVec::new(16, GFP_KERNEL)?;

assert_eq!(16, b.len());
for i in 0..16 {
    if i % 4 == 0 {
      b.set_bit(i);
    }
}
assert_eq!(Some(0), b.next_bit(0));
assert_eq!(Some(1), b.next_zero_bit(0));
assert_eq!(Some(4), b.next_bit(1));
assert_eq!(Some(5), b.next_zero_bit(4));
assert_eq!(Some(12), b.last_bit());

§Invariants

nbits is <= i32::MAX and never changes.
if nbits <= bindings::BITS_PER_LONG, then repr is a usize.
otherwise, repr holds a non-null pointer to an initialized array of unsigned long that is large enough to hold nbits bits.

Implementations§

Source §

impl BitmapVec

Source

pub fn new(nbits: usize, flags: Flags) -> Result<Self, AllocError>

Constructs a new BitmapVec.

Fails with AllocError when the BitmapVec could not be allocated. This includes the case when nbits is greater than i32::MAX.

Source

pub fn len(&self) -> usize

Returns length of this Bitmap.

Source

pub fn fill_random(&mut self)

Fills this Bitmap with random bits.

Methods from Deref<Target = Bitmap>§

Source

pub fn as_ptr(&self) -> *const usize

Returns a raw pointer to the backing Bitmap.

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pub fn as_mut_ptr(&mut self) -> *mut usize

Returns a mutable raw pointer to the backing Bitmap.

Source

pub fn len(&self) -> usize

Returns length of this Bitmap.

Source

pub fn set_bit(&mut self, index: usize)

Set bit with index index.

ATTENTION: set_bit is non-atomic, which differs from the naming convention in C code. The corresponding C function is __set_bit.

If CONFIG_RUST_BITMAP_HARDENED is not enabled and index is greater than or equal to self.nbits, does nothing.

§Panics

Panics if CONFIG_RUST_BITMAP_HARDENED is enabled and index is greater than or equal to self.nbits.

Source

pub fn set_bit_atomic(&self, index: usize)

Set bit with index index, atomically.

This is a relaxed atomic operation (no implied memory barriers).

ATTENTION: The naming convention differs from C, where the corresponding function is called set_bit.

If CONFIG_RUST_BITMAP_HARDENED is not enabled and index is greater than or equal to self.len(), does nothing.

§Panics

Panics if CONFIG_RUST_BITMAP_HARDENED is enabled and index is greater than or equal to self.len().

Source

pub fn clear_bit(&mut self, index: usize)

Clear index bit.

ATTENTION: clear_bit is non-atomic, which differs from the naming convention in C code. The corresponding C function is __clear_bit.

If CONFIG_RUST_BITMAP_HARDENED is not enabled and index is greater than or equal to self.len(), does nothing.

§Panics

Panics if CONFIG_RUST_BITMAP_HARDENED is enabled and index is greater than or equal to self.len().

Source

pub fn clear_bit_atomic(&self, index: usize)

Clear index bit, atomically.

This is a relaxed atomic operation (no implied memory barriers).

ATTENTION: The naming convention differs from C, where the corresponding function is called clear_bit.

If CONFIG_RUST_BITMAP_HARDENED is not enabled and index is greater than or equal to self.len(), does nothing.

§Panics

Panics if CONFIG_RUST_BITMAP_HARDENED is enabled and index is greater than or equal to self.len().

Source

pub fn copy_and_extend(&mut self, src: &Bitmap)

Copy src into this Bitmap and set any remaining bits to zero.

§Examples

use kernel::alloc::{AllocError, flags::GFP_KERNEL};
use kernel::bitmap::BitmapVec;

let mut long_bitmap = BitmapVec::new(256, GFP_KERNEL)?;

assert_eq!(None, long_bitmap.last_bit());

let mut short_bitmap = BitmapVec::new(16, GFP_KERNEL)?;

short_bitmap.set_bit(7);
long_bitmap.copy_and_extend(&short_bitmap);
assert_eq!(Some(7), long_bitmap.last_bit());

Source

pub fn last_bit(&self) -> Option<usize>

Finds last set bit.

§Examples

use kernel::alloc::{AllocError, flags::GFP_KERNEL};
use kernel::bitmap::BitmapVec;

let bitmap = BitmapVec::new(64, GFP_KERNEL)?;

match bitmap.last_bit() {
    Some(idx) => {
        pr_info!("The last bit has index {idx}.\n");
    }
    None => {
        pr_info!("All bits in this bitmap are 0.\n");
    }
}