DragonOS/kernel/crates/bitmap/src/bitmap_core.rs
2025-03-12 11:12:03 +08:00

266 lines
8.0 KiB
Rust

use core::{intrinsics::unlikely, marker::PhantomData};
use crate::traits::BitOps;
#[derive(Debug, Clone)]
pub(crate) struct BitMapCore<T: BitOps> {
phantom: PhantomData<T>,
}
impl<T: BitOps> BitMapCore<T> {
pub const fn new() -> Self {
Self {
phantom: PhantomData,
}
}
/// 获取位图中的某一位
pub(crate) fn get(&self, n: usize, data: &[T], index: usize) -> Option<bool> {
if unlikely(index >= n) {
return None;
}
let element_index = index / T::bit_size();
let bit_index = index % T::bit_size();
let element = data.get(element_index)?;
let bit = <T as BitOps>::get(element, bit_index);
Some(bit)
}
/// 设置位图中的某一位
pub(crate) fn set(&self, n: usize, data: &mut [T], index: usize, value: bool) -> Option<bool> {
if unlikely(index >= n) {
return None;
}
let element_index = index / T::bit_size();
let bit_index = index % T::bit_size();
let element = data.get_mut(element_index)?;
let bit = <T as BitOps>::set(element, bit_index, value);
Some(bit)
}
pub(crate) fn set_all(&self, n: usize, data: &mut [T], value: bool) {
let val = if value { T::max() } else { T::zero() };
for element in data.iter_mut() {
*element = val;
}
// 特殊处理最后一个元素
let last_element = data.last_mut().unwrap();
let mask = T::make_mask(n % T::bit_size());
if mask != T::zero() {
*last_element &= mask;
}
}
/// 获取位图中第一个为1的位
pub(crate) fn first_index(&self, data: &[T]) -> Option<usize> {
for (i, element) in data.iter().enumerate() {
let bit = <T as BitOps>::first_index(element);
if let Some(b) = bit {
return Some(i * T::bit_size() + b);
}
}
None
}
/// 获取位图中第一个为0的位
pub(crate) fn first_false_index(&self, n: usize, data: &[T]) -> Option<usize> {
for (i, element) in data.iter().enumerate() {
if let Some(bit) = <T as BitOps>::first_false_index(element) {
return self.make_index(n, i * T::bit_size() + bit);
}
}
None
}
/// 获取位图中最后一个为1的位
pub(crate) fn last_index(&self, n: usize, data: &[T]) -> Option<usize> {
for (i, element) in data.iter().enumerate().rev() {
if let Some(bit) = <T as BitOps>::last_index(element) {
return self.make_index(n, i * T::bit_size() + bit);
}
}
None
}
/// 获取位图中最后一个为0的位
///
/// ## 参数
///
/// - `data`:位图数据
/// - `n`:位图有效位数
pub(crate) fn last_false_index(&self, n: usize, data: &[T]) -> Option<usize> {
let mut iter = data.iter().rev();
let mut last_element = *iter.next()?;
// 对最后一个元素进行特殊处理,因为最后一个元素可能不是满的
let mut mask = T::make_mask(n % T::bit_size());
if mask != T::zero() {
<T as BitOps>::invert(&mut mask);
last_element |= mask;
}
if let Some(bit) = <T as BitOps>::last_false_index(&last_element) {
return self.make_index(n, (data.len() - 1) * T::bit_size() + bit);
}
for element in iter {
if let Some(bit) = <T as BitOps>::last_false_index(element) {
return self.make_index(n, (data.len() - 1) * T::bit_size() + bit);
}
}
None
}
/// 获取位图中下一个为1的位
pub(crate) fn next_index(&self, n: usize, data: &[T], index: usize) -> Option<usize> {
if unlikely(index >= n) {
return None;
}
let element_index = index / T::bit_size();
let bit_index = index % T::bit_size();
let element = data.get(element_index)?;
if let Some(bit) = <T as BitOps>::next_index(element, bit_index) {
return self.make_index(n, element_index * T::bit_size() + bit);
}
for (i, element) in data.iter().enumerate().skip(element_index + 1) {
if let Some(bit) = <T as BitOps>::first_index(element) {
return self.make_index(n, i * T::bit_size() + bit);
}
}
None
}
/// 获取位图中下一个为0的位
pub(crate) fn next_false_index(&self, n: usize, data: &[T], index: usize) -> Option<usize> {
if unlikely(index >= n) {
return None;
}
let element_index = index / T::bit_size();
let bit_index = index % T::bit_size();
let element = data.get(element_index)?;
if let Some(bit) = <T as BitOps>::next_false_index(element, bit_index) {
return self.make_index(n, element_index * T::bit_size() + bit);
}
for (i, element) in data.iter().enumerate().skip(element_index + 1) {
if let Some(bit) = <T as BitOps>::first_false_index(element) {
return self.make_index(n, i * T::bit_size() + bit);
}
}
None
}
/// 获取位图中上一个为1的位
pub(crate) fn prev_index(&self, n: usize, data: &[T], index: usize) -> Option<usize> {
if unlikely(index >= n) {
return None;
}
let element_index = index / T::bit_size();
let bit_index = index % T::bit_size();
let element = data.get(element_index)?;
if let Some(bit) = <T as BitOps>::prev_index(element, bit_index) {
return self.make_index(n, element_index * T::bit_size() + bit);
}
for (i, element) in data.iter().enumerate().take(element_index).rev() {
if let Some(bit) = <T as BitOps>::last_index(element) {
return self.make_index(n, i * T::bit_size() + bit);
}
}
None
}
pub(crate) fn prev_false_index(&self, n: usize, data: &[T], index: usize) -> Option<usize> {
let element_index = index / T::bit_size();
let bit_index = index % T::bit_size();
let element = data.get(element_index)?;
if let Some(bit) = <T as BitOps>::prev_false_index(element, bit_index) {
return self.make_index(n, element_index * T::bit_size() + bit);
}
for (i, element) in data.iter().enumerate().take(element_index).rev() {
if let Some(bit) = <T as BitOps>::last_false_index(element) {
return self.make_index(n, i * T::bit_size() + bit);
}
}
None
}
pub(crate) fn invert(&self, n: usize, data: &mut [T]) {
for element in data.iter_mut() {
<T as BitOps>::invert(element);
}
// 特殊处理最后一个元素
let last_element = data.last_mut().unwrap();
let mask = T::make_mask(n % T::bit_size());
if mask != T::zero() {
*last_element &= mask;
}
}
pub(crate) fn is_full(&self, n: usize, data: &[T]) -> bool {
let mut iter = data.iter().peekable();
while let Some(element) = iter.next() {
if iter.peek().is_none() {
// 这是最后一个元素,进行特殊处理
let mut element = *element;
let mut mask = T::make_mask(n % T::bit_size());
if mask == T::zero() {
mask = T::max();
}
T::bit_and(&mut element, &mask);
if element == mask {
return true;
}
} else if element != &T::make_mask(T::bit_size()) {
return false;
}
}
return false;
}
pub(crate) fn is_empty(&self, data: &[T]) -> bool {
for element in data.iter() {
if element != &T::zero() {
return false;
}
}
return true;
}
fn make_index(&self, n: usize, index: usize) -> Option<usize> {
if unlikely(index >= n) {
return None;
}
Some(index)
}
}