40 lines
1.1 KiB
Rust
40 lines
1.1 KiB
Rust
use super::AreaFrameAllocator;
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const BITMAP_RESERVED: usize = 0;
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const BITMAP_FREE: usize = 1;
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const BITMAP_USED: usize = 2;
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pub struct BitmapAllocator {
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bitmap: &'static mut [u8]
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}
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impl BitmapAllocator {
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pub fn new(area_frame_allocator: AreaFrameAllocator) -> BitmapAllocator {
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BitmapAllocator {
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bitmap: &mut []
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}
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}
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}
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impl FrameAllocator for BitmapAllocator {
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fn allocate_frame(&mut self) -> Option<Frame> {
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let mut i = 0;
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while i < self.bitmap.len() {
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if self.bitmap[i] == BITMAP_FREE {
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self.bitmap[i] = BITMAP_USED;
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return Some(Frame::containing_address(PhysicalAddress::new(i * 4096)));
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}
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}
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None
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}
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fn deallocate_frame(&mut self, frame: Frame) {
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let i = frame.starting_address().get()/4096;
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if i < self.bitmap.len() && self.bitmap[i] == BITMAP_USED {
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self.bitmap[i] = BITMAP_FREE;
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} else {
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panic!("BitmapAllocator::deallocate_frame: unowned frame {:?}", frame);
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}
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}
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}
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