src/block_device/memory_disk.rs


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use crate::block_device::{BlockDevice, BLOCK_SIZE};
use std::cell::RefCell;

#[repr(C)]
pub struct MemoryDisk {
    /// Emulating a block device with a segment of RAM,
    /// which is 64MiB == 4KiB per block * 16384 blocks
    pub arena: RefCell<Vec<u8>>,
}

impl MemoryDisk {
    pub fn new(block_number: usize) -> Self {
        Self {
            arena: RefCell::new(vec![0u8; BLOCK_SIZE * block_number]),
        }
    }
}

impl BlockDevice for MemoryDisk {
    fn read(&self, block_id: usize, buffer: &mut [u8]) {
        let block_front = block_id * BLOCK_SIZE;
        let block_back = block_front + BLOCK_SIZE;
        let arena = self.arena.borrow();
        buffer.copy_from_slice(&arena[block_front..block_back]);
    }

    fn write(&self, block_id: usize, buffer: &[u8]) {
        let block_front = block_id * BLOCK_SIZE;
        let block_back = block_front + BLOCK_SIZE;
        let mut arena = self.arena.borrow_mut();
        arena[block_front..block_back].copy_from_slice(buffer);
    }
}