osdev5/fs/memfs/src/bvec.rs

612 lines
23 KiB
Rust

use crate::{block, BlockAllocator, BlockRef};
use core::cmp::{max, min};
use core::marker::PhantomData;
use core::mem::MaybeUninit;
use core::ops::{Index, IndexMut};
use error::Errno;
const L0_BLOCKS: usize = 32; // 128K
const L1_BLOCKS: usize = 8; // 16M
pub struct Bvec<'a, A: BlockAllocator + Copy> {
capacity: usize,
size: usize,
l0: [MaybeUninit<BlockRef<'a, A>>; L0_BLOCKS],
l1: [MaybeUninit<BlockRef<'a, A>>; L1_BLOCKS],
l2: MaybeUninit<BlockRef<'a, A>>,
alloc: A,
}
impl<'a, A: BlockAllocator + Copy> Bvec<'a, A> {
pub fn new(alloc: A) -> Self {
let mut res = Self {
capacity: 0,
size: 0,
l0: MaybeUninit::uninit_array(),
l1: MaybeUninit::uninit_array(),
l2: MaybeUninit::uninit(),
alloc,
};
for it in res.l0.iter_mut() {
it.write(BlockRef::null());
}
for it in res.l1.iter_mut() {
it.write(BlockRef::null());
}
res.l2.write(BlockRef::null());
res
}
pub fn resize(&mut self, cap: usize) -> Result<(), Errno> {
if cap <= self.capacity {
let mut curr = self.capacity;
while curr != cap {
curr -= 1;
let mut index = curr;
if index >= L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT {
index -= L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT;
let l1i = index / block::ENTRY_COUNT;
let l0i = index % block::ENTRY_COUNT;
let l2r = unsafe { self.l2.assume_init_mut() };
assert!(!l2r.is_null());
let l1r = unsafe { l2r.as_mut_ref_array()[l1i].assume_init_mut() };
assert!(!l1r.is_null());
let l0r = unsafe { l1r.as_mut_ref_array()[l0i].assume_init_mut() };
assert!(!l0r.is_null());
*l0r = BlockRef::null();
if l0i == 0 {
*l1r = BlockRef::null();
}
if index == 0 {
*l2r = BlockRef::null();
}
continue;
}
if index >= L0_BLOCKS {
index -= L0_BLOCKS;
let l1i = index / block::ENTRY_COUNT;
let l0i = index % block::ENTRY_COUNT;
let l1r = unsafe { self.l1[l1i].assume_init_mut() };
assert!(!l1r.is_null());
let l0r = unsafe { l1r.as_mut_ref_array()[l0i].assume_init_mut() };
assert!(!l0r.is_null());
*l0r = BlockRef::null();
if l0i == 0 {
*l1r = BlockRef::null();
}
continue;
}
let l0r = unsafe { self.l0[index].assume_init_mut() };
assert!(!l0r.is_null());
*l0r = BlockRef::null();
continue;
unimplemented!();
}
} else {
for mut index in self.capacity..cap {
if index < L0_BLOCKS {
let l0r = unsafe { self.l0[index].assume_init_mut() };
assert!(l0r.is_null());
*l0r = BlockRef::new(self.alloc)?;
continue;
}
index -= L0_BLOCKS;
if index < L1_BLOCKS * block::ENTRY_COUNT {
let l1i = index / block::ENTRY_COUNT;
let l0i = index % block::ENTRY_COUNT;
let l1r = unsafe { self.l1[l1i].assume_init_mut() };
if l1r.is_null() {
*l1r = BlockRef::new_indirect(self.alloc)?;
}
let l0r = unsafe { l1r.as_mut_ref_array()[l0i].assume_init_mut() };
assert!(l0r.is_null());
*l0r = BlockRef::new(self.alloc)?;
continue;
}
index -= L1_BLOCKS * block::ENTRY_COUNT;
if index < block::ENTRY_COUNT * block::ENTRY_COUNT {
let l1i = index / block::ENTRY_COUNT;
let l0i = index % block::ENTRY_COUNT;
let l2r = unsafe { self.l2.assume_init_mut() };
if l2r.is_null() {
*l2r = BlockRef::new_indirect(self.alloc)?;
}
let l1r = unsafe { l2r.as_mut_ref_array()[l1i].assume_init_mut() };
if l1r.is_null() {
*l1r = BlockRef::new_indirect(self.alloc)?;
}
let l0r = unsafe { l1r.as_mut_ref_array()[l0i].assume_init_mut() };
assert!(l0r.is_null());
*l0r = BlockRef::new(self.alloc)?;
continue;
}
unimplemented!();
}
}
self.capacity = cap;
Ok(())
}
pub fn write(&mut self, mut pos: usize, data: &[u8]) -> Result<usize, Errno> {
if pos > self.size {
return Err(Errno::InvalidArgument);
}
let mut rem = data.len();
let mut doff = 0usize;
if pos + rem > self.size {
self.size = pos + rem;
self.resize((pos + rem + block::SIZE - 1) / block::SIZE)?;
}
while rem > 0 {
let index = pos / block::SIZE;
let off = pos % block::SIZE;
let count = min(block::SIZE - off, rem);
let block = &mut self[index];
let dst = &mut block[off..off + count];
let src = &data[doff..doff + count];
dst.copy_from_slice(src);
doff += count;
pos += count;
rem -= count;
}
Ok(doff)
}
pub fn read(&self, mut pos: usize, data: &mut [u8]) -> Result<usize, Errno> {
if pos > self.size {
return Err(Errno::InvalidArgument);
}
let mut rem = min(self.size - pos, data.len());
let mut doff = 0usize;
while rem > 0 {
let index = pos / block::SIZE;
let off = pos % block::SIZE;
let count = min(block::SIZE - off, rem);
let block = &self[index];
let src = &block[off..off + count];
let dst = &mut data[doff..doff + count];
dst.copy_from_slice(src);
doff += count;
pos += count;
rem -= count;
}
Ok(doff)
}
}
impl<'a, A: BlockAllocator + Copy> Index<usize> for Bvec<'a, A> {
type Output = BlockRef<'a, A>;
fn index(&self, mut index: usize) -> &Self::Output {
if index >= self.capacity {
panic!(
"Index exceeds bvec capacity ({} >= {})",
index, self.capacity
);
}
if index < L0_BLOCKS {
return unsafe { self.l0[index].assume_init_ref() };
}
index -= L0_BLOCKS;
if index < L1_BLOCKS * block::ENTRY_COUNT {
return unsafe {
let l1 = self.l1[index / block::ENTRY_COUNT].assume_init_ref();
l1.as_ref_array()[index % block::ENTRY_COUNT].assume_init_ref()
};
}
index -= L1_BLOCKS * block::ENTRY_COUNT;
if index < block::ENTRY_COUNT * block::ENTRY_COUNT {
return unsafe {
let l2 = self.l2.assume_init_ref();
let l1 = l2.as_ref_array()[index / block::ENTRY_COUNT].assume_init_ref();
l1.as_ref_array()[index % block::ENTRY_COUNT].assume_init_ref()
};
}
unimplemented!();
}
}
impl<'a, A: BlockAllocator + Copy> IndexMut<usize> for Bvec<'a, A> {
fn index_mut(&mut self, mut index: usize) -> &mut Self::Output {
if index >= self.capacity {
panic!(
"Index exceeds bvec capacity ({} >= {})",
index, self.capacity
);
}
if index < L0_BLOCKS {
return unsafe { self.l0[index].assume_init_mut() };
}
index -= L0_BLOCKS;
if index < L1_BLOCKS * block::ENTRY_COUNT {
return unsafe {
let l1 = self.l1[index / block::ENTRY_COUNT].assume_init_mut();
l1.as_mut_ref_array()[index % block::ENTRY_COUNT].assume_init_mut()
};
}
index -= L1_BLOCKS * block::ENTRY_COUNT;
if index < block::ENTRY_COUNT * block::ENTRY_COUNT {
return unsafe {
let l2 = self.l2.assume_init_mut();
let l1 = l2.as_mut_ref_array()[index / block::ENTRY_COUNT].assume_init_mut();
l1.as_mut_ref_array()[index % block::ENTRY_COUNT].assume_init_mut()
};
}
unimplemented!();
}
}
impl<'a, A: BlockAllocator + Copy> Drop for Bvec<'a, A> {
fn drop(&mut self) {
for i in 0..min(L0_BLOCKS, self.capacity) {
unsafe {
self.l0[i].assume_init_drop();
}
}
if self.capacity > L0_BLOCKS {}
}
}
#[cfg(feature = "test_bvec")]
#[cfg(test)]
mod tests {
use super::*;
use std::boxed::Box;
use std::mem::MaybeUninit;
use std::sync::atomic::{AtomicUsize, Ordering};
static A_COUNTER: AtomicUsize = AtomicUsize::new(0);
#[derive(Clone, Copy)]
struct TestAlloc;
unsafe impl BlockAllocator for TestAlloc {
fn alloc(&self) -> *mut u8 {
let b = Box::leak(Box::new([0; block::SIZE]));
eprintln!("alloc {:p}", b);
b.as_mut_ptr() as *mut _
}
unsafe fn dealloc(&self, ptr: *mut u8) {
eprintln!("drop {:p}", ptr);
drop(Box::from_raw(ptr as *mut [u8; block::SIZE]));
}
}
#[test]
fn bvec_allocation() {
#[derive(Clone, Copy)]
struct A;
unsafe impl BlockAllocator for A {
fn alloc(&self) -> *mut u8 {
let b = Box::leak(Box::new([0; block::SIZE]));
A_COUNTER.fetch_add(1, Ordering::SeqCst);
b.as_mut_ptr() as *mut _
}
unsafe fn dealloc(&self, ptr: *mut u8) {
A_COUNTER.fetch_sub(1, Ordering::SeqCst);
drop(Box::from_raw(ptr as *mut [u8; block::SIZE]));
}
}
let mut bvec = Bvec::new(A {});
assert_eq!(A_COUNTER.load(Ordering::Acquire), 0);
bvec.resize(123).unwrap();
unsafe {
for i in 0..L0_BLOCKS {
assert!(!bvec.l0[i].assume_init_ref().is_null());
}
let l1r = bvec.l1[0].assume_init_ref();
assert!(!l1r.is_null());
for i in 0..123 - L0_BLOCKS {
assert!(!l1r.as_ref_array()[i].assume_init_ref().is_null());
}
}
assert_eq!(A_COUNTER.load(Ordering::Acquire), 123 + 1);
bvec.resize(123 + block::ENTRY_COUNT).unwrap();
unsafe {
for i in 0..L0_BLOCKS {
assert!(!bvec.l0[i].assume_init_ref().is_null());
}
for i in 0..(123 + block::ENTRY_COUNT) - L0_BLOCKS {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let l1r = bvec.l1[l1i].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
}
}
assert_eq!(
A_COUNTER.load(Ordering::Acquire),
123 + block::ENTRY_COUNT + 2
);
bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT)
.unwrap();
unsafe {
for i in 0..L0_BLOCKS {
assert!(!bvec.l0[i].assume_init_ref().is_null());
}
for i in 0..L1_BLOCKS * block::ENTRY_COUNT {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let l1r = bvec.l1[l1i].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
}
}
assert_eq!(
A_COUNTER.load(Ordering::Acquire),
L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + L1_BLOCKS
);
bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 4)
.unwrap();
unsafe {
for i in 0..L0_BLOCKS {
assert!(!bvec.l0[i].assume_init_ref().is_null());
}
for i in 0..L1_BLOCKS * block::ENTRY_COUNT {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let l1r = bvec.l1[l1i].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
}
let l2r = bvec.l2.assume_init_ref();
assert!(!l2r.is_null());
for i in 0..block::ENTRY_COUNT * 4 {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let l1r = l2r.as_ref_array()[l1i].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
}
}
assert_eq!(
A_COUNTER.load(Ordering::Acquire),
L0_BLOCKS + // L0
L1_BLOCKS * block::ENTRY_COUNT + L1_BLOCKS + // L1
block::ENTRY_COUNT * 4 + 4 + 1
);
bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 3 + 1)
.unwrap();
unsafe {
for i in 0..L0_BLOCKS {
assert!(!bvec.l0[i].assume_init_ref().is_null());
}
for i in 0..L1_BLOCKS * block::ENTRY_COUNT {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let l1r = bvec.l1[l1i].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
}
let l2r = bvec.l2.assume_init_ref();
assert!(!l2r.is_null());
for i in 0..block::ENTRY_COUNT * 3 + 1 {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let l1r = l2r.as_ref_array()[l1i].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
}
}
assert_eq!(
A_COUNTER.load(Ordering::Acquire),
L0_BLOCKS + // L0
L1_BLOCKS * block::ENTRY_COUNT + L1_BLOCKS + // L1
block::ENTRY_COUNT * 3 + 1 + 4 + 1
);
bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 2 + 1)
.unwrap();
unsafe {
for i in 0..L0_BLOCKS {
assert!(!bvec.l0[i].assume_init_ref().is_null());
}
for i in 0..L1_BLOCKS * block::ENTRY_COUNT {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let l1r = bvec.l1[l1i].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
}
let l2r = bvec.l2.assume_init_ref();
assert!(!l2r.is_null());
for i in 0..block::ENTRY_COUNT * 2 + 1 {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let l1r = l2r.as_ref_array()[l1i].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
}
}
assert_eq!(
A_COUNTER.load(Ordering::Acquire),
L0_BLOCKS + // L0
L1_BLOCKS * block::ENTRY_COUNT + L1_BLOCKS + // L1
block::ENTRY_COUNT * 2 + 1 + 3 + 1
);
bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 1)
.unwrap();
unsafe {
for i in 0..L0_BLOCKS {
assert!(!bvec.l0[i].assume_init_ref().is_null());
}
for i in 0..L1_BLOCKS * block::ENTRY_COUNT {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let l1r = bvec.l1[l1i].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
}
let l2r = bvec.l2.assume_init_ref();
assert!(!l2r.is_null());
let l1r = l2r.as_ref_array()[0].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[0].assume_init_ref().is_null());
}
assert_eq!(
A_COUNTER.load(Ordering::Acquire),
L0_BLOCKS + // L0
L1_BLOCKS * block::ENTRY_COUNT + L1_BLOCKS + // L1
1 + 1 + 1
);
bvec.resize(L0_BLOCKS + 3 * block::ENTRY_COUNT + 1).unwrap();
unsafe {
for i in 0..L0_BLOCKS {
assert!(!bvec.l0[i].assume_init_ref().is_null());
}
for i in 0..3 * block::ENTRY_COUNT + 1 {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let l1r = bvec.l1[l1i].assume_init_ref();
assert!(!l1r.is_null());
assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
}
let l2r = bvec.l2.assume_init_ref();
assert!(l2r.is_null());
}
assert_eq!(
A_COUNTER.load(Ordering::Acquire),
L0_BLOCKS + // L0
3 * block::ENTRY_COUNT + 1 + 4
);
bvec.resize(L0_BLOCKS).unwrap();
unsafe {
for i in 0..L0_BLOCKS {
assert!(!bvec.l0[i].assume_init_ref().is_null());
}
assert!(bvec.l1[0].assume_init_ref().is_null());
}
assert_eq!(A_COUNTER.load(Ordering::Acquire), L0_BLOCKS);
bvec.resize(12).unwrap();
unsafe {
for i in 0..12 {
assert!(!bvec.l0[i].assume_init_ref().is_null());
}
}
assert_eq!(A_COUNTER.load(Ordering::Acquire), 12);
bvec.resize(0).unwrap();
unsafe {
for i in 0..L0_BLOCKS {
assert!(bvec.l0[i].assume_init_ref().is_null());
}
}
assert_eq!(A_COUNTER.load(Ordering::Acquire), 0);
}
#[test]
fn bvec_index_l0() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(L0_BLOCKS).unwrap();
for i in 0..L0_BLOCKS {
let block = &bvec[i];
assert_eq!(block as *const _, bvec.l0[i].as_ptr());
}
}
#[test]
fn bvec_index_l1() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(L0_BLOCKS + block::ENTRY_COUNT * 2 + 3).unwrap();
for i in 0..block::ENTRY_COUNT * 2 + 3 {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let block = &bvec[i + L0_BLOCKS];
let l1r = unsafe { bvec.l1[l1i].assume_init_ref() };
assert_eq!(block as *const _, l1r.as_ref_array()[l0i].as_ptr());
}
}
#[test]
fn bvec_index_l2() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 3)
.unwrap();
for i in 0..3 {
let l1i = i / block::ENTRY_COUNT;
let l0i = i % block::ENTRY_COUNT;
let block = &bvec[i + L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT];
let l2r = unsafe { bvec.l2.assume_init_ref() };
let l1r = unsafe { l2r.as_ref_array()[l1i].assume_init_ref() };
assert_eq!(block as *const _, l1r.as_ref_array()[l0i].as_ptr());
}
}
#[test]
#[should_panic]
fn bvec_index_invalid_l0_0() {
let bvec = Bvec::new(TestAlloc {});
let _block = &bvec[0];
}
#[test]
#[should_panic]
fn bvec_index_invalid_l0_1() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(13).unwrap();
let _block = &bvec[15];
}
#[test]
#[should_panic]
fn bvec_index_invalid_l1_0() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(13).unwrap();
let _block = &bvec[L0_BLOCKS + 2];
}
#[test]
#[should_panic]
fn bvec_index_invalid_l1_1() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(L0_BLOCKS + block::ENTRY_COUNT * 2 + 3).unwrap();
let _block = &bvec[L0_BLOCKS + block::ENTRY_COUNT * 2 + 6];
}
#[test]
#[should_panic]
fn bvec_index_invalid_l1_2() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(L0_BLOCKS + block::ENTRY_COUNT * 2 + 3).unwrap();
let _block = &bvec[L0_BLOCKS + block::ENTRY_COUNT * 3 + 1];
}
#[test]
#[should_panic]
fn bvec_index_invalid_l2_0() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(13).unwrap();
let _block = &bvec[L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 3];
}
#[test]
#[should_panic]
fn bvec_index_invalid_l2_1() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(L0_BLOCKS + block::ENTRY_COUNT * 3 + 13)
.unwrap();
let _block = &bvec[L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 3];
}
#[test]
#[should_panic]
fn bvec_index_invalid_l2_2() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 6)
.unwrap();
let _block = &bvec[L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 8];
}
#[test]
#[should_panic]
fn bvec_index_invalid_l2_3() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 2 + 7)
.unwrap();
let _block =
&bvec[L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 2 + 13];
}
#[test]
#[should_panic]
fn bvec_index_invalid_l2_4() {
let mut bvec = Bvec::new(TestAlloc {});
bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 2 + 13)
.unwrap();
let _block = &bvec[L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 3 + 2];
}
#[test]
fn bvec_write_read() {
let mut bvec = Bvec::new(TestAlloc {});
const N: usize = block::SIZE * (L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 3);
let mut data = vec![0u8; N];
for i in 0..N {
data[i] = (i & 0xFF) as u8;
}
assert_eq!(bvec.write(0, &data[..]), Ok(N));
let mut buf = vec![0u8; 327];
let mut off = 0usize;
let mut rem = N;
while rem != 0 {
let count = min(rem, buf.len());
assert_eq!(bvec.read(off, &mut buf[..]), Ok(count));
for i in 0..count {
assert_eq!(buf[i], ((i + off) & 0xFF) as u8);
}
rem -= count;
off += count;
}
}
}