136 lines
2.9 KiB
Rust
136 lines
2.9 KiB
Rust
use anyhow::{anyhow, Result};
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use nom::{number::complete::*, IResult};
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use crate::block_manager::*;
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use crate::pdata::btree::Unpack;
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//------------------------------------------
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#[derive(Debug)]
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pub struct SMRoot {
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pub nr_blocks: u64,
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pub nr_allocated: u64,
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pub bitmap_root: u64,
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pub ref_count_root: u64,
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}
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pub fn unpack_root(data: &[u8]) -> Result<SMRoot> {
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match SMRoot::unpack(data) {
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Err(_e) => {
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Err(anyhow!("couldn't parse SMRoot"))
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},
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Ok((_i, v)) => Ok(v),
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}
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}
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impl Unpack for SMRoot {
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fn disk_size() -> u32 {
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32
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}
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fn unpack(data: &[u8]) -> IResult<&[u8], SMRoot> {
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let (i, nr_blocks) = le_u64(data)?;
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let (i, nr_allocated) = le_u64(i)?;
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let (i, bitmap_root) = le_u64(i)?;
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let (i, ref_count_root) = le_u64(i)?;
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Ok ((i, SMRoot {
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nr_blocks,
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nr_allocated,
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bitmap_root,
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ref_count_root,
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}))
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}
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}
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//------------------------------------------
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#[derive(Clone, Debug)]
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pub struct IndexEntry {
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pub blocknr: u64,
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pub nr_free: u32,
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pub none_free_before: u32,
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}
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impl Unpack for IndexEntry {
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fn disk_size() -> u32 {
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16
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}
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fn unpack(data: &[u8]) -> IResult<&[u8], Self> {
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let (i, blocknr) = le_u64(data)?;
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let (i, nr_free) = le_u32(i)?;
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let (i, none_free_before) = le_u32(i)?;
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Ok((i, IndexEntry {blocknr, nr_free, none_free_before}))
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}
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}
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//------------------------------------------
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#[derive(Debug)]
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pub struct BitmapHeader {
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pub csum: u32,
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pub not_used: u32,
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pub blocknr: u64,
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}
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impl Unpack for BitmapHeader {
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fn disk_size() -> u32 {
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16
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}
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fn unpack(data: &[u8]) -> IResult<&[u8], Self> {
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let (i, csum) = le_u32(data)?;
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let (i, not_used) = le_u32(i)?;
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let (i, blocknr) = le_u64(i)?;
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Ok((i, BitmapHeader {csum, not_used, blocknr} ))
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}
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}
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#[derive(Debug)]
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pub enum BitmapEntry {
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Small(u8),
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Overflow,
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}
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#[derive(Debug)]
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pub struct Bitmap {
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pub header: BitmapHeader,
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pub entries: Vec<BitmapEntry>,
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}
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impl Unpack for Bitmap {
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fn disk_size() -> u32 {
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BLOCK_SIZE as u32
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}
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fn unpack(data: &[u8]) -> IResult<&[u8], Self> {
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let (mut i, header) = BitmapHeader::unpack(data)?;
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let mut entries = Vec::new();
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let nr_words = (BLOCK_SIZE - BitmapHeader::disk_size() as usize) / 8;
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for _w in 0..nr_words {
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let (tmp, mut word) = le_u64(i)?;
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for _b in 0..32 {
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let val = word & 0x3;
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word >>= 2;
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if val < 3 {
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entries.push(BitmapEntry::Small(val as u8));
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} else {
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entries.push(BitmapEntry::Overflow);
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}
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}
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i = tmp;
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}
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Ok((i, Bitmap {header, entries}))
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}
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}
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//------------------------------------------
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