43 lines
1.1 KiB
Rust
43 lines
1.1 KiB
Rust
mod builder;
|
|
mod iterator;
|
|
|
|
pub use builder::BlockBuilder;
|
|
use bytes::{Buf, BufMut, Bytes};
|
|
pub use iterator::BlockIterator;
|
|
|
|
pub const SIZEOF_U16: usize = std::mem::size_of::<u16>();
|
|
|
|
/// A block is the smallest unit of read and caching in LSM tree. It is a collection of sorted
|
|
/// key-value pairs.
|
|
pub struct Block {
|
|
data: Vec<u8>,
|
|
offsets: Vec<u16>,
|
|
}
|
|
|
|
impl Block {
|
|
pub fn encode(&self) -> Bytes {
|
|
let mut buf = self.data.clone();
|
|
let offsets_len = self.offsets.len();
|
|
for offset in &self.offsets {
|
|
buf.put_u16(*offset);
|
|
}
|
|
buf.put_u16(offsets_len as u16);
|
|
buf.into()
|
|
}
|
|
|
|
pub fn decode(data: &[u8]) -> Self {
|
|
let entry_offsets_len = (&data[data.len() - SIZEOF_U16..]).get_u16() as usize;
|
|
let data_end = data.len() - SIZEOF_U16 - entry_offsets_len * SIZEOF_U16;
|
|
let offsets_raw = &data[data_end..data.len() - SIZEOF_U16];
|
|
let offsets = offsets_raw
|
|
.chunks(SIZEOF_U16)
|
|
.map(|mut x| x.get_u16())
|
|
.collect();
|
|
let data = data[0..data_end].to_vec();
|
|
Self { data, offsets }
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests;
|