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use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
use flat_tree;
use merkle_tree_stream::Node as NodeTrait;
use pretty_hash::fmt as pretty_fmt;
use std::convert::AsRef;
use std::fmt::{self, Display};
use std::io::Cursor;
use Result;
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Node {
pub(crate) index: usize,
pub(crate) hash: Vec<u8>,
pub(crate) length: usize,
pub(crate) parent: usize,
pub(crate) data: Option<Vec<u8>>,
}
impl Node {
pub fn new(index: usize, hash: Vec<u8>, length: usize) -> Self {
Self {
index,
hash,
length,
parent: flat_tree::parent(index),
data: Some(Vec::with_capacity(0)),
}
}
pub fn from_bytes(index: usize, buffer: &[u8]) -> Result<Self> {
ensure!(buffer.len() == 40, "buffer should be 40 bytes");
let parent = flat_tree::parent(index);
let mut reader = Cursor::new(buffer);
let capacity = 32;
let mut hash = Vec::with_capacity(capacity);
for _ in 0..capacity {
hash.push(reader.read_u8()?);
}
let length = reader.read_u64::<BigEndian>()? as usize;
Ok(Self {
hash,
length,
index,
parent,
data: Some(Vec::with_capacity(0)),
})
}
pub fn to_bytes(&self) -> Result<Vec<u8>> {
let mut writer = Vec::with_capacity(40);
writer.extend_from_slice(&self.hash);
writer.write_u64::<BigEndian>(self.length as u64)?;
Ok(writer)
}
}
impl NodeTrait for Node {
#[inline]
fn index(&self) -> usize {
self.index
}
#[inline]
fn hash(&self) -> &[u8] {
&self.hash
}
#[inline]
fn len(&self) -> usize {
self.length
}
#[inline]
fn is_empty(&self) -> bool {
self.length == 0
}
#[inline]
fn parent(&self) -> usize {
self.parent
}
}
impl AsRef<Node> for Node {
#[inline]
fn as_ref(&self) -> &Self {
self
}
}
impl Display for Node {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"Node {{ index: {}, hash: {}, length: {} }}",
self.index,
pretty_fmt(&self.hash).unwrap(),
self.length
)
}
}