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use byteorder::{BigEndian, ReadBytesExt};
use failure::Fail;
use serde::{Deserialize, Serialize};
use std::fmt;
use std::io::Read;
const HEADER_SIZE: usize = 28;
#[derive(Fail, Debug, PartialEq)]
pub enum Error {
#[fail(display = "Wrong magic number.")]
MagicError,
#[fail(display = "Wrong version: {}, expected 1.", _0)]
Version(u16),
#[fail(display = "Header too small: {} bytes, expected 28.", _0)]
HeaderTooSmall(u16),
}
#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
pub enum ChecksumAlg {
None,
SHA1,
MD5,
SHA256,
SHA512,
Other(String),
Unknown(u32),
}
impl From<u32> for ChecksumAlg {
fn from(i: u32) -> ChecksumAlg {
match i {
0 => ChecksumAlg::None,
1 => ChecksumAlg::SHA1,
2 => ChecksumAlg::MD5,
3 => ChecksumAlg::SHA256,
4 => ChecksumAlg::SHA512,
i => ChecksumAlg::Unknown(i),
}
}
}
#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct Header {
pub magic: u32,
pub size: u16,
pub version: u16,
pub toc_length_compressed: u64,
pub toc_length_uncompressed: u64,
pub checksum_alg: ChecksumAlg,
pub data: Vec<u8>,
}
impl Header {
pub fn check(&self) -> Result<(), Error> {
if self.magic != 0x78617221 {
return Err(Error::MagicError);
}
if self.size < 28 {
return Err(Error::HeaderTooSmall(self.size));
}
if self.version != 1 {
return Err(Error::Version(self.version));
}
Ok(())
}
pub fn to_json(&self) -> Result<String, serde_json::Error> {
serde_json::to_string(self)
}
pub fn from_read<T: Read>(reader: &mut T) -> Result<Header, std::io::Error> {
let magic = reader.read_u32::<BigEndian>()?;
let size = reader.read_u16::<BigEndian>()?;
let version = reader.read_u16::<BigEndian>()?;
let toc_length_compressed = reader.read_u64::<BigEndian>()?;
let toc_length_uncompressed = reader.read_u64::<BigEndian>()?;
let checksum_alg = reader.read_u32::<BigEndian>()?;
let data_size = (size as usize).saturating_sub(HEADER_SIZE);
let mut data = Vec::with_capacity(data_size);
data.resize(data_size, 0);
reader.read_exact(&mut data)?;
let checksum_alg = checksum_alg.into();
Ok(Header {
magic,
size,
version,
toc_length_compressed,
toc_length_uncompressed,
checksum_alg,
data,
})
}
}
impl fmt::Display for Header {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{:25}: {}\n", "magic", self.magic)?;
write!(f, "{:25}: {}\n", "size (header)", self.size)?;
write!(
f,
"{:25}: {}\n",
"toc length (compressed)", self.toc_length_compressed
)?;
write!(f, "{:25}: {}\n", "toc length", self.toc_length_uncompressed)?;
write!(f, "{:25}: {:?}\n", "checksum_alg", self.checksum_alg)?;
write!(f, "{:25}: {:?}", "extra data", self.data)
}
}