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|
use crate::driver::FileDriver;
use crate::zip::{CompressionMethod, ZipError, ZipFileInfo, ZipResult};
use bzip2::read::BzDecoder;
use flate2::read::DeflateDecoder;
use std::io::{
Error as IoError, ErrorKind as IoErrorKind, Read, Result as IoResult, Seek, SeekFrom,
};
use xz2::read::XzDecoder;
enum IoProxy<Io: Read> {
Store(Io),
Deflate(DeflateDecoder<Io>),
BZip2(BzDecoder<Io>),
XZ(XzDecoder<Io>),
}
pub struct ZipFileReader<'d, Io: Read> {
io: IoProxy<&'d mut Io>,
info: &'d ZipFileInfo,
bounds: (u64, u64),
cursor: u64,
}
impl<'d, Io: Read> FileDriver for ZipFileReader<'d, Io> {
type Io = Io;
type FileInfo = ZipFileInfo;
fn info(&self) -> &Self::FileInfo {
self.info
}
}
impl<'d, Io: Read + Seek> ZipFileReader<'d, Io> {
pub fn new(io: &'d mut Io, info: &'d ZipFileInfo) -> ZipResult<Self> {
io.seek(SeekFrom::Start(info.header_pointer))?;
let buf = {
let mut buf = [0; 30];
io.read(&mut buf)?;
buf
};
if u32::from_le_bytes(buf[..4].try_into().unwrap()) != 0x04034b50 {
return Err(ZipError::InvalidFileHeaderSignature.into());
}
let data_pointer = info.header_pointer
+ 30
+ u16::from_le_bytes(buf[26..28].try_into().unwrap()) as u64
+ u16::from_le_bytes(buf[28..30].try_into().unwrap()) as u64;
io.seek(SeekFrom::Start(data_pointer))?;
Ok(Self {
io: match info.compression_method {
CompressionMethod::Store => IoProxy::Store(io),
CompressionMethod::Deflate => IoProxy::Deflate(DeflateDecoder::new(io)),
CompressionMethod::BZip2 => IoProxy::BZip2(BzDecoder::new(io)),
CompressionMethod::LZMA => IoProxy::XZ(XzDecoder::new(io)),
CompressionMethod::XZ => IoProxy::XZ(XzDecoder::new(io)),
},
info,
bounds: (data_pointer, data_pointer + info.compressed_size),
cursor: data_pointer,
})
}
pub fn seekable(&self) -> bool {
match self.io {
IoProxy::Store(..) => true,
_ => false,
}
}
}
impl<'d, Io: Read> Read for ZipFileReader<'d, Io> {
fn read(&mut self, buf: &mut [u8]) -> IoResult<usize> {
let upper = buf.len().min((self.bounds.1 - self.cursor) as usize);
let bytes = match &mut self.io {
IoProxy::Store(io) => io.read(&mut buf[..upper]),
IoProxy::Deflate(io) => io.read(&mut buf[..upper]),
IoProxy::BZip2(io) => io.read(&mut buf[..upper]),
IoProxy::XZ(io) => io.read(&mut buf[..upper]),
}?;
self.cursor += upper as u64;
Ok(bytes)
}
}
impl<'d, Io: Read + Seek> Seek for ZipFileReader<'d, Io> {
fn seek(&mut self, pos: SeekFrom) -> IoResult<u64> {
match &mut self.io {
IoProxy::Store(io) => {
self.cursor = match pos {
SeekFrom::Start(offset) => self.bounds.0 + offset,
SeekFrom::End(offset) => {
let cursor = self.bounds.1.saturating_add_signed(offset);
if cursor < self.bounds.0 {
return Err(IoError::new(
IoErrorKind::InvalidInput,
ZipError::NegativeFileOffset,
));
}
cursor
}
SeekFrom::Current(offset) => {
let cursor = self.cursor.saturating_add_signed(offset);
if cursor < self.bounds.0 {
return Err(IoError::new(
IoErrorKind::InvalidInput,
ZipError::NegativeFileOffset,
));
}
cursor
}
}
.min(self.bounds.1);
Ok(io.seek(SeekFrom::Start(self.cursor))? - self.bounds.0)
}
_ => Err(IoError::new(
IoErrorKind::Unsupported,
ZipError::CompressionDataIsUnseekable,
)),
}
}
}
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