repak/repak/src/entry.rs
2023-02-10 21:50:10 -06:00

392 lines
14 KiB
Rust

use super::{ext::ReadExt, ext::WriteExt, Compression, Version, VersionMajor};
use byteorder::{ReadBytesExt, WriteBytesExt, LE};
use std::io;
#[derive(Debug, PartialEq, Clone, Copy)]
pub enum EntryLocation {
Data,
Index,
}
#[derive(Debug)]
pub struct Block {
pub start: u64,
pub end: u64,
}
impl Block {
pub fn read<R: io::Read>(reader: &mut R) -> Result<Self, super::Error> {
Ok(Self {
start: reader.read_u64::<LE>()?,
end: reader.read_u64::<LE>()?,
})
}
pub fn write<W: io::Write>(&self, writer: &mut W) -> Result<(), super::Error> {
writer.write_u64::<LE>(self.start)?;
writer.write_u64::<LE>(self.end)?;
Ok(())
}
}
fn align(offset: u64) -> u64 {
// add alignment (aes block size: 16) then zero out alignment bits
(offset + 15) & !15
}
#[derive(Debug)]
pub struct Entry {
pub offset: u64,
pub compressed: u64,
pub uncompressed: u64,
pub compression: Compression,
pub timestamp: Option<u64>,
pub hash: Option<[u8; 20]>,
pub blocks: Option<Vec<Block>>,
pub encrypted: bool,
pub compression_block_size: u32,
}
impl Entry {
pub fn get_serialized_size(
version: super::Version,
compression: Compression,
block_count: u32,
) -> u64 {
let mut size = 0;
size += 8; // offset
size += 8; // compressed
size += 8; // uncompressed
size += match version != Version::V8A {
true => 4, // 32 bit compression
false => 1, // 8 bit compression
};
size += match version.version_major() == VersionMajor::Initial {
true => 8, // timestamp
false => 0,
};
size += 20; // hash
size += match compression != Compression::None {
true => 4 + (8 + 8) * block_count as u64, // blocks
false => 0,
};
size += 1; // encrypted
size += match version.version_major() >= VersionMajor::CompressionEncryption {
true => 4, // blocks uncompressed
false => 0,
};
size
}
pub fn read<R: io::Read>(
reader: &mut R,
version: super::Version,
) -> Result<Self, super::Error> {
// since i need the compression flags, i have to store these as variables which is mildly annoying
let offset = reader.read_u64::<LE>()?;
let compressed = reader.read_u64::<LE>()?;
let uncompressed = reader.read_u64::<LE>()?;
let compression = match if version == Version::V8A {
reader.read_u8()? as u32
} else {
reader.read_u32::<LE>()?
} {
0x01 | 0x10 | 0x20 => Compression::Zlib,
_ => Compression::None,
};
Ok(Self {
offset,
compressed,
uncompressed,
compression,
timestamp: match version.version_major() == VersionMajor::Initial {
true => Some(reader.read_u64::<LE>()?),
false => None,
},
hash: Some(reader.read_guid()?),
blocks: match version.version_major() >= VersionMajor::CompressionEncryption
&& compression != Compression::None
{
true => Some(reader.read_array(Block::read)?),
false => None,
},
encrypted: version.version_major() >= VersionMajor::CompressionEncryption
&& reader.read_bool()?,
compression_block_size: match version.version_major()
>= VersionMajor::CompressionEncryption
{
true => reader.read_u32::<LE>()?,
false => 0,
},
})
}
pub fn write<W: io::Write>(
&self,
writer: &mut W,
version: super::Version,
location: EntryLocation,
) -> Result<(), super::Error> {
if version >= super::Version::V10 && location == EntryLocation::Index {
let mut compression_block_size = (self.compression_block_size >> 11) & 0x3f;
if (compression_block_size << 11) != self.compression_block_size {
compression_block_size = 0x3f;
}
let compression_blocks_count = if self.compression != Compression::None {
self.blocks.as_ref().unwrap().len() as u32
} else {
0
};
let is_size_32_bit_safe = self.compressed <= u32::MAX as u64;
let is_uncompressed_size_32_bit_safe = self.uncompressed <= u32::MAX as u64;
let is_offset_32_bit_safe = self.offset <= u32::MAX as u64;
let flags = (compression_block_size)
| (compression_blocks_count << 6)
| ((self.encrypted as u32) << 22)
| ((self.compression as u32) << 23)
| ((is_size_32_bit_safe as u32) << 29)
| ((is_uncompressed_size_32_bit_safe as u32) << 30)
| ((is_offset_32_bit_safe as u32) << 31);
writer.write_u32::<LE>(flags)?;
if compression_block_size == 0x3f {
writer.write_u32::<LE>(self.compression_block_size)?;
}
if is_offset_32_bit_safe {
writer.write_u32::<LE>(self.offset as u32)?;
} else {
writer.write_u64::<LE>(self.offset)?;
}
if is_uncompressed_size_32_bit_safe {
writer.write_u32::<LE>(self.uncompressed as u32)?
} else {
writer.write_u64::<LE>(self.uncompressed)?
}
if self.compression != Compression::None {
if is_size_32_bit_safe {
writer.write_u32::<LE>(self.compressed as u32)?;
} else {
writer.write_u64::<LE>(self.compressed)?;
}
assert!(self.blocks.is_some());
let blocks = self.blocks.as_ref().unwrap();
if blocks.len() > 1 && !(blocks.len() == 1 && !self.encrypted) {
for b in blocks {
let block_size = b.end - b.start;
writer.write_u64::<LE>(block_size)?
}
}
}
Ok(())
} else {
writer.write_u64::<LE>(match location {
EntryLocation::Data => 0,
EntryLocation::Index => self.offset,
})?;
writer.write_u64::<LE>(self.compressed)?;
writer.write_u64::<LE>(self.uncompressed)?;
let compression: u8 = match self.compression {
Compression::None => 0,
Compression::Zlib => 1,
Compression::Gzip => todo!(),
Compression::Oodle => todo!(),
};
match version {
Version::V8A => writer.write_u8(compression)?,
_ => writer.write_u32::<LE>(compression.into())?,
}
if version.version_major() == VersionMajor::Initial {
writer.write_u64::<LE>(self.timestamp.unwrap_or_default())?;
}
if let Some(hash) = self.hash {
writer.write_all(&hash)?;
} else {
panic!("hash missing");
}
if version.version_major() >= VersionMajor::CompressionEncryption {
if let Some(blocks) = &self.blocks {
writer.write_u32::<LE>(blocks.len() as u32)?;
for block in blocks {
block.write(writer)?;
}
}
writer.write_bool(self.encrypted)?;
writer.write_u32::<LE>(self.compression_block_size)?;
}
Ok(())
}
}
pub fn read_encoded<R: io::Read>(
reader: &mut R,
version: super::Version,
) -> Result<Self, super::Error> {
let bits = reader.read_u32::<LE>()?;
let compression = match (bits >> 23) & 0x3f {
0x01 | 0x10 | 0x20 => Compression::Zlib,
_ => Compression::None,
};
let encrypted = (bits & (1 << 22)) != 0;
let compression_block_count: u32 = (bits >> 6) & 0xffff;
let mut compression_block_size = bits & 0x3f;
if compression_block_size == 0x3f {
compression_block_size = reader.read_u32::<LE>()?;
} else {
compression_block_size <<= 11;
}
let mut var_int = |bit: u32| -> Result<_, super::Error> {
Ok(if (bits & (1 << bit)) != 0 {
reader.read_u32::<LE>()? as u64
} else {
reader.read_u64::<LE>()?
})
};
let offset = var_int(31)?;
let uncompressed = var_int(30)?;
let compressed = match compression {
Compression::None => uncompressed,
_ => var_int(29)?,
};
let offset_base =
match version.version_major() >= VersionMajor::RelativeChunkOffsets {
true => 0,
false => offset,
} + Entry::get_serialized_size(version, compression, compression_block_count);
let blocks = if compression_block_count == 1 && !encrypted {
Some(vec![Block {
start: offset_base,
end: offset_base + compressed,
}])
} else if compression_block_count > 0 {
let mut index = offset_base;
Some(
(0..compression_block_count)
.map(|_| {
let mut block_size = reader.read_u32::<LE>()? as u64;
let block = Block {
start: index,
end: index + block_size,
};
if encrypted {
block_size = align(block_size);
}
index += block_size;
Ok(block)
})
.collect::<Result<Vec<_>, super::Error>>()?,
)
} else {
None
};
Ok(Entry {
offset,
compressed,
uncompressed,
timestamp: None,
compression,
hash: None,
blocks,
encrypted,
compression_block_size,
})
}
pub fn read_file<R: io::Read + io::Seek, W: io::Write>(
&self,
reader: &mut R,
version: Version,
key: Option<&aes::Aes256>,
buf: &mut W,
) -> Result<(), super::Error> {
reader.seek(io::SeekFrom::Start(self.offset))?;
Entry::read(reader, version)?;
let data_offset = reader.stream_position()?;
let mut data = reader.read_len(match self.encrypted {
true => align(self.compressed),
false => self.compressed,
} as usize)?;
if self.encrypted {
let Some(key) = key else {
return Err(super::Error::Encrypted);
};
use aes::cipher::BlockDecrypt;
for block in data.chunks_mut(16) {
key.decrypt_block(aes::Block::from_mut_slice(block))
}
data.truncate(self.compressed as usize);
}
macro_rules! decompress {
($decompressor: ty) => {
match &self.blocks {
Some(blocks) => {
for block in blocks {
io::copy(
&mut <$decompressor>::new(
&data[match version.version_major()
>= VersionMajor::RelativeChunkOffsets
{
true => {
(block.start - (data_offset - self.offset)) as usize
..(block.end - (data_offset - self.offset)) as usize
}
false => {
(block.start - data_offset) as usize
..(block.end - data_offset) as usize
}
}],
),
buf,
)?;
}
}
None => {
io::copy(&mut flate2::read::ZlibDecoder::new(data.as_slice()), buf)?;
}
}
};
}
match self.compression {
Compression::None => buf.write_all(&data)?,
Compression::Zlib => decompress!(flate2::read::ZlibDecoder<&[u8]>),
Compression::Gzip => decompress!(flate2::read::GzDecoder<&[u8]>),
Compression::Oodle => todo!(),
}
buf.flush()?;
Ok(())
}
}
mod test {
#[test]
fn test_entry() {
let data = vec![
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x54, 0x02, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x54, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0xDD, 0x94, 0xFD, 0xC3, 0x5F, 0xF5, 0x91, 0xA9, 0x9A, 0x5E, 0x14, 0xDC, 0x9B,
0xD3, 0x58, 0x89, 0x78, 0xA6, 0x1C, 0x00, 0x00, 0x00, 0x00, 0x00,
];
let mut out = vec![];
let entry = super::Entry::read(&mut std::io::Cursor::new(data.clone()), super::Version::V5)
.unwrap();
entry
.write(&mut out, super::Version::V5, super::EntryLocation::Data)
.unwrap();
assert_eq!(&data, &out);
}
}