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use std::mem;
pub use crate::error::Error;
const LZNT1_COMPRESSED_FLAG: usize = 0x8000;
macro_rules! load16le{
($dst:expr,$src:expr,$idx:expr)=>{
{
$dst = (u32::from($src[$idx + 1]) << 8
| u32::from($src[$idx])) as usize;
}
}
}
pub fn decompress(
in_buf: &[u8]
) -> Result<Vec<u8>, Error>
{
let mut out_buf: Vec<u8> = Vec::with_capacity(in_buf.len());
match decompress2(in_buf, &mut out_buf) {
Err(e) => println!("{:?}", e),
_ => ()
}
Ok(out_buf)
}
pub fn decompress2(
in_buf: &[u8],
out_buf: &mut Vec<u8>
) -> Result<(), Error>
{
let mut out_idx: usize = 0;
let mut in_idx: usize = 0;
let mut header: usize;
let mut length: usize;
let mut block_len: usize;
let mut offset: usize;
let mut _block_id = 0;
while in_idx < in_buf.len() {
let in_chunk_base = in_idx;
load16le!(header, in_buf, in_idx);
in_idx += mem::size_of::<u16>();
block_len = (header & 0xfff) + 1;
if block_len > (in_buf.len() - in_idx) {
return Err(Error::MemLimit);
} else {
if header & LZNT1_COMPRESSED_FLAG != 0 {
let in_base_idx = in_idx;
let out_base_idx = out_idx;
while (in_idx - in_base_idx) < block_len {
if in_idx >= in_buf.len() {
break;
}
let flags = in_buf[in_idx];
in_idx += mem::size_of::<u8>();
for n in 0..8 {
if ((flags >> n) & 1) == 0 {
if in_idx >= in_buf.len() || (in_idx - in_base_idx) >= block_len {
break;
}
out_buf.push(in_buf[in_idx]);
out_idx += mem::size_of::<u8>();
in_idx += mem::size_of::<u8>();
} else {
let flag;
if in_idx >= in_buf.len() || (in_idx - in_base_idx) >= block_len {
break;
}
load16le!(flag, in_buf, in_idx);
in_idx += mem::size_of::<u16>();
let mut pos = out_idx - out_base_idx - 1;
let mut l_mask = 0xFFF;
let mut o_shift = 12;
while pos >= 0x10 {
l_mask >>= 1;
o_shift -= 1;
pos >>= 1;
}
length = (flag & l_mask) + 3;
offset = (flag >> o_shift) + 1;
if length >= offset {
let count = (0xfff / offset) + 1;
if offset > out_idx {
return Err(Error::CorruptedData);
}
let chunk_pos = out_idx - offset;
let chunk_len = offset;
let mut x = 0;
while x < length {
for _i in 0..count {
for _j in 0..chunk_len {
out_buf.push(out_buf[chunk_pos + _j]);
out_idx += mem::size_of::<u8>();
x += 1;
if x >= length {
break;
}
}
if x >= length {
break;
}
}
}
} else {
for _i in 0..length {
if offset > out_idx {
return Err(Error::CorruptedData);
}
out_buf.push(out_buf[out_idx - offset]);
out_idx += mem::size_of::<u8>();
}
}
}
}
}
} else {
// Not compressed
for _i in 0..block_len {
out_buf.push(in_buf[in_idx]);
out_idx += mem::size_of::<u8>();
in_idx += mem::size_of::<u8>();
}
}
}
in_idx = in_chunk_base + 2 + block_len;
_block_id += 1;
}
Ok(())
}