1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
use std::io::Cursor;
use byteorder::{LittleEndian, ReadBytesExt};
use encoding::codec::utf_16::{self, Little};
use failure::{ensure, format_err, Error};
#[derive(Debug)]
pub struct PackageWrapper<'a> {
raw_data: &'a [u8],
}
impl<'a> PackageWrapper<'a> {
pub fn new(raw_data: &'a [u8]) -> Self {
Self { raw_data }
}
pub fn get_id(&self) -> Result<u32, Error> {
let mut cursor = Cursor::new(self.raw_data);
cursor.set_position(8);
Ok(cursor.read_u32::<LittleEndian>()?)
}
pub fn get_name(&self) -> Result<String, Error> {
let mut cursor = Cursor::new(self.raw_data);
cursor.set_position(12);
let initial_position = cursor.position();
ensure!(
((initial_position + 256) as usize) < self.raw_data.len(),
"cursor position out of bounds"
);
let final_position = self.find_end_position(initial_position as usize);
ensure!(
self.raw_data.len() >= (initial_position + 256) as usize,
"not enough bytes to retrieve package name"
);
let raw_str = &cursor.get_ref()[initial_position as usize..final_position];
let mut decoder = utf_16::UTF16Decoder::<Little>::new();
let mut o = String::new();
decoder.raw_feed(raw_str, &mut o);
let decode_error = decoder.raw_finish(&mut o);
match decode_error {
None => Ok(o),
Some(_) => Err(format_err!("error decoding UTF8 string")),
}
}
fn find_end_position(&self, initial_position: usize) -> usize {
let buffer = &self.raw_data[initial_position..initial_position + 256];
let mut zeros = 0;
let mut i = 0;
for c in buffer {
if *c == 0 {
zeros += 1;
} else {
zeros = 0;
}
if zeros > 1 {
break;
}
i += 1;
}
initial_position + i
}
}