gdlib 0.3.3

Rust library for editing Geometry Dash savefiles
Documentation 
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

//! Here lies the decryption functions for GD savefiles
use std::{fs, io::Read};

use base64::{Engine, engine::general_purpose};
use flate2::read::DeflateDecoder;

use crate::{core::GDError, core::get_local_levels_path};

/// Decompresses a `Vec<u8>` of a base64ed gzip-compressed payload.
///
/// # Arguments
/// * `data`: compressed input data
///
/// Returns decompressed base64ed gzip as a `Vec<u8>` if it sucessfully decoded, otherwise return Error
pub fn decompress(mut data: Vec<u8>) -> Result<Vec<u8>, GDError> {
    data.retain(|c| *c != 0);

    // decode DEFLATE payload
    let decoded = general_purpose::URL_SAFE.decode(data)?;
    let sliced = &decoded[10..];

    let mut decoder = DeflateDecoder::new(sliced);
    let mut decompressed_buf = Vec::new();

    decoder.read_to_end(&mut decompressed_buf).unwrap();

    Ok(decompressed_buf)
}

/// Decrypts data by xoring with key 11 and decompressing it.
/// This is the algorithm used to decrypt GD savefiles.
///
/// # Arguments
/// * `data`: encrypted payload
///
/// Returns the raw file contents as a `Vec<u8>`
#[inline(always)]
pub fn decrypt(mut data: Vec<u8>) -> Vec<u8> {
    for c in &mut data {
        *c ^= 11;
    }
    decompress(data).unwrap()
}

/// Returns CCLocalLevels.dat decrypted if it exists
pub fn decode_levels_to_string() -> Result<String, GDError> {
    let savefile = match fs::read(get_local_levels_path().unwrap()) {
        Ok(v) => v,
        Err(e) => return Err(GDError::Io(e)),
    };
    let data = decrypt(savefile);

    Ok(String::from_utf8(data.to_vec()).unwrap())
}