roblox_buffer/
lib.rs

1//! # roblox-buffer
2//! This library exposes [`Buffer`] that serializes and deserializes to the `buffer` type in Roblox.
3#![warn(missing_docs)]
4
5use std::io::{Read, Write};
6
7use data_encoding::BASE64;
8use serde::{Deserialize, Serialize};
9
10/// Represents a Roblox `buffer`.
11#[derive(Debug, Clone, PartialEq, Eq, Default, Hash)]
12pub struct Buffer(Vec<u8>);
13
14impl Buffer {
15    /// Creates a new buffer from bytes.
16    pub fn new(data: Vec<u8>) -> Self {
17        Self(data)
18    }
19
20    /// Returns the inner vector of the buffer.
21    pub fn into_vec(self) -> Vec<u8> {
22        self.0
23    }
24}
25
26impl<'de> Deserialize<'de> for Buffer {
27    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
28    where
29        D: serde::Deserializer<'de>,
30    {
31        #[derive(Deserialize)]
32        enum BufferData {
33            #[serde(rename = "base64")]
34            Base64(String),
35            #[serde(rename = "zbase64")]
36            ZBase64(String),
37        }
38
39        #[derive(Deserialize)]
40        struct BufferInner {
41            t: String,
42            #[serde(flatten)]
43            data: BufferData,
44        }
45
46        let BufferInner { t, data } = BufferInner::deserialize(deserializer)?;
47
48        if t != "buffer" {
49            return Err(serde::de::Error::custom("expected buffer"));
50        }
51
52        let data = match data {
53            BufferData::Base64(base64) => BASE64
54                .decode(base64.as_bytes())
55                .map_err(serde::de::Error::custom)?,
56            BufferData::ZBase64(zbase64) => {
57                let compressed = BASE64
58                    .decode(zbase64.as_bytes())
59                    .map_err(serde::de::Error::custom)?;
60                let mut decoder = zstd::stream::Decoder::new(&compressed[..])
61                    .map_err(serde::de::Error::custom)?;
62                let mut data = Vec::new();
63                decoder
64                    .read_to_end(&mut data)
65                    .map_err(serde::de::Error::custom)?;
66                data
67            }
68        };
69
70        Ok(Self(data))
71    }
72}
73
74impl Serialize for Buffer {
75    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
76    where
77        S: serde::ser::Serializer,
78    {
79        use serde::ser::SerializeMap;
80
81        let mut map = serializer.serialize_map(Some(3))?;
82
83        map.serialize_entry("m", &())?; // "m": null
84        map.serialize_entry("t", "buffer")?;
85
86        // This DOESN'T deserialize in Roblox.
87        // I couldn't figure out why.
88        if false {
89            let base64 = BASE64.encode(&self.0);
90
91            let mut compressed: Vec<u8> = Vec::new();
92            let mut encoder = zstd::stream::Encoder::new(&mut compressed, 0).unwrap();
93            encoder
94                .set_pledged_src_size(Some(self.0.len() as u64))
95                .unwrap();
96            encoder.include_contentsize(true).unwrap();
97            encoder.write_all(&self.0).unwrap();
98            encoder.finish().unwrap();
99
100            if compressed.len() < base64.len() {
101                map.serialize_entry("zbase64", &BASE64.encode(&compressed))?;
102            } else {
103                map.serialize_entry("base64", &base64)?;
104            }
105        }
106
107        map.serialize_entry("base64", &BASE64.encode(&self.0))?;
108
109        map.end()
110    }
111}
112
113impl From<Buffer> for Vec<u8> {
114    fn from(value: Buffer) -> Self {
115        value.into_vec()
116    }
117}
118
119impl AsRef<[u8]> for Buffer {
120    fn as_ref(&self) -> &[u8] {
121        &self.0
122    }
123}
124
125impl AsMut<[u8]> for Buffer {
126    fn as_mut(&mut self) -> &mut [u8] {
127        &mut self.0
128    }
129}
130
131impl FromIterator<u8> for Buffer {
132    fn from_iter<T: IntoIterator<Item = u8>>(iter: T) -> Self {
133        Self(Vec::from_iter(iter))
134    }
135}
136
137impl Extend<u8> for Buffer {
138    fn extend<T: IntoIterator<Item = u8>>(&mut self, iter: T) {
139        self.0.extend(iter);
140    }
141}
142
143#[cfg(test)]
144mod tests {
145    use super::*;
146
147    #[test]
148    fn test_base64_de() {
149        assert_eq!(
150            serde_json::from_str::<Buffer>(
151                r#"{"m":null,"t":"buffer","base64":"aGVsbG8gd29ybGQ="}"#
152            )
153            .unwrap(),
154            Buffer::new(b"hello world".to_vec())
155        );
156    }
157
158    #[test]
159    fn test_zbase64_de() {
160        assert_eq!(
161            serde_json::from_str::<Buffer>(r#"{"m":null,"t":"buffer","zbase64":"KLUv/SBfbQAAMGhlbGxvIAEAlqkUAQ=="}"#).unwrap(),
162            Buffer::new(b"hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello".to_vec())
163        )
164    }
165}
roblox_buffer/lib.rs

roblox_buffer/
lib.rs
