rustls_split/
buffer.rs

1use std::io;
2
3pub struct BufCfg<D: Into<Vec<u8>>> {
4    initial_data: D,
5    min_capacity: usize,
6}
7
8impl BufCfg<[u8; 0]> {
9    /// Configure an empty buffer with specified capacity.
10    pub fn with_capacity(capacity: usize) -> Self {
11        Self {
12            initial_data: [],
13            min_capacity: capacity,
14        }
15    }
16}
17
18impl<D: Into<Vec<u8>>> BufCfg<D> {
19    /// Configure a buffer with the data in `initial_data`.
20    /// The buffer capacity will be determined by the greater of `initial_data.len()` and `min_capacity`.
21    pub fn with_data(initial_data: D, min_capacity: usize) -> Self {
22        Self {
23            initial_data,
24            min_capacity,
25        }
26    }
27}
28
29pub struct Buffer {
30    buf: Box<[u8]>,
31    start: usize,
32    end: usize,
33}
34
35impl Buffer {
36    pub fn build_from<D: Into<Vec<u8>>>(cfg: BufCfg<D>) -> Self {
37        let mut buf: Vec<u8> = cfg.initial_data.into();
38        let end = buf.len();
39
40        if buf.len() < cfg.min_capacity {
41            // TODO ensure we're not wasting extra capacity
42            buf.resize(cfg.min_capacity, 0u8);
43        }
44
45        assert_ne!(buf.len(), 0); // TODO add warnings about panics to docs
46
47        let buf = buf.into_boxed_slice();
48
49        Self { buf, start: 0, end }
50    }
51
52    pub fn read_from(&mut self, reader: &mut impl io::Read) -> io::Result<usize> {
53        let bytes_read = reader.read(&mut self.buf[self.end..])?;
54        self.end += bytes_read;
55        Ok(bytes_read)
56    }
57
58    pub fn write_to(&mut self, writer: &mut impl io::Write) -> io::Result<usize> {
59        let bytes_written = writer.write(&self.buf[self.start..self.end])?;
60        self.start += bytes_written;
61        self.check_start();
62        Ok(bytes_written)
63    }
64
65    pub fn is_empty(&self) -> bool {
66        self.end == 0
67    }
68
69    pub fn is_full(&self) -> bool {
70        self.end == self.buf.len()
71    }
72
73    fn check_start(&mut self) {
74        if self.start == self.end {
75            self.start = 0;
76            self.end = 0;
77        }
78    }
79}
80
81impl io::Read for Buffer {
82    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
83        let src = &self.buf[self.start..self.end];
84        let len = std::cmp::min(src.len(), buf.len());
85        buf[..len].copy_from_slice(&src[..len]);
86        self.start += len;
87        self.check_start();
88        Ok(len)
89    }
90}
91
92impl io::Write for Buffer {
93    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
94        let dst = &mut self.buf[self.end..];
95        let len = std::cmp::min(dst.len(), buf.len());
96        dst[..len].copy_from_slice(&buf[..len]);
97        self.end += len;
98        Ok(len)
99    }
100
101    fn flush(&mut self) -> io::Result<()> {
102        Err(io::ErrorKind::InvalidInput.into())
103    }
104}
rustls_split/buffer.rs

rustls_split/
buffer.rs
