mpc_stark/network/
stream_buffer.rs

1//! Defines an `std::io::Cursor` like buffer that tracks a cursor within a buffer that
2//! is incrementally consumed. We use this to allow partial fills across cancelled
3//! futures.
4//!
5//! This will be replaced when the more convenient `std::io::Cursor` is stabilized.
6
7/// A wrapper around a raw `&[u8]` buffer that tracks a cursor within the buffer
8/// to allow partial fills across cancelled futures
9///
10/// Similar to `tokio::io::ReadBuf` but takes ownership of the underlying buffer to
11/// avoid coloring interfaces with lifetime parameters
12///
13/// TODO: Replace this with `std::io::Cursor` once it is stabilized
14#[derive(Debug)]
15pub struct BufferWithCursor {
16    /// The underlying buffer
17    buffer: Vec<u8>,
18    /// The current cursor position
19    cursor: usize,
20}
21
22impl BufferWithCursor {
23    /// Create a new buffer with a cursor at the start of the buffer
24    pub fn new(buf: Vec<u8>) -> Self {
25        assert_eq!(
26            buf.len(),
27            buf.capacity(),
28            "buffer must be fully initialized"
29        );
30
31        Self {
32            buffer: buf,
33            cursor: 0,
34        }
35    }
36
37    /// The number of bytes remaining in the buffer
38    pub fn remaining(&self) -> usize {
39        self.buffer.capacity() - self.cursor
40    }
41
42    /// Whether the buffer is full
43    pub fn is_depleted(&self) -> bool {
44        self.remaining() == 0
45    }
46
47    /// Get a mutable reference to the empty section of the underlying buffer
48    pub fn get_remaining(&mut self) -> &mut [u8] {
49        &mut self.buffer[self.cursor..]
50    }
51
52    /// Advance the cursor by `n` bytes
53    pub fn advance_cursor(&mut self, n: usize) {
54        self.cursor += n
55    }
56
57    /// Take ownership of the underlying buffer
58    pub fn into_vec(self) -> Vec<u8> {
59        self.buffer
60    }
61}
mpc_stark/network/stream_buffer.rs

mpc_stark/network/
stream_buffer.rs
