oxedyne/fe2o3/fe2o3_text/tests/detect_corpus/rust/comment_heavy.txt
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| 1 | // This module implements a simple ring buffer for fixed-size messages. |
| 2 | // |
| 3 | // The buffer is backed by a contiguous allocation. Reads and writes |
| 4 | // wrap around the end of the buffer. The implementation does not |
| 5 | // support concurrent access; callers must synchronise externally. |
| 6 | // |
| 7 | // Design constraints: |
| 8 | // - Fixed capacity, set at construction. |
| 9 | // - Messages are fixed-size byte arrays. |
| 10 | // - No heap allocation after construction. |
| 11 | // - O(1) push and pop. |
| 12 | |
| 13 | /// Ring buffer for fixed-size messages. |
| 14 | pub struct RingBuffer { |
| 15 | // The backing storage. |
| 16 | buf: Vec<u8>, |
| 17 | // Size of each message in bytes. |
| 18 | msg_size: usize, |
| 19 | // Read position (index into buf). |
| 20 | read_pos: usize, |
| 21 | // Write position (index into buf). |
| 22 | write_pos: usize, |
| 23 | // Number of messages currently stored. |
| 24 | count: usize, |
| 25 | // Maximum number of messages. |
| 26 | capacity: usize, |
| 27 | } |
| 28 | |
| 29 | impl RingBuffer { |
| 30 | /// Create a ring buffer that holds `capacity` messages of |
| 31 | /// `msg_size` bytes each. |
| 32 | pub fn new(capacity: usize, msg_size: usize) -> Self { |
| 33 | Self { |
| 34 | buf: vec![0u8; capacity * msg_size], |
| 35 | msg_size, |
| 36 | read_pos: 0, |
| 37 | write_pos: 0, |
| 38 | count: 0, |
| 39 | capacity, |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | /// Push a message. Returns false if the buffer is full. |
| 44 | pub fn push(&mut self, msg: &[u8]) -> bool { |
| 45 | if msg.len() != self.msg_size || self.count == self.capacity { |
| 46 | return false; |
| 47 | } |
| 48 | // Copy message into the write slot. |
| 49 | let start = self.write_pos * self.msg_size; |
| 50 | self.buf[start..start + self.msg_size].copy_from_slice(msg); |
| 51 | // Advance write position, wrapping around. |
| 52 | self.write_pos = (self.write_pos + 1) % self.capacity; |
| 53 | self.count += 1; |
| 54 | true |
| 55 | } |
| 56 | |
| 57 | /// Pop a message. Returns None if the buffer is empty. |
| 58 | pub fn pop(&mut self) -> Option<Vec<u8>> { |
| 59 | if self.count == 0 { |
| 60 | return None; |
| 61 | } |
| 62 | let start = self.read_pos * self.msg_size; |
| 63 | let msg = self.buf[start..start + self.msg_size].to_vec(); |
| 64 | self.read_pos = (self.read_pos + 1) % self.capacity; |
| 65 | self.count -= 1; |
| 66 | Some(msg) |
| 67 | } |
| 68 | } |