snap7_server/
store.rs

1use std::collections::HashMap;
2use std::sync::{Arc, Mutex};
3
4#[derive(Clone, Default)]
5pub struct DataStore {
6    inner: Arc<Mutex<HashMap<(u16, u32), u8>>>,
7}
8
9impl DataStore {
10    pub fn new() -> Self {
11        Self::default()
12    }
13
14    pub fn read_bytes(&self, db: u16, start: u32, count: u32) -> Vec<u8> {
15        let inner = self.inner.lock().unwrap();
16        let end = start.saturating_add(count);
17        (start..end)
18            .map(|offset| *inner.get(&(db, offset)).unwrap_or(&0))
19            .collect()
20    }
21
22    pub fn write_bytes(&self, db: u16, start: u32, data: &[u8]) {
23        let mut inner = self.inner.lock().unwrap();
24        for (i, &byte) in data.iter().enumerate() {
25            if let Some(offset) = start.checked_add(i as u32) {
26                inner.insert((db, offset), byte);
27            }
28        }
29    }
30}
31
32#[cfg(test)]
33mod tests {
34    use super::*;
35
36    #[test]
37    fn read_unset_returns_zeros() {
38        let store = DataStore::new();
39        let data = store.read_bytes(1, 0, 4);
40        assert_eq!(data, vec![0, 0, 0, 0]);
41    }
42
43    #[test]
44    fn write_then_read_roundtrip() {
45        let store = DataStore::new();
46        store.write_bytes(1, 0, &[0xDE, 0xAD, 0xBE, 0xEF]);
47        let data = store.read_bytes(1, 0, 4);
48        assert_eq!(data, vec![0xDE, 0xAD, 0xBE, 0xEF]);
49    }
50
51    #[test]
52    fn partial_read_within_written_range() {
53        let store = DataStore::new();
54        store.write_bytes(1, 0, &[0x01, 0x02, 0x03, 0x04]);
55        let data = store.read_bytes(1, 1, 2);
56        assert_eq!(data, vec![0x02, 0x03]);
57    }
58
59    #[test]
60    fn write_to_different_dbs_isolated() {
61        let store = DataStore::new();
62        store.write_bytes(1, 0, &[0xAA]);
63        store.write_bytes(2, 0, &[0xBB]);
64        assert_eq!(store.read_bytes(1, 0, 1), vec![0xAA]);
65        assert_eq!(store.read_bytes(2, 0, 1), vec![0xBB]);
66    }
67}
snap7_server/store.rs

snap7_server/
store.rs
