android_usb_serial/
rx_filter.rs

1//! RX filter chain (FTDI header strip, XON/XOFF inline).
2
3use crate::xonxoff::XonXoffFilter;
4
5const FTDI_READ_HEADER: usize = 2;
6
7/// Strip FTDI 2-byte status headers from bulk IN data.
8pub fn strip_ftdi_header(packet: &[u8], mps: usize) -> Vec<u8> {
9    let mut out = Vec::new();
10    let mut pos = 0;
11    while pos < packet.len() {
12        let chunk = (pos + mps).min(packet.len());
13        if chunk - pos <= FTDI_READ_HEADER {
14            break;
15        }
16        out.extend_from_slice(&packet[pos + FTDI_READ_HEADER..chunk]);
17        pos += mps;
18    }
19    out
20}
21
22pub trait RxFilter: Send {
23    fn filter(&mut self, input: &[u8]) -> Vec<u8>;
24}
25
26pub struct FtdiHeaderFilter {
27    mps: usize,
28}
29
30impl FtdiHeaderFilter {
31    pub fn new(mps: u16) -> Self {
32        Self {
33            mps: mps.max(1) as usize,
34        }
35    }
36}
37
38impl RxFilter for FtdiHeaderFilter {
39    fn filter(&mut self, input: &[u8]) -> Vec<u8> {
40        strip_ftdi_header(input, self.mps)
41    }
42}
43
44pub struct XonXoffRxFilter {
45    inner: XonXoffFilter,
46}
47
48impl XonXoffRxFilter {
49    pub fn new(enabled: bool) -> Self {
50        Self {
51            inner: XonXoffFilter::new(enabled),
52        }
53    }
54}
55
56impl RxFilter for XonXoffRxFilter {
57    fn filter(&mut self, input: &[u8]) -> Vec<u8> {
58        self.inner.filter(input)
59    }
60}
61
62pub struct ChainedRxFilter {
63    filters: Vec<Box<dyn RxFilter>>,
64}
65
66impl ChainedRxFilter {
67    pub fn new(filters: Vec<Box<dyn RxFilter>>) -> Self {
68        Self { filters }
69    }
70}
71
72impl RxFilter for ChainedRxFilter {
73    fn filter(&mut self, input: &[u8]) -> Vec<u8> {
74        let mut data = input.to_vec();
75        for f in &mut self.filters {
76            data = f.filter(&data);
77        }
78        data
79    }
80}
81
82pub fn apply_filters(filters: &mut [Box<dyn RxFilter>], input: &[u8]) -> Vec<u8> {
83    let mut data = input.to_vec();
84    for f in filters.iter_mut() {
85        data = f.filter(&data);
86    }
87    data
88}
android_usb_serial/rx_filter.rs

android_usb_serial/
rx_filter.rs
