eds_reader/
reader.rs

1//! 数据接收器
2
3use bytes::{Bytes, BytesMut};
4use eds_core::crc::get_crc;
5use eds_core::frame::*;
6
7const MAX_LEN: usize = 4096;
8
9/// 接收器状态
10enum Status {
11    Lead(u8),
12    Start,
13    Length1,
14    Length2,
15    Load,
16    Crc1,
17    Crc2,
18    End,
19    Finish,
20}
21
22/// 接收器
23pub struct Reader {
24    lead_len: u8,
25    /// 已处理的数据
26    load: BytesMut,
27    /// 负载总长度
28    load_len: u16,
29    /// 负载crc
30    load_crc: u16,
31    /// 接收状态
32    status: Status,
33}
34impl Reader {
35    /// 创建一个空的接收器
36    pub fn new(lead_len: u8) -> Self {
37        Reader {
38            lead_len,
39            load: BytesMut::new(),
40            load_len: 0,
41            load_crc: 0,
42            status: Status::Lead(0),
43        }
44    }
45    /// 接收器是否为空
46    pub fn is_empty(&self) -> bool {
47        self.load.is_empty()
48    }
49    /// 清空接收器中处理完的数据
50    fn clean(&mut self) {
51        self.load.clear();
52        self.status = Status::Lead(0);
53    }
54    /// 处理一个字节
55    fn recv_one(&mut self, res: u8) -> bool {
56        match self.status {
57            Status::Lead(mut count) => {
58                if res == CHAR_LEAD {
59                    count += 1;
60                    if count >= self.lead_len {
61                        self.status = Status::Start;
62                    } else {
63                        self.status = Status::Lead(count);
64                    }
65                } else {
66                    self.clean();
67                }
68            }
69            Status::Start => {
70                if res == CHAR_LEAD {
71                } else if res == CHAR_START {
72                    self.status = Status::Length1;
73                } else {
74                    self.clean();
75                }
76            }
77            Status::Length1 => {
78                self.load_len = (res as u16) << 8;
79                self.status = Status::Length2;
80            }
81            Status::Length2 => {
82                self.load_len |= res as u16;
83                if self.load_len as usize > MAX_LEN {
84                    self.clean();
85                    self.recv_one(res);
86                } else {
87                    self.status = Status::Load;
88                }
89            }
90            Status::Load => {
91                let _ = self.load.extend([res]);
92                if self.load.len() >= self.load_len as usize {
93                    self.load_crc = get_crc(&self.load);
94                    self.status = Status::Crc1;
95                }
96            }
97            Status::Crc1 => {
98                if res == (self.load_crc >> 8) as u8 {
99                    self.status = Status::Crc2;
100                } else {
101                    self.clean();
102                    self.recv_one(res);
103                }
104            }
105            Status::Crc2 => {
106                if res == self.load_crc as u8 {
107                    self.status = Status::End;
108                } else {
109                    self.clean();
110                    self.recv_one(res);
111                }
112            }
113            Status::End => {
114                if res == CHAR_END {
115                    self.status = Status::Finish;
116                    return true;
117                } else {
118                    self.clean();
119                    self.recv_one(res);
120                }
121            }
122            Status::Finish => {
123                self.clean();
124                self.recv_one(res);
125            }
126        }
127        return false;
128    }
129    /// 接收数据并找出一个数据帧，返回已处理数据的字节数
130    pub fn recv(&mut self, buf: &[u8]) -> usize {
131        for i in 0..buf.len() {
132            let res = buf[i];
133            let finish = self.recv_one(res);
134            if finish {
135                return i + 1;
136            }
137        }
138        return buf.len();
139    }
140    /// 接收到了完整数据
141    pub fn is_ready(&self) -> bool {
142        if let Status::Finish = self.status {
143            true
144        } else {
145            false
146        }
147    }
148    /// 获取接收到的数据
149    pub fn get_load(&mut self) -> Option<Bytes> {
150        if let Status::Finish = self.status {
151            let load = core::mem::replace(&mut self.load, BytesMut::new());
152            self.status = Status::Lead(0);
153            Some(load.freeze())
154        } else {
155            None
156        }
157    }
158}
eds_reader/reader.rs

eds_reader/
reader.rs
