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1 // Copyright 2022 Google LLC
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //      http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 //! Data types shared between V0 and V1 advertisements
16 
17 /// Power in dBm, calibrated as per
18 /// [Eddystone](https://github.com/google/eddystone/tree/master/eddystone-uid#tx-power)
19 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
20 pub struct TxPower {
21     /// Power in `[-100, 20]`
22     power: i8,
23 }
24 
25 impl TxPower {
26     /// Power in `[-100, 20]`
as_i8(&self) -> i827     pub fn as_i8(&self) -> i8 {
28         self.power
29     }
30 }
31 
32 impl TryFrom<i8> for TxPower {
33     type Error = TxPowerOutOfRange;
34 
try_from(value: i8) -> Result<Self, Self::Error>35     fn try_from(value: i8) -> Result<Self, Self::Error> {
36         if !(-100..=20).contains(&value) {
37             Err(TxPowerOutOfRange)
38         } else {
39             Ok(TxPower { power: value })
40         }
41     }
42 }
43 
44 /// Tx power was out of the valid range `[-100, 20]`.
45 #[derive(Debug, PartialEq, Eq)]
46 pub struct TxPowerOutOfRange;
47 
48 /// MDP's context sync number, used to inform other devices that they have stale context.
49 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
50 pub struct ContextSyncSeqNum {
51     /// 4-bit sequence
52     num: u8,
53 }
54 
55 impl ContextSyncSeqNum {
56     /// Returns the context seq num as a u8
as_u8(&self) -> u857     pub fn as_u8(&self) -> u8 {
58         self.num
59     }
60 }
61 
62 impl TryFrom<u8> for ContextSyncSeqNum {
63     type Error = ContextSyncSeqNumOutOfRange;
64 
try_from(value: u8) -> Result<Self, Self::Error>65     fn try_from(value: u8) -> Result<Self, Self::Error> {
66         // must only have low nibble
67         if value > 0x0F {
68             Err(ContextSyncSeqNumOutOfRange)
69         } else {
70             Ok(ContextSyncSeqNum { num: value })
71         }
72     }
73 }
74 
75 /// Seq num must be in `[0-15]`.
76 #[derive(Debug, PartialEq, Eq)]
77 pub struct ContextSyncSeqNumOutOfRange;
78 
79 #[allow(clippy::unwrap_used)]
80 #[cfg(test)]
81 mod tests {
82     use super::*;
83 
84     #[test]
tx_power_out_of_range()85     fn tx_power_out_of_range() {
86         assert_eq!(TxPowerOutOfRange, TxPower::try_from(-101).unwrap_err());
87         assert_eq!(TxPowerOutOfRange, TxPower::try_from(21).unwrap_err());
88     }
89 
90     #[test]
tx_power_ok()91     fn tx_power_ok() {
92         assert_eq!(-100, TxPower::try_from(-100).unwrap().power);
93         assert_eq!(20, TxPower::try_from(20).unwrap().power);
94     }
95 
96     #[test]
context_sync_seq_num_out_of_range()97     fn context_sync_seq_num_out_of_range() {
98         assert_eq!(ContextSyncSeqNumOutOfRange, ContextSyncSeqNum::try_from(0x10).unwrap_err());
99     }
100 
101     #[test]
context_sync_seq_num_ok()102     fn context_sync_seq_num_ok() {
103         assert_eq!(0x0F, ContextSyncSeqNum::try_from(0x0F).unwrap().num);
104     }
105 }
106