dvb_si/descriptors/
service_move.rs

1//! Service Move Descriptor — ETSI EN 300 468 §6.2.37 (tag 0x60).
2//!
3//! Table 92 (PDF p. 102). Carried in the SDT when a service is being moved to a
4//! new location; gives the new (original_network_id, transport_stream_id,
5//! service_id) triple. Fixed 6-byte payload.
6
7use super::descriptor_body;
8use crate::error::{Error, Result};
9use dvb_common::{Parse, Serialize};
10
11/// Descriptor tag for service_move_descriptor.
12pub const TAG: u8 = 0x60;
13const HEADER_LEN: usize = 2;
14/// Fixed payload length: three 16-bit identifiers (EN 300 468 Table 92).
15const BODY_LEN: u8 = 6;
16
17/// Service Move Descriptor (tag 0x60).
18#[derive(Debug, Clone, PartialEq, Eq)]
19#[cfg_attr(feature = "serde", derive(serde::Serialize))]
20pub struct ServiceMoveDescriptor {
21    /// original_network_id of the service's new location.
22    pub new_original_network_id: u16,
23    /// transport_stream_id of the service's new location.
24    pub new_transport_stream_id: u16,
25    /// service_id of the service at its new location.
26    pub new_service_id: u16,
27}
28
29impl<'a> Parse<'a> for ServiceMoveDescriptor {
30    type Error = crate::error::Error;
31    fn parse(bytes: &'a [u8]) -> Result<Self> {
32        let body = descriptor_body(
33            bytes,
34            TAG,
35            "ServiceMoveDescriptor",
36            "unexpected tag for service_move_descriptor",
37        )?;
38        if body.len() != BODY_LEN as usize {
39            return Err(Error::InvalidDescriptor {
40                tag: TAG,
41                reason: "service_move_descriptor length must equal 6",
42            });
43        }
44        Ok(Self {
45            new_original_network_id: u16::from_be_bytes([body[0], body[1]]),
46            new_transport_stream_id: u16::from_be_bytes([body[2], body[3]]),
47            new_service_id: u16::from_be_bytes([body[4], body[5]]),
48        })
49    }
50}
51
52impl Serialize for ServiceMoveDescriptor {
53    type Error = crate::error::Error;
54    fn serialized_len(&self) -> usize {
55        HEADER_LEN + BODY_LEN as usize
56    }
57
58    fn serialize_into(&self, buf: &mut [u8]) -> Result<usize> {
59        let len = self.serialized_len();
60        if buf.len() < len {
61            return Err(Error::OutputBufferTooSmall {
62                need: len,
63                have: buf.len(),
64            });
65        }
66        buf[0] = TAG;
67        buf[1] = BODY_LEN;
68        let b = HEADER_LEN;
69        buf[b..b + 2].copy_from_slice(&self.new_original_network_id.to_be_bytes());
70        buf[b + 2..b + 4].copy_from_slice(&self.new_transport_stream_id.to_be_bytes());
71        buf[b + 4..b + 6].copy_from_slice(&self.new_service_id.to_be_bytes());
72        Ok(len)
73    }
74}
75impl<'a> crate::traits::DescriptorDef<'a> for ServiceMoveDescriptor {
76    const TAG: u8 = TAG;
77    const NAME: &'static str = "SERVICE_MOVE";
78}
79
80#[cfg(test)]
81mod tests {
82    use super::*;
83
84    #[test]
85    fn parse_extracts_triple() {
86        let bytes = [TAG, 6, 0x00, 0x01, 0x00, 0x02, 0x00, 0x03];
87        let d = ServiceMoveDescriptor::parse(&bytes).unwrap();
88        assert_eq!(d.new_original_network_id, 0x0001);
89        assert_eq!(d.new_transport_stream_id, 0x0002);
90        assert_eq!(d.new_service_id, 0x0003);
91    }
92
93    #[test]
94    fn parse_rejects_wrong_tag() {
95        let err = ServiceMoveDescriptor::parse(&[0x61, 6, 0, 0, 0, 0, 0, 0]).unwrap_err();
96        assert!(matches!(err, Error::InvalidDescriptor { tag: 0x61, .. }));
97    }
98
99    #[test]
100    fn parse_rejects_short_buffer() {
101        let err = ServiceMoveDescriptor::parse(&[TAG]).unwrap_err();
102        assert!(matches!(err, Error::BufferTooShort { .. }));
103    }
104
105    #[test]
106    fn parse_rejects_truncated_body() {
107        // length=6 but only 4 payload bytes present.
108        let err = ServiceMoveDescriptor::parse(&[TAG, 6, 0, 1, 0, 2]).unwrap_err();
109        assert!(matches!(err, Error::BufferTooShort { .. }));
110    }
111
112    #[test]
113    fn parse_rejects_wrong_length() {
114        let err = ServiceMoveDescriptor::parse(&[TAG, 5, 0, 1, 0, 2, 0]).unwrap_err();
115        assert!(matches!(err, Error::InvalidDescriptor { .. }));
116    }
117
118    #[test]
119    fn serialize_round_trip() {
120        let d = ServiceMoveDescriptor {
121            new_original_network_id: 0x1234,
122            new_transport_stream_id: 0x5678,
123            new_service_id: 0x9ABC,
124        };
125        let mut buf = vec![0u8; d.serialized_len()];
126        d.serialize_into(&mut buf).unwrap();
127        let re = ServiceMoveDescriptor::parse(&buf).unwrap();
128        assert_eq!(d, re);
129    }
130
131    #[test]
132    fn serialize_rejects_too_small_buffer() {
133        let d = ServiceMoveDescriptor {
134            new_original_network_id: 1,
135            new_transport_stream_id: 2,
136            new_service_id: 3,
137        };
138        let mut tiny = [0u8; 5];
139        let err = d.serialize_into(&mut tiny).unwrap_err();
140        assert!(matches!(err, Error::OutputBufferTooSmall { .. }));
141    }
142
143    #[test]
144    fn descriptor_length_matches_payload() {
145        let d = ServiceMoveDescriptor {
146            new_original_network_id: 0,
147            new_transport_stream_id: 0,
148            new_service_id: 0,
149        };
150        assert_eq!(d.serialized_len() - 2, 6);
151    }
152
153    #[cfg(feature = "serde")]
154    #[test]
155    fn serde_round_trip() {
156        let d = ServiceMoveDescriptor {
157            new_original_network_id: 0x0001,
158            new_transport_stream_id: 0x0002,
159            new_service_id: 0x0003,
160        };
161        let json = serde_json::to_string(&d).unwrap();
162        // Serialize-only: assert the emitted JSON re-parses (serialize-stable).
163        let _v: serde_json::Value = serde_json::from_str(&json).unwrap();
164    }
165}
dvb_si/descriptors/service_move.rs

dvb_si/descriptors/
service_move.rs
