dvb_si/descriptors/extension/
c2_bundle_delivery_system.rs

1//! C2 Bundle Delivery System Descriptor — ETSI EN 300 468 §6.4.6.4 (tag_extension 0x16).
2use super::*;
3use alloc::vec::Vec;
4
5use super::c2_delivery_system::{ActiveOfdmSymbolDuration, C2GuardInterval, C2TuningFrequencyType};
6
7impl<'a> ExtensionBodyDef<'a> for C2BundleDeliverySystem {
8    const TAG_EXTENSION: u8 = 0x16;
9    const NAME: &'static str = "C2_BUNDLE_DELIVERY_SYSTEM";
10}
11/// One C2 bundle entry (Table 139 inner loop).
12#[derive(Debug, Clone, Copy, PartialEq, Eq)]
13#[cfg_attr(feature = "serde", derive(serde::Serialize))]
14pub struct C2BundleEntry {
15    /// plp_id(8).
16    pub plp_id: u8,
17    /// data_slice_id(8).
18    pub data_slice_id: u8,
19    /// C2_System_tuning_frequency(32).
20    pub c2_system_tuning_frequency: u32,
21    /// C2_System_tuning_frequency_type(2) — Table 116.
22    pub c2_system_tuning_frequency_type: C2TuningFrequencyType,
23    /// active_OFDM_symbol_duration(3).
24    pub active_ofdm_symbol_duration: ActiveOfdmSymbolDuration,
25    /// guard_interval(3).
26    pub guard_interval: C2GuardInterval,
27    /// primary_channel(1).
28    pub primary_channel: bool,
29}
30
31/// C2_bundle_delivery_system body (Table 139) — fully typed.
32#[derive(Debug, Clone, PartialEq, Eq)]
33#[cfg_attr(feature = "serde", derive(serde::Serialize))]
34pub struct C2BundleDeliverySystem {
35    /// Bundle entries in wire order.
36    pub entries: Vec<C2BundleEntry>,
37}
38
39impl<'a> Parse<'a> for C2BundleDeliverySystem {
40    type Error = crate::error::Error;
41    fn parse(sel: &'a [u8]) -> Result<Self> {
42        if sel.len() % C2_BUNDLE_ENTRY_LEN != 0 {
43            return Err(invalid(
44                "C2_bundle_delivery_system: not a whole number of entries",
45            ));
46        }
47        let mut entries = Vec::with_capacity(sel.len() / C2_BUNDLE_ENTRY_LEN);
48        for chunk in sel.chunks_exact(C2_BUNDLE_ENTRY_LEN) {
49            let packed = chunk[6];
50            let freq_bytes = chunk[2..]
51                .first_chunk::<4>()
52                .expect("chunks_exact guarantees length");
53            entries.push(C2BundleEntry {
54                plp_id: chunk[0],
55                data_slice_id: chunk[1],
56                c2_system_tuning_frequency: u32::from_be_bytes(*freq_bytes),
57                c2_system_tuning_frequency_type: C2TuningFrequencyType::from_u8(packed >> 6),
58                active_ofdm_symbol_duration: ActiveOfdmSymbolDuration::from_u8(
59                    (packed >> 3) & 0x07,
60                ),
61                guard_interval: C2GuardInterval::from_u8(packed & 0x07),
62                primary_channel: (chunk[7] & 0x80) != 0,
63            });
64        }
65        Ok(C2BundleDeliverySystem { entries })
66    }
67}
68
69impl Serialize for C2BundleDeliverySystem {
70    type Error = crate::error::Error;
71    fn serialized_len(&self) -> usize {
72        self.entries.len() * C2_BUNDLE_ENTRY_LEN
73    }
74    fn serialize_into(&self, buf: &mut [u8]) -> Result<usize> {
75        let len = self.serialized_len();
76        if buf.len() < len {
77            return Err(Error::OutputBufferTooSmall {
78                need: len,
79                have: buf.len(),
80            });
81        }
82        let mut p = 0;
83        for e in &self.entries {
84            buf[p] = e.plp_id;
85            buf[p + 1] = e.data_slice_id;
86            buf[p + 2..p + 6].copy_from_slice(&e.c2_system_tuning_frequency.to_be_bytes());
87            buf[p + 6] = (e.c2_system_tuning_frequency_type.to_u8() << 6)
88                | ((e.active_ofdm_symbol_duration.to_u8() & 0x07) << 3)
89                | (e.guard_interval.to_u8() & 0x07);
90            buf[p + 7] = u8::from(e.primary_channel) << 7;
91            p += C2_BUNDLE_ENTRY_LEN;
92        }
93        Ok(len)
94    }
95}
96
97#[cfg(test)]
98mod tests {
99    use super::*;
100    use crate::descriptors::extension::test_support::*;
101    use crate::descriptors::extension::{ExtensionBody, ExtensionDescriptor};
102
103    #[test]
104    fn parse_c2_bundle_two_entries() {
105        let entry = |off: u8| {
106            let packed = (0x01u8 << 6) | 0x01;
107            [off, off + 1, 0x00, 0x00, 0x10, 0x00, packed, 0x80]
108        };
109        let mut sel = Vec::new();
110        sel.extend_from_slice(&entry(0x01));
111        sel.extend_from_slice(&entry(0x05));
112        let bytes = wrap(0x16, &sel);
113        let d = ExtensionDescriptor::parse(&bytes).unwrap();
114        match &d.body {
115            ExtensionBody::C2BundleDeliverySystem(b) => {
116                assert_eq!(b.entries.len(), 2);
117                assert_eq!(b.entries[0].plp_id, 0x01);
118                assert!(b.entries[0].primary_channel);
119                assert_eq!(
120                    b.entries[0].c2_system_tuning_frequency_type,
121                    C2TuningFrequencyType::C2SystemCentreFrequency
122                );
123                assert_eq!(b.entries[1].plp_id, 0x05);
124                assert_eq!(b.entries[1].guard_interval, C2GuardInterval::G1_64);
125            }
126            other => panic!("expected C2BundleDeliverySystem, got {other:?}"),
127        }
128        round_trip(&d);
129    }
130
131    #[test]
132    fn parse_c2_bundle_rejects_partial_entry() {
133        let sel = [0x01, 0x02, 0x03];
134        let bytes = wrap(0x16, &sel);
135        assert!(matches!(
136            ExtensionDescriptor::parse(&bytes).unwrap_err(),
137            crate::error::Error::InvalidDescriptor {
138                tag: super::TAG,
139                ..
140            }
141        ));
142    }
143}
dvb_si/descriptors/extension/c2_bundle_delivery_system.rs

dvb_si/descriptors/extension/
c2_bundle_delivery_system.rs
