dvb_si/descriptors/
bouquet_name.rs

1//! Bouquet Name Descriptor — ETSI EN 300 468 §6.2.6 (tag 0x47).
2
3use super::descriptor_body;
4use crate::error::{Error, Result};
5use crate::text::DvbText;
6use dvb_common::{Parse, Serialize};
7
8/// Wire tag for the Bouquet Name Descriptor.
9pub const TAG: u8 = 0x47;
10
11/// Header length (tag byte + length byte, no payload).
12pub const HEADER_LEN: usize = 2;
13
14/// Bouquet Name Descriptor (tag 0x47). Carries the human-readable name of
15/// a bouquet in its BAT's `bouquet_descriptors_loop`.
16#[derive(Debug, Clone, PartialEq, Eq)]
17#[cfg_attr(feature = "serde", derive(serde::Serialize))]
18#[cfg_attr(feature = "yoke", derive(yoke::Yokeable))]
19pub struct BouquetNameDescriptor<'a> {
20    /// DVB Annex-A encoded bouquet name (EN 300 468 §6.2.6).
21    pub bouquet_name: DvbText<'a>,
22}
23
24impl<'a> Parse<'a> for BouquetNameDescriptor<'a> {
25    type Error = crate::error::Error;
26    fn parse(bytes: &'a [u8]) -> Result<Self> {
27        let body = descriptor_body(bytes, TAG, "BouquetNameDescriptor", "expected tag 0x47")?;
28        Ok(BouquetNameDescriptor {
29            bouquet_name: DvbText::new(body),
30        })
31    }
32}
33
34impl Serialize for BouquetNameDescriptor<'_> {
35    type Error = crate::error::Error;
36    fn serialized_len(&self) -> usize {
37        HEADER_LEN + self.bouquet_name.len()
38    }
39
40    fn serialize_into(&self, buf: &mut [u8]) -> Result<usize> {
41        let need = self.serialized_len();
42        if buf.len() < need {
43            return Err(Error::OutputBufferTooSmall {
44                need,
45                have: buf.len(),
46            });
47        }
48
49        buf[0] = TAG;
50        buf[1] = self.bouquet_name.len() as u8;
51        buf[HEADER_LEN..need].copy_from_slice(self.bouquet_name.raw());
52
53        Ok(need)
54    }
55}
56impl<'a> crate::traits::DescriptorDef<'a> for BouquetNameDescriptor<'a> {
57    const TAG: u8 = TAG;
58    const NAME: &'static str = "BOUQUET_NAME";
59}
60
61#[cfg(test)]
62mod tests {
63    use super::*;
64
65    /// Encode a 4-byte name, confirm parse extracts it.
66    #[test]
67    fn parse_extracts_bouquet_name() {
68        let raw: Vec<u8> = vec![
69            TAG, 0x04, // length = 4
70            b'B', b'O', b'U', b'Q',
71        ];
72        let desc = BouquetNameDescriptor::parse(&raw).unwrap();
73        assert_eq!(desc.bouquet_name.raw(), b"BOUQ");
74    }
75
76    /// Wrong tag byte should return InvalidDescriptor.
77    #[test]
78    fn parse_rejects_wrong_tag() {
79        let raw: Vec<u8> = vec![
80            0x48, // wrong tag
81            0x04, b'B', b'O', b'U', b'Q',
82        ];
83        let err = BouquetNameDescriptor::parse(&raw).unwrap_err();
84        assert!(
85            matches!(err, Error::InvalidDescriptor { tag: 0x48, .. }),
86            "expected InvalidDescriptor(tag=0x48), got {err:?}"
87        );
88    }
89
90    /// Only the tag byte — too short for the 2-byte header.
91    #[test]
92    fn parse_rejects_buffer_shorter_than_header() {
93        let raw: &[u8] = &[0x47];
94        let err = BouquetNameDescriptor::parse(raw).unwrap_err();
95        assert!(
96            matches!(err, Error::BufferTooShort { need: 2, .. }),
97            "expected BufferTooShort(need=2), got {err:?}"
98        );
99    }
100
101    /// Length byte says 5 but only 2 bytes follow — mismatch.
102    #[test]
103    fn parse_rejects_length_overrunning_buffer() {
104        let raw: Vec<u8> = vec![
105            0x47, 0x05, // claims 5 bytes follow
106            0xAA, 0xBB, // only 2 bytes available
107        ];
108        let err = BouquetNameDescriptor::parse(&raw).unwrap_err();
109        assert!(matches!(err, Error::BufferTooShort { .. }));
110    }
111
112    /// Descriptor with no bouquet name bytes is valid: `[0x47, 0x00]`.
113    #[test]
114    fn empty_bouquet_name_is_valid() {
115        let raw: &[u8] = &[TAG, 0x00];
116        let desc = BouquetNameDescriptor::parse(raw).unwrap();
117        assert!(desc.bouquet_name.raw().is_empty());
118    }
119
120    /// Parse → serialize → re-parse should yield an equal struct and
121    /// identical bytes.
122    #[test]
123    fn serialize_round_trip_preserves_bytes() {
124        let raw: Vec<u8> = vec![TAG, 0x04, b'B', b'O', b'U', b'Q'];
125        let parsed = BouquetNameDescriptor::parse(&raw).unwrap();
126        let mut buf = vec![0u8; parsed.serialized_len()];
127        let written = parsed.serialize_into(&mut buf).unwrap();
128        assert_eq!(written, parsed.serialized_len());
129
130        let reparsed = BouquetNameDescriptor::parse(&buf).unwrap();
131        assert_eq!(parsed, reparsed);
132        assert_eq!(&raw, &buf[..]);
133    }
134
135    /// Serialise into a buffer smaller than `serialized_len()` must fail.
136    #[test]
137    fn serialize_rejects_too_small_buffer() {
138        let raw: Vec<u8> = vec![TAG, 0x04, b'B', b'O', b'U', b'Q'];
139        let parsed = BouquetNameDescriptor::parse(&raw).unwrap();
140        let mut tiny = vec![0u8; 1];
141        let err = parsed.serialize_into(&mut tiny).unwrap_err();
142        assert!(
143            matches!(err, Error::OutputBufferTooSmall { need, .. } if need == parsed.serialized_len()),
144            "expected OutputBufferTooSmall(need={}), got {err:?}",
145            parsed.serialized_len()
146        );
147    }
148}
dvb_si/descriptors/bouquet_name.rs

dvb_si/descriptors/
bouquet_name.rs
