dvb_si/descriptors/
private_data_indicator.rs

1//! Private Data Indicator Descriptor — ISO/IEC 13818-1 §2.6.22 (tag 0x0F).
2//!
3//! Carries a 4-byte private data specifier that identifies the organization
4//! or entity that defined the private data carried in the associated stream.
5
6use super::descriptor_body;
7pub use super::private_data_specifier::private_data_specifier_name;
8use crate::error::{Error, Result};
9use dvb_common::{Parse, Serialize};
10
11/// Descriptor tag for private_data_indicator_descriptor.
12pub const TAG: u8 = 0x0F;
13const HEADER_LEN: usize = 2;
14const BODY_LEN: u8 = 4;
15
16/// Private Data Indicator Descriptor.
17///
18/// The `private_data_specifier` is a 32-bit value assigned by a standards body
19/// or industry consortium to identify the organization that defined the private
20/// data format used in the associated elementary stream.
21#[derive(Debug, Clone, PartialEq, Eq)]
22#[cfg_attr(feature = "serde", derive(serde::Serialize))]
23pub struct PrivateDataIndicatorDescriptor {
24    /// 32-bit registered private_data_specifier (ETSI Table 85, PDF p. 98).
25    pub private_data_specifier: u32,
26}
27
28impl<'a> Parse<'a> for PrivateDataIndicatorDescriptor {
29    type Error = crate::error::Error;
30
31    fn parse(bytes: &'a [u8]) -> Result<Self> {
32        let body = descriptor_body(
33            bytes,
34            TAG,
35            "PrivateDataIndicatorDescriptor",
36            "unexpected tag for private_data_indicator_descriptor",
37        )?;
38        if body.len() != BODY_LEN as usize {
39            return Err(Error::InvalidDescriptor {
40                tag: TAG,
41                reason: "private_data_indicator_descriptor length must equal 4",
42            });
43        }
44        let private_data_specifier = u32::from_be_bytes([body[0], body[1], body[2], body[3]]);
45        Ok(Self {
46            private_data_specifier,
47        })
48    }
49}
50
51impl Serialize for PrivateDataIndicatorDescriptor {
52    type Error = crate::error::Error;
53
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        buf[HEADER_LEN..HEADER_LEN + 4].copy_from_slice(&self.private_data_specifier.to_be_bytes());
69        Ok(len)
70    }
71}
72impl<'a> crate::traits::DescriptorDef<'a> for PrivateDataIndicatorDescriptor {
73    const TAG: u8 = TAG;
74    const NAME: &'static str = "PRIVATE_DATA_INDICATOR";
75}
76
77#[cfg(test)]
78mod tests {
79    use super::*;
80
81    #[test]
82    fn parse_private_data_specifier() {
83        let bytes = [TAG, 4, 0x00, 0x00, 0x00, 0x01];
84        let d = PrivateDataIndicatorDescriptor::parse(&bytes).unwrap();
85        assert_eq!(d.private_data_specifier, 0x0000_0001);
86    }
87
88    #[test]
89    fn parse_rejects_wrong_tag() {
90        let err = PrivateDataIndicatorDescriptor::parse(&[0x10, 4, 0, 0, 0, 0]).unwrap_err();
91        assert!(matches!(err, Error::InvalidDescriptor { tag: 0x10, .. }));
92    }
93
94    #[test]
95    fn parse_rejects_wrong_length() {
96        let bytes = [TAG, 3, 0, 0, 0, 0];
97        let err = PrivateDataIndicatorDescriptor::parse(&bytes).unwrap_err();
98        assert!(matches!(err, Error::InvalidDescriptor { .. }));
99    }
100
101    #[test]
102    fn parse_rejects_short_buffer() {
103        let err = PrivateDataIndicatorDescriptor::parse(&[TAG]).unwrap_err();
104        assert!(matches!(err, Error::BufferTooShort { .. }));
105    }
106
107    #[test]
108    fn serialize_round_trip() {
109        let d = PrivateDataIndicatorDescriptor {
110            private_data_specifier: 0xAABB_CCDD,
111        };
112        let mut buf = vec![0u8; d.serialized_len()];
113        d.serialize_into(&mut buf).unwrap();
114        let reparsed = PrivateDataIndicatorDescriptor::parse(&buf).unwrap();
115        assert_eq!(d, reparsed);
116    }
117
118    #[test]
119    fn descriptor_length_matches_payload() {
120        let d = PrivateDataIndicatorDescriptor {
121            private_data_specifier: 0x0000_0001,
122        };
123        assert_eq!(d.serialized_len() - 2, 4);
124    }
125}
dvb_si/descriptors/private_data_indicator.rs

dvb_si/descriptors/
private_data_indicator.rs
