dvb_si/tables/any.rs
1//! Unified table dispatch: [`AnyTable`].
2//!
3//! [`AnyTable`] is generated from a single declarative list
4//! (`declare_tables!`) — one line per crate-implemented table type.
5//! The list is the single source of truth: it produces the enum, the
6//! `From<T>` conversions, the table_id range dispatcher, and a drift test
7//! that pins each range literal to the type's
8//! [`crate::traits::TableDef::TABLE_ID_RANGES`].
9//!
10//! [`AnyTable::parse`] dispatches on the first byte (table_id) using range
11//! patterns. An unrecognised table_id yields
12//! `AnyTable::Unknown { table_id, raw }` — the full section bytes are
13//! retained.
14//!
15//! [`AnyTable::parse_as`] is a type-keyed thin alias to `T::parse` — it
16//! bypasses dispatch entirely and lets callers obtain, for example, a
17//! [`crate::tables::mpe::MpeDatagramSection`] for a `0x3E` section that the
18//! default dispatcher would route to `DsmccSection`.
19//!
20//! ```
21//! use dvb_common::Serialize;
22//! use dvb_si::tables::AnyTable;
23//! use dvb_si::tables::pat::{Pat, PatEntry};
24//!
25//! // Serialize a small PAT, then dispatch the bytes back through AnyTable::parse.
26//! let pat = Pat {
27//! transport_stream_id: 1, version_number: 0, current_next_indicator: true,
28//! section_number: 0, last_section_number: 0,
29//! entries: vec![PatEntry { program_number: 1, pid: 0x0100 }],
30//! };
31//! let mut section = vec![0u8; pat.serialized_len()];
32//! pat.serialize_into(&mut section).unwrap();
33//!
34//! match AnyTable::parse(§ion).unwrap() {
35//! AnyTable::Pat(parsed) => assert_eq!(parsed.entries[0].pid, 0x0100),
36//! other => panic!("expected Pat, got {other:?}"),
37//! }
38//! ```
39//!
40//! # Adding a table
41//!
42//! 1. Create the module with the wire layout, a `pub const TABLE_ID: u8` (or
43//! `TABLE_ID_FIRST`/`TABLE_ID_LAST` for a range), and the symmetric
44//! [`dvb_common::Parse`]/[`dvb_common::Serialize`] impls + round-trip tests
45//! (copy an existing module).
46//! 2. `impl TableDef` for the type (`TABLE_ID_RANGES` covering the full
47//! table_id range, `NAME` in SCREAMING_SNAKE without the `_section` or
48//! `_table` suffix).
49//! 3. Add one line to the `declare_tables!` invocation below — the enum
50//! variant, dispatcher arm, and drift test entry are generated from it.
51//! If the type should NOT be auto-dispatched (e.g. `MpeDatagramSection`,
52//! whose `0x3E` id is claimed by the `DsmccSection` range), add it to the
53//! `@no_dispatch` section instead.
54//! 4. The disjointness test in `declare_tables_tests` catches any overlapping
55//! range entries automatically — no manual test edits needed.
56
57/// Declares [`AnyTable`] + its dispatcher from one range list.
58///
59/// Each dispatch line is `Variant = [lo..=hi, …] => module::Type[<'a>]`.
60/// The optional trailing `@no_dispatch …` section adds variants that are NOT
61/// reachable from the generated dispatcher — the variant exists for callers
62/// that obtain the type via `AnyTable::parse_as` or direct `T::parse`.
63macro_rules! declare_tables {
64 (
65 $lt:lifetime;
66 $( $variant:ident = [ $( $lo:literal ..= $hi:literal ),+ ] => $($path:ident)::+ $(<$plt:lifetime>)? ),+ $(,)?
67 $( ; @no_dispatch $( $nd_variant:ident => $($nd_path:ident)::+ $(<$nd_plt:lifetime>)? ),+ $(,)? )?
68 ) => {
69 /// Every crate-implemented table, plus an `Unknown` fallthrough.
70 ///
71 /// serde uses external tagging with camelCase variant keys — a parsed
72 /// PAT serializes as `{"pat": {…}}`.
73 /// Variant names map 1:1 to the table modules; see each module for the
74 /// wire layout.
75 ///
76 /// `0x3E` (`datagram_section`) is routed to `DsmccSection` by the
77 /// default dispatcher. The typed MPE view is reachable via
78 /// `AnyTable::parse_as::<MpeDatagramSection>` or
79 /// `MpeDatagramSection::parse` directly; the `MpeDatagram` variant
80 /// exists in this enum for API completeness but is never produced by
81 /// `AnyTable::parse`.
82 #[derive(Debug)]
83 #[cfg_attr(feature = "serde", derive(serde::Serialize))]
84 #[cfg_attr(feature = "serde", serde(rename_all = "camelCase"))]
85 // Covariant in `$lt`: every variant holds only lifetime-parametrised
86 // table views or `&$lt [u8]` (`Unknown`), so the derived impl is sound.
87 #[cfg_attr(feature = "yoke", derive(yoke::Yokeable))]
88 #[non_exhaustive]
89 pub enum AnyTable<$lt> {
90 $(
91 #[allow(missing_docs)]
92 $variant($($path)::+ $(<$plt>)?),
93 )+
94 $($(
95 #[allow(missing_docs)]
96 $nd_variant($($nd_path)::+ $(<$nd_plt>)?),
97 )+)?
98 /// table_id with no typed implementation; `raw` is the full
99 /// section bytes including the table_id header.
100 Unknown {
101 /// The raw table_id byte.
102 table_id: u8,
103 /// The raw section bytes (full, header included).
104 raw: &$lt [u8],
105 },
106 }
107
108 $(
109 impl<$lt> From<$($path)::+ $(<$plt>)?> for AnyTable<$lt> {
110 fn from(t: $($path)::+ $(<$plt>)?) -> Self {
111 Self::$variant(t)
112 }
113 }
114 )+
115 $($(
116 impl<$lt> From<$($nd_path)::+ $(<$nd_plt>)?> for AnyTable<$lt> {
117 fn from(t: $($nd_path)::+ $(<$nd_plt>)?) -> Self {
118 Self::$nd_variant(t)
119 }
120 }
121 )+)?
122
123 impl<$lt> AnyTable<$lt> {
124 /// All table_id ranges covered by the auto-dispatcher (excludes
125 /// `@no_dispatch` variants). Each entry is `(lo, hi)` inclusive.
126 pub const DISPATCHED_RANGES: &'static [(u8, u8)] =
127 &[$( $( ($lo, $hi) ),+ ),+];
128
129 /// Diagnostic name of the contained table — the type's
130 /// [`TableDef::NAME`](crate::traits::TableDef::NAME)
131 /// (`"EVENT_INFORMATION"`, `"PROGRAM_ASSOCIATION"`, …);
132 /// `"UNKNOWN"` for [`AnyTable::Unknown`].
133 #[must_use]
134 pub fn name(&self) -> &'static str {
135 match self {
136 $(
137 Self::$variant(_) =>
138 <$($path)::+ as crate::traits::TableDef>::NAME,
139 )+
140 $($(
141 Self::$nd_variant(_) =>
142 <$($nd_path)::+ as crate::traits::TableDef>::NAME,
143 )+)?
144 Self::Unknown { .. } => "UNKNOWN",
145 }
146 }
147
148 /// Dispatch one complete section by its table_id (byte 0).
149 ///
150 /// Returns `Err(BufferTooShort)` when `bytes` is empty.
151 /// Unknown table_ids produce `Ok(AnyTable::Unknown { … })`.
152 ///
153 /// # Errors
154 /// - [`crate::Error::BufferTooShort`] — `bytes` is empty.
155 /// - Any parse error from the dispatched type.
156 pub fn parse(bytes: &$lt [u8]) -> crate::Result<Self> {
157 let table_id = *bytes.first().ok_or(crate::Error::BufferTooShort {
158 need: 1,
159 have: 0,
160 what: "section table_id",
161 })?;
162 match table_id {
163 $(
164 $( $lo..=$hi )|+ => {
165 <$($path)::+ as dvb_common::Parse>::parse(bytes).map(Self::$variant)
166 }
167 )+
168 _ => Ok(Self::Unknown { table_id, raw: bytes }),
169 }
170 }
171
172 /// Type-keyed parse: bypass the dispatcher and parse `bytes`
173 /// directly as `T`. Useful for types excluded from the default
174 /// dispatch, e.g.:
175 ///
176 /// ```rust
177 /// use dvb_si::tables::AnyTable;
178 /// use dvb_si::tables::mpe::MpeDatagramSection;
179 ///
180 /// // A deliberately-too-short slice: parse_as propagates the
181 /// // BufferTooShort error from MpeDatagramSection::parse.
182 /// let err = AnyTable::parse_as::<MpeDatagramSection>(&[0x3E, 0x00]);
183 /// assert!(err.is_err());
184 /// ```
185 ///
186 /// # Errors
187 /// Propagates `T::parse` errors.
188 pub fn parse_as<T>(bytes: &$lt [u8]) -> crate::Result<T>
189 where
190 T: crate::traits::TableDef<$lt>,
191 {
192 <T as dvb_common::Parse>::parse(bytes)
193 }
194 }
195
196 #[cfg(test)]
197 mod macro_drift {
198 #[test]
199 fn ranges_match_tabledef() {
200 use crate::traits::TableDef;
201 $(
202 assert_eq!(
203 &[ $( ($lo, $hi) ),+ ][..],
204 <$($path)::+ as TableDef>::TABLE_ID_RANGES,
205 concat!("TABLE_ID_RANGES drift for ", stringify!($variant)),
206 );
207 assert!(
208 !<$($path)::+ as TableDef>::NAME.is_empty(),
209 concat!("empty NAME for ", stringify!($variant)),
210 );
211 )+
212 $($(
213 assert!(
214 !<$($nd_path)::+ as TableDef>::NAME.is_empty(),
215 concat!("empty NAME for no-dispatch ", stringify!($nd_variant)),
216 );
217 )+)?
218 }
219
220 #[test]
221 fn dispatched_ranges_are_disjoint() {
222 // Collect all (lo, hi) pairs, sort by lo, then check no
223 // two adjacent entries overlap.
224 let mut ranges: Vec<(u8, u8)> = vec![
225 $( $( ($lo, $hi), )+ )+
226 ];
227 ranges.sort_by_key(|r| r.0);
228 for w in ranges.windows(2) {
229 let (_, prev_hi) = w[0];
230 let (next_lo, _) = w[1];
231 assert!(
232 next_lo > prev_hi,
233 "overlapping dispatch ranges: {w:?}",
234 );
235 }
236 }
237 }
238 };
239}
240
241declare_tables! {'a;
242 // MPEG-2 systems tables (ISO/IEC 13818-1).
243 Pat = [0x00..=0x00] => crate::tables::pat::Pat,
244 Cat = [0x01..=0x01] => crate::tables::cat::Cat<'a>,
245 Pmt = [0x02..=0x02] => crate::tables::pmt::Pmt<'a>,
246 Tsdt = [0x03..=0x03] => crate::tables::tsdt::Tsdt<'a>,
247 // DSM-CC sections (ISO/IEC 13818-6) — 0x3E is included; the MPE typed
248 // view (`MpeDatagramSection`) is reachable via `AnyTable::parse_as` or
249 // `MpeDatagramSection::parse`.
250 DsmccSection = [0x3A..=0x3F] => crate::tables::dsmcc::DsmccSection<'a>,
251 // DVB tables (ETSI EN 300 468).
252 Nit = [0x40..=0x41] => crate::tables::nit::Nit<'a>,
253 Sdt = [0x42..=0x42, 0x46..=0x46] => crate::tables::sdt::Sdt<'a>,
254 Bat = [0x4A..=0x4A] => crate::tables::bat::Bat<'a>,
255 Unt = [0x4B..=0x4B] => crate::tables::unt::Unt<'a>,
256 Int = [0x4C..=0x4C] => crate::tables::int::Int<'a>,
257 Sat = [0x4D..=0x4D] => crate::tables::sat::Sat<'a>,
258 Eit = [0x4E..=0x6F] => crate::tables::eit::Eit<'a>,
259 Tdt = [0x70..=0x70] => crate::tables::tdt::Tdt,
260 Rst = [0x71..=0x71] => crate::tables::rst::Rst,
261 St = [0x72..=0x72] => crate::tables::st::St,
262 Tot = [0x73..=0x73] => crate::tables::tot::Tot<'a>,
263 Ait = [0x74..=0x74] => crate::tables::ait::Ait<'a>,
264 Container = [0x75..=0x75] => crate::tables::container::Container<'a>,
265 Rct = [0x76..=0x76] => crate::tables::rct::Rct<'a>,
266 Cit = [0x77..=0x77] => crate::tables::cit::Cit<'a>,
267 MpeFec = [0x78..=0x78] => crate::tables::mpe_fec::MpeFec<'a>,
268 Rnt = [0x79..=0x79] => crate::tables::rnt::Rnt<'a>,
269 MpeIfec = [0x7A..=0x7A] => crate::tables::mpe_ifec::MpeIfec<'a>,
270 ProtectionMessage = [0x7B..=0x7B] => crate::tables::protection_message::ProtectionMessageSection<'a>,
271 DownloadableFontInfo = [0x7C..=0x7C] => crate::tables::downloadable_font_info::DownloadableFontInfoSection<'a>,
272 Dit = [0x7E..=0x7E] => crate::tables::dit::Dit,
273 Sit = [0x7F..=0x7F] => crate::tables::sit::Sit<'a>;
274 // MPE datagram_section (ETSI EN 301 192 §7.1): table_id 0x3E overlaps
275 // the DsmccSection range above, so it is NOT auto-dispatched. Use
276 // `AnyTable::parse_as::<MpeDatagramSection>(bytes)` for the typed view.
277 @no_dispatch
278 MpeDatagram => crate::tables::mpe::MpeDatagramSection<'a>,
279}