One table lookup per byte instead of eight shift steps. Proved equal to the
old bitwise loop (kept in the test as the reference) for every single byte,
random inputs of 0..4096 bytes, the CRC-32/MPEG-2 check value and the
section-plus-own-CRC-is-zero property.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Problem: in ts::scan every packet-parse failure re-read a whole 4096-packet
block from an offset that advanced about one packet. packet() returned None
both for a bad sync byte and for an adaptation_field_length that overruns the
packet, so aligned packets with a bad adaptation field cost one ~770 KB read
each (a 564 KB file made ByteSource::read_at fetch 846 MB). The fallback
offset (`pos + got`) also overshot by k packets, skipping unread data, and the
five-packet sync window only looked at the first packet_size start positions.
Fix: packet() distinguishes Bad::Sync from Bad::Adaptation. A bad adaptation
field means "no payload, grid intact": count a warning and go on with the next
packet. A real sync loss is repaired inside the loaded block (resync(): first
start whose five sync bytes line up, any distance); the block is refilled
from the file at the exact new offset only when it is used up. read() skips a
bad-adaptation packet instead of ending the unit.
Tests: read-volume tests with a counting ByteSource (bad adaptation fields,
sync byte every 189 bytes), and a resync test with a garbage prefix and
mid-stream garbage around the block boundary for 188- and 192-byte packets.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Problem: frame_info indexed byte 6 of an AC-3 header that is only guaranteed
6 bytes long (panic), and gave E-AC-3 fscod2 3 a sample rate of 0. The PES
modes of Splitter never pruned their chunk list. read_unit reserved up to
4 GiB up front, the unit table was uncapped and 4-byte E-AC-3 "frames"
amplified input 16x. PesAsm kept passing continuation packets of a non-PES
unit start, and an adaptation-field-only unit start destroyed the PES in
progress.
Fix: b.get(6)? and None for the reserved rate; no chunk bookkeeping where
positions come from feed(); EAC3_MIN_FRAME = 8; MAX_UNITS (2^23) per stream
with a warning; read_unit preallocates at most 1 MiB and refuses units over
128 MiB; PesAsm gets a dropping state and ignores payload-less unit starts.
Regression tests for each.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Rust/clippy 1.99 added `chunks_exact_to_as_chunks` and tightened
`needless_late_init` and `drain_collect`, failing `clippy -D warnings`
on main.
- `chunks_exact(N)` / `chunks_exact_mut(N)` with a constant N become
`as_chunks::<N>()` / `as_chunks_mut::<N>()` (fixed-size arrays, so
several byte reads drop their per-element indexing). relink's
fingerprint uses the `(chunks, remainder)` split; its hash output is
unchanged.
- Late-initialised `let`s in ac3 bit allocation and opus CELT
bands/rate become `let x = if/match …`.
- `dpb.drain(..).collect()` becomes `std::mem::take(&mut dpb)`.
No behaviour change; `cargo xtask ci` passes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- mpegts: a PES unit is built before it is stored (no `as_mut().expect`); stream maps are
drained with `let … else` instead of `remove().expect`.
- ogg: completing a packet and reading the page granule no longer expect.
- mxf writer: the picture descriptor uses `let … else` on the picture configuration.
- matroska: the `Lacing::None` arm returns the single frame instead of `unreachable!`.
- Each crate denies unwrap/expect/panic/unimplemented/todo/unreachable outside tests.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Brandon Thomas
vangel76