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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//
// Originally written for jxl-oxide.
use super::{BitstreamKind, ContainerParser, DetectState, JxlpIndexState, box_header::*};
use crate::{
api::{CODESTREAM_SIGNATURE, CONTAINER_SIGNATURE},
error::{Error, Result},
util::tracing_wrappers::*,
};
/// Iterator that reads over a buffer and emits parser events.
pub struct ParseEvents<'inner, 'buf> {
inner: &'inner mut ContainerParser,
remaining_input: &'buf [u8],
finished: bool,
}
impl<'inner, 'buf> ParseEvents<'inner, 'buf> {
pub(super) fn new(parser: &'inner mut ContainerParser, input: &'buf [u8]) -> Self {
parser.previous_consumed_bytes = 0;
Self {
inner: parser,
remaining_input: input,
finished: false,
}
}
fn emit_single(&mut self) -> Result<Option<ParseEvent<'buf>>> {
let state = &mut self.inner.state;
let jxlp_index_state = &mut self.inner.jxlp_index_state;
let buf = &mut self.remaining_input;
loop {
if buf.is_empty() {
self.finished = true;
return Ok(None);
}
match state {
DetectState::WaitingSignature => {
if buf.starts_with(&CODESTREAM_SIGNATURE) {
info!("Codestream signature found");
*state = DetectState::InCodestream {
kind: BitstreamKind::BareCodestream,
bytes_left: None,
};
return Ok(Some(ParseEvent::BitstreamKind(
BitstreamKind::BareCodestream,
)));
} else if buf.starts_with(&CONTAINER_SIGNATURE) {
info!("Container signature found");
*state = DetectState::WaitingBoxHeader;
*buf = &buf[CONTAINER_SIGNATURE.len()..];
return Ok(Some(ParseEvent::BitstreamKind(BitstreamKind::Container)));
} else if !CODESTREAM_SIGNATURE.starts_with(buf)
&& !CONTAINER_SIGNATURE.starts_with(buf)
{
warn!(?buf, "Invalid signature");
*state = DetectState::InCodestream {
kind: BitstreamKind::Invalid,
bytes_left: None,
};
return Ok(Some(ParseEvent::BitstreamKind(BitstreamKind::Invalid)));
} else {
return Ok(None);
}
}
DetectState::WaitingBoxHeader => match ContainerBoxHeader::parse(buf)? {
HeaderParseResult::Done {
header,
header_size,
} => {
*buf = &buf[header_size..];
let tbox = header.box_type();
if tbox == ContainerBoxType::CODESTREAM {
match jxlp_index_state {
JxlpIndexState::Initial => {
*jxlp_index_state = JxlpIndexState::SingleJxlc;
}
JxlpIndexState::SingleJxlc => {
warn!("Duplicate jxlc box found");
return Err(Error::InvalidBox);
}
JxlpIndexState::Jxlp(_) | JxlpIndexState::JxlpFinished => {
warn!("Found jxlc box instead of jxlp box");
return Err(Error::InvalidBox);
}
}
*state = DetectState::InCodestream {
kind: BitstreamKind::Container,
bytes_left: header.box_size().map(|x| x as usize),
};
} else if tbox == ContainerBoxType::PARTIAL_CODESTREAM {
if let Some(box_size) = header.box_size()
&& box_size < 4
{
return Err(Error::InvalidBox);
}
match jxlp_index_state {
JxlpIndexState::Initial => {
*jxlp_index_state = JxlpIndexState::Jxlp(0);
}
JxlpIndexState::Jxlp(index) => {
*index += 1;
}
JxlpIndexState::SingleJxlc => {
warn!("jxlp box found after jxlc box");
return Err(Error::InvalidBox);
}
JxlpIndexState::JxlpFinished => {
warn!("found another jxlp box after the final one");
return Err(Error::InvalidBox);
}
}
*state = DetectState::WaitingJxlpIndex(header);
} else {
let bytes_left = header.box_size().map(|x| x as usize);
*state = DetectState::InAuxBox { header, bytes_left };
}
}
HeaderParseResult::NeedMoreData => return Ok(None),
},
DetectState::WaitingJxlpIndex(header) => {
let &[b0, b1, b2, b3, ..] = &**buf else {
return Ok(None);
};
let index = u32::from_be_bytes([b0, b1, b2, b3]);
*buf = &buf[4..];
let is_last = index & 0x80000000 != 0;
let index = index & 0x7fffffff;
match *jxlp_index_state {
JxlpIndexState::Jxlp(expected_index) if expected_index == index => {
if is_last {
*jxlp_index_state = JxlpIndexState::JxlpFinished;
}
}
#[allow(unused_variables)]
JxlpIndexState::Jxlp(expected_index) => {
warn!(
expected_index,
actual_index = index,
"Out-of-order jxlp box found",
);
return Err(Error::InvalidBox);
}
state => {
unreachable!("invalid jxlp index state in WaitingJxlpIndex: {state:?}");
}
}
*state = DetectState::InCodestream {
kind: BitstreamKind::Container,
bytes_left: header.box_size().map(|x| x as usize - 4),
};
}
DetectState::InCodestream {
bytes_left: None, ..
} => {
let payload = *buf;
*buf = &[];
return Ok(Some(ParseEvent::Codestream(payload)));
}
DetectState::InCodestream {
bytes_left: Some(bytes_left),
..
} => {
let payload = if buf.len() >= *bytes_left {
let (payload, remaining) = buf.split_at(*bytes_left);
*state = DetectState::WaitingBoxHeader;
*buf = remaining;
payload
} else {
let payload = *buf;
*bytes_left -= buf.len();
*buf = &[];
payload
};
return Ok(Some(ParseEvent::Codestream(payload)));
}
DetectState::InAuxBox {
header: _,
bytes_left: None,
} => {
let _payload = *buf;
*buf = &[];
// FIXME: emit auxiliary box event
}
DetectState::InAuxBox {
header: _,
bytes_left: Some(bytes_left),
} => {
let _payload = if buf.len() >= *bytes_left {
let (payload, remaining) = buf.split_at(*bytes_left);
*state = DetectState::WaitingBoxHeader;
*buf = remaining;
payload
} else {
let payload = *buf;
*bytes_left -= buf.len();
*buf = &[];
payload
};
// FIXME: emit auxiliary box event
}
}
}
}
}
impl std::fmt::Debug for ParseEvents<'_, '_> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("ParseEvents")
.field("inner", &self.inner)
.field(
"remaining_input",
&format_args!("({} byte(s))", self.remaining_input.len()),
)
.field("finished", &self.finished)
.finish()
}
}
impl<'buf> Iterator for ParseEvents<'_, 'buf> {
type Item = Result<ParseEvent<'buf>>;
fn next(&mut self) -> Option<Self::Item> {
if self.finished {
return None;
}
let initial_buf = self.remaining_input;
let event = self.emit_single();
if event.is_err() {
self.finished = true;
}
self.inner.previous_consumed_bytes += initial_buf.len() - self.remaining_input.len();
event.transpose()
}
}
/// Parser event emitted by [`ParseEvents`].
pub enum ParseEvent<'buf> {
/// Bitstream structure is detected.
BitstreamKind(BitstreamKind),
/// Codestream data is read.
///
/// Returned data may be partial. Complete codestream can be obtained by concatenating all data
/// of `Codestream` events.
Codestream(&'buf [u8]),
}
impl std::fmt::Debug for ParseEvent<'_> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
Self::BitstreamKind(kind) => f.debug_tuple("BitstreamKind").field(kind).finish(),
Self::Codestream(buf) => f
.debug_tuple("Codestream")
.field(&format_args!("{} byte(s)", buf.len()))
.finish(),
}
}
}