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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.
use std::io::IoSliceMut;
use crate::container::frame_index::FrameIndexBox;
use crate::container::gain_map::GainMapBundle;
use crate::error::{Error, Result};
use crate::util::NewWithCapacity;
use crate::api::{
JxlBitstreamInput, JxlSignatureType, check_signature_internal, inner::process::SmallBuffer,
};
#[derive(Clone)]
enum ParseState {
SignatureNeeded,
BoxNeeded,
CodestreamBox(u64),
SkippableBox(u64),
#[cfg(feature = "jpeg")]
JbrdBox(u64),
/// Buffering a jxli box: (remaining bytes, accumulated content).
BufferingFrameIndex(u64, Vec<u8>),
/// Buffering a jhgm box: (remaining bytes, accumulated content).
BufferingGainMap(u64, Vec<u8>),
/// Buffering an Exif box: (remaining bytes, accumulated content).
BufferingExif(u64, Vec<u8>),
/// Buffering an xml (XMP) box: (remaining bytes, accumulated content).
BufferingXmp(u64, Vec<u8>),
/// Buffering a brob (brotli-compressed) box: (remaining bytes, accumulated
/// content). The content is `[4-byte inner box type][brotli payload]`; once
/// complete it is decompressed and routed to exif/xmp by the inner type.
#[cfg(feature = "jpeg")]
BufferingBrob(u64, Vec<u8>),
}
enum CodestreamBoxType {
None,
Jxlc,
Jxlp(u32),
LastJxlp,
}
pub(super) struct BoxParser {
pub(super) box_buffer: SmallBuffer,
state: ParseState,
box_type: CodestreamBoxType,
#[cfg(feature = "jpeg")]
jbrd_data: Option<Vec<u8>>,
/// Parsed frame index box, if present in the file.
pub(super) frame_index: Option<FrameIndexBox>,
/// Parsed gain map bundle, if present in the file.
pub(super) gain_map: Option<GainMapBundle>,
/// Raw EXIF data from the `Exif` container box (without the 4-byte TIFF offset prefix).
pub(super) exif: Option<Vec<u8>>,
/// Raw XMP data from the `xml ` container box.
pub(super) xmp: Option<Vec<u8>>,
}
impl BoxParser {
pub(super) fn new() -> Self {
BoxParser {
box_buffer: SmallBuffer::new(128),
state: ParseState::SignatureNeeded,
box_type: CodestreamBoxType::None,
#[cfg(feature = "jpeg")]
jbrd_data: None,
frame_index: None,
gain_map: None,
exif: None,
xmp: None,
}
}
/// Take the accumulated JBRD box data, if any was found.
#[cfg(feature = "jpeg")]
pub(super) fn take_jbrd_data(&mut self) -> Option<Vec<u8>> {
self.jbrd_data.take()
}
// Reads input until the next byte of codestream is available.
// This function might over-read bytes. Thus, the contents of self.box_buffer should always be
// read after this function call.
// Returns the number of codestream bytes that will be available to be read after this call,
// including any bytes in self.box_buffer.
// Might return `u64::MAX`, indicating that the rest of the file is codestream.
pub(super) fn get_more_codestream(&mut self, input: &mut dyn JxlBitstreamInput) -> Result<u64> {
loop {
match self.state.clone() {
ParseState::SignatureNeeded => {
self.box_buffer.refill(|b| input.read(b), None)?;
match check_signature_internal(&self.box_buffer)? {
None => return Err(Error::InvalidSignature),
Some(JxlSignatureType::Codestream) => {
self.state = ParseState::CodestreamBox(u64::MAX);
return Ok(u64::MAX);
}
Some(JxlSignatureType::Container) => {
self.box_buffer
.consume(JxlSignatureType::Container.signature().len());
self.state = ParseState::BoxNeeded;
}
}
}
ParseState::CodestreamBox(b) => {
return Ok(b);
}
ParseState::SkippableBox(mut s) => {
let num = s.min(usize::MAX as u64) as usize;
let skipped = if !self.box_buffer.is_empty() {
self.box_buffer.consume(num)
} else {
input.skip(num)?
};
if skipped == 0 {
return Err(Error::OutOfBounds(num));
}
s -= skipped as u64;
if s == 0 {
self.state = ParseState::BoxNeeded;
} else {
self.state = ParseState::SkippableBox(s);
}
}
#[cfg(feature = "jpeg")]
ParseState::JbrdBox(mut remaining) => {
// Read jbrd box content into buffer
let num = remaining.min(usize::MAX as u64) as usize;
let jbrd = self.jbrd_data.get_or_insert_with(Vec::new);
if !self.box_buffer.is_empty() {
let avail = self.box_buffer.len().min(num);
jbrd.extend_from_slice(&self.box_buffer[..avail]);
self.box_buffer.consume(avail);
remaining -= avail as u64;
} else {
// Read from input using IoSliceMut
let chunk_size = num.min(65536);
let start = jbrd.len();
jbrd.resize(start + chunk_size, 0);
let read =
input.read(&mut [std::io::IoSliceMut::new(&mut jbrd[start..])])?;
if read == 0 {
jbrd.truncate(start);
return Err(Error::OutOfBounds(num));
}
jbrd.truncate(start + read);
remaining -= read as u64;
}
if remaining == 0 {
self.state = ParseState::BoxNeeded;
} else {
self.state = ParseState::JbrdBox(remaining);
}
}
ParseState::BufferingFrameIndex(mut remaining, mut buf) => {
let num = remaining.min(usize::MAX as u64) as usize;
if !self.box_buffer.is_empty() {
let take = num.min(self.box_buffer.len());
buf.extend_from_slice(&self.box_buffer[..take]);
self.box_buffer.consume(take);
remaining -= take as u64;
} else {
let old_len = buf.len();
buf.resize(old_len + num, 0);
let read = input.read(&mut [IoSliceMut::new(&mut buf[old_len..])])?;
if read == 0 {
return Err(Error::OutOfBounds(num));
}
buf.truncate(old_len + read);
remaining -= read as u64;
}
if remaining == 0 {
// Parse the buffered frame index box.
self.frame_index = Some(FrameIndexBox::parse(&buf)?);
self.state = ParseState::BoxNeeded;
} else {
self.state = ParseState::BufferingFrameIndex(remaining, buf);
}
}
ParseState::BufferingGainMap(mut remaining, mut buf) => {
let num = remaining.min(usize::MAX as u64) as usize;
if !self.box_buffer.is_empty() {
let take = num.min(self.box_buffer.len());
buf.extend_from_slice(&self.box_buffer[..take]);
self.box_buffer.consume(take);
remaining -= take as u64;
} else {
let old_len = buf.len();
buf.resize(old_len + num, 0);
let read = input.read(&mut [IoSliceMut::new(&mut buf[old_len..])])?;
if read == 0 {
return Err(Error::OutOfBounds(num));
}
buf.truncate(old_len + read);
remaining -= read as u64;
}
if remaining == 0 {
// Parse the buffered gain map bundle.
self.gain_map = Some(GainMapBundle::parse(&buf)?);
self.state = ParseState::BoxNeeded;
} else {
self.state = ParseState::BufferingGainMap(remaining, buf);
}
}
ParseState::BufferingExif(mut remaining, mut buf) => {
let num = remaining.min(usize::MAX as u64) as usize;
if !self.box_buffer.is_empty() {
let take = num.min(self.box_buffer.len());
buf.extend_from_slice(&self.box_buffer[..take]);
self.box_buffer.consume(take);
remaining -= take as u64;
} else {
let old_len = buf.len();
buf.resize(old_len + num, 0);
let read = input.read(&mut [IoSliceMut::new(&mut buf[old_len..])])?;
if read == 0 {
return Err(Error::OutOfBounds(num));
}
buf.truncate(old_len + read);
remaining -= read as u64;
}
if remaining == 0 {
// Exif box payload starts with a 4-byte TIFF header offset
// (big-endian u32). Strip it to return raw EXIF/TIFF data.
if buf.len() >= 4 {
self.exif = Some(buf[4..].to_vec());
}
self.state = ParseState::BoxNeeded;
} else {
self.state = ParseState::BufferingExif(remaining, buf);
}
}
ParseState::BufferingXmp(mut remaining, mut buf) => {
let num = remaining.min(usize::MAX as u64) as usize;
if !self.box_buffer.is_empty() {
let take = num.min(self.box_buffer.len());
buf.extend_from_slice(&self.box_buffer[..take]);
self.box_buffer.consume(take);
remaining -= take as u64;
} else {
let old_len = buf.len();
buf.resize(old_len + num, 0);
let read = input.read(&mut [IoSliceMut::new(&mut buf[old_len..])])?;
if read == 0 {
return Err(Error::OutOfBounds(num));
}
buf.truncate(old_len + read);
remaining -= read as u64;
}
if remaining == 0 {
self.xmp = Some(buf);
self.state = ParseState::BoxNeeded;
} else {
self.state = ParseState::BufferingXmp(remaining, buf);
}
}
#[cfg(feature = "jpeg")]
ParseState::BufferingBrob(mut remaining, mut buf) => {
let num = remaining.min(usize::MAX as u64) as usize;
if !self.box_buffer.is_empty() {
let take = num.min(self.box_buffer.len());
buf.extend_from_slice(&self.box_buffer[..take]);
self.box_buffer.consume(take);
remaining -= take as u64;
} else {
let old_len = buf.len();
buf.resize(old_len + num, 0);
let read = input.read(&mut [IoSliceMut::new(&mut buf[old_len..])])?;
if read == 0 {
return Err(Error::OutOfBounds(num));
}
buf.truncate(old_len + read);
remaining -= read as u64;
}
if remaining == 0 {
// brob payload = [4-byte inner box type][brotli stream].
if buf.len() >= 4
&& let Some(out) = brotli_decompress_box(&buf[4..])
{
match &buf[0..4] {
// Same handling as a raw Exif box: strip the
// 4-byte TIFF-header offset.
b"Exif" if out.len() >= 4 => self.exif = Some(out[4..].to_vec()),
b"xml " => self.xmp = Some(out),
_ => {}
}
}
self.state = ParseState::BoxNeeded;
} else {
self.state = ParseState::BufferingBrob(remaining, buf);
}
}
ParseState::BoxNeeded => {
self.box_buffer.refill(|b| input.read(b), None)?;
let min_len = match &self.box_buffer[..] {
[0, 0, 0, 1, ..] => 16,
_ => 8,
};
if self.box_buffer.len() <= min_len {
return Err(Error::OutOfBounds(min_len - self.box_buffer.len()));
}
let ty: [_; 4] = self.box_buffer[4..8].try_into().unwrap();
let extra_len = if &ty == b"jxlp" { 4 } else { 0 };
if self.box_buffer.len() <= min_len + extra_len {
return Err(Error::OutOfBounds(
min_len + extra_len - self.box_buffer.len(),
));
}
let box_len = match &self.box_buffer[..] {
[0, 0, 0, 1, ..] => {
u64::from_be_bytes(self.box_buffer[8..16].try_into().unwrap())
}
_ => u32::from_be_bytes(self.box_buffer[0..4].try_into().unwrap()) as u64,
};
// Per JXL spec: jxlc box with length 0 has special meaning "extends to EOF"
let content_len = if box_len == 0 && (&ty == b"jxlp" || &ty == b"jxlc") {
u64::MAX
} else {
if box_len <= (min_len + extra_len) as u64 {
return Err(Error::InvalidBox);
}
box_len - min_len as u64 - extra_len as u64
};
match &ty {
b"jxlc" => {
if matches!(
self.box_type,
CodestreamBoxType::Jxlp(..) | CodestreamBoxType::LastJxlp
) {
return Err(Error::InvalidBox);
}
self.box_type = CodestreamBoxType::Jxlc;
self.state = ParseState::CodestreamBox(content_len);
}
b"jxlp" => {
let index = u32::from_be_bytes(
self.box_buffer[min_len..min_len + 4].try_into().unwrap(),
);
let wanted_idx = match self.box_type {
CodestreamBoxType::Jxlc | CodestreamBoxType::LastJxlp => {
return Err(Error::InvalidBox);
}
CodestreamBoxType::None => 0,
CodestreamBoxType::Jxlp(i) => i + 1,
};
let last = index & 0x80000000 != 0;
let idx = index & 0x7fffffff;
if idx != wanted_idx {
return Err(Error::InvalidBox);
}
self.box_type = if last {
CodestreamBoxType::LastJxlp
} else {
CodestreamBoxType::Jxlp(idx)
};
self.state = ParseState::CodestreamBox(content_len);
}
#[cfg(feature = "jpeg")]
b"jbrd" => {
self.state = ParseState::JbrdBox(content_len);
}
b"jhgm" => {
if content_len == u64::MAX {
return Err(Error::InvalidBox);
}
// Reasonable size limit for a gain map bundle (256 MB).
// Gain maps contain a full JXL codestream so they can be large.
if content_len > 256 * 1024 * 1024 {
self.state = ParseState::SkippableBox(content_len);
} else {
// Use fallible alloc — capacity reserves up to
// 256 MB and a global allocator that can't
// satisfy the request must surface as a graceful
// error, never an `abort()` on the parser thread.
self.state = ParseState::BufferingGainMap(
content_len,
Vec::<u8>::new_with_capacity(content_len as usize)?,
);
}
}
b"jxli" => {
if content_len == u64::MAX {
return Err(Error::InvalidBox);
}
// Reasonable size limit for a frame index box (16 MB).
if content_len > 16 * 1024 * 1024 {
self.state = ParseState::SkippableBox(content_len);
} else {
self.state = ParseState::BufferingFrameIndex(
content_len,
Vec::<u8>::new_with_capacity(content_len as usize)?,
);
}
}
b"Exif" => {
if content_len == u64::MAX {
return Err(Error::InvalidBox);
}
// Reasonable size limit for EXIF data (16 MB).
if content_len > 16 * 1024 * 1024 {
self.state = ParseState::SkippableBox(content_len);
} else {
self.state = ParseState::BufferingExif(
content_len,
Vec::<u8>::new_with_capacity(content_len as usize)?,
);
}
}
b"xml " => {
if content_len == u64::MAX {
return Err(Error::InvalidBox);
}
// Reasonable size limit for XMP data (16 MB).
if content_len > 16 * 1024 * 1024 {
self.state = ParseState::SkippableBox(content_len);
} else {
self.state = ParseState::BufferingXmp(
content_len,
Vec::<u8>::new_with_capacity(content_len as usize)?,
);
}
}
// Brotli-compressed metadata box. The encoder wraps EXIF
// / XMP in `brob` when brotli shrinks them; decompress
// and route by inner box type. Needs brotli (jpeg feat).
#[cfg(feature = "jpeg")]
b"brob" => {
if content_len == u64::MAX || content_len > 16 * 1024 * 1024 {
self.state = ParseState::SkippableBox(content_len);
} else {
self.state = ParseState::BufferingBrob(
content_len,
Vec::<u8>::new_with_capacity(content_len as usize)?,
);
}
}
_ => {
self.state = ParseState::SkippableBox(content_len);
}
}
self.box_buffer.consume(min_len + extra_len);
}
}
}
}
pub(super) fn consume_codestream(&mut self, amount: u64) {
if let ParseState::CodestreamBox(cb) = &mut self.state {
*cb = cb.checked_sub(amount).unwrap();
if *cb == 0 {
self.state = ParseState::BoxNeeded;
}
} else if amount != 0 {
unreachable!()
}
}
}
/// Brotli-decompress a `brob` box payload (the bytes after the 4-byte inner box
/// type). Returns `None` on malformed input. Only built with the `jpeg` feature
/// (which provides `brotli`); without it `brob` boxes are skipped.
#[cfg(feature = "jpeg")]
fn brotli_decompress_box(compressed: &[u8]) -> Option<Vec<u8>> {
use std::io::Read;
let mut out = Vec::new();
brotli::Decompressor::new(compressed, 4096)
.read_to_end(&mut out)
.ok()?;
Some(out)
}