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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::{collections::VecDeque, io::IoSliceMut};
use sections::SectionState;
use crate::{
api::{
JxlBasicInfo, JxlBitstreamInput, JxlColorProfile, JxlDecoderOptions, JxlOutputBuffer,
JxlPixelFormat,
inner::{box_parser::BoxParser, process::SmallBuffer},
},
error::{Error, Result},
frame::{DecoderState, Frame, Section},
headers::{Animation, FileHeader, frame_header::FrameHeader},
icc::IncrementalIccReader,
};
mod non_section;
mod sections;
struct SectionBuffer {
len: usize,
data: Vec<u8>,
section: Section,
}
// This number should be big enough to guarantee that we can always make progress by reading
// fragments of size at most *half* of it, if not reading a section.
const NON_SECTION_CHUNK_SIZE: usize = 4096;
pub(super) struct CodestreamParser {
// TODO(veluca): this would probably be cleaner with some kind of state enum.
pub(super) file_header: Option<FileHeader>,
icc_parser: Option<IncrementalIccReader>,
// These fields are populated once image information is available.
decoder_state: Option<DecoderState>,
pub(super) basic_info: Option<JxlBasicInfo>,
pub(super) animation: Option<Animation>,
pub(super) embedded_color_profile: Option<JxlColorProfile>,
pub(super) output_color_profile: Option<JxlColorProfile>,
pub(super) pixel_format: Option<JxlPixelFormat>,
// These fields are populated when starting to decode a frame, and cleared once
// the frame is done.
frame_header: Option<FrameHeader>,
pub(super) frame: Option<Frame>,
// Buffers.
non_section_buf: SmallBuffer<NON_SECTION_CHUNK_SIZE>,
non_section_bit_offset: u8,
sections: VecDeque<SectionBuffer>,
ready_section_data: usize,
skip_sections: bool,
// True when we need to process frames without copying them to output buffers, e.g. reference frames
process_without_output: bool,
section_state: SectionState,
available_sections: Vec<SectionBuffer>,
pub(super) has_more_frames: bool,
}
impl CodestreamParser {
pub(super) fn new() -> Self {
Self {
file_header: None,
icc_parser: None,
decoder_state: None,
basic_info: None,
animation: None,
embedded_color_profile: None,
output_color_profile: None,
pixel_format: None,
frame_header: None,
frame: None,
non_section_buf: SmallBuffer::new(),
non_section_bit_offset: 0,
sections: VecDeque::new(),
ready_section_data: 0,
skip_sections: false,
process_without_output: false,
section_state: SectionState::new(0, 0),
available_sections: vec![],
has_more_frames: true,
}
}
fn has_visible_frame(&self) -> bool {
if let Some(frame) = &self.frame {
frame.header().is_visible()
} else {
false
}
}
pub(super) fn process<In: JxlBitstreamInput>(
&mut self,
box_parser: &mut BoxParser,
input: &mut In,
decode_options: &JxlDecoderOptions,
mut output_buffers: Option<&mut [JxlOutputBuffer]>,
) -> Result<()> {
// If we have sections to read, read into sections; otherwise, read into the local buffer.
loop {
if !self.sections.is_empty() {
let regular_frame = self.has_visible_frame();
if !self.process_without_output && output_buffers.is_none() {
self.skip_sections = true;
}
if !self.skip_sections {
// This is just an estimate as there could be box bytes in the middle.
let mut readable_section_data = (self.non_section_buf.len()
+ input.available_bytes()?
+ self.ready_section_data)
.max(1);
// Ensure enough section buffers are available for reading available data.
for buf in self.sections.iter_mut() {
if buf.data.is_empty() {
buf.data.resize(buf.len, 0);
}
readable_section_data =
readable_section_data.saturating_sub(buf.data.len());
if readable_section_data == 0 {
break;
}
}
// Read sections up to the end of the current box.
let mut available_codestream = match box_parser.get_more_codestream(input) {
Err(Error::OutOfBounds(_)) => 0,
Ok(c) => c as usize,
Err(e) => return Err(e),
};
let mut section_buffers = vec![];
let mut ready = self.ready_section_data;
for buf in self.sections.iter_mut() {
if buf.data.is_empty() {
break;
}
let len = buf.data.len();
if len > ready {
let readable = (available_codestream + ready).min(len);
section_buffers.push(IoSliceMut::new(&mut buf.data[ready..readable]));
available_codestream =
available_codestream.saturating_sub(readable - ready);
if available_codestream == 0 {
break;
}
}
ready = ready.saturating_sub(len);
}
let mut buffers = &mut section_buffers[..];
loop {
let num = if !box_parser.box_buffer.is_empty() {
box_parser.box_buffer.take(buffers)
} else {
input.read(buffers)?
};
self.ready_section_data += num;
box_parser.consume_codestream(num as u64);
IoSliceMut::advance_slices(&mut buffers, num);
if num == 0 || buffers.is_empty() {
break;
}
}
match self.process_sections(&mut output_buffers) {
Ok(None) => Ok(()),
Ok(Some(missing)) => Err(Error::OutOfBounds(missing)),
Err(Error::OutOfBounds(_)) => Err(Error::SectionTooShort),
Err(err) => Err(err),
}?;
} else {
let total_size = self.sections.iter().map(|x| x.len).sum::<usize>();
loop {
let to_skip = total_size - self.ready_section_data;
if to_skip == 0 {
break;
}
let available_codestream = box_parser.get_more_codestream(input)? as usize;
let to_skip = to_skip.min(available_codestream);
let skipped = if !box_parser.box_buffer.is_empty() {
box_parser.box_buffer.consume(to_skip)
} else {
input.skip(to_skip)?
};
box_parser.consume_codestream(skipped as u64);
self.ready_section_data += skipped;
if skipped == 0 {
break;
}
}
if self.ready_section_data < total_size {
return Err(Error::OutOfBounds(total_size - self.ready_section_data));
} else {
self.sections.clear();
}
}
if self.sections.is_empty() {
// Go back to parsing a new frame header, if any.
self.process_without_output = false;
if regular_frame {
return Ok(());
}
continue;
}
} else {
// Trying to read a frame or a file header.
assert!(self.frame.is_none());
assert!(self.has_more_frames);
let available_codestream = match box_parser.get_more_codestream(input) {
Err(Error::OutOfBounds(_)) => 0,
Ok(c) => c as usize,
Err(e) => return Err(e),
};
let c = self.non_section_buf.refill(
|buf| {
if !box_parser.box_buffer.is_empty() {
Ok(box_parser.box_buffer.take(buf))
} else {
input.read(buf)
}
},
Some(available_codestream),
)?;
box_parser.consume_codestream(c as u64);
self.process_non_section(decode_options)?;
if self.decoder_state.is_some() && self.frame_header.is_none() {
// Return to caller if we found image info.
return Ok(());
}
if self.frame.is_some() {
if self.has_visible_frame() {
// Return to caller if we found visible frame info.
return Ok(());
} else {
self.process_without_output = true;
continue;
}
}
}
}
}
}