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Make decoding internally operate on byte buffers (#230)
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@fintelia
fintelia authored Jul 23, 2024
1 parent 307cd8b commit 6dc7a26
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Showing 4 changed files with 229 additions and 271 deletions.
144 changes: 78 additions & 66 deletions src/decoder/image.rs
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
use super::ifd::{Directory, Value};
use super::stream::{ByteOrder, DeflateReader, LZWReader, PackBitsReader};
use super::tag_reader::TagReader;
use super::{fp_predict_f32, fp_predict_f64, DecodingBuffer, Limits};
use super::{predict_f32, predict_f64, Limits};
use super::{stream::SmartReader, ChunkType};
use crate::tags::{
CompressionMethod, PhotometricInterpretation, PlanarConfiguration, Predictor, SampleFormat, Tag,
Expand Down Expand Up @@ -64,7 +64,6 @@ pub(crate) struct Image {
pub width: u32,
pub height: u32,
pub bits_per_sample: u8,
#[allow(unused)]
pub samples: u16,
pub sample_format: SampleFormat,
pub photometric_interpretation: PhotometricInterpretation,
Expand Down Expand Up @@ -171,8 +170,9 @@ impl Image {
));
}

// This library (and libtiff) do not support mixed sample formats.
if bits_per_sample.iter().any(|&b| b != bits_per_sample[0]) {
// This library (and libtiff) do not support mixed sample formats and zero bits per sample
// doesn't make sense.
if bits_per_sample.iter().any(|&b| b != bits_per_sample[0]) || bits_per_sample[0] == 0 {
return Err(TiffUnsupportedError::InconsistentBitsPerSample(bits_per_sample).into());
}

Expand Down Expand Up @@ -546,35 +546,29 @@ impl Image {
pub(crate) fn expand_chunk(
&self,
reader: impl Read,
mut buffer: DecodingBuffer,
output_width: usize,
buf: &mut [u8],
output_row_stride: usize,
byte_order: ByteOrder,
chunk_index: u32,
limits: &Limits,
) -> TiffResult<()> {
// Validate that the provided buffer is of the expected type.
// Validate that the color type is supported.
let color_type = self.colortype()?;
match (color_type, &buffer) {
(ColorType::RGB(n), _)
| (ColorType::RGBA(n), _)
| (ColorType::CMYK(n), _)
| (ColorType::YCbCr(n), _)
| (ColorType::Gray(n), _)
| (
ColorType::Multiband {
bit_depth: n,
num_samples: _,
},
_,
) if usize::from(n) == buffer.byte_len() * 8 => {}
(
ColorType::Gray(n)
| ColorType::Multiband {
bit_depth: n,
num_samples: _,
},
DecodingBuffer::U8(_),
) if n < 8 => match self.predictor {
match color_type {
ColorType::RGB(n)
| ColorType::RGBA(n)
| ColorType::CMYK(n)
| ColorType::YCbCr(n)
| ColorType::Gray(n)
| ColorType::Multiband {
bit_depth: n,
num_samples: _,
} if n == 8 || n == 16 || n == 32 || n == 64 => {}
ColorType::Gray(n)
| ColorType::Multiband {
bit_depth: n,
num_samples: _,
} if n < 8 => match self.predictor {
Predictor::None => {}
Predictor::Horizontal => {
return Err(TiffError::UnsupportedError(
Expand All @@ -587,23 +581,22 @@ impl Image {
));
}
},
(type_, _) => {
type_ => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::UnsupportedColorType(type_),
));
}
}

// Validate that the predictor is supported for the sample type.
match (self.predictor, &buffer) {
(Predictor::Horizontal, DecodingBuffer::F32(_))
| (Predictor::Horizontal, DecodingBuffer::F64(_)) => {
match (self.predictor, self.sample_format) {
(Predictor::Horizontal, SampleFormat::Int | SampleFormat::Uint) => {}
(Predictor::Horizontal, _) => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::HorizontalPredictor(color_type),
));
}
(Predictor::FloatingPoint, DecodingBuffer::F32(_))
| (Predictor::FloatingPoint, DecodingBuffer::F64(_)) => {}
(Predictor::FloatingPoint, SampleFormat::IEEEFP) => {}
(Predictor::FloatingPoint, _) => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::FloatingPointPredictor(color_type),
Expand All @@ -622,7 +615,6 @@ impl Image {
return Err(TiffError::LimitsExceeded);
}

let byte_len = buffer.byte_len();
let compression_method = self.compression_method;
let photometric_interpretation = self.photometric_interpretation;
let predictor = self.predictor;
Expand All @@ -631,7 +623,19 @@ impl Image {
let chunk_dims = self.chunk_dimensions()?;
let data_dims = self.chunk_data_dimensions(chunk_index)?;

let padding_right = chunk_dims.0 - data_dims.0;
let chunk_row_bits = (u64::from(chunk_dims.0) * u64::from(self.bits_per_sample))
.checked_mul(samples as u64)
.ok_or(TiffError::LimitsExceeded)?;
let chunk_row_bytes: usize = ((chunk_row_bits + 7) / 8).try_into()?;

let data_row_bits = (u64::from(data_dims.0) * u64::from(self.bits_per_sample))
.checked_mul(samples as u64)
.ok_or(TiffError::LimitsExceeded)?;
let data_row_bytes: usize = ((data_row_bits + 7) / 8).try_into()?;

// TODO: Should these return errors instead?
assert!(output_row_stride >= data_row_bytes);
assert!(buf.len() >= output_row_stride * (data_dims.1 as usize - 1) + data_row_bytes);

let mut reader = Self::create_reader(
reader,
Expand All @@ -641,57 +645,65 @@ impl Image {
self.jpeg_tables.as_deref().map(|a| &**a),
)?;

if output_width == data_dims.0 as usize && padding_right == 0 {
let total_samples = data_dims.0 as usize * data_dims.1 as usize * samples;
let tile = &mut buffer.as_bytes_mut()[..total_samples * byte_len];
if output_row_stride == chunk_row_bytes as usize {
let tile = &mut buf[..chunk_row_bytes * data_dims.1 as usize];
reader.read_exact(tile)?;

for row in 0..data_dims.1 as usize {
let row_start = row * output_width * samples;
let row_end = (row + 1) * output_width * samples;
let row = buffer.subrange(row_start..row_end);
super::fix_endianness_and_predict(row, samples, byte_order, predictor);
for row in tile.chunks_mut(chunk_row_bytes as usize) {
super::fix_endianness_and_predict(
row,
color_type.bit_depth(),
samples,
byte_order,
predictor,
);
}
if photometric_interpretation == PhotometricInterpretation::WhiteIsZero {
super::invert_colors(&mut buffer.subrange(0..total_samples), color_type);
super::invert_colors(tile, color_type, self.sample_format);
}
} else if padding_right > 0 && self.predictor == Predictor::FloatingPoint {
} else if chunk_row_bytes > data_row_bytes && self.predictor == Predictor::FloatingPoint {
// The floating point predictor shuffles the padding bytes into the encoded output, so
// this case is handled specially when needed.
let mut encoded = vec![0u8; chunk_dims.0 as usize * samples * byte_len];

for row in 0..data_dims.1 as usize {
let row_start = row * output_width * samples;
let row_end = row_start + data_dims.0 as usize * samples;

let mut encoded = vec![0u8; chunk_row_bytes];
for row in buf.chunks_mut(output_row_stride).take(data_dims.1 as usize) {
reader.read_exact(&mut encoded)?;
match buffer.subrange(row_start..row_end) {
DecodingBuffer::F32(buf) => fp_predict_f32(&mut encoded, buf, samples),
DecodingBuffer::F64(buf) => fp_predict_f64(&mut encoded, buf, samples),

let row = &mut row[..data_row_bytes];
match color_type.bit_depth() {
32 => predict_f32(&mut encoded, row, samples),
64 => predict_f64(&mut encoded, row, samples),
_ => unreachable!(),
}
if photometric_interpretation == PhotometricInterpretation::WhiteIsZero {
super::invert_colors(&mut buffer.subrange(row_start..row_end), color_type);
super::invert_colors(row, color_type, self.sample_format);
}
}
} else {
for row in 0..data_dims.1 as usize {
let row_start = row * output_width * samples;
let row_end = row_start + data_dims.0 as usize * samples;

let row = &mut buffer.as_bytes_mut()[(row_start * byte_len)..(row_end * byte_len)];
for (i, row) in buf
.chunks_mut(output_row_stride)
.take(data_dims.1 as usize)
.enumerate()
{
let row = &mut row[..data_row_bytes];
reader.read_exact(row)?;

println!("chunk={chunk_index}, index={i}");

// Skip horizontal padding
if padding_right > 0 {
let len = u64::try_from(padding_right as usize * samples * byte_len)?;
if chunk_row_bytes > data_row_bytes {
let len = u64::try_from(chunk_row_bytes - data_row_bytes)?;
io::copy(&mut reader.by_ref().take(len), &mut io::sink())?;
}

let mut row = buffer.subrange(row_start..row_end);
super::fix_endianness_and_predict(row.copy(), samples, byte_order, predictor);
super::fix_endianness_and_predict(
row,
color_type.bit_depth(),
samples,
byte_order,
predictor,
);
if photometric_interpretation == PhotometricInterpretation::WhiteIsZero {
super::invert_colors(&mut row, color_type);
super::invert_colors(row, color_type, self.sample_format);
}
}
}
Expand Down
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