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Merge pull request #347 from image-rs/iterate-over-raw-tiff-or-exif

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Enable iteration over raw, malformed tiff or exif
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Aurelia Molzer authored and GitHub committed 2026-03-06 07:31:13 +00:00
2 parents 31c49ea6ef 08f1b25fac
commit 54dddc4943
4 files changed
+335 -122
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CHANGES.md
+13
View File
@@ -1,3 +1,16 @@
# Version 0.12.0 (unreleased)
Additions:
- Added the `TiffHeader` type. It can be used to create a `Decoder` in a state
before the first IFD and allows opening files at an arbitrary first IFD
offset rather than one indicated by an encoded header at the start.
Changes:
- The IFD iteration methods on `Decoder` (`next_image`, `seek_to_image`, etc)
now come with a strong error guarantee. They will not modify the current
directory state if they fail. This includes the failure to interpret an IFD
as a supported image in the case of `*_image` variants.
# Version 0.11.3
Additions:
src/decoder/image.rs
+26 -4
View File
@@ -64,7 +64,6 @@ impl TileAttributes {
#[derive(Debug)]
pub(crate) struct Image {
pub ifd: Option<Directory>,
pub width: u32,
pub height: u32,
pub bits_per_sample: u8,
@@ -147,11 +146,35 @@ pub(crate) struct ReadoutLayout {
}
impl Image {
pub(crate) fn no_image() -> Image {
Image {
width: 0,
height: 0,
bits_per_sample: 1,
samples: 1,
extra_samples: vec![],
photometric_samples: 1,
sample_format: SampleFormat::Uint,
photometric_interpretation: PhotometricInterpretation::BlackIsZero,
compression_method: CompressionMethod::None,
jpeg_tables: None,
predictor: Predictor::None,
chunk_type: ChunkType::Strip,
planar_config: PlanarConfiguration::Chunky,
strip_decoder: None,
tile_attributes: None,
chunk_offsets: Vec::new(),
chunk_bytes: Vec::new(),
chroma_subsampling: (2, 2),
decompression_to_host_endian: false,
}
}
pub fn from_reader<R: Read + Seek>(
decoder: &mut ValueReader<R>,
ifd: Directory,
ifd: &Directory,
) -> TiffResult<Image> {
let mut tag_reader = TagReader { decoder, ifd: &ifd };
let mut tag_reader = TagReader { decoder, ifd };
let width = tag_reader.require_tag(Tag::ImageWidth)?.into_u32()?;
let height = tag_reader.require_tag(Tag::ImageLength)?.into_u32()?;
@@ -435,7 +458,6 @@ impl Image {
}
Ok(Image {
ifd: Some(ifd),
width,
height,
bits_per_sample,
src/decoder/mod.rs
+287 -118
View File
@@ -4,8 +4,8 @@ use std::io::{self, Read, Seek};
use std::num::NonZeroUsize;
use crate::tags::{
CompressionMethod, IfdPointer, PhotometricInterpretation, PlanarConfiguration, Predictor,
SampleFormat, Tag, Type, ValueBuffer,
ByteOrder, IfdPointer, PlanarConfiguration, Predictor, SampleFormat, Tag, TiffVariant, Type,
ValueBuffer,
};
use crate::{
bytecast, ColorType, Directory, TiffError, TiffFormatError, TiffResult, TiffUnsupportedError,
@@ -14,7 +14,7 @@ use crate::{
use half::f16;
use self::image::Image;
use self::stream::{ByteOrder, EndianReader};
use self::stream::EndianReader;
mod cycles;
pub mod ifd;
@@ -505,6 +505,14 @@ impl Default for Limits {
}
}
/// Describe the header of TIFF file, including where to find the first image directory.
#[derive(Debug)]
pub struct TiffHeader {
pub byte_order: ByteOrder,
pub variant: TiffVariant,
pub first_ifd: IfdPointer,
}
/// The representation of a TIFF decoder
///
/// Currently does not support decoding of interlaced images
@@ -516,8 +524,8 @@ where
/// There are grouped for borrow checker reasons. This allows us to implement methods that
/// borrow the stream access and the other fields mutably at the same time.
value_reader: ValueReader<R>,
current_ifd: Option<IfdPointer>,
next_ifd: Option<IfdPointer>,
current_ifd_pointer: Option<IfdPointer>,
directory: Directory,
/// The IFDs we visited already in this chain of IFDs.
ifd_offsets: Vec<IfdPointer>,
/// Map from the ifd into the `ifd_offsets` ordered list.
@@ -766,8 +774,8 @@ fn fix_endianness(buf: &mut [u8], byte_order: ByteOrder, bit_depth: u8) {
host.convert_endian_bytes(class, buf, byte_order);
}
impl<R: Read + Seek> Decoder<R> {
pub fn new(mut r: R) -> TiffResult<Decoder<R>> {
impl TiffHeader {
pub fn parse<R: Read + Seek>(mut r: R) -> TiffResult<Self> {
let mut endianess = Vec::with_capacity(2);
(&mut r).take(2).read_to_end(&mut endianess)?;
let byte_order = match &*endianess {
@@ -779,6 +787,7 @@ impl<R: Read + Seek> Decoder<R> {
))
}
};
let mut reader = EndianReader::new(r, byte_order);
let bigtiff = match reader.read_u16()? {
@@ -805,49 +814,71 @@ impl<R: Read + Seek> Decoder<R> {
}
};
let next_ifd = if bigtiff {
Some(reader.read_u64()?)
let next_ifd = IfdPointer(if bigtiff {
reader.read_u64()?
} else {
Some(u64::from(reader.read_u32()?))
}
.map(IfdPointer);
u64::from(reader.read_u32()?)
});
let current_ifd = *next_ifd.as_ref().unwrap();
let ifd_offsets = vec![current_ifd];
Ok(TiffHeader {
byte_order,
variant: if bigtiff {
TiffVariant::BigTiff
} else {
TiffVariant::Standard
},
first_ifd: next_ifd,
})
}
/// Open a file, without seeking to any IFD yet.
pub fn open<R: Read + Seek>(&self, r: R) -> Decoder<R> {
let reader = EndianReader::new(r, self.byte_order);
Decoder {
value_reader: ValueReader {
reader,
bigtiff: matches!(self.variant, TiffVariant::BigTiff),
limits: Default::default(),
},
ifd_offsets: vec![],
current_ifd_pointer: None,
directory: {
let mut dir = Directory::empty();
dir.set_next(Some(self.first_ifd));
dir
},
seen_ifds: cycles::IfdCycles::new(),
image: Image::no_image(),
}
}
}
impl<R: Read + Seek> Decoder<R> {
pub fn new(mut r: R) -> TiffResult<Decoder<R>> {
let header = TiffHeader::parse(&mut r)?;
let reader = EndianReader::new(r, header.byte_order);
let first_ifd = header.first_ifd;
let ifd_offsets = vec![first_ifd];
let mut decoder = Decoder {
value_reader: ValueReader {
reader,
bigtiff,
bigtiff: matches!(header.variant, TiffVariant::BigTiff),
limits: Default::default(),
},
next_ifd,
ifd_offsets,
current_ifd: None,
seen_ifds: cycles::IfdCycles::new(),
image: Image {
ifd: None,
width: 0,
height: 0,
bits_per_sample: 1,
samples: 1,
extra_samples: vec![],
photometric_samples: 1,
sample_format: SampleFormat::Uint,
photometric_interpretation: PhotometricInterpretation::BlackIsZero,
compression_method: CompressionMethod::None,
jpeg_tables: None,
predictor: Predictor::None,
chunk_type: ChunkType::Strip,
planar_config: PlanarConfiguration::Chunky,
strip_decoder: None,
tile_attributes: None,
chunk_offsets: Vec::new(),
chunk_bytes: Vec::new(),
chroma_subsampling: (2, 2),
decompression_to_host_endian: false,
current_ifd_pointer: None,
directory: {
let mut dir = Directory::empty();
dir.set_next(Some(first_ifd));
dir
},
seen_ifds: cycles::IfdCycles::new(),
image: Image::no_image(),
};
decoder.next_image()?;
Ok(decoder)
}
@@ -858,66 +889,79 @@ impl<R: Read + Seek> Decoder<R> {
}
pub fn dimensions(&mut self) -> TiffResult<(u32, u32)> {
Ok((self.image().width, self.image().height))
Ok((self.image.width, self.image.height))
}
pub fn colortype(&mut self) -> TiffResult<ColorType> {
self.image().colortype()
self.image.colortype()
}
/// The offset of the directory representing the current image.
pub fn ifd_pointer(&mut self) -> Option<IfdPointer> {
self.current_ifd
}
fn image(&self) -> &Image {
&self.image
self.current_ifd_pointer
}
/// Loads the IFD at the specified index in the list, if one exists
pub fn seek_to_image(&mut self, ifd_index: usize) -> TiffResult<()> {
// Check whether we have seen this IFD before, if so then the index will be less than the length of the list of ifd offsets
if ifd_index >= self.ifd_offsets.len() {
// We possibly need to load in the next IFD
if self.next_ifd.is_none() {
self.current_ifd = None;
return Err(TiffError::FormatError(
TiffFormatError::ImageFileDirectoryNotFound,
));
///
/// Error guarantee: the current directory and its offset is not modified when an error occurs.
pub fn seek_to_directory(&mut self, ifd_index: usize) -> TiffResult<()> {
let (offset, directory) = self.find_nth_ifd(ifd_index)?;
self.image = Image::no_image();
self.current_ifd_pointer = Some(offset);
self.directory = directory;
Ok(())
}
/// Loads the IFD at the specified index in the list, if one exists
///
/// The directory is then decoded as an image.
///
/// Error guarantee: the current directory and its offset is not modified when an error occurs.
pub fn seek_to_image(&mut self, ifd_index: usize) -> TiffResult<()> {
let (offset, directory) = self.find_nth_ifd(ifd_index)?;
self.image = Image::from_reader(&mut self.value_reader, &directory)?;
self.current_ifd_pointer = Some(offset);
self.directory = directory;
Ok(())
}
/// Change the directory to the nth in the linked-list chain of IFDs.
fn find_nth_ifd(&mut self, ifd_index: usize) -> TiffResult<(IfdPointer, Directory)> {
// Check whether we have seen this IFD before, if so then the index will be less than the
// length of the list of ifd offsets If the index is within the list of ifds then we can
// load the selected image/IFD. Otherwise we iterate the chain until the selected index.
if let Some(&ifd_offset) = self.ifd_offsets.get(ifd_index) {
let directory = self.value_reader.read_directory(ifd_offset)?;
Ok((ifd_offset, directory))
} else {
// We do not know if we are at the last IFD in the chain if we previous did seek back.
// The `read_next_ifd_pointer` correctly handles this.
let mut chained_ifd = self.current_ifd_pointer;
let mut next_ifd = self.directory.next();
loop {
// Follow the list until we find the one we want, or we reach the end, whichever happens first
let ifd = self.next_ifd()?;
if ifd.next().is_none() {
break;
}
let (ifd_pointer, ifd) = self.read_chained_ifd(chained_ifd, next_ifd)?;
chained_ifd = Some(ifd_pointer);
next_ifd = ifd.next();
if ifd_index < self.ifd_offsets.len() {
break;
// We only end up here if initially `ifd_index >= self.ifd_offsets.len()` and
// each loop iteration increases the length of `self.ifd_offsets` by (at most)
// one.
debug_assert!(ifd_index + 1 == self.ifd_offsets.len());
return Ok((ifd_pointer, ifd));
}
}
}
}
// If the index is within the list of ifds then we can load the selected image/IFD
if let Some(ifd_offset) = self.ifd_offsets.get(ifd_index) {
let ifd = self.value_reader.read_directory(*ifd_offset)?;
self.next_ifd = ifd.next();
self.current_ifd = Some(*ifd_offset);
self.image = Image::from_reader(&mut self.value_reader, ifd)?;
Ok(())
} else {
Err(TiffError::FormatError(
TiffFormatError::ImageFileDirectoryNotFound,
))
}
}
fn next_ifd(&mut self) -> TiffResult<Directory> {
let Some(next_ifd) = self.next_ifd.take() else {
fn read_chained_ifd(
&mut self,
current_ifd_pointer: Option<IfdPointer>,
next_ifd: Option<IfdPointer>,
) -> TiffResult<(IfdPointer, Directory)> {
let Some(next_ifd) = next_ifd else {
return Err(TiffError::FormatError(
TiffFormatError::ImageFileDirectoryNotFound,
));
@@ -929,28 +973,46 @@ impl<R: Read + Seek> Decoder<R> {
self.seen_ifds.insert_next(next_ifd, ifd.next())?;
// Extend the list of known IFD offsets in this chain, if needed.
if self.ifd_offsets.last().copied() == self.current_ifd {
if self.ifd_offsets.last().copied() == current_ifd_pointer {
self.ifd_offsets.push(next_ifd);
}
self.current_ifd = Some(next_ifd);
self.next_ifd = ifd.next();
Ok((next_ifd, ifd))
}
Ok(ifd)
/// Reads the next IFD.
///
/// If there is no further image in the TIFF file a format error is returned.
/// To determine whether there are more images call `TIFFDecoder::more_images` instead.
///
/// Error guarantee: the current directory and its offset is not modified when an error occurs.
pub fn next_directory(&mut self) -> TiffResult<()> {
let next_ifd = self.directory.next();
let (offset, directory) = self.read_chained_ifd(self.current_ifd_pointer, next_ifd)?;
self.image = Image::no_image();
self.current_ifd_pointer = Some(offset);
self.directory = directory;
Ok(())
}
/// Reads in the next image.
///
/// If there is no further image in the TIFF file a format error is returned.
/// To determine whether there are more images call `TIFFDecoder::more_images` instead.
///
/// Error guarantee: the current directory and its offset is not modified when an error occurs.
pub fn next_image(&mut self) -> TiffResult<()> {
let ifd = self.next_ifd()?;
self.image = Image::from_reader(&mut self.value_reader, ifd)?;
let next_ifd = self.directory.next();
let (offset, directory) = self.read_chained_ifd(self.current_ifd_pointer, next_ifd)?;
self.image = Image::from_reader(&mut self.value_reader, &directory)?;
self.current_ifd_pointer = Some(offset);
self.directory = directory;
Ok(())
}
/// Returns `true` if there is at least one more image available.
pub fn more_images(&self) -> bool {
self.next_ifd.is_some()
self.directory.next().is_some()
}
/// Returns the byte_order of the file.
@@ -1099,10 +1161,10 @@ impl<R: Read + Seek> Decoder<R> {
}
fn check_chunk_type(&self, expected: ChunkType) -> TiffResult<()> {
if expected != self.image().chunk_type {
if expected != self.image.chunk_type {
return Err(TiffError::UsageError(UsageError::InvalidChunkType(
expected,
self.image().chunk_type,
self.image.chunk_type,
)));
}
@@ -1111,27 +1173,27 @@ impl<R: Read + Seek> Decoder<R> {
/// The chunk type (Strips / Tiles) of the image
pub fn get_chunk_type(&self) -> ChunkType {
self.image().chunk_type
self.image.chunk_type
}
/// Number of strips in image
pub fn strip_count(&mut self) -> TiffResult<u32> {
self.check_chunk_type(ChunkType::Strip)?;
let rows_per_strip = self.image().strip_decoder.as_ref().unwrap().rows_per_strip;
let rows_per_strip = self.image.strip_decoder.as_ref().unwrap().rows_per_strip;
if rows_per_strip == 0 {
return Ok(0);
}
// rows_per_strip - 1 can never fail since we know it's at least 1
let height = match self.image().height.checked_add(rows_per_strip - 1) {
let height = match self.image.height.checked_add(rows_per_strip - 1) {
Some(h) => h,
None => return Err(TiffError::IntSizeError),
};
let strips = match self.image().planar_config {
let strips = match self.image.planar_config {
PlanarConfiguration::Chunky => height / rows_per_strip,
PlanarConfiguration::Planar => height / rows_per_strip * self.image().samples as u32,
PlanarConfiguration::Planar => height / rows_per_strip * self.image.samples as u32,
};
Ok(strips)
@@ -1140,7 +1202,7 @@ impl<R: Read + Seek> Decoder<R> {
/// Number of tiles in image
pub fn tile_count(&mut self) -> TiffResult<u32> {
self.check_chunk_type(ChunkType::Tile)?;
Ok(u32::try_from(self.image().chunk_offsets.len())?)
Ok(u32::try_from(self.image.chunk_offsets.len())?)
}
fn read_chunk_to_bytes(
@@ -1169,8 +1231,8 @@ impl<R: Read + Seek> Decoder<R> {
&mut self,
chunk_index: u32,
) -> TiffResult<BufferLayoutPreference> {
let data_dims = self.image().chunk_data_dimensions(chunk_index)?;
let readout = self.image().readout_for_size(data_dims.0, data_dims.1)?;
let data_dims = self.image.chunk_data_dimensions(chunk_index)?;
let readout = self.image.readout_for_size(data_dims.0, data_dims.1)?;
let extent = readout.result_extent_for_planes(0..1)?;
let sample_type = extent.sample_type();
@@ -1185,7 +1247,7 @@ impl<R: Read + Seek> Decoder<R> {
planes: 1,
plane_stride,
complete_len: layout.size(),
sample_format: self.image().sample_format,
sample_format: self.image.sample_format,
sample_type: Some(sample_type),
})
}
@@ -1202,15 +1264,15 @@ impl<R: Read + Seek> Decoder<R> {
&mut self,
code_unit: TiffCodingUnit,
) -> TiffResult<BufferLayoutPreference> {
match self.image().planar_config {
match self.image.planar_config {
PlanarConfiguration::Chunky => return self.image_chunk_buffer_layout(code_unit.0),
PlanarConfiguration::Planar => {}
}
let (width, height) = self.image().chunk_data_dimensions(code_unit.0)?;
let (width, height) = self.image.chunk_data_dimensions(code_unit.0)?;
let layout = self
.image()
.image
.readout_for_size(width, height)?
.to_plane_layout()?;
@@ -1228,9 +1290,9 @@ impl<R: Read + Seek> Decoder<R> {
///
/// Note that for planar images each chunk contains only one sample of the underlying data.
pub fn read_chunk(&mut self, chunk_index: u32) -> TiffResult<DecodingResult> {
let (width, height) = self.image().chunk_data_dimensions(chunk_index)?;
let (width, height) = self.image.chunk_data_dimensions(chunk_index)?;
let readout = self.image().readout_for_size(width, height)?;
let readout = self.image.readout_for_size(width, height)?;
let mut result = readout
.result_extent_for_planes(0..1)?
@@ -1249,9 +1311,9 @@ impl<R: Read + Seek> Decoder<R> {
///
/// Note that for planar images each chunk contains only one sample of the underlying data.
pub fn read_chunk_bytes(&mut self, chunk_index: u32, buffer: &mut [u8]) -> TiffResult<()> {
let (width, height) = self.image().chunk_data_dimensions(chunk_index)?;
let (width, height) = self.image.chunk_data_dimensions(chunk_index)?;
let layout = self.image().readout_for_size(width, height)?;
let layout = self.image.readout_for_size(width, height)?;
layout.assert_min_layout(buffer)?;
self.read_chunk_to_bytes(buffer, chunk_index, &layout)?;
@@ -1272,9 +1334,9 @@ impl<R: Read + Seek> Decoder<R> {
chunk_index: u32,
output_width: usize,
) -> TiffResult<()> {
let (width, height) = self.image().chunk_data_dimensions(chunk_index)?;
let (width, height) = self.image.chunk_data_dimensions(chunk_index)?;
let mut layout = self.image().readout_for_size(width, height)?;
let mut layout = self.image.readout_for_size(width, height)?;
layout.set_row_stride(output_width)?;
let extent = layout.result_extent_for_planes(0..1)?;
@@ -1304,8 +1366,8 @@ impl<R: Read + Seek> Decoder<R> {
slice: TiffCodingUnit,
buffer: &mut [u8],
) -> TiffResult<()> {
let (width, height) = self.image().chunk_data_dimensions(slice.0)?;
let readout = self.image().readout_for_size(width, height)?;
let (width, height) = self.image.chunk_data_dimensions(slice.0)?;
let readout = self.image.readout_for_size(width, height)?;
let ref layout @ image::PlaneLayout {
ref plane_offsets,
@@ -1327,7 +1389,7 @@ impl<R: Read + Seek> Decoder<R> {
for (idx, &plane_offset) in plane_offsets[..used_plane_offsets].iter().enumerate() {
let chunk = slice.0 + idx as u32 * readout.chunks_per_plane;
self.goto_offset_u64(self.image().chunk_offsets[chunk as usize])?;
self.goto_offset_u64(self.image.chunk_offsets[chunk as usize])?;
self.image.expand_chunk(
&mut self.value_reader,
@@ -1343,13 +1405,13 @@ impl<R: Read + Seek> Decoder<R> {
/// Returns the default chunk size for the current image. Any given chunk in the image is at most as large as
/// the value returned here. For the size of the data (chunk minus padding), use `chunk_data_dimensions`.
pub fn chunk_dimensions(&self) -> (u32, u32) {
self.image().chunk_dimensions().unwrap()
self.image.chunk_dimensions().unwrap()
}
/// Returns the size of the data in the chunk with the specified index. This is the default size of the chunk,
/// minus any padding.
pub fn chunk_data_dimensions(&self, chunk_index: u32) -> (u32, u32) {
self.image()
self.image
.chunk_data_dimensions(chunk_index)
.expect("invalid chunk_index")
}
@@ -1368,7 +1430,7 @@ impl<R: Read + Seek> Decoder<R> {
/// indicate the layout needed to read the first data plane. This will be fixed in a future
/// major version of `tiff`.
pub fn image_buffer_layout(&mut self) -> TiffResult<BufferLayoutPreference> {
let layout = self.image().readout_for_image()?.to_plane_layout()?;
let layout = self.image.readout_for_image()?.to_plane_layout()?;
Ok(BufferLayoutPreference::from_planes(&layout))
}
@@ -1392,7 +1454,7 @@ impl<R: Read + Seek> Decoder<R> {
/// replaced, to ensure that existing code will not run into unexpectedly large allocations
/// that will error on limits instead.
pub fn read_image(&mut self) -> TiffResult<DecodingResult> {
let readout = self.image().readout_for_image()?;
let readout = self.image.readout_for_image()?;
let mut result = readout
.result_extent_for_planes(0..1)?
@@ -1453,7 +1515,7 @@ impl<R: Read + Seek> Decoder<R> {
&mut self,
result: &mut DecodingResult,
) -> TiffResult<BufferLayoutPreference> {
let readout = self.image().readout_for_image()?;
let readout = self.image.readout_for_image()?;
let planes = readout.to_plane_layout()?;
let num_planes = if planes.total_bytes <= self.value_reader.limits.decoding_buffer_size {
@@ -1484,7 +1546,7 @@ impl<R: Read + Seek> Decoder<R> {
/// Returns an error if the buffer fits less than one plane. In particular, for non-planar
/// images returns an error if the buffer does not fit the required size.
pub fn read_image_bytes(&mut self, buffer: &mut [u8]) -> TiffResult<()> {
let readout = self.image().readout_for_image()?;
let readout = self.image.readout_for_image()?;
let ref layout @ image::PlaneLayout {
ref plane_offsets,
@@ -1508,7 +1570,7 @@ impl<R: Read + Seek> Decoder<R> {
for (idx, &plane_offset) in plane_offsets[..used_plane_offsets].iter().enumerate() {
let chunk = chunk + idx as u32 * readout.chunks_per_plane;
self.goto_offset_u64(self.image().chunk_offsets[chunk as usize])?;
self.goto_offset_u64(self.image.chunk_offsets[chunk as usize])?;
self.image.expand_chunk(
&mut self.value_reader,
@@ -1527,7 +1589,7 @@ impl<R: Read + Seek> Decoder<R> {
IfdDecoder {
inner: tag_reader::TagReader {
decoder: &mut self.value_reader,
ifd: self.image.ifd.as_ref().unwrap(),
ifd: &self.directory,
},
}
}
@@ -1894,7 +1956,7 @@ impl<'l> IfdDecoder<'l> {
mod tests {
use super::Decoder;
use crate::{
bytecast,
bytecast, encoder,
tags::{ByteOrder, Tag, ValueBuffer},
};
@@ -1955,4 +2017,111 @@ mod tests {
assert_eq!(&by_bytes[..3], &[8, 8, 8]);
}
}
#[test]
fn non_image_directory_between() {
let mut cursor = std::io::Cursor::new(vec![]);
{
let mut encoder = encoder::TiffEncoder::new(&mut cursor).unwrap();
encoder
.write_image::<encoder::colortype::Gray8>(1, 1, &[0])
.unwrap();
encoder.image_directory().unwrap().finish().unwrap();
encoder
.write_image::<encoder::colortype::Gray8>(1, 1, &[0])
.unwrap();
}
cursor.set_position(0);
let (first_ptr, second_ptr, third_ptr);
{
let mut decoder = Decoder::new(&mut cursor).unwrap();
first_ptr = decoder.ifd_pointer();
let first_ifd = decoder.image_ifd();
assert!(first_ifd.directory().get(Tag::ImageWidth).is_some());
assert!(decoder.more_images());
assert!(decoder.next_image().is_err());
let broken_ifd = decoder.image_ifd();
assert!(broken_ifd.directory().get(Tag::ImageWidth).is_some());
assert!(decoder.next_directory().is_ok());
second_ptr = decoder.ifd_pointer();
let second_ifd = decoder.image_ifd();
assert!(second_ifd.directory().get(Tag::ImageWidth).is_none());
assert!(decoder.more_images());
assert!(decoder.next_image().is_ok());
third_ptr = decoder.ifd_pointer();
let third_ifd = decoder.image_ifd();
assert!(third_ifd.directory().get(Tag::ImageWidth).is_some());
assert!(!decoder.more_images());
assert!(decoder.seek_to_image(1).is_err());
assert_eq!(decoder.ifd_pointer(), third_ptr);
assert!(decoder.seek_to_directory(1).is_ok());
assert_eq!(decoder.ifd_pointer(), second_ptr);
}
cursor.set_position(0);
{
let mut seek_immediately = Decoder::new(&mut cursor).unwrap();
assert_eq!(seek_immediately.ifd_pointer(), first_ptr);
assert!(seek_immediately.seek_to_image(1).is_err());
assert!(seek_immediately.seek_to_image(2).is_ok());
assert_eq!(seek_immediately.ifd_pointer(), third_ptr);
assert!(seek_immediately
.image_ifd()
.directory()
.get(Tag::ImageWidth)
.is_some());
}
cursor.set_position(0);
{
let mut seek_immediately = Decoder::new(&mut cursor).unwrap();
assert!(seek_immediately.seek_to_directory(1).is_ok());
assert_eq!(seek_immediately.ifd_pointer(), second_ptr);
assert!(seek_immediately
.image_ifd()
.directory()
.get(Tag::ImageWidth)
.is_none());
}
}
#[test]
fn non_image_directory_start() {
let mut cursor = std::io::Cursor::new(vec![]);
{
let mut encoder = encoder::TiffEncoder::new(&mut cursor).unwrap();
encoder.image_directory().unwrap().finish().unwrap();
encoder
.write_image::<encoder::colortype::Gray8>(1, 1, &[0])
.unwrap();
}
cursor.set_position(0);
let header = super::TiffHeader::parse(&mut cursor).unwrap();
let mut decoder = header.open(cursor);
assert!(decoder.more_images());
assert_eq!(decoder.ifd_pointer(), None);
assert!(decoder.next_directory().is_ok());
let first_ifd = decoder.image_ifd();
assert!(first_ifd.directory().get(Tag::ImageWidth).is_none());
assert!(decoder.more_images());
assert!(decoder.next_image().is_ok());
let second_ifd = decoder.image_ifd();
assert!(second_ifd.directory().get(Tag::ImageWidth).is_some());
assert!(!decoder.more_images());
}
}
src/tags.rs
+9
View File
@@ -589,3 +589,12 @@ pub(crate) enum EndianBytes {
Four,
Eight,
}
/// Defines how directories are laid out in the file.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum TiffVariant {
/// TIFF-V6.0 with 32-bit offsets and counts.
Standard,
/// Extended TIFF with 64-bit offsets and counts and long directories.
BigTiff,
}