wim/image-tiff
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Factor tags into own module

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Tag representations are not decoder- or encoder-specific, so should live
in their own module accessible to both for reuse. The decoder::ifd
module remains since this module is mainly dedicated to decoding the
IFD.
This commit is contained in:
Andrew Champion committed 2019-12-21 15:57:24 +00:00
1 parent f9cace84da
commit f92be13f6c
9 files changed
+242 -238
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src/decoder/mod.rs
+25 -66
View File
@@ -5,11 +5,11 @@ use std::cmp;
use {ColorType, TiffError, TiffFormatError, TiffResult, TiffUnsupportedError};
use self::ifd::{Directory, U16Tag};
use self::ifd::Directory;
use tags::{CompressionMethod, PhotometricInterpretation, Predictor, Tag, Type, U16Tag};
use self::stream::{ByteOrder, EndianReader, LZWReader, DeflateReader, PackBitsReader, SmartReader};
#[macro_use]
pub mod ifd;
mod stream;
@@ -113,47 +113,6 @@ impl<'a> DecodingBuffer<'a> {
}
}
tags! {
pub enum PhotometricInterpretation(u16) {
WhiteIsZero = 0,
BlackIsZero = 1,
RGB = 2,
RGBPalette = 3,
TransparencyMask = 4,
CMYK = 5,
YCbCr = 6,
CIELab = 8,
}
}
tags! {
pub enum CompressionMethod(u16) {
None = 1,
Huffman = 2,
Fax3 = 3,
Fax4 = 4,
LZW = 5,
JPEG = 6,
Deflate = 8,
OldDeflate = 0x80B2,
PackBits = 0x8005,
}
}
tags! {
pub enum PlanarConfiguration(u16) {
Chunky = 1,
Planar = 2,
}
}
tags! {
enum Predictor(u16) {
None = 1,
Horizontal = 2,
}
}
#[derive(Debug)]
struct StripDecodeState {
strip_index: usize,
@@ -385,24 +344,24 @@ impl<R: Read + Seek> Decoder<R> {
/// To determine whether there are more images call `TIFFDecoder::more_images` instead.
pub fn next_image(&mut self) -> TiffResult<()> {
self.ifd = Some(self.read_ifd()?);
self.width = self.get_tag_u32(ifd::Tag::ImageWidth)?;
self.height = self.get_tag_u32(ifd::Tag::ImageLength)?;
self.width = self.get_tag_u32(Tag::ImageWidth)?;
self.height = self.get_tag_u32(Tag::ImageLength)?;
self.strip_decoder = None;
self.photometric_interpretation = self
.find_tag_unsigned(ifd::Tag::PhotometricInterpretation)?
.find_tag_unsigned(Tag::PhotometricInterpretation)?
.and_then(PhotometricInterpretation::from_u16)
.ok_or(TiffUnsupportedError::UnknownInterpretation)?;
if let Some(val) = self.find_tag_unsigned(ifd::Tag::Compression)? {
if let Some(val) = self.find_tag_unsigned(Tag::Compression)? {
self.compression_method = CompressionMethod::from_u16(val)
.ok_or(TiffUnsupportedError::UnknownCompressionMethod)?;
}
if let Some(val) = self.find_tag_unsigned(ifd::Tag::SamplesPerPixel)? {
if let Some(val) = self.find_tag_unsigned(Tag::SamplesPerPixel)? {
self.samples = val;
}
match self.samples {
1 | 3 | 4 => if let Some(val) = self.find_tag_unsigned_vec(ifd::Tag::BitsPerSample)? {
1 | 3 | 4 => if let Some(val) = self.find_tag_unsigned_vec(Tag::BitsPerSample)? {
self.bits_per_sample = val;
},
_ => return Err(TiffUnsupportedError::UnsupportedSampleDepth(self.samples).into()),
@@ -485,9 +444,9 @@ impl<R: Read + Seek> Decoder<R> {
// Type 2 bytes
// Count 4 bytes
// Value 4 bytes either a pointer the value itself
fn read_entry(&mut self) -> TiffResult<Option<(ifd::Tag, ifd::Entry)>> {
let tag = ifd::Tag::from_u16_exhaustive(self.read_short()?);
let type_ = match ifd::Type::from_u16(self.read_short()?) {
fn read_entry(&mut self) -> TiffResult<Option<(Tag, ifd::Entry)>> {
let tag = Tag::from_u16_exhaustive(self.read_short()?);
let type_ = match Type::from_u16(self.read_short()?) {
Some(t) => t,
None => {
// Unknown type. Skip this entry according to spec.
@@ -533,7 +492,7 @@ impl<R: Read + Seek> Decoder<R> {
/// Tries to retrieve a tag.
/// Return `Ok(None)` if the tag is not present.
pub fn find_tag(&mut self, tag: ifd::Tag) -> TiffResult<Option<ifd::Value>> {
pub fn find_tag(&mut self, tag: Tag) -> TiffResult<Option<ifd::Value>> {
let entry = match self.ifd.as_ref().unwrap().get(&tag) {
None => return Ok(None),
Some(entry) => entry.clone(),
@@ -545,7 +504,7 @@ impl<R: Read + Seek> Decoder<R> {
}
/// Tries to retrieve a tag and convert it to the desired unsigned type.
pub fn find_tag_unsigned<T: TryFrom<u32>>(&mut self, tag: ifd::Tag) -> TiffResult<Option<T>> {
pub fn find_tag_unsigned<T: TryFrom<u32>>(&mut self, tag: Tag) -> TiffResult<Option<T>> {
self.find_tag(tag)?
.map(|v| v.into_u32()).transpose()?
.map(|value| T::try_from(value)
@@ -555,7 +514,7 @@ impl<R: Read + Seek> Decoder<R> {
/// Tries to retrieve a vector of all a tag's values and convert them to
/// the desired unsigned type.
pub fn find_tag_unsigned_vec<T: TryFrom<u32>>(&mut self, tag: ifd::Tag) -> TiffResult<Option<Vec<T>>> {
pub fn find_tag_unsigned_vec<T: TryFrom<u32>>(&mut self, tag: Tag) -> TiffResult<Option<Vec<T>>> {
self.find_tag(tag)?
.map(|v| v.into_u32_vec()).transpose()?
.map(|v| v.into_iter()
@@ -566,14 +525,14 @@ impl<R: Read + Seek> Decoder<R> {
/// Tries to retrieve a tag and convert it to the desired unsigned type.
/// Returns an error if the tag is not present.
pub fn get_tag_unsigned<T: TryFrom<u32>>(&mut self, tag: ifd::Tag) -> TiffResult<T> {
pub fn get_tag_unsigned<T: TryFrom<u32>>(&mut self, tag: Tag) -> TiffResult<T> {
self.find_tag_unsigned(tag)?
.ok_or_else(|| TiffFormatError::RequiredTagNotFound(tag).into())
}
/// Tries to retrieve a tag.
/// Returns an error if the tag is not present
pub fn get_tag(&mut self, tag: ifd::Tag) -> TiffResult<ifd::Value> {
pub fn get_tag(&mut self, tag: Tag) -> TiffResult<ifd::Value> {
match self.find_tag(tag)? {
Some(val) => Ok(val),
None => Err(TiffError::FormatError(
@@ -583,12 +542,12 @@ impl<R: Read + Seek> Decoder<R> {
}
/// Tries to retrieve a tag and convert it to the desired type.
pub fn get_tag_u32(&mut self, tag: ifd::Tag) -> TiffResult<u32> {
pub fn get_tag_u32(&mut self, tag: Tag) -> TiffResult<u32> {
self.get_tag(tag)?.into_u32()
}
/// Tries to retrieve a tag and convert it to the desired type.
pub fn get_tag_u32_vec(&mut self, tag: ifd::Tag) -> TiffResult<Vec<u32>> {
pub fn get_tag_u32_vec(&mut self, tag: Tag) -> TiffResult<Vec<u32>> {
self.get_tag(tag)?.into_u32_vec()
}
@@ -714,7 +673,7 @@ impl<R: Read + Seek> Decoder<R> {
/// Number of strips in image
pub fn strip_count(&mut self) -> TiffResult<u32> {
let rows_per_strip = self
.get_tag_u32(ifd::Tag::RowsPerStrip)
.get_tag_u32(Tag::RowsPerStrip)
.unwrap_or(self.height);
if rows_per_strip == 0 {
@@ -726,8 +685,8 @@ impl<R: Read + Seek> Decoder<R> {
fn initialize_strip_decoder(&mut self) -> TiffResult<()> {
if self.strip_decoder.is_none() {
let strip_offsets = self.get_tag_u32_vec(ifd::Tag::StripOffsets)?;
let strip_bytes = self.get_tag_u32_vec(ifd::Tag::StripByteCounts)?;
let strip_offsets = self.get_tag_u32_vec(Tag::StripOffsets)?;
let strip_bytes = self.get_tag_u32_vec(Tag::StripByteCounts)?;
self.strip_decoder = Some(StripDecodeState {
strip_index: 0,
@@ -762,7 +721,7 @@ impl<R: Read + Seek> Decoder<R> {
))?;
let rows_per_strip = self
.get_tag_u32(ifd::Tag::RowsPerStrip)
.get_tag_u32(Tag::RowsPerStrip)
.unwrap_or(self.height) as usize;
let strip_height = cmp::min(
@@ -791,7 +750,7 @@ impl<R: Read + Seek> Decoder<R> {
TiffFormatError::InconsistentSizesEncountered,
));
}
if let Ok(predictor) = self.get_tag_unsigned(ifd::Tag::Predictor) {
if let Ok(predictor) = self.get_tag_unsigned(Tag::Predictor) {
match Predictor::from_u16(predictor) {
Some(Predictor::None) => (),
Some(Predictor::Horizontal) => {
@@ -834,7 +793,7 @@ impl<R: Read + Seek> Decoder<R> {
let index = self.strip_decoder.as_ref().unwrap().strip_index;
let rows_per_strip = self
.get_tag_u32(ifd::Tag::RowsPerStrip)
.get_tag_u32(Tag::RowsPerStrip)
.unwrap_or(self.height) as usize;
let strip_height = cmp::min(
@@ -853,7 +812,7 @@ impl<R: Read + Seek> Decoder<R> {
pub fn read_image(&mut self) -> TiffResult<DecodingResult> {
self.initialize_strip_decoder()?;
let rows_per_strip = self
.get_tag_u32(ifd::Tag::RowsPerStrip)
.get_tag_u32(Tag::RowsPerStrip)
.unwrap_or(self.height) as usize;
let samples_per_strip =