use num_traits::{FromPrimitive, Num};
use std::collections::HashMap;
use std::io::{self, Read, Seek};
use std::cmp;
use {ColorType, TiffError, TiffFormatError, TiffResult, TiffUnsupportedError};
use self::ifd::Directory;
use self::stream::{ByteOrder, EndianReader, LZWReader, PackBitsReader, SmartReader};
pub mod ifd;
mod stream;
#[derive(Debug)]
pub enum DecodingResult {
U8(Vec<u8>),
U16(Vec<u16>),
}
impl DecodingResult {
fn new_u8(size: usize, limits: &Limits) -> TiffResult<DecodingResult> {
if size > limits.decoding_buffer_size {
Err(TiffError::LimitsExceeded)
} else {
Ok(DecodingResult::U8(vec![0; size]))
}
}
fn new_u16(size: usize, limits: &Limits) -> TiffResult<DecodingResult> {
if size > limits.decoding_buffer_size / 2 {
Err(TiffError::LimitsExceeded)
} else {
Ok(DecodingResult::U16(vec![0; size]))
}
}
pub fn as_buffer(&mut self, start: usize) -> DecodingBuffer {
match *self {
DecodingResult::U8(ref mut buf) => DecodingBuffer::U8(&mut buf[start..]),
DecodingResult::U16(ref mut buf) => DecodingBuffer::U16(&mut buf[start..]),
}
}
}
pub enum DecodingBuffer<'a> {
U8(&'a mut [u8]),
U16(&'a mut [u16]),
}
impl<'a> DecodingBuffer<'a> {
fn len(&self) -> usize {
match *self {
DecodingBuffer::U8(ref buf) => buf.len(),
DecodingBuffer::U16(ref buf) => buf.len(),
}
}
fn byte_len(&self) -> usize {
match *self {
DecodingBuffer::U8(_) => 1,
DecodingBuffer::U16(_) => 2,
}
}
fn copy<'b>(&'b mut self) -> DecodingBuffer<'b>
where
'a: 'b,
{
match *self {
DecodingBuffer::U8(ref mut buf) => DecodingBuffer::U8(buf),
DecodingBuffer::U16(ref mut buf) => DecodingBuffer::U16(buf),
}
}
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, FromPrimitive)]
pub enum PhotometricInterpretation {
WhiteIsZero = 0,
BlackIsZero = 1,
RGB = 2,
RGBPalette = 3,
TransparencyMask = 4,
CMYK = 5,
YCbCr = 6,
CIELab = 8,
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, FromPrimitive)]
pub enum CompressionMethod {
None = 1,
Huffman = 2,
Fax3 = 3,
Fax4 = 4,
LZW = 5,
JPEG = 6,
PackBits = 0x8005,
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, FromPrimitive)]
pub enum PlanarConfiguration {
Chunky = 1,
Planar = 2,
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, FromPrimitive)]
enum Predictor {
None = 1,
Horizontal = 2,
}
#[derive(Debug)]
struct StripDecodeState {
strip_index: usize,
strip_offsets: Vec<u32>,
strip_bytes: Vec<u32>,
}
#[derive(Clone, Debug)]
pub struct Limits {
decoding_buffer_size: usize,
ifd_value_size: usize,
}
impl Default for Limits {
fn default() -> Limits {
Limits {
decoding_buffer_size: 256 * 1024 * 1024,
ifd_value_size: 1024 * 1024,
}
}
}
#[derive(Debug)]
pub struct Decoder<R>
where
R: Read + Seek,
{
reader: SmartReader<R>,
byte_order: ByteOrder,
limits: Limits,
next_ifd: Option<u32>,
ifd: Option<Directory>,
width: u32,
height: u32,
bits_per_sample: Vec<u8>,
samples: u8,
photometric_interpretation: PhotometricInterpretation,
compression_method: CompressionMethod,
strip_decoder: Option<StripDecodeState>,
}
trait Wrapping {
fn wrapping_add(&self, other: Self) -> Self;
}
impl Wrapping for u8 {
fn wrapping_add(&self, other: Self) -> Self {
u8::wrapping_add(*self, other)
}
}
impl Wrapping for u16 {
fn wrapping_add(&self, other: Self) -> Self {
u16::wrapping_add(*self, other)
}
}
fn rev_hpredict_nsamp<T>(image: &mut [T], size: (u32, u32), samples: usize)
where
T: Num + Copy + Wrapping,
{
let width = size.0 as usize;
let height = size.1 as usize;
for row in 0..height {
for col in samples..width * samples {
let prev_pixel = image[(row * width * samples + col - samples)];
let pixel = &mut image[(row * width * samples + col)];
*pixel = pixel.wrapping_add(prev_pixel);
}
}
}
fn rev_hpredict(image: DecodingBuffer, size: (u32, u32), color_type: ColorType) -> TiffResult<()> {
let samples = match color_type {
ColorType::Gray(8) | ColorType::Gray(16) => 1,
ColorType::RGB(8) | ColorType::RGB(16) => 3,
ColorType::RGBA(8) | ColorType::RGBA(16) | ColorType::CMYK(8) => 4,
_ => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::HorizontalPredictor(color_type),
))
}
};
match image {
DecodingBuffer::U8(buf) => {
rev_hpredict_nsamp(buf, size, samples);
}
DecodingBuffer::U16(buf) => {
rev_hpredict_nsamp(buf, size, samples);
}
}
Ok(())
}
impl<R: Read + Seek> Decoder<R> {
pub fn new(r: R) -> TiffResult<Decoder<R>> {
Decoder {
reader: SmartReader::wrap(r, ByteOrder::LittleEndian),
byte_order: ByteOrder::LittleEndian,
limits: Default::default(),
next_ifd: None,
ifd: None,
width: 0,
height: 0,
bits_per_sample: vec![1],
samples: 1,
photometric_interpretation: PhotometricInterpretation::BlackIsZero,
compression_method: CompressionMethod::None,
strip_decoder: None,
}
.init()
}
pub fn with_limits(mut self, limits: Limits) -> Decoder<R> {
self.limits = limits;
self
}
pub fn dimensions(&mut self) -> TiffResult<(u32, u32)> {
Ok((self.width, self.height))
}
pub fn colortype(&mut self) -> TiffResult<ColorType> {
match self.photometric_interpretation {
PhotometricInterpretation::RGB if self.bits_per_sample == [8, 8, 8, 8] => {
Ok(ColorType::RGBA(8))
}
PhotometricInterpretation::RGB if self.bits_per_sample == [8, 8, 8] => {
Ok(ColorType::RGB(8))
}
PhotometricInterpretation::RGB if self.bits_per_sample == [16, 16, 16, 16] => {
Ok(ColorType::RGBA(16))
}
PhotometricInterpretation::RGB if self.bits_per_sample == [16, 16, 16] => {
Ok(ColorType::RGB(16))
}
PhotometricInterpretation::CMYK if self.bits_per_sample == [8, 8, 8, 8] => {
Ok(ColorType::CMYK(8))
}
PhotometricInterpretation::BlackIsZero | PhotometricInterpretation::WhiteIsZero
if self.bits_per_sample.len() == 1 =>
{
Ok(ColorType::Gray(self.bits_per_sample[0]))
}
_ => Err(TiffError::UnsupportedError(
TiffUnsupportedError::InterpretationWithBits(
self.photometric_interpretation,
self.bits_per_sample.clone(),
),
)),
}
}
fn read_header(&mut self) -> TiffResult<()> {
let mut endianess = Vec::with_capacity(2);
try!(self.reader.by_ref().take(2).read_to_end(&mut endianess));
match &*endianess {
b"II" => {
self.byte_order = ByteOrder::LittleEndian;
self.reader.byte_order = ByteOrder::LittleEndian;
}
b"MM" => {
self.byte_order = ByteOrder::BigEndian;
self.reader.byte_order = ByteOrder::BigEndian;
}
_ => {
return Err(TiffError::FormatError(
TiffFormatError::TiffSignatureNotFound,
))
}
}
if try!(self.read_short()) != 42 {
return Err(TiffError::FormatError(
TiffFormatError::TiffSignatureInvalid,
));
}
self.next_ifd = match try!(self.read_long()) {
0 => None,
n => Some(n),
};
Ok(())
}
pub fn init(mut self) -> TiffResult<Decoder<R>> {
try!(self.read_header());
self.next_image()?;
Ok(self)
}
pub fn next_image(&mut self) -> TiffResult<()> {
self.ifd = Some(try!(self.read_ifd()));
self.width = try!(self.get_tag_u32(ifd::Tag::ImageWidth));
self.height = try!(self.get_tag_u32(ifd::Tag::ImageLength));
self.strip_decoder = None;
self.photometric_interpretation = match FromPrimitive::from_u32(try!(
self.get_tag_u32(ifd::Tag::PhotometricInterpretation)
)) {
Some(val) => val,
None => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::UnknownInterpretation,
))
}
};
if let Some(val) = try!(self.find_tag_u32(ifd::Tag::Compression)) {
match FromPrimitive::from_u32(val) {
Some(method) => self.compression_method = method,
None => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::UnknownCompressionMethod,
))
}
}
}
if let Some(val) = try!(self.find_tag_u32(ifd::Tag::SamplesPerPixel)) {
self.samples = val as u8
}
match self.samples {
1 => {
if let Some(val) = try!(self.find_tag_u32(ifd::Tag::BitsPerSample)) {
self.bits_per_sample = vec![val as u8]
}
}
3 | 4 => {
if let Some(val) = try!(self.find_tag_u32_vec(ifd::Tag::BitsPerSample)) {
self.bits_per_sample = val.iter().map(|&v| v as u8).collect()
}
}
_ => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::UnsupportedSampleDepth(self.samples),
))
}
}
Ok(())
}
pub fn more_images(&self) -> bool {
self.next_ifd.is_some()
}
pub fn byte_order(&self) -> ByteOrder {
self.byte_order
}
#[inline]
pub fn read_short(&mut self) -> Result<u16, io::Error> {
self.reader.read_u16()
}
#[inline]
pub fn read_long(&mut self) -> Result<u32, io::Error> {
self.reader.read_u32()
}
#[inline]
pub fn read_string(&mut self, length: usize) -> TiffResult<String> {
let mut out = String::with_capacity(length);
self.reader.read_to_string(&mut out)?;
let trimmed = out.bytes().take_while(|&n| n != 0).collect::<Vec<u8>>();
Ok(String::from_utf8(trimmed)?)
}
#[inline]
pub fn read_offset(&mut self) -> Result<[u8; 4], io::Error> {
let mut val = [0; 4];
try!(self.reader.read_exact(&mut val));
Ok(val)
}
#[inline]
pub fn goto_offset(&mut self, offset: u32) -> io::Result<()> {
self.reader
.seek(io::SeekFrom::Start(u64::from(offset)))
.map(|_| ())
}
fn read_entry(&mut self) -> TiffResult<Option<(ifd::Tag, ifd::Entry)>> {
let tag = ifd::Tag::from_u16(try!(self.read_short()));
let type_: ifd::Type = match FromPrimitive::from_u16(try!(self.read_short())) {
Some(t) => t,
None => {
try!(self.read_long());
try!(self.read_long());
return Ok(None);
}
};
Ok(Some((
tag,
ifd::Entry::new(
type_,
try!(self.read_long()),
try!(self.read_offset()),
),
)))
}
fn read_ifd(&mut self) -> TiffResult<Directory> {
let mut dir: Directory = HashMap::new();
match self.next_ifd {
None => {
return Err(TiffError::FormatError(
TiffFormatError::ImageFileDirectoryNotFound,
))
}
Some(offset) => try!(self.goto_offset(offset)),
}
for _ in 0..try!(self.read_short()) {
let (tag, entry) = match try!(self.read_entry()) {
Some(val) => val,
None => continue,
};
dir.insert(tag, entry);
}
self.next_ifd = match try!(self.read_long()) {
0 => None,
n => Some(n),
};
Ok(dir)
}
pub fn find_tag(&mut self, tag: ifd::Tag) -> TiffResult<Option<ifd::Value>> {
let entry = match self.ifd.as_ref().unwrap().get(&tag) {
None => return Ok(None),
Some(entry) => entry.clone(),
};
let limits = self.limits.clone();
Ok(Some(try!(entry.val(&limits, self))))
}
pub fn find_tag_u32(&mut self, tag: ifd::Tag) -> TiffResult<Option<u32>> {
match self.find_tag(tag)? {
Some(val) => val.into_u32().map(Some),
None => Ok(None),
}
}
pub fn find_tag_u32_vec(&mut self, tag: ifd::Tag) -> TiffResult<Option<Vec<u32>>> {
match self.find_tag(tag)? {
Some(val) => val.into_u32_vec().map(Some),
None => Ok(None),
}
}
pub fn get_tag(&mut self, tag: ifd::Tag) -> TiffResult<ifd::Value> {
match try!(self.find_tag(tag)) {
Some(val) => Ok(val),
None => Err(TiffError::FormatError(
TiffFormatError::RequiredTagNotFound(tag),
)),
}
}
pub fn get_tag_u32(&mut self, tag: ifd::Tag) -> TiffResult<u32> {
self.get_tag(tag)?.into_u32()
}
pub fn get_tag_u32_vec(&mut self, tag: ifd::Tag) -> TiffResult<Vec<u32>> {
self.get_tag(tag)?.into_u32_vec()
}
fn expand_strip<'a>(
&mut self,
buffer: DecodingBuffer<'a>,
offset: u32,
length: u32,
max_uncompressed_length: usize,
) -> TiffResult<usize> {
let color_type = try!(self.colortype());
try!(self.goto_offset(offset));
let (bytes, mut reader): (usize, Box<EndianReader>) = match self.compression_method {
CompressionMethod::None => {
let order = self.reader.byte_order;
(
length as usize,
Box::new(SmartReader::wrap(&mut self.reader, order)),
)
}
CompressionMethod::LZW => {
let (bytes, reader) = try!(LZWReader::new(
&mut self.reader,
length as usize,
max_uncompressed_length
));
(bytes, Box::new(reader))
}
CompressionMethod::PackBits => {
let order = self.reader.byte_order;
let (bytes, reader) = try!(PackBitsReader::new(
&mut self.reader,
order,
length as usize
));
(bytes, Box::new(reader))
}
method => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::UnsupportedCompressionMethod(method),
))
}
};
if bytes / buffer.byte_len() > max_uncompressed_length {
return Err(TiffError::FormatError(
TiffFormatError::InconsistentSizesEncountered,
));
}
Ok(match (color_type, buffer) {
(ColorType::RGB(8), DecodingBuffer::U8(ref mut buffer))
| (ColorType::RGBA(8), DecodingBuffer::U8(ref mut buffer))
| (ColorType::CMYK(8), DecodingBuffer::U8(ref mut buffer)) => {
try!(reader.read_exact(&mut buffer[..bytes]));
bytes
}
(ColorType::RGBA(16), DecodingBuffer::U16(ref mut buffer))
| (ColorType::RGB(16), DecodingBuffer::U16(ref mut buffer)) => {
try!(reader.read_u16_into(&mut buffer[..bytes / 2]));
bytes / 2
}
(ColorType::Gray(16), DecodingBuffer::U16(ref mut buffer)) => {
try!(reader.read_u16_into(&mut buffer[..bytes / 2]));
if self.photometric_interpretation == PhotometricInterpretation::WhiteIsZero {
for datum in buffer[..bytes / 2].iter_mut() {
*datum = 0xffff - *datum
}
}
bytes / 2
}
(ColorType::Gray(n), DecodingBuffer::U8(ref mut buffer)) if n <= 8 => {
try!(reader.read_exact(&mut buffer[..bytes]));
if self.photometric_interpretation == PhotometricInterpretation::WhiteIsZero {
for byte in buffer[..bytes].iter_mut() {
*byte = 0xff - *byte
}
}
bytes
}
(type_, _) => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::UnsupportedColorType(type_),
))
}
})
}
pub fn strip_count(&mut self) -> TiffResult<u32> {
let rows_per_strip = self
.get_tag_u32(ifd::Tag::RowsPerStrip)
.unwrap_or(self.height);
if rows_per_strip == 0 {
return Ok(0);
}
Ok((self.height + rows_per_strip - 1) / rows_per_strip)
}
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)?;
self.strip_decoder = Some(StripDecodeState {
strip_index: 0,
strip_offsets,
strip_bytes,
});
}
Ok(())
}
pub fn read_strip_to_buffer(&mut self, mut buffer: DecodingBuffer) -> TiffResult<()> {
self.initialize_strip_decoder()?;
let index = self.strip_decoder.as_ref().unwrap().strip_index;
let offset = *self
.strip_decoder
.as_ref()
.unwrap()
.strip_offsets
.get(index)
.ok_or(TiffError::FormatError(
TiffFormatError::InconsistentSizesEncountered,
))?;
let byte_count = *self
.strip_decoder
.as_ref()
.unwrap()
.strip_bytes
.get(index)
.ok_or(TiffError::FormatError(
TiffFormatError::InconsistentSizesEncountered,
))?;
let rows_per_strip = self
.get_tag_u32(ifd::Tag::RowsPerStrip)
.unwrap_or(self.height) as usize;
let strip_height = cmp::min(
rows_per_strip,
self.height as usize - index * rows_per_strip,
);
let buffer_size = self.width as usize * strip_height * self.bits_per_sample.len();
if buffer.len() < buffer_size || byte_count as usize / buffer.byte_len() > buffer_size {
return Err(TiffError::FormatError(
TiffFormatError::InconsistentSizesEncountered,
));
}
let units_read = self.expand_strip(buffer.copy(), offset, byte_count, buffer_size)?;
self.strip_decoder.as_mut().unwrap().strip_index += 1;
if index as u32 == self.strip_count()? {
self.strip_decoder = None;
}
if units_read < buffer_size {
return Err(TiffError::FormatError(
TiffFormatError::InconsistentSizesEncountered,
));
}
if let Ok(predictor) = self.get_tag_u32(ifd::Tag::Predictor) {
match FromPrimitive::from_u32(predictor) {
Some(Predictor::None) => (),
Some(Predictor::Horizontal) => {
rev_hpredict(
buffer.copy(),
(self.width, strip_height as u32),
self.colortype()?,
)?;
}
None => {
return Err(TiffError::FormatError(TiffFormatError::UnknownPredictor(
predictor,
)))
}
}
}
Ok(())
}
pub fn read_strip(&mut self) -> TiffResult<DecodingResult> {
self.initialize_strip_decoder()?;
let index = self.strip_decoder.as_ref().unwrap().strip_index;
let rows_per_strip = self
.get_tag_u32(ifd::Tag::RowsPerStrip)
.unwrap_or(self.height) as usize;
let strip_height = cmp::min(
rows_per_strip,
self.height as usize - index * rows_per_strip,
);
let buffer_size = self.width as usize * strip_height * self.bits_per_sample.iter().count();
let mut result = match self.bits_per_sample.iter().cloned().max().unwrap_or(8) {
n if n <= 8 => DecodingResult::new_u8(buffer_size, &self.limits)?,
n if n <= 16 => DecodingResult::new_u16(buffer_size, &self.limits)?,
n => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::UnsupportedBitsPerChannel(n),
))
}
};
self.read_strip_to_buffer(result.as_buffer(0))?;
Ok(result)
}
pub fn read_image(&mut self) -> TiffResult<DecodingResult> {
self.initialize_strip_decoder()?;
let rows_per_strip = self
.get_tag_u32(ifd::Tag::RowsPerStrip)
.unwrap_or(self.height) as usize;
let samples_per_strip =
self.width as usize * rows_per_strip * self.bits_per_sample.iter().count();
let buffer_size =
self.width as usize * self.height as usize * self.bits_per_sample.iter().count();
let mut result = match self.bits_per_sample.iter().cloned().max().unwrap_or(8) {
n if n <= 8 => DecodingResult::new_u8(buffer_size, &self.limits)?,
n if n <= 16 => DecodingResult::new_u16(buffer_size, &self.limits)?,
n => {
return Err(TiffError::UnsupportedError(
TiffUnsupportedError::UnsupportedBitsPerChannel(n),
))
}
};
for i in 0..self.strip_count()? as usize {
self.read_strip_to_buffer(result.as_buffer(samples_per_strip * i))?;
}
Ok(result)
}
}