Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

1 files changed, 1033 insertions, 0 deletions

diff --git a/vendor/image/src/codecs/hdr/decoder.rs b/vendor/image/src/codecs/hdr/decoder.rs
new file mode 100644
index 0000000..8329d57
--- /dev/null
+++ b/vendor/image/src/codecs/hdr/decoder.rs
@@ -0,0 +1,1033 @@
+use crate::Primitive;
+use num_traits::identities::Zero;
+#[cfg(test)]
+use std::borrow::Cow;
+use std::convert::TryFrom;
+use std::io::{self, BufRead, Cursor, Read, Seek};
+use std::iter::Iterator;
+use std::marker::PhantomData;
+use std::num::{ParseFloatError, ParseIntError};
+use std::path::Path;
+use std::{error, fmt, mem};
+
+use crate::color::{ColorType, Rgb};
+use crate::error::{
+    DecodingError, ImageError, ImageFormatHint, ImageResult, ParameterError, ParameterErrorKind,
+    UnsupportedError, UnsupportedErrorKind,
+};
+use crate::image::{self, ImageDecoder, ImageDecoderRect, ImageFormat, Progress};
+
+/// Errors that can occur during decoding and parsing of a HDR image
+#[derive(Debug, Clone, PartialEq, Eq)]
+enum DecoderError {
+    /// HDR's "#?RADIANCE" signature wrong or missing
+    RadianceHdrSignatureInvalid,
+    /// EOF before end of header
+    TruncatedHeader,
+    /// EOF instead of image dimensions
+    TruncatedDimensions,
+
+    /// A value couldn't be parsed
+    UnparsableF32(LineType, ParseFloatError),
+    /// A value couldn't be parsed
+    UnparsableU32(LineType, ParseIntError),
+    /// Not enough numbers in line
+    LineTooShort(LineType),
+
+    /// COLORCORR contains too many numbers in strict mode
+    ExtraneousColorcorrNumbers,
+
+    /// Dimensions line had too few elements
+    DimensionsLineTooShort(usize, usize),
+    /// Dimensions line had too many elements
+    DimensionsLineTooLong(usize),
+
+    /// The length of a scanline (1) wasn't a match for the specified length (2)
+    WrongScanlineLength(usize, usize),
+    /// First pixel of a scanline is a run length marker
+    FirstPixelRlMarker,
+}
+
+impl fmt::Display for DecoderError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            DecoderError::RadianceHdrSignatureInvalid => {
+                f.write_str("Radiance HDR signature not found")
+            }
+            DecoderError::TruncatedHeader => f.write_str("EOF in header"),
+            DecoderError::TruncatedDimensions => f.write_str("EOF in dimensions line"),
+            DecoderError::UnparsableF32(line, pe) => {
+                f.write_fmt(format_args!("Cannot parse {} value as f32: {}", line, pe))
+            }
+            DecoderError::UnparsableU32(line, pe) => {
+                f.write_fmt(format_args!("Cannot parse {} value as u32: {}", line, pe))
+            }
+            DecoderError::LineTooShort(line) => {
+                f.write_fmt(format_args!("Not enough numbers in {}", line))
+            }
+            DecoderError::ExtraneousColorcorrNumbers => f.write_str("Extra numbers in COLORCORR"),
+            DecoderError::DimensionsLineTooShort(elements, expected) => f.write_fmt(format_args!(
+                "Dimensions line too short: have {} elements, expected {}",
+                elements, expected
+            )),
+            DecoderError::DimensionsLineTooLong(expected) => f.write_fmt(format_args!(
+                "Dimensions line too long, expected {} elements",
+                expected
+            )),
+            DecoderError::WrongScanlineLength(len, expected) => f.write_fmt(format_args!(
+                "Wrong length of decoded scanline: got {}, expected {}",
+                len, expected
+            )),
+            DecoderError::FirstPixelRlMarker => {
+                f.write_str("First pixel of a scanline shouldn't be run length marker")
+            }
+        }
+    }
+}
+
+impl From<DecoderError> for ImageError {
+    fn from(e: DecoderError) -> ImageError {
+        ImageError::Decoding(DecodingError::new(ImageFormat::Hdr.into(), e))
+    }
+}
+
+impl error::Error for DecoderError {
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        match self {
+            DecoderError::UnparsableF32(_, err) => Some(err),
+            DecoderError::UnparsableU32(_, err) => Some(err),
+            _ => None,
+        }
+    }
+}
+
+/// Lines which contain parsable data that can fail
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
+enum LineType {
+    Exposure,
+    Pixaspect,
+    Colorcorr,
+    DimensionsHeight,
+    DimensionsWidth,
+}
+
+impl fmt::Display for LineType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(match self {
+            LineType::Exposure => "EXPOSURE",
+            LineType::Pixaspect => "PIXASPECT",
+            LineType::Colorcorr => "COLORCORR",
+            LineType::DimensionsHeight => "height dimension",
+            LineType::DimensionsWidth => "width dimension",
+        })
+    }
+}
+
+/// Adapter to conform to `ImageDecoder` trait
+#[derive(Debug)]
+pub struct HdrAdapter<R: Read> {
+    inner: Option<HdrDecoder<R>>,
+    // data: Option<Vec<u8>>,
+    meta: HdrMetadata,
+}
+
+impl<R: BufRead> HdrAdapter<R> {
+    /// Creates adapter
+    pub fn new(r: R) -> ImageResult<HdrAdapter<R>> {
+        let decoder = HdrDecoder::new(r)?;
+        let meta = decoder.metadata();
+        Ok(HdrAdapter {
+            inner: Some(decoder),
+            meta,
+        })
+    }
+
+    /// Allows reading old Radiance HDR images
+    pub fn new_nonstrict(r: R) -> ImageResult<HdrAdapter<R>> {
+        let decoder = HdrDecoder::with_strictness(r, false)?;
+        let meta = decoder.metadata();
+        Ok(HdrAdapter {
+            inner: Some(decoder),
+            meta,
+        })
+    }
+
+    /// Read the actual data of the image, and store it in Self::data.
+    fn read_image_data(&mut self, buf: &mut [u8]) -> ImageResult<()> {
+        assert_eq!(u64::try_from(buf.len()), Ok(self.total_bytes()));
+        match self.inner.take() {
+            Some(decoder) => {
+                let img: Vec<Rgb<u8>> = decoder.read_image_ldr()?;
+                for (i, Rgb(data)) in img.into_iter().enumerate() {
+                    buf[(i * 3)..][..3].copy_from_slice(&data);
+                }
+
+                Ok(())
+            }
+            None => Err(ImageError::Parameter(ParameterError::from_kind(
+                ParameterErrorKind::NoMoreData,
+            ))),
+        }
+    }
+}
+
+/// Wrapper struct around a `Cursor<Vec<u8>>`
+pub struct HdrReader<R>(Cursor<Vec<u8>>, PhantomData<R>);
+impl<R> Read for HdrReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        self.0.read(buf)
+    }
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        if self.0.position() == 0 && buf.is_empty() {
+            mem::swap(buf, self.0.get_mut());
+            Ok(buf.len())
+        } else {
+            self.0.read_to_end(buf)
+        }
+    }
+}
+
+impl<'a, R: 'a + BufRead> ImageDecoder<'a> for HdrAdapter<R> {
+    type Reader = HdrReader<R>;
+
+    fn dimensions(&self) -> (u32, u32) {
+        (self.meta.width, self.meta.height)
+    }
+
+    fn color_type(&self) -> ColorType {
+        ColorType::Rgb8
+    }
+
+    fn into_reader(self) -> ImageResult<Self::Reader> {
+        Ok(HdrReader(
+            Cursor::new(image::decoder_to_vec(self)?),
+            PhantomData,
+        ))
+    }
+
+    fn read_image(mut self, buf: &mut [u8]) -> ImageResult<()> {
+        self.read_image_data(buf)
+    }
+}
+
+impl<'a, R: 'a + BufRead + Seek> ImageDecoderRect<'a> for HdrAdapter<R> {
+    fn read_rect_with_progress<F: Fn(Progress)>(
+        &mut self,
+        x: u32,
+        y: u32,
+        width: u32,
+        height: u32,
+        buf: &mut [u8],
+        progress_callback: F,
+    ) -> ImageResult<()> {
+        image::load_rect(
+            x,
+            y,
+            width,
+            height,
+            buf,
+            progress_callback,
+            self,
+            |_, _| unreachable!(),
+            |s, buf| s.read_image_data(buf),
+        )
+    }
+}
+
+/// Radiance HDR file signature
+pub const SIGNATURE: &[u8] = b"#?RADIANCE";
+const SIGNATURE_LENGTH: usize = 10;
+
+/// An Radiance HDR decoder
+#[derive(Debug)]
+pub struct HdrDecoder<R> {
+    r: R,
+    width: u32,
+    height: u32,
+    meta: HdrMetadata,
+}
+
+/// Refer to [wikipedia](https://en.wikipedia.org/wiki/RGBE_image_format)
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub struct Rgbe8Pixel {
+    /// Color components
+    pub c: [u8; 3],
+    /// Exponent
+    pub e: u8,
+}
+
+/// Creates `Rgbe8Pixel` from components
+pub fn rgbe8(r: u8, g: u8, b: u8, e: u8) -> Rgbe8Pixel {
+    Rgbe8Pixel { c: [r, g, b], e }
+}
+
+impl Rgbe8Pixel {
+    /// Converts `Rgbe8Pixel` into `Rgb<f32>` linearly
+    #[inline]
+    pub fn to_hdr(self) -> Rgb<f32> {
+        if self.e == 0 {
+            Rgb([0.0, 0.0, 0.0])
+        } else {
+            //            let exp = f32::ldexp(1., self.e as isize - (128 + 8)); // unstable
+            let exp = f32::exp2(<f32 as From<_>>::from(self.e) - (128.0 + 8.0));
+            Rgb([
+                exp * <f32 as From<_>>::from(self.c[0]),
+                exp * <f32 as From<_>>::from(self.c[1]),
+                exp * <f32 as From<_>>::from(self.c[2]),
+            ])
+        }
+    }
+
+    /// Converts `Rgbe8Pixel` into `Rgb<T>` with scale=1 and gamma=2.2
+    ///
+    /// color_ldr = (color_hdr*scale)<sup>gamma</sup>
+    ///
+    /// # Panic
+    ///
+    /// Panics when `T::max_value()` cannot be represented as f32.
+    #[inline]
+    pub fn to_ldr<T: Primitive + Zero>(self) -> Rgb<T> {
+        self.to_ldr_scale_gamma(1.0, 2.2)
+    }
+
+    /// Converts `Rgbe8Pixel` into `Rgb<T>` using provided scale and gamma
+    ///
+    /// color_ldr = (color_hdr*scale)<sup>gamma</sup>
+    ///
+    /// # Panic
+    ///
+    /// Panics when `T::max_value()` cannot be represented as f32.
+    /// Panics when scale or gamma is NaN
+    #[inline]
+    pub fn to_ldr_scale_gamma<T: Primitive + Zero>(self, scale: f32, gamma: f32) -> Rgb<T> {
+        let Rgb(data) = self.to_hdr();
+        let (r, g, b) = (data[0], data[1], data[2]);
+        #[inline]
+        fn sg<T: Primitive + Zero>(v: f32, scale: f32, gamma: f32) -> T {
+            let t_max = T::max_value();
+            // Disassembly shows that t_max_f32 is compiled into constant
+            let t_max_f32: f32 = num_traits::NumCast::from(t_max)
+                .expect("to_ldr_scale_gamma: maximum value of type is not representable as f32");
+            let fv = f32::powf(v * scale, gamma) * t_max_f32 + 0.5;
+            if fv < 0.0 {
+                T::zero()
+            } else if fv > t_max_f32 {
+                t_max
+            } else {
+                num_traits::NumCast::from(fv)
+                    .expect("to_ldr_scale_gamma: cannot convert f32 to target type. NaN?")
+            }
+        }
+        Rgb([
+            sg(r, scale, gamma),
+            sg(g, scale, gamma),
+            sg(b, scale, gamma),
+        ])
+    }
+}
+
+impl<R: BufRead> HdrDecoder<R> {
+    /// Reads Radiance HDR image header from stream `r`
+    /// if the header is valid, creates HdrDecoder
+    /// strict mode is enabled
+    pub fn new(reader: R) -> ImageResult<HdrDecoder<R>> {
+        HdrDecoder::with_strictness(reader, true)
+    }
+
+    /// Reads Radiance HDR image header from stream `reader`,
+    /// if the header is valid, creates `HdrDecoder`.
+    ///
+    /// strict enables strict mode
+    ///
+    /// Warning! Reading wrong file in non-strict mode
+    ///   could consume file size worth of memory in the process.
+    pub fn with_strictness(mut reader: R, strict: bool) -> ImageResult<HdrDecoder<R>> {
+        let mut attributes = HdrMetadata::new();
+
+        {
+            // scope to make borrowck happy
+            let r = &mut reader;
+            if strict {
+                let mut signature = [0; SIGNATURE_LENGTH];
+                r.read_exact(&mut signature)?;
+                if signature != SIGNATURE {
+                    return Err(DecoderError::RadianceHdrSignatureInvalid.into());
+                } // no else
+                  // skip signature line ending
+                read_line_u8(r)?;
+            } else {
+                // Old Radiance HDR files (*.pic) don't use signature
+                // Let them be parsed in non-strict mode
+            }
+            // read header data until empty line
+            loop {
+                match read_line_u8(r)? {
+                    None => {
+                        // EOF before end of header
+                        return Err(DecoderError::TruncatedHeader.into());
+                    }
+                    Some(line) => {
+                        if line.is_empty() {
+                            // end of header
+                            break;
+                        } else if line[0] == b'#' {
+                            // line[0] will not panic, line.len() == 0 is false here
+                            // skip comments
+                            continue;
+                        } // no else
+                          // process attribute line
+                        let line = String::from_utf8_lossy(&line[..]);
+                        attributes.update_header_info(&line, strict)?;
+                    } // <= Some(line)
+                } // match read_line_u8()
+            } // loop
+        } // scope to end borrow of reader
+          // parse dimensions
+        let (width, height) = match read_line_u8(&mut reader)? {
+            None => {
+                // EOF instead of image dimensions
+                return Err(DecoderError::TruncatedDimensions.into());
+            }
+            Some(dimensions) => {
+                let dimensions = String::from_utf8_lossy(&dimensions[..]);
+                parse_dimensions_line(&dimensions, strict)?
+            }
+        };
+
+        // color type is always rgb8
+        if crate::utils::check_dimension_overflow(width, height, ColorType::Rgb8.bytes_per_pixel())
+        {
+            return Err(ImageError::Unsupported(
+                UnsupportedError::from_format_and_kind(
+                    ImageFormat::Hdr.into(),
+                    UnsupportedErrorKind::GenericFeature(format!(
+                        "Image dimensions ({}x{}) are too large",
+                        width, height
+                    )),
+                ),
+            ));
+        }
+
+        Ok(HdrDecoder {
+            r: reader,
+
+            width,
+            height,
+            meta: HdrMetadata {
+                width,
+                height,
+                ..attributes
+            },
+        })
+    } // end with_strictness
+
+    /// Returns file metadata. Refer to `HdrMetadata` for details.
+    pub fn metadata(&self) -> HdrMetadata {
+        self.meta.clone()
+    }
+
+    /// Consumes decoder and returns a vector of RGBE8 pixels
+    pub fn read_image_native(mut self) -> ImageResult<Vec<Rgbe8Pixel>> {
+        // Don't read anything if image is empty
+        if self.width == 0 || self.height == 0 {
+            return Ok(vec![]);
+        }
+        // expression self.width > 0 && self.height > 0 is true from now to the end of this method
+        let pixel_count = self.width as usize * self.height as usize;
+        let mut ret = vec![Default::default(); pixel_count];
+        for chunk in ret.chunks_mut(self.width as usize) {
+            read_scanline(&mut self.r, chunk)?;
+        }
+        Ok(ret)
+    }
+
+    /// Consumes decoder and returns a vector of transformed pixels
+    pub fn read_image_transform<T: Send, F: Send + Sync + Fn(Rgbe8Pixel) -> T>(
+        mut self,
+        f: F,
+        output_slice: &mut [T],
+    ) -> ImageResult<()> {
+        assert_eq!(
+            output_slice.len(),
+            self.width as usize * self.height as usize
+        );
+
+        // Don't read anything if image is empty
+        if self.width == 0 || self.height == 0 {
+            return Ok(());
+        }
+
+        let chunks_iter = output_slice.chunks_mut(self.width as usize);
+
+        let mut buf = vec![Default::default(); self.width as usize];
+        for chunk in chunks_iter {
+            // read_scanline overwrites the entire buffer or returns an Err,
+            // so not resetting the buffer here is ok.
+            read_scanline(&mut self.r, &mut buf[..])?;
+            for (dst, &pix) in chunk.iter_mut().zip(buf.iter()) {
+                *dst = f(pix);
+            }
+        }
+        Ok(())
+    }
+
+    /// Consumes decoder and returns a vector of `Rgb<u8>` pixels.
+    /// scale = 1, gamma = 2.2
+    pub fn read_image_ldr(self) -> ImageResult<Vec<Rgb<u8>>> {
+        let mut ret = vec![Rgb([0, 0, 0]); self.width as usize * self.height as usize];
+        self.read_image_transform(|pix| pix.to_ldr(), &mut ret[..])?;
+        Ok(ret)
+    }
+
+    /// Consumes decoder and returns a vector of `Rgb<f32>` pixels.
+    ///
+    pub fn read_image_hdr(self) -> ImageResult<Vec<Rgb<f32>>> {
+        let mut ret = vec![Rgb([0.0, 0.0, 0.0]); self.width as usize * self.height as usize];
+        self.read_image_transform(|pix| pix.to_hdr(), &mut ret[..])?;
+        Ok(ret)
+    }
+}
+
+impl<R: Read> IntoIterator for HdrDecoder<R> {
+    type Item = ImageResult<Rgbe8Pixel>;
+    type IntoIter = HdrImageDecoderIterator<R>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        HdrImageDecoderIterator {
+            r: self.r,
+            scanline_cnt: self.height as usize,
+            buf: vec![Default::default(); self.width as usize],
+            col: 0,
+            scanline: 0,
+            trouble: true, // make first call to `next()` read scanline
+            error_encountered: false,
+        }
+    }
+}
+
+/// Scanline buffered pixel by pixel iterator
+pub struct HdrImageDecoderIterator<R: Read> {
+    r: R,
+    scanline_cnt: usize,
+    buf: Vec<Rgbe8Pixel>, // scanline buffer
+    col: usize,           // current position in scanline
+    scanline: usize,      // current scanline
+    trouble: bool,        // optimization, true indicates that we need to check something
+    error_encountered: bool,
+}
+
+impl<R: Read> HdrImageDecoderIterator<R> {
+    // Advances counter to the next pixel
+    #[inline]
+    fn advance(&mut self) {
+        self.col += 1;
+        if self.col == self.buf.len() {
+            self.col = 0;
+            self.scanline += 1;
+            self.trouble = true;
+        }
+    }
+}
+
+impl<R: Read> Iterator for HdrImageDecoderIterator<R> {
+    type Item = ImageResult<Rgbe8Pixel>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if !self.trouble {
+            let ret = self.buf[self.col];
+            self.advance();
+            Some(Ok(ret))
+        } else {
+            // some condition is pending
+            if self.buf.is_empty() || self.scanline == self.scanline_cnt {
+                // No more pixels
+                return None;
+            } // no else
+            if self.error_encountered {
+                self.advance();
+                // Error was encountered. Keep producing errors.
+                // ImageError can't implement Clone, so just dump some error
+                return Some(Err(ImageError::Parameter(ParameterError::from_kind(
+                    ParameterErrorKind::FailedAlready,
+                ))));
+            } // no else
+            if self.col == 0 {
+                // fill scanline buffer
+                match read_scanline(&mut self.r, &mut self.buf[..]) {
+                    Ok(_) => {
+                        // no action required
+                    }
+                    Err(err) => {
+                        self.advance();
+                        self.error_encountered = true;
+                        self.trouble = true;
+                        return Some(Err(err));
+                    }
+                }
+            } // no else
+            self.trouble = false;
+            let ret = self.buf[0];
+            self.advance();
+            Some(Ok(ret))
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let total_cnt = self.buf.len() * self.scanline_cnt;
+        let cur_cnt = self.buf.len() * self.scanline + self.col;
+        let remaining = total_cnt - cur_cnt;
+        (remaining, Some(remaining))
+    }
+}
+
+impl<R: Read> ExactSizeIterator for HdrImageDecoderIterator<R> {}
+
+// Precondition: buf.len() > 0
+fn read_scanline<R: Read>(r: &mut R, buf: &mut [Rgbe8Pixel]) -> ImageResult<()> {
+    assert!(!buf.is_empty());
+    let width = buf.len();
+    // first 4 bytes in scanline allow to determine compression method
+    let fb = read_rgbe(r)?;
+    if fb.c[0] == 2 && fb.c[1] == 2 && fb.c[2] < 128 {
+        // denormalized pixel value (2,2,<128,_) indicates new per component RLE method
+        // decode_component guarantees that offset is within 0 .. width
+        // therefore we can skip bounds checking here, but we will not
+        decode_component(r, width, |offset, value| buf[offset].c[0] = value)?;
+        decode_component(r, width, |offset, value| buf[offset].c[1] = value)?;
+        decode_component(r, width, |offset, value| buf[offset].c[2] = value)?;
+        decode_component(r, width, |offset, value| buf[offset].e = value)?;
+    } else {
+        // old RLE method (it was considered old around 1991, should it be here?)
+        decode_old_rle(r, fb, buf)?;
+    }
+    Ok(())
+}
+
+#[inline(always)]
+fn read_byte<R: Read>(r: &mut R) -> io::Result<u8> {
+    let mut buf = [0u8];
+    r.read_exact(&mut buf[..])?;
+    Ok(buf[0])
+}
+
+// Guarantees that first parameter of set_component will be within pos .. pos+width
+#[inline]
+fn decode_component<R: Read, S: FnMut(usize, u8)>(
+    r: &mut R,
+    width: usize,
+    mut set_component: S,
+) -> ImageResult<()> {
+    let mut buf = [0; 128];
+    let mut pos = 0;
+    while pos < width {
+        // increment position by a number of decompressed values
+        pos += {
+            let rl = read_byte(r)?;
+            if rl <= 128 {
+                // sanity check
+                if pos + rl as usize > width {
+                    return Err(DecoderError::WrongScanlineLength(pos + rl as usize, width).into());
+                }
+                // read values
+                r.read_exact(&mut buf[0..rl as usize])?;
+                for (offset, &value) in buf[0..rl as usize].iter().enumerate() {
+                    set_component(pos + offset, value);
+                }
+                rl as usize
+            } else {
+                // run
+                let rl = rl - 128;
+                // sanity check
+                if pos + rl as usize > width {
+                    return Err(DecoderError::WrongScanlineLength(pos + rl as usize, width).into());
+                }
+                // fill with same value
+                let value = read_byte(r)?;
+                for offset in 0..rl as usize {
+                    set_component(pos + offset, value);
+                }
+                rl as usize
+            }
+        };
+    }
+    if pos != width {
+        return Err(DecoderError::WrongScanlineLength(pos, width).into());
+    }
+    Ok(())
+}
+
+// Decodes scanline, places it into buf
+// Precondition: buf.len() > 0
+// fb - first 4 bytes of scanline
+fn decode_old_rle<R: Read>(r: &mut R, fb: Rgbe8Pixel, buf: &mut [Rgbe8Pixel]) -> ImageResult<()> {
+    assert!(!buf.is_empty());
+    let width = buf.len();
+    // convenience function.
+    // returns run length if pixel is a run length marker
+    #[inline]
+    fn rl_marker(pix: Rgbe8Pixel) -> Option<usize> {
+        if pix.c == [1, 1, 1] {
+            Some(pix.e as usize)
+        } else {
+            None
+        }
+    }
+    // first pixel in scanline should not be run length marker
+    // it is error if it is
+    if rl_marker(fb).is_some() {
+        return Err(DecoderError::FirstPixelRlMarker.into());
+    }
+    buf[0] = fb; // set first pixel of scanline
+
+    let mut x_off = 1; // current offset from beginning of a scanline
+    let mut rl_mult = 1; // current run length multiplier
+    let mut prev_pixel = fb;
+    while x_off < width {
+        let pix = read_rgbe(r)?;
+        // it's harder to forget to increase x_off if I write this this way.
+        x_off += {
+            if let Some(rl) = rl_marker(pix) {
+                // rl_mult takes care of consecutive RL markers
+                let rl = rl * rl_mult;
+                rl_mult *= 256;
+                if x_off + rl <= width {
+                    // do run
+                    for b in &mut buf[x_off..x_off + rl] {
+                        *b = prev_pixel;
+                    }
+                } else {
+                    return Err(DecoderError::WrongScanlineLength(x_off + rl, width).into());
+                };
+                rl // value to increase x_off by
+            } else {
+                rl_mult = 1; // chain of consecutive RL markers is broken
+                prev_pixel = pix;
+                buf[x_off] = pix;
+                1 // value to increase x_off by
+            }
+        };
+    }
+    if x_off != width {
+        return Err(DecoderError::WrongScanlineLength(x_off, width).into());
+    }
+    Ok(())
+}
+
+fn read_rgbe<R: Read>(r: &mut R) -> io::Result<Rgbe8Pixel> {
+    let mut buf = [0u8; 4];
+    r.read_exact(&mut buf[..])?;
+    Ok(Rgbe8Pixel {
+        c: [buf[0], buf[1], buf[2]],
+        e: buf[3],
+    })
+}
+
+/// Metadata for Radiance HDR image
+#[derive(Debug, Clone)]
+pub struct HdrMetadata {
+    /// Width of decoded image. It could be either scanline length,
+    /// or scanline count, depending on image orientation.
+    pub width: u32,
+    /// Height of decoded image. It depends on orientation too.
+    pub height: u32,
+    /// Orientation matrix. For standard orientation it is ((1,0),(0,1)) - left to right, top to bottom.
+    /// First pair tells how resulting pixel coordinates change along a scanline.
+    /// Second pair tells how they change from one scanline to the next.
+    pub orientation: ((i8, i8), (i8, i8)),
+    /// Divide color values by exposure to get to get physical radiance in
+    /// watts/steradian/m<sup>2</sup>
+    ///
+    /// Image may not contain physical data, even if this field is set.
+    pub exposure: Option<f32>,
+    /// Divide color values by corresponding tuple member (r, g, b) to get to get physical radiance
+    /// in watts/steradian/m<sup>2</sup>
+    ///
+    /// Image may not contain physical data, even if this field is set.
+    pub color_correction: Option<(f32, f32, f32)>,
+    /// Pixel height divided by pixel width
+    pub pixel_aspect_ratio: Option<f32>,
+    /// All lines contained in image header are put here. Ordering of lines is preserved.
+    /// Lines in the form "key=value" are represented as ("key", "value").
+    /// All other lines are ("", "line")
+    pub custom_attributes: Vec<(String, String)>,
+}
+
+impl HdrMetadata {
+    fn new() -> HdrMetadata {
+        HdrMetadata {
+            width: 0,
+            height: 0,
+            orientation: ((1, 0), (0, 1)),
+            exposure: None,
+            color_correction: None,
+            pixel_aspect_ratio: None,
+            custom_attributes: vec![],
+        }
+    }
+
+    // Updates header info, in strict mode returns error for malformed lines (no '=' separator)
+    // unknown attributes are skipped
+    fn update_header_info(&mut self, line: &str, strict: bool) -> ImageResult<()> {
+        // split line at first '='
+        // old Radiance HDR files (*.pic) feature tabs in key, so                vvv trim
+        let maybe_key_value = split_at_first(line, "=").map(|(key, value)| (key.trim(), value));
+        // save all header lines in custom_attributes
+        match maybe_key_value {
+            Some((key, val)) => self
+                .custom_attributes
+                .push((key.to_owned(), val.to_owned())),
+            None => self.custom_attributes.push(("".into(), line.to_owned())),
+        }
+        // parse known attributes
+        match maybe_key_value {
+            Some(("FORMAT", val)) => {
+                if val.trim() != "32-bit_rle_rgbe" {
+                    // XYZE isn't supported yet
+                    return Err(ImageError::Unsupported(
+                        UnsupportedError::from_format_and_kind(
+                            ImageFormat::Hdr.into(),
+                            UnsupportedErrorKind::Format(ImageFormatHint::Name(limit_string_len(
+                                val, 20,
+                            ))),
+                        ),
+                    ));
+                }
+            }
+            Some(("EXPOSURE", val)) => {
+                match val.trim().parse::<f32>() {
+                    Ok(v) => {
+                        self.exposure = Some(self.exposure.unwrap_or(1.0) * v); // all encountered exposure values should be multiplied
+                    }
+                    Err(parse_error) => {
+                        if strict {
+                            return Err(DecoderError::UnparsableF32(
+                                LineType::Exposure,
+                                parse_error,
+                            )
+                            .into());
+                        } // no else, skip this line in non-strict mode
+                    }
+                };
+            }
+            Some(("PIXASPECT", val)) => {
+                match val.trim().parse::<f32>() {
+                    Ok(v) => {
+                        self.pixel_aspect_ratio = Some(self.pixel_aspect_ratio.unwrap_or(1.0) * v);
+                        // all encountered exposure values should be multiplied
+                    }
+                    Err(parse_error) => {
+                        if strict {
+                            return Err(DecoderError::UnparsableF32(
+                                LineType::Pixaspect,
+                                parse_error,
+                            )
+                            .into());
+                        } // no else, skip this line in non-strict mode
+                    }
+                };
+            }
+            Some(("COLORCORR", val)) => {
+                let mut rgbcorr = [1.0, 1.0, 1.0];
+                match parse_space_separated_f32(val, &mut rgbcorr, LineType::Colorcorr) {
+                    Ok(extra_numbers) => {
+                        if strict && extra_numbers {
+                            return Err(DecoderError::ExtraneousColorcorrNumbers.into());
+                        } // no else, just ignore extra numbers
+                        let (rc, gc, bc) = self.color_correction.unwrap_or((1.0, 1.0, 1.0));
+                        self.color_correction =
+                            Some((rc * rgbcorr[0], gc * rgbcorr[1], bc * rgbcorr[2]));
+                    }
+                    Err(err) => {
+                        if strict {
+                            return Err(err);
+                        } // no else, skip malformed line in non-strict mode
+                    }
+                }
+            }
+            None => {
+                // old Radiance HDR files (*.pic) contain commands in a header
+                // just skip them
+            }
+            _ => {
+                // skip unknown attribute
+            }
+        } // match attributes
+        Ok(())
+    }
+}
+
+fn parse_space_separated_f32(line: &str, vals: &mut [f32], line_tp: LineType) -> ImageResult<bool> {
+    let mut nums = line.split_whitespace();
+    for val in vals.iter_mut() {
+        if let Some(num) = nums.next() {
+            match num.parse::<f32>() {
+                Ok(v) => *val = v,
+                Err(err) => return Err(DecoderError::UnparsableF32(line_tp, err).into()),
+            }
+        } else {
+            // not enough numbers in line
+            return Err(DecoderError::LineTooShort(line_tp).into());
+        }
+    }
+    Ok(nums.next().is_some())
+}
+
+// Parses dimension line "-Y height +X width"
+// returns (width, height) or error
+fn parse_dimensions_line(line: &str, strict: bool) -> ImageResult<(u32, u32)> {
+    const DIMENSIONS_COUNT: usize = 4;
+
+    let mut dim_parts = line.split_whitespace();
+    let c1_tag = dim_parts
+        .next()
+        .ok_or(DecoderError::DimensionsLineTooShort(0, DIMENSIONS_COUNT))?;
+    let c1_str = dim_parts
+        .next()
+        .ok_or(DecoderError::DimensionsLineTooShort(1, DIMENSIONS_COUNT))?;
+    let c2_tag = dim_parts
+        .next()
+        .ok_or(DecoderError::DimensionsLineTooShort(2, DIMENSIONS_COUNT))?;
+    let c2_str = dim_parts
+        .next()
+        .ok_or(DecoderError::DimensionsLineTooShort(3, DIMENSIONS_COUNT))?;
+    if strict && dim_parts.next().is_some() {
+        // extra data in dimensions line
+        return Err(DecoderError::DimensionsLineTooLong(DIMENSIONS_COUNT).into());
+    } // no else
+      // dimensions line is in the form "-Y 10 +X 20"
+      // There are 8 possible orientations: +Y +X, +X -Y and so on
+    match (c1_tag, c2_tag) {
+        ("-Y", "+X") => {
+            // Common orientation (left-right, top-down)
+            // c1_str is height, c2_str is width
+            let height = c1_str
+                .parse::<u32>()
+                .map_err(|pe| DecoderError::UnparsableU32(LineType::DimensionsHeight, pe))?;
+            let width = c2_str
+                .parse::<u32>()
+                .map_err(|pe| DecoderError::UnparsableU32(LineType::DimensionsWidth, pe))?;
+            Ok((width, height))
+        }
+        _ => Err(ImageError::Unsupported(
+            UnsupportedError::from_format_and_kind(
+                ImageFormat::Hdr.into(),
+                UnsupportedErrorKind::GenericFeature(format!(
+                    "Orientation {} {}",
+                    limit_string_len(c1_tag, 4),
+                    limit_string_len(c2_tag, 4)
+                )),
+            ),
+        )),
+    } // final expression. Returns value
+}
+
+// Returns string with no more than len+3 characters
+fn limit_string_len(s: &str, len: usize) -> String {
+    let s_char_len = s.chars().count();
+    if s_char_len > len {
+        s.chars().take(len).chain("...".chars()).collect()
+    } else {
+        s.into()
+    }
+}
+
+// Splits string into (before separator, after separator) tuple
+// or None if separator isn't found
+fn split_at_first<'a>(s: &'a str, separator: &str) -> Option<(&'a str, &'a str)> {
+    match s.find(separator) {
+        None | Some(0) => None,
+        Some(p) if p >= s.len() - separator.len() => None,
+        Some(p) => Some((&s[..p], &s[(p + separator.len())..])),
+    }
+}
+
+#[test]
+fn split_at_first_test() {
+    assert_eq!(split_at_first(&Cow::Owned("".into()), "="), None);
+    assert_eq!(split_at_first(&Cow::Owned("=".into()), "="), None);
+    assert_eq!(split_at_first(&Cow::Owned("= ".into()), "="), None);
+    assert_eq!(
+        split_at_first(&Cow::Owned(" = ".into()), "="),
+        Some((" ", " "))
+    );
+    assert_eq!(
+        split_at_first(&Cow::Owned("EXPOSURE= ".into()), "="),
+        Some(("EXPOSURE", " "))
+    );
+    assert_eq!(
+        split_at_first(&Cow::Owned("EXPOSURE= =".into()), "="),
+        Some(("EXPOSURE", " ="))
+    );
+    assert_eq!(
+        split_at_first(&Cow::Owned("EXPOSURE== =".into()), "=="),
+        Some(("EXPOSURE", " ="))
+    );
+    assert_eq!(split_at_first(&Cow::Owned("EXPOSURE".into()), ""), None);
+}
+
+// Reads input until b"\n" or EOF
+// Returns vector of read bytes NOT including end of line characters
+//   or return None to indicate end of file
+fn read_line_u8<R: BufRead>(r: &mut R) -> ::std::io::Result<Option<Vec<u8>>> {
+    let mut ret = Vec::with_capacity(16);
+    match r.read_until(b'\n', &mut ret) {
+        Ok(0) => Ok(None),
+        Ok(_) => {
+            if let Some(&b'\n') = ret[..].last() {
+                let _ = ret.pop();
+            }
+            Ok(Some(ret))
+        }
+        Err(err) => Err(err),
+    }
+}
+
+#[test]
+fn read_line_u8_test() {
+    let buf: Vec<_> = (&b"One\nTwo\nThree\nFour\n\n\n"[..]).into();
+    let input = &mut ::std::io::Cursor::new(buf);
+    assert_eq!(&read_line_u8(input).unwrap().unwrap()[..], &b"One"[..]);
+    assert_eq!(&read_line_u8(input).unwrap().unwrap()[..], &b"Two"[..]);
+    assert_eq!(&read_line_u8(input).unwrap().unwrap()[..], &b"Three"[..]);
+    assert_eq!(&read_line_u8(input).unwrap().unwrap()[..], &b"Four"[..]);
+    assert_eq!(&read_line_u8(input).unwrap().unwrap()[..], &b""[..]);
+    assert_eq!(&read_line_u8(input).unwrap().unwrap()[..], &b""[..]);
+    assert_eq!(read_line_u8(input).unwrap(), None);
+}
+
+/// Helper function for reading raw 3-channel f32 images
+pub fn read_raw_file<P: AsRef<Path>>(path: P) -> ::std::io::Result<Vec<Rgb<f32>>> {
+    use byteorder::{LittleEndian as LE, ReadBytesExt};
+    use std::fs::File;
+    use std::io::BufReader;
+
+    let mut r = BufReader::new(File::open(path)?);
+    let w = r.read_u32::<LE>()? as usize;
+    let h = r.read_u32::<LE>()? as usize;
+    let c = r.read_u32::<LE>()? as usize;
+    assert_eq!(c, 3);
+    let cnt = w * h;
+    let mut ret = Vec::with_capacity(cnt);
+    for _ in 0..cnt {
+        let cr = r.read_f32::<LE>()?;
+        let cg = r.read_f32::<LE>()?;
+        let cb = r.read_f32::<LE>()?;
+        ret.push(Rgb([cr, cg, cb]));
+    }
+    Ok(ret)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use std::io::Cursor;
+
+    #[test]
+    fn dimension_overflow() {
+        let data = b"#?RADIANCE\nFORMAT=32-bit_rle_rgbe\n\n -Y 4294967295 +X 4294967295";
+
+        assert!(HdrAdapter::new(Cursor::new(data)).is_err());
+        assert!(HdrAdapter::new_nonstrict(Cursor::new(data)).is_err());
+    }
+}