1 files changed, 447 insertions, 0 deletions
diff --git a/vendor/exr/src/io.rs b/vendor/exr/src/io.rs
new file mode 100644
index 0000000..1fb863b
--- /dev/null
+++ b/vendor/exr/src/io.rs
@@ -0,0 +1,447 @@
+
+//! Specialized binary input and output.
+//! Uses the error handling for this crate.
+
+#![doc(hidden)]
+pub use ::std::io::{Read, Write};
+
+use half::slice::{HalfFloatSliceExt};
+use lebe::prelude::*;
+use ::half::f16;
+use crate::error::{Error, Result, UnitResult, IoResult};
+use std::io::{Seek, SeekFrom};
+use std::path::Path;
+use std::fs::File;
+use std::convert::TryFrom;
+
+
+/// Skip reading uninteresting bytes without allocating.
+#[inline]
+pub fn skip_bytes(read: &mut impl Read, count: usize) -> IoResult<()> {
+    let count = u64::try_from(count).unwrap();
+
+    let skipped = std::io::copy(
+        &mut read.by_ref().take(count),
+        &mut std::io::sink()
+    )?;
+
+    // the reader may have ended before we skipped the desired number of bytes
+    if skipped < count {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::UnexpectedEof,
+            "cannot skip more bytes than exist"
+        ));
+    }
+
+    debug_assert_eq!(skipped, count, "skip bytes bug");
+    Ok(())
+}
+
+/// If an error occurs while writing, attempts to delete the partially written file.
+/// Creates a file just before the first write operation, not when this function is called.
+#[inline]
+pub fn attempt_delete_file_on_write_error<'p>(path: &'p Path, write: impl FnOnce(LateFile<'p>) -> UnitResult) -> UnitResult {
+    match write(LateFile::from(path)) {
+        Err(error) => { // FIXME deletes existing file if creation of new file fails?
+            let _deleted = std::fs::remove_file(path); // ignore deletion errors
+            Err(error)
+        },
+
+        ok => ok,
+    }
+}
+
+#[derive(Debug)]
+pub struct LateFile<'p> {
+    path: &'p Path,
+    file: Option<File>
+}
+
+impl<'p> From<&'p Path> for LateFile<'p> {
+    fn from(path: &'p Path) -> Self { Self { path, file: None } }
+}
+
+impl<'p> LateFile<'p> {
+    fn file(&mut self) -> std::io::Result<&mut File> {
+        if self.file.is_none() { self.file = Some(File::create(self.path)?); }
+        Ok(self.file.as_mut().unwrap()) // will not be reached if creation fails
+    }
+}
+
+impl<'p> std::io::Write for LateFile<'p> {
+    fn write(&mut self, buffer: &[u8]) -> std::io::Result<usize> {
+        self.file()?.write(buffer)
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        if let Some(file) = &mut self.file { file.flush() }
+        else { Ok(()) }
+    }
+}
+
+impl<'p> Seek for LateFile<'p> {
+    fn seek(&mut self, position: SeekFrom) -> std::io::Result<u64> {
+        self.file()?.seek(position)
+    }
+}
+
+
+/// Peek a single byte without consuming it.
+#[derive(Debug)]
+pub struct PeekRead<T> {
+
+    /// Cannot be exposed as it will not contain peeked values anymore.
+    inner: T,
+
+    peeked: Option<IoResult<u8>>,
+}
+
+impl<T: Read> PeekRead<T> {
+
+    /// Wrap a reader to make it peekable.
+    #[inline]
+    pub fn new(inner: T) -> Self {
+        Self { inner, peeked: None }
+    }
+
+    /// Read a single byte and return that without consuming it.
+    /// The next `read` call will include that byte.
+    #[inline]
+    pub fn peek_u8(&mut self) -> &IoResult<u8> {
+        self.peeked = self.peeked.take().or_else(|| Some(u8::read_from_little_endian(&mut self.inner)));
+        self.peeked.as_ref().unwrap() // unwrap cannot fail because we just set it
+    }
+
+    /// Skip a single byte if it equals the specified value.
+    /// Returns whether the value was found.
+    /// Consumes the peeked result if an error occurred.
+    #[inline]
+    pub fn skip_if_eq(&mut self, value: u8) -> IoResult<bool> {
+        match self.peek_u8() {
+            Ok(peeked) if *peeked == value =>  {
+                self.peeked = None; // consume the byte
+                Ok(true)
+            },
+
+            Ok(_) => Ok(false),
+
+            // return the error otherwise.
+            // unwrap is safe because this branch cannot be reached otherwise.
+            // we need to take() from self because io errors cannot be cloned.
+            Err(_) => Err(self.peeked.take().unwrap().err().unwrap())
+        }
+    }
+}
+
+
+impl<T: Read> Read for PeekRead<T> {
+    fn read(&mut self, target_buffer: &mut [u8]) -> IoResult<usize> {
+        if target_buffer.is_empty() {
+            return Ok(0)
+        }
+
+        match self.peeked.take() {
+            None => self.inner.read(target_buffer),
+            Some(peeked) => {
+                target_buffer[0] = peeked?;
+
+                // indexing [1..] is safe because an empty buffer already returned ok
+                Ok(1 + self.inner.read(&mut target_buffer[1..])?)
+            }
+        }
+    }
+}
+
+impl<T: Read + Seek> PeekRead<Tracking<T>> {
+
+    /// Seek this read to the specified byte position.
+    /// Discards any previously peeked value.
+    pub fn skip_to(&mut self, position: usize) -> std::io::Result<()> {
+        self.inner.seek_read_to(position)?;
+        self.peeked = None;
+        Ok(())
+    }
+}
+
+impl<T: Read> PeekRead<Tracking<T>> {
+
+    /// Current number of bytes read.
+    pub fn byte_position(&self) -> usize {
+        self.inner.byte_position()
+    }
+}
+
+/// Keep track of what byte we are at.
+/// Used to skip back to a previous place after writing some information.
+#[derive(Debug)]
+pub struct Tracking<T> {
+
+    /// Do not expose to prevent seeking without updating position
+    inner: T,
+
+    position: usize,
+}
+
+impl<T: Read> Read for Tracking<T> {
+    fn read(&mut self, buffer: &mut [u8]) -> std::io::Result<usize> {
+        let count = self.inner.read(buffer)?;
+        self.position += count;
+        Ok(count)
+    }
+}
+
+impl<T: Write> Write for Tracking<T> {
+    fn write(&mut self, buffer: &[u8]) -> std::io::Result<usize> {
+        let count = self.inner.write(buffer)?;
+        self.position += count;
+        Ok(count)
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        self.inner.flush()
+    }
+}
+
+impl<T> Tracking<T> {
+
+    /// If `inner` is a reference, if must never be seeked directly,
+    /// but only through this `Tracking` instance.
+    pub fn new(inner: T) -> Self {
+        Tracking { inner, position: 0 }
+    }
+
+    /// Current number of bytes written or read.
+    pub fn byte_position(&self) -> usize {
+        self.position
+    }
+}
+
+impl<T: Read + Seek> Tracking<T> {
+
+    /// Set the reader to the specified byte position.
+    /// If it is only a couple of bytes, no seek system call is performed.
+    pub fn seek_read_to(&mut self, target_position: usize) -> std::io::Result<()> {
+        let delta = target_position as i128 - self.position as i128; // FIXME  panicked at 'attempt to subtract with overflow'
+        debug_assert!(delta.abs() < usize::MAX as i128);
+
+        if delta > 0 && delta < 16 { // TODO profile that this is indeed faster than a syscall! (should be because of bufread buffer discard)
+            skip_bytes(self, delta as usize)?;
+            self.position += delta as usize;
+        }
+        else if delta != 0 {
+            self.inner.seek(SeekFrom::Start(u64::try_from(target_position).unwrap()))?;
+            self.position = target_position;
+        }
+
+        Ok(())
+    }
+}
+
+impl<T: Write + Seek> Tracking<T> {
+
+    /// Move the writing cursor to the specified target byte index.
+    /// If seeking forward, this will write zeroes.
+    pub fn seek_write_to(&mut self, target_position: usize) -> std::io::Result<()> {
+        if target_position < self.position {
+            self.inner.seek(SeekFrom::Start(u64::try_from(target_position).unwrap()))?;
+        }
+        else if target_position > self.position {
+            std::io::copy(
+                &mut std::io::repeat(0).take(u64::try_from(target_position - self.position).unwrap()),
+                self
+            )?;
+        }
+
+        self.position = target_position;
+        Ok(())
+    }
+}
+
+
+/// Generic trait that defines common binary operations such as reading and writing for this type.
+pub trait Data: Sized + Default + Clone {
+
+    /// Number of bytes this would consume in an exr file.
+    const BYTE_SIZE: usize = ::std::mem::size_of::<Self>();
+
+    /// Read a value of type `Self`.
+    fn read(read: &mut impl Read) -> Result<Self>;
+
+    /// Read as many values of type `Self` as fit into the specified slice.
+    /// If the slice cannot be filled completely, returns `Error::Invalid`.
+    fn read_slice(read: &mut impl Read, slice: &mut[Self]) -> UnitResult;
+
+    /// Read as many values of type `Self` as specified with `data_size`.
+    ///
+    /// This method will not allocate more memory than `soft_max` at once.
+    /// If `hard_max` is specified, it will never read any more than that.
+    /// Returns `Error::Invalid` if reader does not contain the desired number of elements.
+    #[inline]
+    fn read_vec(read: &mut impl Read, data_size: usize, soft_max: usize, hard_max: Option<usize>, purpose: &'static str) -> Result<Vec<Self>> {
+        let mut vec = Vec::with_capacity(data_size.min(soft_max));
+        Self::read_into_vec(read, &mut vec, data_size, soft_max, hard_max, purpose)?;
+        Ok(vec)
+    }
+
+    /// Write this value to the writer.
+    fn write(self, write: &mut impl Write) -> UnitResult;
+
+    /// Write all values of that slice to the writer.
+    fn write_slice(write: &mut impl Write, slice: &[Self]) -> UnitResult;
+
+
+    /// Read as many values of type `Self` as specified with `data_size` into the provided vector.
+    ///
+    /// This method will not allocate more memory than `soft_max` at once.
+    /// If `hard_max` is specified, it will never read any more than that.
+    /// Returns `Error::Invalid` if reader does not contain the desired number of elements.
+    #[inline]
+    fn read_into_vec(read: &mut impl Read, data: &mut Vec<Self>, data_size: usize, soft_max: usize, hard_max: Option<usize>, purpose: &'static str) -> UnitResult {
+        if let Some(max) = hard_max {
+            if data_size > max {
+                return Err(Error::invalid(purpose))
+            }
+        }
+
+        let soft_max = hard_max.unwrap_or(soft_max).min(soft_max);
+        let end = data.len() + data_size;
+
+        // do not allocate more than $chunks memory at once
+        // (most of the time, this loop will run only once)
+        while data.len() < end {
+            let chunk_start = data.len();
+            let chunk_end = (chunk_start + soft_max).min(data_size);
+
+            data.resize(chunk_end, Self::default());
+            Self::read_slice(read, &mut data[chunk_start .. chunk_end])?; // safe because of `min(data_size)``
+        }
+
+        Ok(())
+    }
+
+    /// Write the length of the slice and then its contents.
+    #[inline]
+    fn write_i32_sized_slice<W: Write>(write: &mut W, slice: &[Self]) -> UnitResult {
+        i32::try_from(slice.len())?.write(write)?;
+        Self::write_slice(write, slice)
+    }
+
+    /// Read the desired element count and then read that many items into a vector.
+    ///
+    /// This method will not allocate more memory than `soft_max` at once.
+    /// If `hard_max` is specified, it will never read any more than that.
+    /// Returns `Error::Invalid` if reader does not contain the desired number of elements.
+    #[inline]
+    fn read_i32_sized_vec(read: &mut impl Read, soft_max: usize, hard_max: Option<usize>, purpose: &'static str) -> Result<Vec<Self>> {
+        let size = usize::try_from(i32::read(read)?)?;
+        Self::read_vec(read, size, soft_max, hard_max, purpose)
+    }
+
+    /// Fill the slice with this value.
+    #[inline]
+    fn fill_slice(self, slice: &mut [Self]) where Self: Copy {
+        // hopefully compiles down to a single memset call
+        for value in slice {
+            *value = self;
+        }
+    }
+}
+
+
+macro_rules! implement_data_for_primitive {
+    ($kind: ident) => {
+        impl Data for $kind {
+            #[inline]
+            fn read(read: &mut impl Read) -> Result<Self> {
+                Ok(read.read_from_little_endian()?)
+            }
+
+            #[inline]
+            fn write(self, write: &mut impl Write) -> Result<()> {
+                write.write_as_little_endian(&self)?;
+                Ok(())
+            }
+
+            #[inline]
+            fn read_slice(read: &mut impl Read, slice: &mut [Self]) -> Result<()> {
+                read.read_from_little_endian_into(slice)?;
+                Ok(())
+            }
+
+            #[inline]
+            fn write_slice(write: &mut impl Write, slice: &[Self]) -> Result<()> {
+                write.write_as_little_endian(slice)?;
+                Ok(())
+            }
+        }
+    };
+}
+
+implement_data_for_primitive!(u8);
+implement_data_for_primitive!(i8);
+implement_data_for_primitive!(i16);
+implement_data_for_primitive!(u16);
+implement_data_for_primitive!(u32);
+implement_data_for_primitive!(i32);
+implement_data_for_primitive!(i64);
+implement_data_for_primitive!(u64);
+implement_data_for_primitive!(f32);
+implement_data_for_primitive!(f64);
+
+
+impl Data for f16 {
+    #[inline]
+    fn read(read: &mut impl Read) -> Result<Self> {
+        u16::read(read).map(f16::from_bits)
+    }
+
+    #[inline]
+    fn read_slice(read: &mut impl Read, slice: &mut [Self]) -> Result<()> {
+        let bits = slice.reinterpret_cast_mut();
+        u16::read_slice(read, bits)
+    }
+
+    #[inline]
+    fn write(self, write: &mut impl Write) -> Result<()> {
+        self.to_bits().write(write)
+    }
+
+    #[inline]
+    fn write_slice(write: &mut impl Write, slice: &[Self]) -> Result<()> {
+        let bits = slice.reinterpret_cast();
+        u16::write_slice(write, bits)
+    }
+}
+
+
+#[cfg(test)]
+mod test {
+    use crate::io::PeekRead;
+    use std::io::Read;
+
+    #[test]
+    fn peek(){
+        use lebe::prelude::*;
+        let buffer: &[u8] = &[0,1,2,3];
+        let mut peek = PeekRead::new(buffer);
+
+        assert_eq!(peek.peek_u8().as_ref().unwrap(), &0);
+        assert_eq!(peek.peek_u8().as_ref().unwrap(), &0);
+        assert_eq!(peek.peek_u8().as_ref().unwrap(), &0);
+        assert_eq!(u8::read_from_little_endian(&mut peek).unwrap(), 0_u8);
+
+        assert_eq!(peek.read(&mut [0,0]).unwrap(), 2);
+
+        assert_eq!(peek.peek_u8().as_ref().unwrap(), &3);
+        assert_eq!(u8::read_from_little_endian(&mut peek).unwrap(), 3_u8);
+
+        assert!(peek.peek_u8().is_err());
+        assert!(peek.peek_u8().is_err());
+        assert!(peek.peek_u8().is_err());
+        assert!(peek.peek_u8().is_err());
+
+        assert!(u8::read_from_little_endian(&mut peek).is_err());
+    }
+}
+
+