crates_std/vendor/embedded-io-0.4.0/src/blocking.rs - third_party/rust_crates - Git at Google

 //! Blocking IO traits

 use core::fmt;

 /// Error returned by [`Read::read_exact`]
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum ReadExactError<E> {
     /// An EOF error was encountered before reading the exact amount of requested bytes.
     UnexpectedEof,
     /// Error returned by the inner Read.
     Other(E),
 }

 impl<E: fmt::Debug> fmt::Display for ReadExactError<E> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{:?}", self)
     }
 }

 #[cfg(feature = "std")]
 impl<E: fmt::Debug> std::error::Error for ReadExactError<E> {}

 /// Error returned by [`Write::write_fmt`]
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum WriteFmtError<E> {
     /// An error was encountered while formatting.
     FmtError,
     /// Error returned by the inner Write.
     Other(E),
 }

 impl<E: fmt::Debug> fmt::Display for WriteFmtError<E> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{:?}", self)
     }
 }

 #[cfg(feature = "std")]
 impl<E: fmt::Debug> std::error::Error for WriteFmtError<E> {}

 /// Blocking reader.
 ///
 /// Semantics are the same as [`std::io::Read`], check its documentation for details.
 pub trait Read: crate::Io {
     /// Pull some bytes from this source into the specified buffer, returning how many bytes were read.
     fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error>;

     /// Read the exact number of bytes required to fill `buf`.
     fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<(), ReadExactError<Self::Error>> {
         while !buf.is_empty() {
             match self.read(buf) {
                 Ok(0) => break,
                 Ok(n) => buf = &mut buf[n..],
                 Err(e) => return Err(ReadExactError::Other(e)),
             }
         }
         if !buf.is_empty() {
             Err(ReadExactError::UnexpectedEof)
         } else {
             Ok(())
         }
     }
 }

 /// Blocking buffered reader.
 ///
 /// Semantics are the same as [`std::io::BufRead`], check its documentation for details.
 pub trait BufRead: crate::Io {
     /// Return the contents of the internal buffer, filling it with more data from the inner reader if it is empty.
     fn fill_buf(&mut self) -> Result<&[u8], Self::Error>;

     /// Tell this buffer that `amt` bytes have been consumed from the buffer, so they should no longer be returned in calls to `fill_buf`.
     fn consume(&mut self, amt: usize);
 }

 /// Blocking writer.
 ///
 /// Semantics are the same as [`std::io::Write`], check its documentation for details.
 pub trait Write: crate::Io {
     /// Write a buffer into this writer, returning how many bytes were written.
     fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error>;

     /// Flush this output stream, ensuring that all intermediately buffered contents reach their destination.
     fn flush(&mut self) -> Result<(), Self::Error>;

     /// Write an entire buffer into this writer.
     fn write_all(&mut self, mut buf: &[u8]) -> Result<(), Self::Error> {
         while !buf.is_empty() {
             match self.write(buf) {
                 Ok(0) => panic!("zero-length write."),
                 Ok(n) => buf = &buf[n..],
                 Err(e) => return Err(e),
             }
         }
         Ok(())
     }

     /// Write a formatted string into this writer, returning any error encountered.
     fn write_fmt(&mut self, fmt: fmt::Arguments<'_>) -> Result<(), WriteFmtError<Self::Error>> {
         // Create a shim which translates a Write to a fmt::Write and saves
         // off I/O errors. instead of discarding them
         struct Adapter<'a, T: Write + ?Sized + 'a> {
             inner: &'a mut T,
             error: Result<(), T::Error>,
         }

         impl<T: Write + ?Sized> fmt::Write for Adapter<'_, T> {
             fn write_str(&mut self, s: &str) -> fmt::Result {
                 match self.inner.write_all(s.as_bytes()) {
                     Ok(()) => Ok(()),
                     Err(e) => {
                         self.error = Err(e);
                         Err(fmt::Error)
                     }
                 }
             }
         }

         let mut output = Adapter {
             inner: self,
             error: Ok(()),
         };
         match fmt::write(&mut output, fmt) {
             Ok(()) => Ok(()),
             Err(..) => match output.error {
                 // check if the error came from the underlying `Write` or not
                 Err(e) => Err(WriteFmtError::Other(e)),
                 Ok(()) => Err(WriteFmtError::FmtError),
             },
         }
     }
 }

 /// Blocking seek within streams.
 ///
 /// Semantics are the same as [`std::io::Seek`], check its documentation for details.
 pub trait Seek: crate::Io {
     /// Seek to an offset, in bytes, in a stream.
     fn seek(&mut self, pos: crate::SeekFrom) -> Result<u64, Self::Error>;

     /// Rewind to the beginning of a stream.
     fn rewind(&mut self) -> Result<(), Self::Error> {
         self.seek(crate::SeekFrom::Start(0))?;
         Ok(())
     }

     /// Returns the current seek position from the start of the stream.
     fn stream_position(&mut self) -> Result<u64, Self::Error> {
         self.seek(crate::SeekFrom::Current(0))
     }
 }

 impl<T: ?Sized + Read> Read for &mut T {
     #[inline]
     fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
         T::read(self, buf)
     }
 }

 impl<T: ?Sized + BufRead> BufRead for &mut T {
     fn fill_buf(&mut self) -> Result<&[u8], Self::Error> {
         T::fill_buf(self)
     }

     fn consume(&mut self, amt: usize) {
         T::consume(self, amt)
     }
 }

 impl<T: ?Sized + Write> Write for &mut T {
     #[inline]
     fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
         T::write(self, buf)
     }

     #[inline]
     fn flush(&mut self) -> Result<(), Self::Error> {
         T::flush(self)
     }
 }

 impl<T: ?Sized + Seek> Seek for &mut T {
     #[inline]
     fn seek(&mut self, pos: crate::SeekFrom) -> Result<u64, Self::Error> {
         T::seek(self, pos)
     }
 }

 /// Read is implemented for `&[u8]` by copying from the slice.
 ///
 /// Note that reading updates the slice to point to the yet unread part.
 /// The slice will be empty when EOF is reached.
 impl Read for &[u8] {
     #[inline]
     fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
         let amt = core::cmp::min(buf.len(), self.len());
         let (a, b) = self.split_at(amt);

         // First check if the amount of bytes we want to read is small:
         // `copy_from_slice` will generally expand to a call to `memcpy`, and
         // for a single byte the overhead is significant.
         if amt == 1 {
             buf[0] = a[0];
         } else {
             buf[..amt].copy_from_slice(a);
         }

         *self = b;
         Ok(amt)
     }
 }

 impl BufRead for &[u8] {
     #[inline]
     fn fill_buf(&mut self) -> Result<&[u8], Self::Error> {
         Ok(*self)
     }

     #[inline]
     fn consume(&mut self, amt: usize) {
         *self = &self[amt..];
     }
 }

 /// Write is implemented for `&mut [u8]` by copying into the slice, overwriting
 /// its data.
 ///
 /// Note that writing updates the slice to point to the yet unwritten part.
 /// The slice will be empty when it has been completely overwritten.
 ///
 /// If the number of bytes to be written exceeds the size of the slice, write operations will
 /// return short writes: ultimately, `Ok(0)`; in this situation, `write_all` returns an error of
 /// kind `ErrorKind::WriteZero`.
 impl Write for &mut [u8] {
     #[inline]
     fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
         let amt = core::cmp::min(buf.len(), self.len());
         let (a, b) = core::mem::replace(self, &mut []).split_at_mut(amt);
         a.copy_from_slice(&buf[..amt]);
         *self = b;
         Ok(amt)
     }

     #[inline]
     fn flush(&mut self) -> Result<(), Self::Error> {
         Ok(())
     }
 }

 #[cfg(feature = "alloc")]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<T: ?Sized + Read> Read for alloc::boxed::Box<T> {
     #[inline]
     fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
         T::read(self, buf)
     }
 }

 #[cfg(feature = "alloc")]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<T: ?Sized + BufRead> BufRead for alloc::boxed::Box<T> {
     fn fill_buf(&mut self) -> Result<&[u8], Self::Error> {
         T::fill_buf(self)
     }

     fn consume(&mut self, amt: usize) {
         T::consume(self, amt)
     }
 }

 #[cfg(feature = "alloc")]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<T: ?Sized + Write> Write for alloc::boxed::Box<T> {
     #[inline]
     fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
         T::write(self, buf)
     }

     #[inline]
     fn flush(&mut self) -> Result<(), Self::Error> {
         T::flush(self)
     }
 }

 #[cfg(feature = "alloc")]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<T: ?Sized + Seek> Seek for alloc::boxed::Box<T> {
     #[inline]
     fn seek(&mut self, pos: crate::SeekFrom) -> Result<u64, Self::Error> {
         T::seek(self, pos)
     }
 }

 #[cfg(feature = "alloc")]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl Write for alloc::vec::Vec<u8> {
     #[inline]
     fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
         self.extend_from_slice(buf);
         Ok(buf.len())
     }

     #[inline]
     fn flush(&mut self) -> Result<(), Self::Error> {
         Ok(())
     }
 }
	//! Blocking IO traits

	use core::fmt;

	/// Error returned by [`Read::read_exact`]
	#[derive(Debug, Copy, Clone, Eq, PartialEq)]
	#[cfg_attr(feature = "defmt", derive(defmt::Format))]
	pub enum ReadExactError<E> {
	/// An EOF error was encountered before reading the exact amount of requested bytes.
	UnexpectedEof,
	/// Error returned by the inner Read.
	Other(E),
	}

	impl<E: fmt::Debug> fmt::Display for ReadExactError<E> {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	write!(f, "{:?}", self)
	}
	}

	#[cfg(feature = "std")]
	impl<E: fmt::Debug> std::error::Error for ReadExactError<E> {}

	/// Error returned by [`Write::write_fmt`]
	#[derive(Debug, Copy, Clone, Eq, PartialEq)]
	#[cfg_attr(feature = "defmt", derive(defmt::Format))]
	pub enum WriteFmtError<E> {
	/// An error was encountered while formatting.
	FmtError,
	/// Error returned by the inner Write.
	Other(E),
	}

	impl<E: fmt::Debug> fmt::Display for WriteFmtError<E> {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	write!(f, "{:?}", self)
	}
	}

	#[cfg(feature = "std")]
	impl<E: fmt::Debug> std::error::Error for WriteFmtError<E> {}

	/// Blocking reader.
	///
	/// Semantics are the same as [`std::io::Read`], check its documentation for details.
	pub trait Read: crate::Io {
	/// Pull some bytes from this source into the specified buffer, returning how many bytes were read.
	fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error>;

	/// Read the exact number of bytes required to fill `buf`.
	fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<(), ReadExactError<Self::Error>> {
	while !buf.is_empty() {
	match self.read(buf) {
	Ok(0) => break,
	Ok(n) => buf = &mut buf[n..],
	Err(e) => return Err(ReadExactError::Other(e)),
	}
	}
	if !buf.is_empty() {
	Err(ReadExactError::UnexpectedEof)
	} else {
	Ok(())
	}
	}
	}

	/// Blocking buffered reader.
	///
	/// Semantics are the same as [`std::io::BufRead`], check its documentation for details.
	pub trait BufRead: crate::Io {
	/// Return the contents of the internal buffer, filling it with more data from the inner reader if it is empty.
	fn fill_buf(&mut self) -> Result<&[u8], Self::Error>;

	/// Tell this buffer that `amt` bytes have been consumed from the buffer, so they should no longer be returned in calls to `fill_buf`.
	fn consume(&mut self, amt: usize);
	}

	/// Blocking writer.
	///
	/// Semantics are the same as [`std::io::Write`], check its documentation for details.
	pub trait Write: crate::Io {
	/// Write a buffer into this writer, returning how many bytes were written.
	fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error>;

	/// Flush this output stream, ensuring that all intermediately buffered contents reach their destination.
	fn flush(&mut self) -> Result<(), Self::Error>;

	/// Write an entire buffer into this writer.
	fn write_all(&mut self, mut buf: &[u8]) -> Result<(), Self::Error> {
	while !buf.is_empty() {
	match self.write(buf) {
	Ok(0) => panic!("zero-length write."),
	Ok(n) => buf = &buf[n..],
	Err(e) => return Err(e),
	}
	}
	Ok(())
	}

	/// Write a formatted string into this writer, returning any error encountered.
	fn write_fmt(&mut self, fmt: fmt::Arguments<'_>) -> Result<(), WriteFmtError<Self::Error>> {
	// Create a shim which translates a Write to a fmt::Write and saves
	// off I/O errors. instead of discarding them
	struct Adapter<'a, T: Write + ?Sized + 'a> {
	inner: &'a mut T,
	error: Result<(), T::Error>,
	}

	impl<T: Write + ?Sized> fmt::Write for Adapter<'_, T> {
	fn write_str(&mut self, s: &str) -> fmt::Result {
	match self.inner.write_all(s.as_bytes()) {
	Ok(()) => Ok(()),
	Err(e) => {
	self.error = Err(e);
	Err(fmt::Error)
	}
	}
	}
	}

	let mut output = Adapter {
	inner: self,
	error: Ok(()),
	};
	match fmt::write(&mut output, fmt) {
	Ok(()) => Ok(()),
	Err(..) => match output.error {
	// check if the error came from the underlying `Write` or not
	Err(e) => Err(WriteFmtError::Other(e)),
	Ok(()) => Err(WriteFmtError::FmtError),
	},
	}
	}
	}

	/// Blocking seek within streams.
	///
	/// Semantics are the same as [`std::io::Seek`], check its documentation for details.
	pub trait Seek: crate::Io {
	/// Seek to an offset, in bytes, in a stream.
	fn seek(&mut self, pos: crate::SeekFrom) -> Result<u64, Self::Error>;

	/// Rewind to the beginning of a stream.
	fn rewind(&mut self) -> Result<(), Self::Error> {
	self.seek(crate::SeekFrom::Start(0))?;
	Ok(())
	}

	/// Returns the current seek position from the start of the stream.
	fn stream_position(&mut self) -> Result<u64, Self::Error> {
	self.seek(crate::SeekFrom::Current(0))
	}
	}

	impl<T: ?Sized + Read> Read for &mut T {
	#[inline]
	fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
	T::read(self, buf)
	}
	}

	impl<T: ?Sized + BufRead> BufRead for &mut T {
	fn fill_buf(&mut self) -> Result<&[u8], Self::Error> {
	T::fill_buf(self)
	}

	fn consume(&mut self, amt: usize) {
	T::consume(self, amt)
	}
	}

	impl<T: ?Sized + Write> Write for &mut T {
	#[inline]
	fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
	T::write(self, buf)
	}

	#[inline]
	fn flush(&mut self) -> Result<(), Self::Error> {
	T::flush(self)
	}
	}

	impl<T: ?Sized + Seek> Seek for &mut T {
	#[inline]
	fn seek(&mut self, pos: crate::SeekFrom) -> Result<u64, Self::Error> {
	T::seek(self, pos)
	}
	}

	/// Read is implemented for `&[u8]` by copying from the slice.
	///
	/// Note that reading updates the slice to point to the yet unread part.
	/// The slice will be empty when EOF is reached.
	impl Read for &[u8] {
	#[inline]
	fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
	let amt = core::cmp::min(buf.len(), self.len());
	let (a, b) = self.split_at(amt);

	// First check if the amount of bytes we want to read is small:
	// `copy_from_slice` will generally expand to a call to `memcpy`, and
	// for a single byte the overhead is significant.
	if amt == 1 {
	buf[0] = a[0];
	} else {
	buf[..amt].copy_from_slice(a);
	}

	*self = b;
	Ok(amt)
	}
	}

	impl BufRead for &[u8] {
	#[inline]
	fn fill_buf(&mut self) -> Result<&[u8], Self::Error> {
	Ok(*self)
	}

	#[inline]
	fn consume(&mut self, amt: usize) {
	*self = &self[amt..];
	}
	}

	/// Write is implemented for `&mut [u8]` by copying into the slice, overwriting
	/// its data.
	///
	/// Note that writing updates the slice to point to the yet unwritten part.
	/// The slice will be empty when it has been completely overwritten.
	///
	/// If the number of bytes to be written exceeds the size of the slice, write operations will
	/// return short writes: ultimately, `Ok(0)`; in this situation, `write_all` returns an error of
	/// kind `ErrorKind::WriteZero`.
	impl Write for &mut [u8] {
	#[inline]
	fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
	let amt = core::cmp::min(buf.len(), self.len());
	let (a, b) = core::mem::replace(self, &mut []).split_at_mut(amt);
	a.copy_from_slice(&buf[..amt]);
	*self = b;
	Ok(amt)
	}

	#[inline]
	fn flush(&mut self) -> Result<(), Self::Error> {
	Ok(())
	}
	}

	#[cfg(feature = "alloc")]
	#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
	impl<T: ?Sized + Read> Read for alloc::boxed::Box<T> {
	#[inline]
	fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
	T::read(self, buf)
	}
	}

	#[cfg(feature = "alloc")]
	#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
	impl<T: ?Sized + BufRead> BufRead for alloc::boxed::Box<T> {
	fn fill_buf(&mut self) -> Result<&[u8], Self::Error> {
	T::fill_buf(self)
	}

	fn consume(&mut self, amt: usize) {
	T::consume(self, amt)
	}
	}

	#[cfg(feature = "alloc")]
	#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
	impl<T: ?Sized + Write> Write for alloc::boxed::Box<T> {
	#[inline]
	fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
	T::write(self, buf)
	}

	#[inline]
	fn flush(&mut self) -> Result<(), Self::Error> {
	T::flush(self)
	}
	}

	#[cfg(feature = "alloc")]
	#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
	impl<T: ?Sized + Seek> Seek for alloc::boxed::Box<T> {
	#[inline]
	fn seek(&mut self, pos: crate::SeekFrom) -> Result<u64, Self::Error> {
	T::seek(self, pos)
	}
	}

	#[cfg(feature = "alloc")]
	#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
	impl Write for alloc::vec::Vec<u8> {
	#[inline]
	fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
	self.extend_from_slice(buf);
	Ok(buf.len())
	}

	#[inline]
	fn flush(&mut self) -> Result<(), Self::Error> {
	Ok(())
	}
	}