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Diffstat (limited to 'library/std/src/io/cursor.rs')
| -rw-r--r-- | library/std/src/io/cursor.rs | 981 |
1 files changed, 981 insertions, 0 deletions
diff --git a/library/std/src/io/cursor.rs b/library/std/src/io/cursor.rs new file mode 100644 index 00000000000..f4db5f81450 --- /dev/null +++ b/library/std/src/io/cursor.rs @@ -0,0 +1,981 @@ +use crate::io::prelude::*; + +use crate::cmp; +use crate::io::{self, Error, ErrorKind, Initializer, IoSlice, IoSliceMut, SeekFrom}; + +use core::convert::TryInto; + +/// A `Cursor` wraps an in-memory buffer and provides it with a +/// [`Seek`] implementation. +/// +/// `Cursor`s are used with in-memory buffers, anything implementing +/// `AsRef<[u8]>`, to allow them to implement [`Read`] and/or [`Write`], +/// allowing these buffers to be used anywhere you might use a reader or writer +/// that does actual I/O. +/// +/// The standard library implements some I/O traits on various types which +/// are commonly used as a buffer, like `Cursor<`[`Vec`]`<u8>>` and +/// `Cursor<`[`&[u8]`][bytes]`>`. +/// +/// # Examples +/// +/// We may want to write bytes to a [`File`] in our production +/// code, but use an in-memory buffer in our tests. We can do this with +/// `Cursor`: +/// +/// [`Seek`]: trait.Seek.html +/// [`Read`]: ../../std/io/trait.Read.html +/// [`Write`]: ../../std/io/trait.Write.html +/// [`Vec`]: ../../std/vec/struct.Vec.html +/// [bytes]: ../../std/primitive.slice.html +/// [`File`]: ../fs/struct.File.html +/// +/// ```no_run +/// use std::io::prelude::*; +/// use std::io::{self, SeekFrom}; +/// use std::fs::File; +/// +/// // a library function we've written +/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> { +/// writer.seek(SeekFrom::End(-10))?; +/// +/// for i in 0..10 { +/// writer.write(&[i])?; +/// } +/// +/// // all went well +/// Ok(()) +/// } +/// +/// # fn foo() -> io::Result<()> { +/// // Here's some code that uses this library function. +/// // +/// // We might want to use a BufReader here for efficiency, but let's +/// // keep this example focused. +/// let mut file = File::create("foo.txt")?; +/// +/// write_ten_bytes_at_end(&mut file)?; +/// # Ok(()) +/// # } +/// +/// // now let's write a test +/// #[test] +/// fn test_writes_bytes() { +/// // setting up a real File is much slower than an in-memory buffer, +/// // let's use a cursor instead +/// use std::io::Cursor; +/// let mut buff = Cursor::new(vec![0; 15]); +/// +/// write_ten_bytes_at_end(&mut buff).unwrap(); +/// +/// assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]); +/// } +/// ``` +#[stable(feature = "rust1", since = "1.0.0")] +#[derive(Clone, Debug, Default, Eq, PartialEq)] +pub struct Cursor<T> { + inner: T, + pos: u64, +} + +impl<T> Cursor<T> { + /// Creates a new cursor wrapping the provided underlying in-memory buffer. + /// + /// Cursor initial position is `0` even if underlying buffer (e.g., `Vec`) + /// is not empty. So writing to cursor starts with overwriting `Vec` + /// content, not with appending to it. + /// + /// # Examples + /// + /// ``` + /// use std::io::Cursor; + /// + /// let buff = Cursor::new(Vec::new()); + /// # fn force_inference(_: &Cursor<Vec<u8>>) {} + /// # force_inference(&buff); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + pub fn new(inner: T) -> Cursor<T> { + Cursor { pos: 0, inner } + } + + /// Consumes this cursor, returning the underlying value. + /// + /// # Examples + /// + /// ``` + /// use std::io::Cursor; + /// + /// let buff = Cursor::new(Vec::new()); + /// # fn force_inference(_: &Cursor<Vec<u8>>) {} + /// # force_inference(&buff); + /// + /// let vec = buff.into_inner(); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + pub fn into_inner(self) -> T { + self.inner + } + + /// Gets a reference to the underlying value in this cursor. + /// + /// # Examples + /// + /// ``` + /// use std::io::Cursor; + /// + /// let buff = Cursor::new(Vec::new()); + /// # fn force_inference(_: &Cursor<Vec<u8>>) {} + /// # force_inference(&buff); + /// + /// let reference = buff.get_ref(); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + pub fn get_ref(&self) -> &T { + &self.inner + } + + /// Gets a mutable reference to the underlying value in this cursor. + /// + /// Care should be taken to avoid modifying the internal I/O state of the + /// underlying value as it may corrupt this cursor's position. + /// + /// # Examples + /// + /// ``` + /// use std::io::Cursor; + /// + /// let mut buff = Cursor::new(Vec::new()); + /// # fn force_inference(_: &Cursor<Vec<u8>>) {} + /// # force_inference(&buff); + /// + /// let reference = buff.get_mut(); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + pub fn get_mut(&mut self) -> &mut T { + &mut self.inner + } + + /// Returns the current position of this cursor. + /// + /// # Examples + /// + /// ``` + /// use std::io::Cursor; + /// use std::io::prelude::*; + /// use std::io::SeekFrom; + /// + /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]); + /// + /// assert_eq!(buff.position(), 0); + /// + /// buff.seek(SeekFrom::Current(2)).unwrap(); + /// assert_eq!(buff.position(), 2); + /// + /// buff.seek(SeekFrom::Current(-1)).unwrap(); + /// assert_eq!(buff.position(), 1); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + pub fn position(&self) -> u64 { + self.pos + } + + /// Sets the position of this cursor. + /// + /// # Examples + /// + /// ``` + /// use std::io::Cursor; + /// + /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]); + /// + /// assert_eq!(buff.position(), 0); + /// + /// buff.set_position(2); + /// assert_eq!(buff.position(), 2); + /// + /// buff.set_position(4); + /// assert_eq!(buff.position(), 4); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + pub fn set_position(&mut self, pos: u64) { + self.pos = pos; + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl<T> io::Seek for Cursor<T> +where + T: AsRef<[u8]>, +{ + fn seek(&mut self, style: SeekFrom) -> io::Result<u64> { + let (base_pos, offset) = match style { + SeekFrom::Start(n) => { + self.pos = n; + return Ok(n); + } + SeekFrom::End(n) => (self.inner.as_ref().len() as u64, n), + SeekFrom::Current(n) => (self.pos, n), + }; + let new_pos = if offset >= 0 { + base_pos.checked_add(offset as u64) + } else { + base_pos.checked_sub((offset.wrapping_neg()) as u64) + }; + match new_pos { + Some(n) => { + self.pos = n; + Ok(self.pos) + } + None => Err(Error::new( + ErrorKind::InvalidInput, + "invalid seek to a negative or overflowing position", + )), + } + } + + fn stream_len(&mut self) -> io::Result<u64> { + Ok(self.inner.as_ref().len() as u64) + } + + fn stream_position(&mut self) -> io::Result<u64> { + Ok(self.pos) + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl<T> Read for Cursor<T> +where + T: AsRef<[u8]>, +{ + fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { + let n = Read::read(&mut self.fill_buf()?, buf)?; + self.pos += n as u64; + Ok(n) + } + + fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> { + let mut nread = 0; + for buf in bufs { + let n = self.read(buf)?; + nread += n; + if n < buf.len() { + break; + } + } + Ok(nread) + } + + fn is_read_vectored(&self) -> bool { + true + } + + fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> { + let n = buf.len(); + Read::read_exact(&mut self.fill_buf()?, buf)?; + self.pos += n as u64; + Ok(()) + } + + #[inline] + unsafe fn initializer(&self) -> Initializer { + Initializer::nop() + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl<T> BufRead for Cursor<T> +where + T: AsRef<[u8]>, +{ + fn fill_buf(&mut self) -> io::Result<&[u8]> { + let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64); + Ok(&self.inner.as_ref()[(amt as usize)..]) + } + fn consume(&mut self, amt: usize) { + self.pos += amt as u64; + } +} + +// Non-resizing write implementation +#[inline] +fn slice_write(pos_mut: &mut u64, slice: &mut [u8], buf: &[u8]) -> io::Result<usize> { + let pos = cmp::min(*pos_mut, slice.len() as u64); + let amt = (&mut slice[(pos as usize)..]).write(buf)?; + *pos_mut += amt as u64; + Ok(amt) +} + +#[inline] +fn slice_write_vectored( + pos_mut: &mut u64, + slice: &mut [u8], + bufs: &[IoSlice<'_>], +) -> io::Result<usize> { + let mut nwritten = 0; + for buf in bufs { + let n = slice_write(pos_mut, slice, buf)?; + nwritten += n; + if n < buf.len() { + break; + } + } + Ok(nwritten) +} + +// Resizing write implementation +fn vec_write(pos_mut: &mut u64, vec: &mut Vec<u8>, buf: &[u8]) -> io::Result<usize> { + let pos: usize = (*pos_mut).try_into().map_err(|_| { + Error::new( + ErrorKind::InvalidInput, + "cursor position exceeds maximum possible vector length", + ) + })?; + // Make sure the internal buffer is as least as big as where we + // currently are + let len = vec.len(); + if len < pos { + // use `resize` so that the zero filling is as efficient as possible + vec.resize(pos, 0); + } + // Figure out what bytes will be used to overwrite what's currently + // there (left), and what will be appended on the end (right) + { + let space = vec.len() - pos; + let (left, right) = buf.split_at(cmp::min(space, buf.len())); + vec[pos..pos + left.len()].copy_from_slice(left); + vec.extend_from_slice(right); + } + + // Bump us forward + *pos_mut = (pos + buf.len()) as u64; + Ok(buf.len()) +} + +fn vec_write_vectored( + pos_mut: &mut u64, + vec: &mut Vec<u8>, + bufs: &[IoSlice<'_>], +) -> io::Result<usize> { + let mut nwritten = 0; + for buf in bufs { + nwritten += vec_write(pos_mut, vec, buf)?; + } + Ok(nwritten) +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl Write for Cursor<&mut [u8]> { + #[inline] + fn write(&mut self, buf: &[u8]) -> io::Result<usize> { + slice_write(&mut self.pos, self.inner, buf) + } + + #[inline] + fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { + slice_write_vectored(&mut self.pos, self.inner, bufs) + } + + #[inline] + fn is_write_vectored(&self) -> bool { + true + } + + #[inline] + fn flush(&mut self) -> io::Result<()> { + Ok(()) + } +} + +#[stable(feature = "cursor_mut_vec", since = "1.25.0")] +impl Write for Cursor<&mut Vec<u8>> { + fn write(&mut self, buf: &[u8]) -> io::Result<usize> { + vec_write(&mut self.pos, self.inner, buf) + } + + fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { + vec_write_vectored(&mut self.pos, self.inner, bufs) + } + + #[inline] + fn is_write_vectored(&self) -> bool { + true + } + + #[inline] + fn flush(&mut self) -> io::Result<()> { + Ok(()) + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl Write for Cursor<Vec<u8>> { + fn write(&mut self, buf: &[u8]) -> io::Result<usize> { + vec_write(&mut self.pos, &mut self.inner, buf) + } + + fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { + vec_write_vectored(&mut self.pos, &mut self.inner, bufs) + } + + #[inline] + fn is_write_vectored(&self) -> bool { + true + } + + #[inline] + fn flush(&mut self) -> io::Result<()> { + Ok(()) + } +} + +#[stable(feature = "cursor_box_slice", since = "1.5.0")] +impl Write for Cursor<Box<[u8]>> { + #[inline] + fn write(&mut self, buf: &[u8]) -> io::Result<usize> { + slice_write(&mut self.pos, &mut self.inner, buf) + } + + #[inline] + fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { + slice_write_vectored(&mut self.pos, &mut self.inner, bufs) + } + + #[inline] + fn is_write_vectored(&self) -> bool { + true + } + + #[inline] + fn flush(&mut self) -> io::Result<()> { + Ok(()) + } +} + +#[cfg(test)] +mod tests { + use crate::io::prelude::*; + use crate::io::{Cursor, IoSlice, IoSliceMut, SeekFrom}; + + #[test] + fn test_vec_writer() { + let mut writer = Vec::new(); + assert_eq!(writer.write(&[0]).unwrap(), 1); + assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3); + assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4); + assert_eq!( + writer + .write_vectored(&[IoSlice::new(&[]), IoSlice::new(&[8, 9]), IoSlice::new(&[10])],) + .unwrap(), + 3 + ); + let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + assert_eq!(writer, b); + } + + #[test] + fn test_mem_writer() { + let mut writer = Cursor::new(Vec::new()); + assert_eq!(writer.write(&[0]).unwrap(), 1); + assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3); + assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4); + assert_eq!( + writer + .write_vectored(&[IoSlice::new(&[]), IoSlice::new(&[8, 9]), IoSlice::new(&[10])],) + .unwrap(), + 3 + ); + let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + assert_eq!(&writer.get_ref()[..], b); + } + + #[test] + fn test_mem_mut_writer() { + let mut vec = Vec::new(); + let mut writer = Cursor::new(&mut vec); + assert_eq!(writer.write(&[0]).unwrap(), 1); + assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3); + assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4); + assert_eq!( + writer + .write_vectored(&[IoSlice::new(&[]), IoSlice::new(&[8, 9]), IoSlice::new(&[10])],) + .unwrap(), + 3 + ); + let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + assert_eq!(&writer.get_ref()[..], b); + } + + #[test] + fn test_box_slice_writer() { + let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice()); + assert_eq!(writer.position(), 0); + assert_eq!(writer.write(&[0]).unwrap(), 1); + assert_eq!(writer.position(), 1); + assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3); + assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4); + assert_eq!(writer.position(), 8); + assert_eq!(writer.write(&[]).unwrap(), 0); + assert_eq!(writer.position(), 8); + + assert_eq!(writer.write(&[8, 9]).unwrap(), 1); + assert_eq!(writer.write(&[10]).unwrap(), 0); + let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8]; + assert_eq!(&**writer.get_ref(), b); + } + + #[test] + fn test_box_slice_writer_vectored() { + let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice()); + assert_eq!(writer.position(), 0); + assert_eq!(writer.write_vectored(&[IoSlice::new(&[0])]).unwrap(), 1); + assert_eq!(writer.position(), 1); + assert_eq!( + writer + .write_vectored(&[IoSlice::new(&[1, 2, 3]), IoSlice::new(&[4, 5, 6, 7]),]) + .unwrap(), + 7, + ); + assert_eq!(writer.position(), 8); + assert_eq!(writer.write_vectored(&[]).unwrap(), 0); + assert_eq!(writer.position(), 8); + + assert_eq!(writer.write_vectored(&[IoSlice::new(&[8, 9])]).unwrap(), 1); + assert_eq!(writer.write_vectored(&[IoSlice::new(&[10])]).unwrap(), 0); + let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8]; + assert_eq!(&**writer.get_ref(), b); + } + + #[test] + fn test_buf_writer() { + let mut buf = [0 as u8; 9]; + { + let mut writer = Cursor::new(&mut buf[..]); + assert_eq!(writer.position(), 0); + assert_eq!(writer.write(&[0]).unwrap(), 1); + assert_eq!(writer.position(), 1); + assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3); + assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4); + assert_eq!(writer.position(), 8); + assert_eq!(writer.write(&[]).unwrap(), 0); + assert_eq!(writer.position(), 8); + + assert_eq!(writer.write(&[8, 9]).unwrap(), 1); + assert_eq!(writer.write(&[10]).unwrap(), 0); + } + let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8]; + assert_eq!(buf, b); + } + + #[test] + fn test_buf_writer_vectored() { + let mut buf = [0 as u8; 9]; + { + let mut writer = Cursor::new(&mut buf[..]); + assert_eq!(writer.position(), 0); + assert_eq!(writer.write_vectored(&[IoSlice::new(&[0])]).unwrap(), 1); + assert_eq!(writer.position(), 1); + assert_eq!( + writer + .write_vectored(&[IoSlice::new(&[1, 2, 3]), IoSlice::new(&[4, 5, 6, 7])],) + .unwrap(), + 7, + ); + assert_eq!(writer.position(), 8); + assert_eq!(writer.write_vectored(&[]).unwrap(), 0); + assert_eq!(writer.position(), 8); + + assert_eq!(writer.write_vectored(&[IoSlice::new(&[8, 9])]).unwrap(), 1); + assert_eq!(writer.write_vectored(&[IoSlice::new(&[10])]).unwrap(), 0); + } + let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8]; + assert_eq!(buf, b); + } + + #[test] + fn test_buf_writer_seek() { + let mut buf = [0 as u8; 8]; + { + let mut writer = Cursor::new(&mut buf[..]); + assert_eq!(writer.position(), 0); + assert_eq!(writer.write(&[1]).unwrap(), 1); + assert_eq!(writer.position(), 1); + + assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2); + assert_eq!(writer.position(), 2); + assert_eq!(writer.write(&[2]).unwrap(), 1); + assert_eq!(writer.position(), 3); + + assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1); + assert_eq!(writer.position(), 1); + assert_eq!(writer.write(&[3]).unwrap(), 1); + assert_eq!(writer.position(), 2); + + assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7); + assert_eq!(writer.position(), 7); + assert_eq!(writer.write(&[4]).unwrap(), 1); + assert_eq!(writer.position(), 8); + } + let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4]; + assert_eq!(buf, b); + } + + #[test] + fn test_buf_writer_error() { + let mut buf = [0 as u8; 2]; + let mut writer = Cursor::new(&mut buf[..]); + assert_eq!(writer.write(&[0]).unwrap(), 1); + assert_eq!(writer.write(&[0, 0]).unwrap(), 1); + assert_eq!(writer.write(&[0, 0]).unwrap(), 0); + } + + #[test] + fn test_mem_reader() { + let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]); + let mut buf = []; + assert_eq!(reader.read(&mut buf).unwrap(), 0); + assert_eq!(reader.position(), 0); + let mut buf = [0]; + assert_eq!(reader.read(&mut buf).unwrap(), 1); + assert_eq!(reader.position(), 1); + let b: &[_] = &[0]; + assert_eq!(buf, b); + let mut buf = [0; 4]; + assert_eq!(reader.read(&mut buf).unwrap(), 4); + assert_eq!(reader.position(), 5); + let b: &[_] = &[1, 2, 3, 4]; + assert_eq!(buf, b); + assert_eq!(reader.read(&mut buf).unwrap(), 3); + let b: &[_] = &[5, 6, 7]; + assert_eq!(&buf[..3], b); + assert_eq!(reader.read(&mut buf).unwrap(), 0); + } + + #[test] + fn test_mem_reader_vectored() { + let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]); + let mut buf = []; + assert_eq!(reader.read_vectored(&mut [IoSliceMut::new(&mut buf)]).unwrap(), 0); + assert_eq!(reader.position(), 0); + let mut buf = [0]; + assert_eq!( + reader + .read_vectored(&mut [IoSliceMut::new(&mut []), IoSliceMut::new(&mut buf),]) + .unwrap(), + 1, + ); + assert_eq!(reader.position(), 1); + let b: &[_] = &[0]; + assert_eq!(buf, b); + let mut buf1 = [0; 4]; + let mut buf2 = [0; 4]; + assert_eq!( + reader + .read_vectored(&mut [IoSliceMut::new(&mut buf1), IoSliceMut::new(&mut buf2),]) + .unwrap(), + 7, + ); + let b1: &[_] = &[1, 2, 3, 4]; + let b2: &[_] = &[5, 6, 7]; + assert_eq!(buf1, b1); + assert_eq!(&buf2[..3], b2); + assert_eq!(reader.read(&mut buf).unwrap(), 0); + } + + #[test] + fn test_boxed_slice_reader() { + let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7].into_boxed_slice()); + let mut buf = []; + assert_eq!(reader.read(&mut buf).unwrap(), 0); + assert_eq!(reader.position(), 0); + let mut buf = [0]; + assert_eq!(reader.read(&mut buf).unwrap(), 1); + assert_eq!(reader.position(), 1); + let b: &[_] = &[0]; + assert_eq!(buf, b); + let mut buf = [0; 4]; + assert_eq!(reader.read(&mut buf).unwrap(), 4); + assert_eq!(reader.position(), 5); + let b: &[_] = &[1, 2, 3, 4]; + assert_eq!(buf, b); + assert_eq!(reader.read(&mut buf).unwrap(), 3); + let b: &[_] = &[5, 6, 7]; + assert_eq!(&buf[..3], b); + assert_eq!(reader.read(&mut buf).unwrap(), 0); + } + + #[test] + fn test_boxed_slice_reader_vectored() { + let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7].into_boxed_slice()); + let mut buf = []; + assert_eq!(reader.read_vectored(&mut [IoSliceMut::new(&mut buf)]).unwrap(), 0); + assert_eq!(reader.position(), 0); + let mut buf = [0]; + assert_eq!( + reader + .read_vectored(&mut [IoSliceMut::new(&mut []), IoSliceMut::new(&mut buf),]) + .unwrap(), + 1, + ); + assert_eq!(reader.position(), 1); + let b: &[_] = &[0]; + assert_eq!(buf, b); + let mut buf1 = [0; 4]; + let mut buf2 = [0; 4]; + assert_eq!( + reader + .read_vectored(&mut [IoSliceMut::new(&mut buf1), IoSliceMut::new(&mut buf2)],) + .unwrap(), + 7, + ); + let b1: &[_] = &[1, 2, 3, 4]; + let b2: &[_] = &[5, 6, 7]; + assert_eq!(buf1, b1); + assert_eq!(&buf2[..3], b2); + assert_eq!(reader.read(&mut buf).unwrap(), 0); + } + + #[test] + fn read_to_end() { + let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]); + let mut v = Vec::new(); + reader.read_to_end(&mut v).unwrap(); + assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]); + } + + #[test] + fn test_slice_reader() { + let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7]; + let reader = &mut &in_buf[..]; + let mut buf = []; + assert_eq!(reader.read(&mut buf).unwrap(), 0); + let mut buf = [0]; + assert_eq!(reader.read(&mut buf).unwrap(), 1); + assert_eq!(reader.len(), 7); + let b: &[_] = &[0]; + assert_eq!(&buf[..], b); + let mut buf = [0; 4]; + assert_eq!(reader.read(&mut buf).unwrap(), 4); + assert_eq!(reader.len(), 3); + let b: &[_] = &[1, 2, 3, 4]; + assert_eq!(&buf[..], b); + assert_eq!(reader.read(&mut buf).unwrap(), 3); + let b: &[_] = &[5, 6, 7]; + assert_eq!(&buf[..3], b); + assert_eq!(reader.read(&mut buf).unwrap(), 0); + } + + #[test] + fn test_slice_reader_vectored() { + let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7]; + let reader = &mut &in_buf[..]; + let mut buf = []; + assert_eq!(reader.read_vectored(&mut [IoSliceMut::new(&mut buf)]).unwrap(), 0); + let mut buf = [0]; + assert_eq!( + reader + .read_vectored(&mut [IoSliceMut::new(&mut []), IoSliceMut::new(&mut buf),]) + .unwrap(), + 1, + ); + assert_eq!(reader.len(), 7); + let b: &[_] = &[0]; + assert_eq!(buf, b); + let mut buf1 = [0; 4]; + let mut buf2 = [0; 4]; + assert_eq!( + reader + .read_vectored(&mut [IoSliceMut::new(&mut buf1), IoSliceMut::new(&mut buf2)],) + .unwrap(), + 7, + ); + let b1: &[_] = &[1, 2, 3, 4]; + let b2: &[_] = &[5, 6, 7]; + assert_eq!(buf1, b1); + assert_eq!(&buf2[..3], b2); + assert_eq!(reader.read(&mut buf).unwrap(), 0); + } + + #[test] + fn test_read_exact() { + let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7]; + let reader = &mut &in_buf[..]; + let mut buf = []; + assert!(reader.read_exact(&mut buf).is_ok()); + let mut buf = [8]; + assert!(reader.read_exact(&mut buf).is_ok()); + assert_eq!(buf[0], 0); + assert_eq!(reader.len(), 7); + let mut buf = [0, 0, 0, 0, 0, 0, 0]; + assert!(reader.read_exact(&mut buf).is_ok()); + assert_eq!(buf, [1, 2, 3, 4, 5, 6, 7]); + assert_eq!(reader.len(), 0); + let mut buf = [0]; + assert!(reader.read_exact(&mut buf).is_err()); + } + + #[test] + fn test_buf_reader() { + let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7]; + let mut reader = Cursor::new(&in_buf[..]); + let mut buf = []; + assert_eq!(reader.read(&mut buf).unwrap(), 0); + assert_eq!(reader.position(), 0); + let mut buf = [0]; + assert_eq!(reader.read(&mut buf).unwrap(), 1); + assert_eq!(reader.position(), 1); + let b: &[_] = &[0]; + assert_eq!(buf, b); + let mut buf = [0; 4]; + assert_eq!(reader.read(&mut buf).unwrap(), 4); + assert_eq!(reader.position(), 5); + let b: &[_] = &[1, 2, 3, 4]; + assert_eq!(buf, b); + assert_eq!(reader.read(&mut buf).unwrap(), 3); + let b: &[_] = &[5, 6, 7]; + assert_eq!(&buf[..3], b); + assert_eq!(reader.read(&mut buf).unwrap(), 0); + } + + #[test] + fn seek_past_end() { + let buf = [0xff]; + let mut r = Cursor::new(&buf[..]); + assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10); + assert_eq!(r.read(&mut [0]).unwrap(), 0); + + let mut r = Cursor::new(vec![10]); + assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10); + assert_eq!(r.read(&mut [0]).unwrap(), 0); + + let mut buf = [0]; + let mut r = Cursor::new(&mut buf[..]); + assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10); + assert_eq!(r.write(&[3]).unwrap(), 0); + + let mut r = Cursor::new(vec![10].into_boxed_slice()); + assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10); + assert_eq!(r.write(&[3]).unwrap(), 0); + } + + #[test] + fn seek_past_i64() { + let buf = [0xff]; + let mut r = Cursor::new(&buf[..]); + assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6); + assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6); + assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006); + assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006); + assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err()); + assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6); + + let mut r = Cursor::new(vec![10]); + assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6); + assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6); + assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006); + assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006); + assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err()); + assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6); + + let mut buf = [0]; + let mut r = Cursor::new(&mut buf[..]); + assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6); + assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6); + assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006); + assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006); + assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err()); + assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6); + + let mut r = Cursor::new(vec![10].into_boxed_slice()); + assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6); + assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6); + assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006); + assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006); + assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err()); + assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6); + } + + #[test] + fn seek_before_0() { + let buf = [0xff]; + let mut r = Cursor::new(&buf[..]); + assert!(r.seek(SeekFrom::End(-2)).is_err()); + + let mut r = Cursor::new(vec![10]); + assert!(r.seek(SeekFrom::End(-2)).is_err()); + + let mut buf = [0]; + let mut r = Cursor::new(&mut buf[..]); + assert!(r.seek(SeekFrom::End(-2)).is_err()); + + let mut r = Cursor::new(vec![10].into_boxed_slice()); + assert!(r.seek(SeekFrom::End(-2)).is_err()); + } + + #[test] + fn test_seekable_mem_writer() { + let mut writer = Cursor::new(Vec::<u8>::new()); + assert_eq!(writer.position(), 0); + assert_eq!(writer.write(&[0]).unwrap(), 1); + assert_eq!(writer.position(), 1); + assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3); + assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4); + assert_eq!(writer.position(), 8); + let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7]; + assert_eq!(&writer.get_ref()[..], b); + + assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0); + assert_eq!(writer.position(), 0); + assert_eq!(writer.write(&[3, 4]).unwrap(), 2); + let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7]; + assert_eq!(&writer.get_ref()[..], b); + + assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3); + assert_eq!(writer.write(&[0, 1]).unwrap(), 2); + let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7]; + assert_eq!(&writer.get_ref()[..], b); + + assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7); + assert_eq!(writer.write(&[1, 2]).unwrap(), 2); + let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2]; + assert_eq!(&writer.get_ref()[..], b); + + assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10); + assert_eq!(writer.write(&[1]).unwrap(), 1); + let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1]; + assert_eq!(&writer.get_ref()[..], b); + } + + #[test] + fn vec_seek_past_end() { + let mut r = Cursor::new(Vec::new()); + assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10); + assert_eq!(r.write(&[3]).unwrap(), 1); + } + + #[test] + fn vec_seek_before_0() { + let mut r = Cursor::new(Vec::new()); + assert!(r.seek(SeekFrom::End(-2)).is_err()); + } + + #[test] + #[cfg(target_pointer_width = "32")] + fn vec_seek_and_write_past_usize_max() { + let mut c = Cursor::new(Vec::new()); + c.set_position(usize::MAX as u64 + 1); + assert!(c.write_all(&[1, 2, 3]).is_err()); + } + + #[test] + fn test_partial_eq() { + assert_eq!(Cursor::new(Vec::<u8>::new()), Cursor::new(Vec::<u8>::new())); + } + + #[test] + fn test_eq() { + struct AssertEq<T: Eq>(pub T); + + let _: AssertEq<Cursor<Vec<u8>>> = AssertEq(Cursor::new(Vec::new())); + } +} |