[−][src]Struct olio::fs::ReadSlice
Re-implements Read
and Seek
over PosRead
using only positioned
reads, and by maintaining instance independent start, end, and position.
PosRead
is implemented for any Borrow<File>
so
this can own via ReadSlice<File>
or use a shared reference, as in
ReadSlice<&File>
or ReadSlice<Arc<File>>
.
As compared with ReadPos
, ReadSlice
adds a
general start offset, and limits access to the start..end range. Seeks are
relative, so a seek to SeekFrom::Start(0)
is always the first byte of
the slice.
Fixed start
and end
offsets are passed on construction and used to
constrain reads and interpret SeekFrom::Start
and SeekFrom::End
. These
offsets are neither checked against nor updated from the inner PosRead
(for example via file metadata) and could deviate if concurrent writes or
truncation is possible. Reads beyond end
or the end of the inner
PosRead
will return 0 length. Seeking past the end is allowed by the
platforms for File
, and is also allowed for ReadSlice
.
Methods
impl<P> ReadSlice<P> where
P: PosRead,
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P: PosRead,
pub fn new(pos_read: P, start: u64, end: u64) -> Self
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New instance by PosRead
instance, fixed start and end offsets. The
initial position is at the start (relative offset 0).
pub fn len(&self) -> u64
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Return the total size of the slice in bytes. This is based on the
start and end offsets as constructed and can differ from the inner
PosRead
length.
pub fn is_empty(&self) -> bool
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Return true
if length is 0.
pub fn tell(&self) -> u64
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Return the current instance position, relative to the slice. This is a
convenience shorthand for seek(SeekFrom::Current(0))
, is infallable,
and does not require a mutable reference.
impl<P> ReadSlice<P> where
P: PosRead + Clone,
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P: PosRead + Clone,
ⓘImportant traits for ReadSlice<P>pub fn subslice(&self, start: u64, end: u64) -> ReadSlice<P>
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Return a new and independent ReadSlice
by clone of the inner
PosRead
, for the range of byte offsets start..end
which are
relative to, and must be fully contained by self. This implementation
panics on overflow, if start..end is not fully contained, or if
start is greater-than end.
impl<P> ReadSlice<P> where
P: PosRead + Borrow<File>,
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P: PosRead + Borrow<File>,
pub fn mem_map(&self) -> Result<Mmap, Error>
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Return a new read-only memory map handle Mmap
for the complete
region of the underlying File
, from start to end.
Trait Implementations
impl<P> PosRead for ReadSlice<P> where
P: PosRead,
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P: PosRead,
impl<P> Clone for ReadSlice<P> where
P: PosRead + Clone,
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P: PosRead + Clone,
fn clone(&self) -> Self
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Return a new, independent ReadSlice
by clone of the inner PosRead
,
with the same start and end as self, and positioned at start.
fn clone_from(&mut self, source: &Self)
1.0.0[src]
impl<P: Debug> Debug for ReadSlice<P> where
P: PosRead,
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P: PosRead,
impl<P> Read for ReadSlice<P> where
P: PosRead,
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P: PosRead,
fn read(&mut self, buf: &mut [u8]) -> Result<usize>
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fn read_vectored(&mut self, bufs: &mut [IoSliceMut]) -> Result<usize, Error>
1.36.0[src]
unsafe fn initializer(&self) -> Initializer
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fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>
1.0.0[src]
fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>
1.0.0[src]
fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>
1.6.0[src]
fn by_ref(&mut self) -> &mut Self
1.0.0[src]
fn bytes(self) -> Bytes<Self>
1.0.0[src]
fn chain<R>(self, next: R) -> Chain<Self, R> where
R: Read,
1.0.0[src]
R: Read,
fn take(self, limit: u64) -> Take<Self>
1.0.0[src]
impl<P> Seek for ReadSlice<P> where
P: PosRead,
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P: PosRead,
fn seek(&mut self, from: SeekFrom) -> Result<u64>
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Seek to an offset, in bytes, in a stream. In this implementation,
seeks are relative to the fixed start offset so a seek to
SeekFrom::Start(0)
is always the first byte of the slice.
fn stream_len(&mut self) -> Result<u64, Error>
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fn stream_position(&mut self) -> Result<u64, Error>
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Auto Trait Implementations
impl<P> Send for ReadSlice<P> where
P: Send,
P: Send,
impl<P> Sync for ReadSlice<P> where
P: Sync,
P: Sync,
impl<P> Unpin for ReadSlice<P> where
P: Unpin,
P: Unpin,
impl<P> RefUnwindSafe for ReadSlice<P> where
P: RefUnwindSafe,
P: RefUnwindSafe,
impl<P> UnwindSafe for ReadSlice<P> where
P: UnwindSafe,
P: UnwindSafe,
Blanket Implementations
impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,