Trait bytes::buf::Buf [−][src]
Read bytes from a buffer.
A buffer stores bytes in memory such that read operations are infallible.
The underlying storage may or may not be in contiguous memory. A Buf
value
is a cursor into the buffer. Reading from Buf
advances the cursor
position. It can be thought of as an efficient Iterator
for collections of
bytes.
The simplest Buf
is a &[u8]
.
use bytes::Buf; let mut buf = &b"hello world"[..]; assert_eq!(b'h', buf.get_u8()); assert_eq!(b'e', buf.get_u8()); assert_eq!(b'l', buf.get_u8()); let mut rest = [0; 8]; buf.copy_to_slice(&mut rest); assert_eq!(&rest[..], &b"lo world"[..]);
Required methods
fn remaining(&self) -> usize
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Returns the number of bytes between the current position and the end of the buffer.
This value is greater than or equal to the length of the slice returned
by bytes
.
Examples
use bytes::Buf; let mut buf = &b"hello world"[..]; assert_eq!(buf.remaining(), 11); buf.get_u8(); assert_eq!(buf.remaining(), 10);
Implementer notes
Implementations of remaining
should ensure that the return value does
not change unless a call is made to advance
or any other function that
is documented to change the Buf
’s current position.
fn bytes(&self) -> &[u8]ⓘ
[src]
Returns a slice starting at the current position and of length between 0
and Buf::remaining()
. Note that this can return shorter slice (this allows
non-continuous internal representation).
This is a lower level function. Most operations are done with other functions.
Examples
use bytes::Buf; let mut buf = &b"hello world"[..]; assert_eq!(buf.bytes(), &b"hello world"[..]); buf.advance(6); assert_eq!(buf.bytes(), &b"world"[..]);
Implementer notes
This function should never panic. Once the end of the buffer is reached,
i.e., Buf::remaining
returns 0, calls to bytes
should return an
empty slice.
fn advance(&mut self, cnt: usize)
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Advance the internal cursor of the Buf
The next call to bytes
will return a slice starting cnt
bytes
further into the underlying buffer.
Examples
use bytes::Buf; let mut buf = &b"hello world"[..]; assert_eq!(buf.bytes(), &b"hello world"[..]); buf.advance(6); assert_eq!(buf.bytes(), &b"world"[..]);
Panics
This function may panic if cnt > self.remaining()
.
Implementer notes
It is recommended for implementations of advance
to panic if cnt > self.remaining()
. If the implementation does not panic, the call must
behave as if cnt == self.remaining()
.
A call with cnt == 0
should never panic and be a no-op.
Provided methods
fn bytes_vectored<'a>(&'a self, dst: &mut [IoSlice<'a>]) -> usize
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Fills dst
with potentially multiple slices starting at self
’s
current position.
If the Buf
is backed by disjoint slices of bytes, bytes_vectored
enables
fetching more than one slice at once. dst
is a slice of IoSlice
references, enabling the slice to be directly used with writev
without any further conversion. The sum of the lengths of all the
buffers in dst
will be less than or equal to Buf::remaining()
.
The entries in dst
will be overwritten, but the data contained by
the slices will not be modified. If bytes_vectored
does not fill every
entry in dst
, then dst
is guaranteed to contain all remaining slices
in `self.
This is a lower level function. Most operations are done with other functions.
Implementer notes
This function should never panic. Once the end of the buffer is reached,
i.e., Buf::remaining
returns 0, calls to bytes_vectored
must return 0
without mutating dst
.
Implementations should also take care to properly handle being called
with dst
being a zero length slice.
fn has_remaining(&self) -> bool
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Returns true if there are any more bytes to consume
This is equivalent to self.remaining() != 0
.
Examples
use bytes::Buf; let mut buf = &b"a"[..]; assert!(buf.has_remaining()); buf.get_u8(); assert!(!buf.has_remaining());
fn copy_to_slice(&mut self, dst: &mut [u8])
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Copies bytes from self
into dst
.
The cursor is advanced by the number of bytes copied. self
must have
enough remaining bytes to fill dst
.
Examples
use bytes::Buf; let mut buf = &b"hello world"[..]; let mut dst = [0; 5]; buf.copy_to_slice(&mut dst); assert_eq!(&b"hello"[..], &dst); assert_eq!(6, buf.remaining());
Panics
This function panics if self.remaining() < dst.len()
fn get_u8(&mut self) -> u8
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Gets an unsigned 8 bit integer from self
.
The current position is advanced by 1.
Examples
use bytes::Buf; let mut buf = &b"\x08 hello"[..]; assert_eq!(8, buf.get_u8());
Panics
This function panics if there is no more remaining data in self
.
fn get_i8(&mut self) -> i8
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Gets a signed 8 bit integer from self
.
The current position is advanced by 1.
Examples
use bytes::Buf; let mut buf = &b"\x08 hello"[..]; assert_eq!(8, buf.get_i8());
Panics
This function panics if there is no more remaining data in self
.
fn get_u16(&mut self) -> u16
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Gets an unsigned 16 bit integer from self
in big-endian byte order.
The current position is advanced by 2.
Examples
use bytes::Buf; let mut buf = &b"\x08\x09 hello"[..]; assert_eq!(0x0809, buf.get_u16());
Panics
This function panics if there is not enough remaining data in self
.
fn get_u16_le(&mut self) -> u16
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Gets an unsigned 16 bit integer from self
in little-endian byte order.
The current position is advanced by 2.
Examples
use bytes::Buf; let mut buf = &b"\x09\x08 hello"[..]; assert_eq!(0x0809, buf.get_u16_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i16(&mut self) -> i16
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Gets a signed 16 bit integer from self
in big-endian byte order.
The current position is advanced by 2.
Examples
use bytes::Buf; let mut buf = &b"\x08\x09 hello"[..]; assert_eq!(0x0809, buf.get_i16());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i16_le(&mut self) -> i16
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Gets a signed 16 bit integer from self
in little-endian byte order.
The current position is advanced by 2.
Examples
use bytes::Buf; let mut buf = &b"\x09\x08 hello"[..]; assert_eq!(0x0809, buf.get_i16_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_u32(&mut self) -> u32
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Gets an unsigned 32 bit integer from self
in the big-endian byte order.
The current position is advanced by 4.
Examples
use bytes::Buf; let mut buf = &b"\x08\x09\xA0\xA1 hello"[..]; assert_eq!(0x0809A0A1, buf.get_u32());
Panics
This function panics if there is not enough remaining data in self
.
fn get_u32_le(&mut self) -> u32
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Gets an unsigned 32 bit integer from self
in the little-endian byte order.
The current position is advanced by 4.
Examples
use bytes::Buf; let mut buf = &b"\xA1\xA0\x09\x08 hello"[..]; assert_eq!(0x0809A0A1, buf.get_u32_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i32(&mut self) -> i32
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Gets a signed 32 bit integer from self
in big-endian byte order.
The current position is advanced by 4.
Examples
use bytes::Buf; let mut buf = &b"\x08\x09\xA0\xA1 hello"[..]; assert_eq!(0x0809A0A1, buf.get_i32());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i32_le(&mut self) -> i32
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Gets a signed 32 bit integer from self
in little-endian byte order.
The current position is advanced by 4.
Examples
use bytes::Buf; let mut buf = &b"\xA1\xA0\x09\x08 hello"[..]; assert_eq!(0x0809A0A1, buf.get_i32_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_u64(&mut self) -> u64
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Gets an unsigned 64 bit integer from self
in big-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf; let mut buf = &b"\x01\x02\x03\x04\x05\x06\x07\x08 hello"[..]; assert_eq!(0x0102030405060708, buf.get_u64());
Panics
This function panics if there is not enough remaining data in self
.
fn get_u64_le(&mut self) -> u64
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Gets an unsigned 64 bit integer from self
in little-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf; let mut buf = &b"\x08\x07\x06\x05\x04\x03\x02\x01 hello"[..]; assert_eq!(0x0102030405060708, buf.get_u64_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i64(&mut self) -> i64
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Gets a signed 64 bit integer from self
in big-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf; let mut buf = &b"\x01\x02\x03\x04\x05\x06\x07\x08 hello"[..]; assert_eq!(0x0102030405060708, buf.get_i64());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i64_le(&mut self) -> i64
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Gets a signed 64 bit integer from self
in little-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf; let mut buf = &b"\x08\x07\x06\x05\x04\x03\x02\x01 hello"[..]; assert_eq!(0x0102030405060708, buf.get_i64_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_u128(&mut self) -> u128
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Gets an unsigned 128 bit integer from self
in big-endian byte order.
The current position is advanced by 16.
Examples
use bytes::Buf; let mut buf = &b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16 hello"[..]; assert_eq!(0x01020304050607080910111213141516, buf.get_u128());
Panics
This function panics if there is not enough remaining data in self
.
fn get_u128_le(&mut self) -> u128
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Gets an unsigned 128 bit integer from self
in little-endian byte order.
The current position is advanced by 16.
Examples
use bytes::Buf; let mut buf = &b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01 hello"[..]; assert_eq!(0x01020304050607080910111213141516, buf.get_u128_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i128(&mut self) -> i128
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Gets a signed 128 bit integer from self
in big-endian byte order.
The current position is advanced by 16.
Examples
use bytes::Buf; let mut buf = &b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16 hello"[..]; assert_eq!(0x01020304050607080910111213141516, buf.get_i128());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i128_le(&mut self) -> i128
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Gets a signed 128 bit integer from self
in little-endian byte order.
The current position is advanced by 16.
Examples
use bytes::Buf; let mut buf = &b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01 hello"[..]; assert_eq!(0x01020304050607080910111213141516, buf.get_i128_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_uint(&mut self, nbytes: usize) -> u64
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Gets an unsigned n-byte integer from self
in big-endian byte order.
The current position is advanced by nbytes
.
Examples
use bytes::Buf; let mut buf = &b"\x01\x02\x03 hello"[..]; assert_eq!(0x010203, buf.get_uint(3));
Panics
This function panics if there is not enough remaining data in self
.
fn get_uint_le(&mut self, nbytes: usize) -> u64
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Gets an unsigned n-byte integer from self
in little-endian byte order.
The current position is advanced by nbytes
.
Examples
use bytes::Buf; let mut buf = &b"\x03\x02\x01 hello"[..]; assert_eq!(0x010203, buf.get_uint_le(3));
Panics
This function panics if there is not enough remaining data in self
.
fn get_int(&mut self, nbytes: usize) -> i64
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Gets a signed n-byte integer from self
in big-endian byte order.
The current position is advanced by nbytes
.
Examples
use bytes::Buf; let mut buf = &b"\x01\x02\x03 hello"[..]; assert_eq!(0x010203, buf.get_int(3));
Panics
This function panics if there is not enough remaining data in self
.
fn get_int_le(&mut self, nbytes: usize) -> i64
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Gets a signed n-byte integer from self
in little-endian byte order.
The current position is advanced by nbytes
.
Examples
use bytes::Buf; let mut buf = &b"\x03\x02\x01 hello"[..]; assert_eq!(0x010203, buf.get_int_le(3));
Panics
This function panics if there is not enough remaining data in self
.
fn get_f32(&mut self) -> f32
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Gets an IEEE754 single-precision (4 bytes) floating point number from
self
in big-endian byte order.
The current position is advanced by 4.
Examples
use bytes::Buf; let mut buf = &b"\x3F\x99\x99\x9A hello"[..]; assert_eq!(1.2f32, buf.get_f32());
Panics
This function panics if there is not enough remaining data in self
.
fn get_f32_le(&mut self) -> f32
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Gets an IEEE754 single-precision (4 bytes) floating point number from
self
in little-endian byte order.
The current position is advanced by 4.
Examples
use bytes::Buf; let mut buf = &b"\x9A\x99\x99\x3F hello"[..]; assert_eq!(1.2f32, buf.get_f32_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_f64(&mut self) -> f64
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Gets an IEEE754 double-precision (8 bytes) floating point number from
self
in big-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf; let mut buf = &b"\x3F\xF3\x33\x33\x33\x33\x33\x33 hello"[..]; assert_eq!(1.2f64, buf.get_f64());
Panics
This function panics if there is not enough remaining data in self
.
fn get_f64_le(&mut self) -> f64
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Gets an IEEE754 double-precision (8 bytes) floating point number from
self
in little-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf; let mut buf = &b"\x33\x33\x33\x33\x33\x33\xF3\x3F hello"[..]; assert_eq!(1.2f64, buf.get_f64_le());
Panics
This function panics if there is not enough remaining data in self
.
fn to_bytes(&mut self) -> Bytes
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Consumes remaining bytes inside self and returns new instance of Bytes
Examples
use bytes::Buf; let bytes = (&b"hello world"[..]).to_bytes(); assert_eq!(&bytes[..], &b"hello world"[..]);
Implementations on Foreign Types
impl<T: Buf + ?Sized> Buf for &mut T
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fn remaining(&self) -> usize
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fn bytes(&self) -> &[u8]ⓘ
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fn bytes_vectored<'b>(&'b self, dst: &mut [IoSlice<'b>]) -> usize
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fn advance(&mut self, cnt: usize)
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fn has_remaining(&self) -> bool
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fn copy_to_slice(&mut self, dst: &mut [u8])
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fn get_u8(&mut self) -> u8
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fn get_i8(&mut self) -> i8
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fn get_u16(&mut self) -> u16
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fn get_u16_le(&mut self) -> u16
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fn get_i16(&mut self) -> i16
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fn get_i16_le(&mut self) -> i16
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fn get_u32(&mut self) -> u32
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fn get_u32_le(&mut self) -> u32
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fn get_i32(&mut self) -> i32
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fn get_i32_le(&mut self) -> i32
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fn get_u64(&mut self) -> u64
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fn get_u64_le(&mut self) -> u64
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fn get_i64(&mut self) -> i64
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fn get_i64_le(&mut self) -> i64
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fn get_uint(&mut self, nbytes: usize) -> u64
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fn get_uint_le(&mut self, nbytes: usize) -> u64
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fn get_int(&mut self, nbytes: usize) -> i64
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fn get_int_le(&mut self, nbytes: usize) -> i64
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fn to_bytes(&mut self) -> Bytes
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impl<T: Buf + ?Sized> Buf for Box<T>
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fn remaining(&self) -> usize
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fn bytes(&self) -> &[u8]ⓘ
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fn bytes_vectored<'b>(&'b self, dst: &mut [IoSlice<'b>]) -> usize
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fn advance(&mut self, cnt: usize)
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fn has_remaining(&self) -> bool
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fn copy_to_slice(&mut self, dst: &mut [u8])
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fn get_u8(&mut self) -> u8
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fn get_i8(&mut self) -> i8
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fn get_u16(&mut self) -> u16
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fn get_u16_le(&mut self) -> u16
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fn get_i16(&mut self) -> i16
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fn get_i16_le(&mut self) -> i16
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fn get_u32(&mut self) -> u32
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fn get_u32_le(&mut self) -> u32
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fn get_i32(&mut self) -> i32
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fn get_i32_le(&mut self) -> i32
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fn get_u64(&mut self) -> u64
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fn get_u64_le(&mut self) -> u64
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fn get_i64(&mut self) -> i64
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fn get_i64_le(&mut self) -> i64
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fn get_uint(&mut self, nbytes: usize) -> u64
[src]
fn get_uint_le(&mut self, nbytes: usize) -> u64
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fn get_int(&mut self, nbytes: usize) -> i64
[src]
fn get_int_le(&mut self, nbytes: usize) -> i64
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fn to_bytes(&mut self) -> Bytes
[src]
impl Buf for &[u8]
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fn remaining(&self) -> usize
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fn bytes(&self) -> &[u8]ⓘ
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fn advance(&mut self, cnt: usize)
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impl Buf for Option<[u8; 1]>
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fn remaining(&self) -> usize
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fn bytes(&self) -> &[u8]ⓘ
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fn advance(&mut self, cnt: usize)
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impl<T: AsRef<[u8]>> Buf for Cursor<T>
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fn remaining(&self) -> usize
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fn bytes(&self) -> &[u8]ⓘ
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fn advance(&mut self, cnt: usize)
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impl Buf for VecDeque<u8>
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fn remaining(&self) -> usize
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fn bytes(&self) -> &[u8]ⓘ
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fn advance(&mut self, cnt: usize)
[src]
Implementors
impl Buf for Bytes
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fn remaining(&self) -> usize
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fn bytes(&self) -> &[u8]ⓘ
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fn advance(&mut self, cnt: usize)
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fn to_bytes(&mut self) -> Bytes
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impl Buf for BytesMut
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fn remaining(&self) -> usize
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fn bytes(&self) -> &[u8]ⓘ
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fn advance(&mut self, cnt: usize)
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fn to_bytes(&mut self) -> Bytes
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impl<T, U> Buf for Chain<T, U> where
T: Buf,
U: Buf,
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T: Buf,
U: Buf,