Quelle buf_mut.rs
Sprache: unbekannt
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use crate::buf::{limit, Chain, Limit, UninitSlice};
#[cfg(feature = "std")]
use crate::buf::{writer, Writer};
use core::{cmp, mem, ptr, usize};
use alloc::{boxed::Box, vec::Vec};
/// A trait for values that provide sequential write access to bytes.
///
/// Write bytes to a buffer
///
/// A buffer stores bytes in memory such that write operations are infallible.
/// The underlying storage may or may not be in contiguous memory. A `BufMut`
/// value is a cursor into the buffer. Writing to `BufMut` advances the cursor
/// position.
///
/// The simplest `BufMut` is a `Vec<u8>`.
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
///
/// buf.put(&b"hello world"[..]);
///
/// assert_eq!(buf, b"hello world");
/// ```
pub unsafe trait BufMut {
/// Returns the number of bytes that can be written from the current
/// position until the end of the buffer is reached.
///
/// This value is greater than or equal to the length of the slice returned
/// by `chunk_mut()`.
///
/// Writing to a `BufMut` may involve allocating more memory on the fly.
/// Implementations may fail before reaching the number of bytes indicated
/// by this method if they encounter an allocation failure.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut dst = [0; 10];
/// let mut buf = &mut dst[..];
///
/// let original_remaining = buf.remaining_mut();
/// buf.put(&b"hello"[..]);
///
/// assert_eq!(original_remaining - 5, buf.remaining_mut());
/// ```
///
/// # Implementer notes
///
/// Implementations of `remaining_mut` should ensure that the return value
/// does not change unless a call is made to `advance_mut` or any other
/// function that is documented to change the `BufMut`'s current position.
///
/// # Note
///
/// `remaining_mut` may return value smaller than actual available space.
fn remaining_mut(&self) -> usize;
/// Advance the internal cursor of the BufMut
///
/// The next call to `chunk_mut` will return a slice starting `cnt` bytes
/// further into the underlying buffer.
///
/// This function is unsafe because there is no guarantee that the bytes
/// being advanced past have been initialized.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = Vec::with_capacity(16);
///
/// // Write some data
/// buf.chunk_mut()[0..2].copy_from_slice(b"he");
/// unsafe { buf.advance_mut(2) };
///
/// // write more bytes
/// buf.chunk_mut()[0..3].copy_from_slice(b"llo");
///
/// unsafe { buf.advance_mut(3); }
///
/// assert_eq!(5, buf.len());
/// assert_eq!(buf, b"hello");
/// ```
///
/// # Panics
///
/// This function **may** panic if `cnt > self.remaining_mut()`.
///
/// # Implementer notes
///
/// It is recommended for implementations of `advance_mut` to panic if
/// `cnt > self.remaining_mut()`. If the implementation does not panic,
/// the call must behave as if `cnt == self.remaining_mut()`.
///
/// A call with `cnt == 0` should never panic and be a no-op.
unsafe fn advance_mut(&mut self, cnt: usize);
/// Returns true if there is space in `self` for more bytes.
///
/// This is equivalent to `self.remaining_mut() != 0`.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut dst = [0; 5];
/// let mut buf = &mut dst[..];
///
/// assert!(buf.has_remaining_mut());
///
/// buf.put(&b"hello"[..]);
///
/// assert!(!buf.has_remaining_mut());
/// ```
fn has_remaining_mut(&self) -> bool {
self.remaining_mut() > 0
}
/// Returns a mutable slice starting at the current BufMut position and of
/// length between 0 and `BufMut::remaining_mut()`. Note that this *can* be shorter than the
/// whole remainder of the buffer (this allows non-continuous implementation).
///
/// This is a lower level function. Most operations are done with other
/// functions.
///
/// The returned byte slice may represent uninitialized memory.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = Vec::with_capacity(16);
///
/// unsafe {
/// // MaybeUninit::as_mut_ptr
/// buf.chunk_mut()[0..].as_mut_ptr().write(b'h');
/// buf.chunk_mut()[1..].as_mut_ptr().write(b'e');
///
/// buf.advance_mut(2);
///
/// buf.chunk_mut()[0..].as_mut_ptr().write(b'l');
/// buf.chunk_mut()[1..].as_mut_ptr().write(b'l');
/// buf.chunk_mut()[2..].as_mut_ptr().write(b'o');
///
/// buf.advance_mut(3);
/// }
///
/// assert_eq!(5, buf.len());
/// assert_eq!(buf, b"hello");
/// ```
///
/// # Implementer notes
///
/// This function should never panic. `chunk_mut` should return an empty
/// slice **if and only if** `remaining_mut()` returns 0. In other words,
/// `chunk_mut()` returning an empty slice implies that `remaining_mut()` will
/// return 0 and `remaining_mut()` returning 0 implies that `chunk_mut()` will
/// return an empty slice.
///
/// This function may trigger an out-of-memory abort if it tries to allocate
/// memory and fails to do so.
// The `chunk_mut` method was previously called `bytes_mut`. This alias makes the
// rename more easily discoverable.
#[cfg_attr(docsrs, doc(alias = "bytes_mut"))]
fn chunk_mut(&mut self) -> &mut UninitSlice;
/// Transfer bytes into `self` from `src` and advance the cursor by the
/// number of bytes written.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
///
/// buf.put_u8(b'h');
/// buf.put(&b"ello"[..]);
/// buf.put(&b" world"[..]);
///
/// assert_eq!(buf, b"hello world");
/// ```
///
/// # Panics
///
/// Panics if `self` does not have enough capacity to contain `src`.
fn put<T: super::Buf>(&mut self, mut src: T)
where
Self: Sized,
{
assert!(self.remaining_mut() >= src.remaining());
while src.has_remaining() {
let l;
unsafe {
let s = src.chunk();
let d = self.chunk_mut();
l = cmp::min(s.len(), d.len());
ptr::copy_nonoverlapping(s.as_ptr(), d.as_mut_ptr() as *mut u8, l);
}
src.advance(l);
unsafe {
self.advance_mut(l);
}
}
}
/// Transfer bytes into `self` from `src` and advance the cursor by the
/// number of bytes written.
///
/// `self` must have enough remaining capacity to contain all of `src`.
///
/// ```
/// use bytes::BufMut;
///
/// let mut dst = [0; 6];
///
/// {
/// let mut buf = &mut dst[..];
/// buf.put_slice(b"hello");
///
/// assert_eq!(1, buf.remaining_mut());
/// }
///
/// assert_eq!(b"hello\0", &dst);
/// ```
fn put_slice(&mut self, src: &[u8]) {
let mut off = 0;
assert!(
self.remaining_mut() >= src.len(),
"buffer overflow; remaining = {}; src = {}",
self.remaining_mut(),
src.len()
);
while off < src.len() {
let cnt;
unsafe {
let dst = self.chunk_mut();
cnt = cmp::min(dst.len(), src.len() - off);
ptr::copy_nonoverlapping(src[off..].as_ptr(), dst.as_mut_ptr() as *mut u8, cnt);
off += cnt;
}
unsafe {
self.advance_mut(cnt);
}
}
}
/// Put `cnt` bytes `val` into `self`.
///
/// Logically equivalent to calling `self.put_u8(val)` `cnt` times, but may work faster.
///
/// `self` must have at least `cnt` remaining capacity.
///
/// ```
/// use bytes::BufMut;
///
/// let mut dst = [0; 6];
///
/// {
/// let mut buf = &mut dst[..];
/// buf.put_bytes(b'a', 4);
///
/// assert_eq!(2, buf.remaining_mut());
/// }
///
/// assert_eq!(b"aaaa\0\0", &dst);
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_bytes(&mut self, val: u8, cnt: usize) {
for _ in 0..cnt {
self.put_u8(val);
}
}
/// Writes an unsigned 8 bit integer to `self`.
///
/// The current position is advanced by 1.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u8(0x01);
/// assert_eq!(buf, b"\x01");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u8(&mut self, n: u8) {
let src = [n];
self.put_slice(&src);
}
/// Writes a signed 8 bit integer to `self`.
///
/// The current position is advanced by 1.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i8(0x01);
/// assert_eq!(buf, b"\x01");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i8(&mut self, n: i8) {
let src = [n as u8];
self.put_slice(&src)
}
/// Writes an unsigned 16 bit integer to `self` in big-endian byte order.
///
/// The current position is advanced by 2.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u16(0x0809);
/// assert_eq!(buf, b"\x08\x09");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u16(&mut self, n: u16) {
self.put_slice(&n.to_be_bytes())
}
/// Writes an unsigned 16 bit integer to `self` in little-endian byte order.
///
/// The current position is advanced by 2.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u16_le(0x0809);
/// assert_eq!(buf, b"\x09\x08");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u16_le(&mut self, n: u16) {
self.put_slice(&n.to_le_bytes())
}
/// Writes an unsigned 16 bit integer to `self` in native-endian byte order.
///
/// The current position is advanced by 2.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u16_ne(0x0809);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x08\x09");
/// } else {
/// assert_eq!(buf, b"\x09\x08");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u16_ne(&mut self, n: u16) {
self.put_slice(&n.to_ne_bytes())
}
/// Writes a signed 16 bit integer to `self` in big-endian byte order.
///
/// The current position is advanced by 2.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i16(0x0809);
/// assert_eq!(buf, b"\x08\x09");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i16(&mut self, n: i16) {
self.put_slice(&n.to_be_bytes())
}
/// Writes a signed 16 bit integer to `self` in little-endian byte order.
///
/// The current position is advanced by 2.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i16_le(0x0809);
/// assert_eq!(buf, b"\x09\x08");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i16_le(&mut self, n: i16) {
self.put_slice(&n.to_le_bytes())
}
/// Writes a signed 16 bit integer to `self` in native-endian byte order.
///
/// The current position is advanced by 2.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i16_ne(0x0809);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x08\x09");
/// } else {
/// assert_eq!(buf, b"\x09\x08");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i16_ne(&mut self, n: i16) {
self.put_slice(&n.to_ne_bytes())
}
/// Writes an unsigned 32 bit integer to `self` in big-endian byte order.
///
/// The current position is advanced by 4.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u32(0x0809A0A1);
/// assert_eq!(buf, b"\x08\x09\xA0\xA1");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u32(&mut self, n: u32) {
self.put_slice(&n.to_be_bytes())
}
/// Writes an unsigned 32 bit integer to `self` in little-endian byte order.
///
/// The current position is advanced by 4.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u32_le(0x0809A0A1);
/// assert_eq!(buf, b"\xA1\xA0\x09\x08");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u32_le(&mut self, n: u32) {
self.put_slice(&n.to_le_bytes())
}
/// Writes an unsigned 32 bit integer to `self` in native-endian byte order.
///
/// The current position is advanced by 4.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u32_ne(0x0809A0A1);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x08\x09\xA0\xA1");
/// } else {
/// assert_eq!(buf, b"\xA1\xA0\x09\x08");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u32_ne(&mut self, n: u32) {
self.put_slice(&n.to_ne_bytes())
}
/// Writes a signed 32 bit integer to `self` in big-endian byte order.
///
/// The current position is advanced by 4.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i32(0x0809A0A1);
/// assert_eq!(buf, b"\x08\x09\xA0\xA1");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i32(&mut self, n: i32) {
self.put_slice(&n.to_be_bytes())
}
/// Writes a signed 32 bit integer to `self` in little-endian byte order.
///
/// The current position is advanced by 4.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i32_le(0x0809A0A1);
/// assert_eq!(buf, b"\xA1\xA0\x09\x08");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i32_le(&mut self, n: i32) {
self.put_slice(&n.to_le_bytes())
}
/// Writes a signed 32 bit integer to `self` in native-endian byte order.
///
/// The current position is advanced by 4.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i32_ne(0x0809A0A1);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x08\x09\xA0\xA1");
/// } else {
/// assert_eq!(buf, b"\xA1\xA0\x09\x08");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i32_ne(&mut self, n: i32) {
self.put_slice(&n.to_ne_bytes())
}
/// Writes an unsigned 64 bit integer to `self` in the big-endian byte order.
///
/// The current position is advanced by 8.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u64(0x0102030405060708);
/// assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u64(&mut self, n: u64) {
self.put_slice(&n.to_be_bytes())
}
/// Writes an unsigned 64 bit integer to `self` in little-endian byte order.
///
/// The current position is advanced by 8.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u64_le(0x0102030405060708);
/// assert_eq!(buf, b"\x08\x07\x06\x05\x04\x03\x02\x01");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u64_le(&mut self, n: u64) {
self.put_slice(&n.to_le_bytes())
}
/// Writes an unsigned 64 bit integer to `self` in native-endian byte order.
///
/// The current position is advanced by 8.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u64_ne(0x0102030405060708);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08");
/// } else {
/// assert_eq!(buf, b"\x08\x07\x06\x05\x04\x03\x02\x01");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u64_ne(&mut self, n: u64) {
self.put_slice(&n.to_ne_bytes())
}
/// Writes a signed 64 bit integer to `self` in the big-endian byte order.
///
/// The current position is advanced by 8.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i64(0x0102030405060708);
/// assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i64(&mut self, n: i64) {
self.put_slice(&n.to_be_bytes())
}
/// Writes a signed 64 bit integer to `self` in little-endian byte order.
///
/// The current position is advanced by 8.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i64_le(0x0102030405060708);
/// assert_eq!(buf, b"\x08\x07\x06\x05\x04\x03\x02\x01");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i64_le(&mut self, n: i64) {
self.put_slice(&n.to_le_bytes())
}
/// Writes a signed 64 bit integer to `self` in native-endian byte order.
///
/// The current position is advanced by 8.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i64_ne(0x0102030405060708);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08");
/// } else {
/// assert_eq!(buf, b"\x08\x07\x06\x05\x04\x03\x02\x01");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i64_ne(&mut self, n: i64) {
self.put_slice(&n.to_ne_bytes())
}
/// Writes an unsigned 128 bit integer to `self` in the big-endian byte order.
///
/// The current position is advanced by 16.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u128(0x01020304050607080910111213141516);
/// assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u128(&mut self, n: u128) {
self.put_slice(&n.to_be_bytes())
}
/// Writes an unsigned 128 bit integer to `self` in little-endian byte order.
///
/// The current position is advanced by 16.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u128_le(0x01020304050607080910111213141516);
/// assert_eq!(buf, b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u128_le(&mut self, n: u128) {
self.put_slice(&n.to_le_bytes())
}
/// Writes an unsigned 128 bit integer to `self` in native-endian byte order.
///
/// The current position is advanced by 16.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_u128_ne(0x01020304050607080910111213141516);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16");
/// } else {
/// assert_eq!(buf, b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_u128_ne(&mut self, n: u128) {
self.put_slice(&n.to_ne_bytes())
}
/// Writes a signed 128 bit integer to `self` in the big-endian byte order.
///
/// The current position is advanced by 16.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i128(0x01020304050607080910111213141516);
/// assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i128(&mut self, n: i128) {
self.put_slice(&n.to_be_bytes())
}
/// Writes a signed 128 bit integer to `self` in little-endian byte order.
///
/// The current position is advanced by 16.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i128_le(0x01020304050607080910111213141516);
/// assert_eq!(buf, b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i128_le(&mut self, n: i128) {
self.put_slice(&n.to_le_bytes())
}
/// Writes a signed 128 bit integer to `self` in native-endian byte order.
///
/// The current position is advanced by 16.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_i128_ne(0x01020304050607080910111213141516);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16");
/// } else {
/// assert_eq!(buf, b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_i128_ne(&mut self, n: i128) {
self.put_slice(&n.to_ne_bytes())
}
/// Writes an unsigned n-byte integer to `self` in big-endian byte order.
///
/// The current position is advanced by `nbytes`.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_uint(0x010203, 3);
/// assert_eq!(buf, b"\x01\x02\x03");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_uint(&mut self, n: u64, nbytes: usize) {
self.put_slice(&n.to_be_bytes()[mem::size_of_val(&n) - nbytes..]);
}
/// Writes an unsigned n-byte integer to `self` in the little-endian byte order.
///
/// The current position is advanced by `nbytes`.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_uint_le(0x010203, 3);
/// assert_eq!(buf, b"\x03\x02\x01");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_uint_le(&mut self, n: u64, nbytes: usize) {
self.put_slice(&n.to_le_bytes()[0..nbytes]);
}
/// Writes an unsigned n-byte integer to `self` in the native-endian byte order.
///
/// The current position is advanced by `nbytes`.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_uint_ne(0x010203, 3);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x01\x02\x03");
/// } else {
/// assert_eq!(buf, b"\x03\x02\x01");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_uint_ne(&mut self, n: u64, nbytes: usize) {
if cfg!(target_endian = "big") {
self.put_uint(n, nbytes)
} else {
self.put_uint_le(n, nbytes)
}
}
/// Writes low `nbytes` of a signed integer to `self` in big-endian byte order.
///
/// The current position is advanced by `nbytes`.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_int(0x0504010203, 3);
/// assert_eq!(buf, b"\x01\x02\x03");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self` or if `nbytes` is greater than 8.
fn put_int(&mut self, n: i64, nbytes: usize) {
self.put_slice(&n.to_be_bytes()[mem::size_of_val(&n) - nbytes..]);
}
/// Writes low `nbytes` of a signed integer to `self` in little-endian byte order.
///
/// The current position is advanced by `nbytes`.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_int_le(0x0504010203, 3);
/// assert_eq!(buf, b"\x03\x02\x01");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self` or if `nbytes` is greater than 8.
fn put_int_le(&mut self, n: i64, nbytes: usize) {
self.put_slice(&n.to_le_bytes()[0..nbytes]);
}
/// Writes low `nbytes` of a signed integer to `self` in native-endian byte order.
///
/// The current position is advanced by `nbytes`.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_int_ne(0x010203, 3);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x01\x02\x03");
/// } else {
/// assert_eq!(buf, b"\x03\x02\x01");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self` or if `nbytes` is greater than 8.
fn put_int_ne(&mut self, n: i64, nbytes: usize) {
if cfg!(target_endian = "big") {
self.put_int(n, nbytes)
} else {
self.put_int_le(n, nbytes)
}
}
/// Writes an IEEE754 single-precision (4 bytes) floating point number to
/// `self` in big-endian byte order.
///
/// The current position is advanced by 4.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_f32(1.2f32);
/// assert_eq!(buf, b"\x3F\x99\x99\x9A");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_f32(&mut self, n: f32) {
self.put_u32(n.to_bits());
}
/// Writes an IEEE754 single-precision (4 bytes) floating point number to
/// `self` in little-endian byte order.
///
/// The current position is advanced by 4.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_f32_le(1.2f32);
/// assert_eq!(buf, b"\x9A\x99\x99\x3F");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_f32_le(&mut self, n: f32) {
self.put_u32_le(n.to_bits());
}
/// Writes an IEEE754 single-precision (4 bytes) floating point number to
/// `self` in native-endian byte order.
///
/// The current position is advanced by 4.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_f32_ne(1.2f32);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x3F\x99\x99\x9A");
/// } else {
/// assert_eq!(buf, b"\x9A\x99\x99\x3F");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_f32_ne(&mut self, n: f32) {
self.put_u32_ne(n.to_bits());
}
/// Writes an IEEE754 double-precision (8 bytes) floating point number to
/// `self` in big-endian byte order.
///
/// The current position is advanced by 8.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_f64(1.2f64);
/// assert_eq!(buf, b"\x3F\xF3\x33\x33\x33\x33\x33\x33");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_f64(&mut self, n: f64) {
self.put_u64(n.to_bits());
}
/// Writes an IEEE754 double-precision (8 bytes) floating point number to
/// `self` in little-endian byte order.
///
/// The current position is advanced by 8.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_f64_le(1.2f64);
/// assert_eq!(buf, b"\x33\x33\x33\x33\x33\x33\xF3\x3F");
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_f64_le(&mut self, n: f64) {
self.put_u64_le(n.to_bits());
}
/// Writes an IEEE754 double-precision (8 bytes) floating point number to
/// `self` in native-endian byte order.
///
/// The current position is advanced by 8.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut buf = vec![];
/// buf.put_f64_ne(1.2f64);
/// if cfg!(target_endian = "big") {
/// assert_eq!(buf, b"\x3F\xF3\x33\x33\x33\x33\x33\x33");
/// } else {
/// assert_eq!(buf, b"\x33\x33\x33\x33\x33\x33\xF3\x3F");
/// }
/// ```
///
/// # Panics
///
/// This function panics if there is not enough remaining capacity in
/// `self`.
fn put_f64_ne(&mut self, n: f64) {
self.put_u64_ne(n.to_bits());
}
/// Creates an adaptor which can write at most `limit` bytes to `self`.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let arr = &mut [0u8; 128][..];
/// assert_eq!(arr.remaining_mut(), 128);
///
/// let dst = arr.limit(10);
/// assert_eq!(dst.remaining_mut(), 10);
/// ```
fn limit(self, limit: usize) -> Limit<Self>
where
Self: Sized,
{
limit::new(self, limit)
}
/// Creates an adaptor which implements the `Write` trait for `self`.
///
/// This function returns a new value which implements `Write` by adapting
/// the `Write` trait functions to the `BufMut` trait functions. Given that
/// `BufMut` operations are infallible, none of the `Write` functions will
/// return with `Err`.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
/// use std::io::Write;
///
/// let mut buf = vec![].writer();
///
/// let num = buf.write(&b"hello world"[..]).unwrap();
/// assert_eq!(11, num);
///
/// let buf = buf.into_inner();
///
/// assert_eq!(*buf, b"hello world"[..]);
/// ```
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
fn writer(self) -> Writer<Self>
where
Self: Sized,
{
writer::new(self)
}
/// Creates an adapter which will chain this buffer with another.
///
/// The returned `BufMut` instance will first write to all bytes from
/// `self`. Afterwards, it will write to `next`.
///
/// # Examples
///
/// ```
/// use bytes::BufMut;
///
/// let mut a = [0u8; 5];
/// let mut b = [0u8; 6];
///
/// let mut chain = (&mut a[..]).chain_mut(&mut b[..]);
///
/// chain.put_slice(b"hello world");
///
/// assert_eq!(&a[..], b"hello");
/// assert_eq!(&b[..], b" world");
/// ```
fn chain_mut<U: BufMut>(self, next: U) -> Chain<Self, U>
where
Self: Sized,
{
Chain::new(self, next)
}
}
macro_rules! deref_forward_bufmut {
() => {
fn remaining_mut(&self) -> usize {
(**self).remaining_mut()
}
fn chunk_mut(&mut self) -> &mut UninitSlice {
(**self).chunk_mut()
}
unsafe fn advance_mut(&mut self, cnt: usize) {
(**self).advance_mut(cnt)
}
fn put_slice(&mut self, src: &[u8]) {
(**self).put_slice(src)
}
fn put_u8(&mut self, n: u8) {
(**self).put_u8(n)
}
fn put_i8(&mut self, n: i8) {
(**self).put_i8(n)
}
fn put_u16(&mut self, n: u16) {
(**self).put_u16(n)
}
fn put_u16_le(&mut self, n: u16) {
(**self).put_u16_le(n)
}
fn put_u16_ne(&mut self, n: u16) {
(**self).put_u16_ne(n)
}
fn put_i16(&mut self, n: i16) {
(**self).put_i16(n)
}
fn put_i16_le(&mut self, n: i16) {
(**self).put_i16_le(n)
}
fn put_i16_ne(&mut self, n: i16) {
(**self).put_i16_ne(n)
}
fn put_u32(&mut self, n: u32) {
(**self).put_u32(n)
}
fn put_u32_le(&mut self, n: u32) {
(**self).put_u32_le(n)
}
fn put_u32_ne(&mut self, n: u32) {
(**self).put_u32_ne(n)
}
fn put_i32(&mut self, n: i32) {
(**self).put_i32(n)
}
fn put_i32_le(&mut self, n: i32) {
(**self).put_i32_le(n)
}
fn put_i32_ne(&mut self, n: i32) {
(**self).put_i32_ne(n)
}
fn put_u64(&mut self, n: u64) {
(**self).put_u64(n)
}
fn put_u64_le(&mut self, n: u64) {
(**self).put_u64_le(n)
}
fn put_u64_ne(&mut self, n: u64) {
(**self).put_u64_ne(n)
}
fn put_i64(&mut self, n: i64) {
(**self).put_i64(n)
}
fn put_i64_le(&mut self, n: i64) {
(**self).put_i64_le(n)
}
fn put_i64_ne(&mut self, n: i64) {
(**self).put_i64_ne(n)
}
};
}
unsafe impl<T: BufMut + ?Sized> BufMut for &mut T {
deref_forward_bufmut!();
}
unsafe impl<T: BufMut + ?Sized> BufMut for Box<T> {
deref_forward_bufmut!();
}
unsafe impl BufMut for &mut [u8] {
#[inline]
fn remaining_mut(&self) -> usize {
self.len()
}
#[inline]
fn chunk_mut(&mut self) -> &mut UninitSlice {
// UninitSlice is repr(transparent), so safe to transmute
unsafe { &mut *(*self as *mut [u8] as *mut _) }
}
#[inline]
unsafe fn advance_mut(&mut self, cnt: usize) {
// Lifetime dance taken from `impl Write for &mut [u8]`.
let (_, b) = core::mem::replace(self, &mut []).split_at_mut(cnt);
*self = b;
}
#[inline]
fn put_slice(&mut self, src: &[u8]) {
self[..src.len()].copy_from_slice(src);
unsafe {
self.advance_mut(src.len());
}
}
fn put_bytes(&mut self, val: u8, cnt: usize) {
assert!(self.remaining_mut() >= cnt);
unsafe {
ptr::write_bytes(self.as_mut_ptr(), val, cnt);
self.advance_mut(cnt);
}
}
}
unsafe impl BufMut for Vec<u8> {
#[inline]
fn remaining_mut(&self) -> usize {
// A vector can never have more than isize::MAX bytes
core::isize::MAX as usize - self.len()
}
#[inline]
unsafe fn advance_mut(&mut self, cnt: usize) {
let len = self.len();
let remaining = self.capacity() - len;
assert!(
cnt <= remaining,
"cannot advance past `remaining_mut`: {:?} <= {:?}",
cnt,
remaining
);
self.set_len(len + cnt);
}
#[inline]
fn chunk_mut(&mut self) -> &mut UninitSlice {
if self.capacity() == self.len() {
self.reserve(64); // Grow the vec
}
let cap = self.capacity();
let len = self.len();
let ptr = self.as_mut_ptr();
unsafe { &mut UninitSlice::from_raw_parts_mut(ptr, cap)[len..] }
}
// Specialize these methods so they can skip checking `remaining_mut`
// and `advance_mut`.
fn put<T: super::Buf>(&mut self, mut src: T)
where
Self: Sized,
{
// In case the src isn't contiguous, reserve upfront
self.reserve(src.remaining());
while src.has_remaining() {
let l;
// a block to contain the src.bytes() borrow
{
let s = src.chunk();
l = s.len();
self.extend_from_slice(s);
}
src.advance(l);
}
}
#[inline]
fn put_slice(&mut self, src: &[u8]) {
self.extend_from_slice(src);
}
fn put_bytes(&mut self, val: u8, cnt: usize) {
let new_len = self.len().checked_add(cnt).unwrap();
self.resize(new_len, val);
}
}
// The existence of this function makes the compiler catch if the BufMut
// trait is "object-safe" or not.
fn _assert_trait_object(_b: &dyn BufMut) {}
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2026-04-02
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