| use core::{ |
| cmp, |
| mem::{self, MaybeUninit}, |
| ptr, usize, |
| }; |
| |
| #[cfg(feature = "std")] |
| use std::fmt; |
| |
| 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 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 `bytes_mut`. |
| /// |
| /// # 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. |
| fn remaining_mut(&self) -> usize; |
| |
| /// Advance the internal cursor of the BufMut |
| /// |
| /// The next call to `bytes_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); |
| /// |
| /// unsafe { |
| /// // MaybeUninit::as_mut_ptr |
| /// buf.bytes_mut()[0].as_mut_ptr().write(b'h'); |
| /// buf.bytes_mut()[1].as_mut_ptr().write(b'e'); |
| /// |
| /// buf.advance_mut(2); |
| /// |
| /// buf.bytes_mut()[0].as_mut_ptr().write(b'l'); |
| /// buf.bytes_mut()[1].as_mut_ptr().write(b'l'); |
| /// buf.bytes_mut()[2].as_mut_ptr().write(b'o'); |
| /// |
| /// 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.bytes_mut()[0].as_mut_ptr().write(b'h'); |
| /// buf.bytes_mut()[1].as_mut_ptr().write(b'e'); |
| /// |
| /// buf.advance_mut(2); |
| /// |
| /// buf.bytes_mut()[0].as_mut_ptr().write(b'l'); |
| /// buf.bytes_mut()[1].as_mut_ptr().write(b'l'); |
| /// buf.bytes_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. `bytes_mut` should return an empty |
| /// slice **if and only if** `remaining_mut` returns 0. In other words, |
| /// `bytes_mut` returning an empty slice implies that `remaining_mut` will |
| /// return 0 and `remaining_mut` returning 0 implies that `bytes_mut` will |
| /// return an empty slice. |
| fn bytes_mut(&mut self) -> &mut [MaybeUninit<u8>]; |
| |
| /// Fills `dst` with potentially multiple mutable slices starting at `self`'s |
| /// current position. |
| /// |
| /// If the `BufMut` is backed by disjoint slices of bytes, `bytes_vectored_mut` |
| /// enables fetching more than one slice at once. `dst` is a slice of |
| /// mutable `IoSliceMut` references, enabling the slice to be directly used with |
| /// [`readv`] without any further conversion. The sum of the lengths of all |
| /// the buffers in `dst` will be less than or equal to |
| /// `Buf::remaining_mut()`. |
| /// |
| /// The entries in `dst` will be overwritten, but the data **contained** by |
| /// the slices **will not** be modified. If `bytes_vectored_mut` 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., `BufMut::remaining_mut` returns 0, calls to `bytes_vectored_mut` must |
| /// return 0 without mutating `dst`. |
| /// |
| /// Implementations should also take care to properly handle being called |
| /// with `dst` being a zero length slice. |
| /// |
| /// [`readv`]: http://man7.org/linux/man-pages/man2/readv.2.html |
| #[cfg(feature = "std")] |
| fn bytes_vectored_mut<'a>(&'a mut self, dst: &mut [IoSliceMut<'a>]) -> usize { |
| if dst.is_empty() { |
| return 0; |
| } |
| |
| if self.has_remaining_mut() { |
| dst[0] = IoSliceMut::from(self.bytes_mut()); |
| 1 |
| } else { |
| 0 |
| } |
| } |
| |
| /// 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.bytes(); |
| let d = self.bytes_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.bytes_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); |
| } |
| } |
| } |
| |
| /// 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 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 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 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 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 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 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 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 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 a signed 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_int(0x010203, 3); |
| /// assert_eq!(buf, b"\x01\x02\x03"); |
| /// ``` |
| /// |
| /// # Panics |
| /// |
| /// This function panics if there is not enough remaining capacity in |
| /// `self`. |
| fn put_int(&mut self, n: i64, nbytes: usize) { |
| self.put_slice(&n.to_be_bytes()[mem::size_of_val(&n) - nbytes..]); |
| } |
| |
| /// Writes a signed n-byte 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(0x010203, 3); |
| /// assert_eq!(buf, b"\x03\x02\x01"); |
| /// ``` |
| /// |
| /// # Panics |
| /// |
| /// This function panics if there is not enough remaining capacity in |
| /// `self`. |
| fn put_int_le(&mut self, n: i64, nbytes: usize) { |
| self.put_slice(&n.to_le_bytes()[0..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 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()); |
| } |
| } |
| |
| macro_rules! deref_forward_bufmut { |
| () => { |
| fn remaining_mut(&self) -> usize { |
| (**self).remaining_mut() |
| } |
| |
| fn bytes_mut(&mut self) -> &mut [MaybeUninit<u8>] { |
| (**self).bytes_mut() |
| } |
| |
| #[cfg(feature = "std")] |
| fn bytes_vectored_mut<'b>(&'b mut self, dst: &mut [IoSliceMut<'b>]) -> usize { |
| (**self).bytes_vectored_mut(dst) |
| } |
| |
| 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_i16(&mut self, n: i16) { |
| (**self).put_i16(n) |
| } |
| |
| fn put_i16_le(&mut self, n: i16) { |
| (**self).put_i16_le(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_i32(&mut self, n: i32) { |
| (**self).put_i32(n) |
| } |
| |
| fn put_i32_le(&mut self, n: i32) { |
| (**self).put_i32_le(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_i64(&mut self, n: i64) { |
| (**self).put_i64(n) |
| } |
| |
| fn put_i64_le(&mut self, n: i64) { |
| (**self).put_i64_le(n) |
| } |
| }; |
| } |
| |
| impl<T: BufMut + ?Sized> BufMut for &mut T { |
| deref_forward_bufmut!(); |
| } |
| |
| impl<T: BufMut + ?Sized> BufMut for Box<T> { |
| deref_forward_bufmut!(); |
| } |
| |
| impl BufMut for &mut [u8] { |
| #[inline] |
| fn remaining_mut(&self) -> usize { |
| self.len() |
| } |
| |
| #[inline] |
| fn bytes_mut(&mut self) -> &mut [MaybeUninit<u8>] { |
| // MaybeUninit is repr(transparent), so safe to transmute |
| unsafe { mem::transmute(&mut **self) } |
| } |
| |
| #[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; |
| } |
| } |
| |
| impl BufMut for Vec<u8> { |
| #[inline] |
| fn remaining_mut(&self) -> usize { |
| usize::MAX - 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 bytes_mut(&mut self) -> &mut [MaybeUninit<u8>] { |
| use core::slice; |
| |
| 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() as *mut MaybeUninit<u8>; |
| unsafe { &mut slice::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.bytes(); |
| l = s.len(); |
| self.extend_from_slice(s); |
| } |
| |
| src.advance(l); |
| } |
| } |
| |
| fn put_slice(&mut self, src: &[u8]) { |
| self.extend_from_slice(src); |
| } |
| } |
| |
| // 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) {} |
| |
| // ===== impl IoSliceMut ===== |
| |
| /// A buffer type used for `readv`. |
| /// |
| /// This is a wrapper around an `std::io::IoSliceMut`, but does not expose |
| /// the inner bytes in a safe API, as they may point at uninitialized memory. |
| /// |
| /// This is `repr(transparent)` of the `std::io::IoSliceMut`, so it is valid to |
| /// transmute them. However, as the memory might be uninitialized, care must be |
| /// taken to not *read* the internal bytes, only *write* to them. |
| #[repr(transparent)] |
| #[cfg(feature = "std")] |
| pub struct IoSliceMut<'a>(std::io::IoSliceMut<'a>); |
| |
| #[cfg(feature = "std")] |
| impl fmt::Debug for IoSliceMut<'_> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.debug_struct("IoSliceMut") |
| .field("len", &self.0.len()) |
| .finish() |
| } |
| } |
| |
| #[cfg(feature = "std")] |
| impl<'a> From<&'a mut [u8]> for IoSliceMut<'a> { |
| fn from(buf: &'a mut [u8]) -> IoSliceMut<'a> { |
| IoSliceMut(std::io::IoSliceMut::new(buf)) |
| } |
| } |
| |
| #[cfg(feature = "std")] |
| impl<'a> From<&'a mut [MaybeUninit<u8>]> for IoSliceMut<'a> { |
| fn from(buf: &'a mut [MaybeUninit<u8>]) -> IoSliceMut<'a> { |
| IoSliceMut(std::io::IoSliceMut::new(unsafe { |
| // We don't look at the contents, and `std::io::IoSliceMut` |
| // doesn't either. |
| mem::transmute::<&'a mut [MaybeUninit<u8>], &'a mut [u8]>(buf) |
| })) |
| } |
| } |