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//! # byteio //! //! byteio is a simple crate that exposes lightweight abstractions for //! read/write operations on contiguous slices of memory. //! //! The crate is based around two core traits: [`ReadBytes`][readbytes] and //! [`WriteBytes`][writebytes]. Two extension traits which add functionality for //! reading and writing numbers also have blanket implementations for any types //! that implement the core traits. //! //! [readbytes]: trait.ReadBytes.html //! [writebytes]: trait.WriteBytes.html //! //! # Installation //! //! To start using `byteio` add it to your `Cargo.toml` like so: //! //! ```toml //! [dependencies] //! byteio = "0.1" //! ``` //! //! By default this will active the `std` feature which enables functionality in //! the crate which is only available when compiling with the standard library. //! //! To use the crate in a `no_std` environment you just need to disable this //! feature. This can be done by adjusting your `Cargo.toml`: //! //! ```toml //! [dependencies] //! byteio = { version = "0.1", default-features = false } //! ``` //! //! The crate has a final feature: `alloc`. This should be used when you are //! building in a `no_std` environment, have an allocator, and want //! functionality for working with `Vec<u8>`. You can activate this by adjusting //! your `Cargo.toml` again: //! //! ```toml //! [dependencies] //! byteio = { version = "0.1", default-features = false, features = ["alloc"] } //! ``` //! //! # Usage //! //! Manual serialization and deserialization of a simple network packet: //! //! ``` //! use std::convert::TryInto; //! //! use byteio::prelude::*; //! use byteorder::NetworkEndian; //! //! /// A packet whose payload is encoded as `[n_msb, n_lsb, b_0, b_1, ..., b_n-1]`. //! struct Packet<'a> { //! payload: &'a [u8], //! } //! //! impl<'a> Packet<'a> { //! fn decode<R: ReadBytes<'a>>(mut reader: R) -> byteio::Result<Self> { //! let len: usize = reader.try_read_u16::<NetworkEndian>()?.into(); //! let payload = reader.try_read_exact(len)?; //! //! Ok(Self { payload }) //! } //! //! fn encode<W: WriteBytes>(&self, mut writer: W) -> byteio::Result<()> { //! let len: u16 = self.payload.len().try_into().unwrap_or_else(|_| !0); //! //! writer.try_write_u16::<NetworkEndian>(len)?; //! writer.try_write_exact(&self.payload[..usize::from(len)])?; //! //! Ok(()) //! } //! } //! //! fn main() -> byteio::Result<()> { //! let data = b"\x00\x0Chello, world"; //! //! let packet = Packet::decode(&data[..])?; //! assert_eq!(packet.payload, b"hello, world"); //! //! let mut buf = Vec::new(); //! packet.encode(&mut buf)?; //! assert_eq!(&*buf, data); //! //! Ok(()) //! } //! ``` #![no_std] #![allow(clippy::cast_possible_wrap, clippy::cast_sign_loss)] #![deny(missing_docs)] use core::{fmt, marker::PhantomData, mem}; #[cfg(feature = "std")] extern crate std; #[cfg(feature = "alloc")] extern crate alloc; #[cfg(feature = "std")] use std::{error, io, vec::Vec}; #[cfg(feature = "alloc")] use alloc::vec::Vec; use byteorder::ByteOrder; pub mod prelude { //! The `byteio` prelude. //! //! ``` //! use byteio::prelude::*; //! ``` //! //! The purpose of this module is to alleviate imports by adding a glob //! `use` to the top of `byteio` heavy modules. pub use crate::{ReadBytes, ReadBytesExt, WriteBytes, WriteBytesExt}; } /// A specialized [`Result`][core-result-result] type for `byteio` operations. /// /// This type alias is broadly used across `byteio` for operations that may /// produce an error, that is, overflow the underlying buffer. /// /// As with [`std::io::Result`][std-io-result], it is not recommended to import /// this type directly and shadow [`core::result::Result`](core-result-result), /// but instead to use `byteio::Result` to make it easier to distinguish. /// /// # Examples /// /// Trying to decode a string from raw bytes: /// /// ``` /// use core::str::{self, Utf8Error}; /// /// use byteio::WriteBytes; /// /// fn decode_str(buf: &[u8]) -> Result<&str, Utf8Error> { /// str::from_utf8(buf) /// } /// /// fn main() -> byteio::Result<()> { /// let mut buf = [0; 5]; /// /// (&mut buf[..]).try_write_exact(b"hello")?; /// /// match decode_str(&buf) { /// Ok(s) => println!("str from utf8 success!"), /// Err(e) => println!("str from utf8 failure: {}", e), /// } /// /// Ok(()) /// } /// ``` /// /// [core-result-result]: https://doc.rust-lang.org/core/result/enum.Result.html /// [std-io-result]: https://doc.rust-lang.org/std/io/type.Result.html pub type Result<T> = ::core::result::Result<T, Error>; /// The errors that can occur during `byteio` operations. /// /// When using the `std` feature of `byteio`, this type implements /// [`Into<std::io::Error>`][core-convert-into], which allows you to yield /// `byteio` errors with the `?` operator in functions which return /// [`std::io::Result`][std-io-result]. /// /// # Non-exhaustive /// /// This enum is non-exhaustive; additional variants may be added in the future. /// /// [core-convert-into]: https://doc.rust-lang.org/core/convert/trait.Into.html /// [std-io-result]: https://doc.rust-lang.org/std/io/type.Result.html #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)] pub enum Error { /// The error returned when a `byteio` operation would overflow the buffer. /// /// # Examples /// /// ``` /// use byteio::{Error, WriteBytes}; /// /// fn main() { /// let mut buf = [0; 2]; /// /// let err = (&mut buf[..]).try_write_exact(&[1, 1, 1]).unwrap_err(); /// assert_eq!(err, Error::EndOfStream); /// } /// ``` EndOfStream, #[doc(hidden)] #[allow(non_camel_case_types)] _nonexhaustive(()), } impl fmt::Display for Error { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { match *self { Error::EndOfStream => f.write_str("unexpected end of stream"), _ => unreachable!(), } } } #[cfg(feature = "std")] impl error::Error for Error {} #[cfg(feature = "std")] impl From<Error> for io::Error { fn from(error: Error) -> Self { match error { Error::EndOfStream => io::ErrorKind::UnexpectedEof.into(), _ => unreachable!(), } } } /* * * ReadBytes * */ /// Read a slice of bytes from a buffer. /// /// Readers can be thought of as cursors that only allow you to seek forward /// from the current position. They can be implemented with one method; /// [`read_exact`][read-exact]. This forcibly attempts to split the underlying /// buffer in order to extract a sub-slice with a given length, and advance the /// buffer forward such that the next call to [`read_exact`][read-exact] will /// return subsequent bytes in the buffer. /// /// The lifetime of the slices extracted are tied to the underlying buffer. This /// allows you to compose structures borrowing from the underlying buffer. /// /// `ReadBytes` uses [`AsRef<[u8]>`][as-ref-u8] as a supertrait. This means that /// a generic reader can obtain its current length or peek at the underlying /// bytes without advancing the cursor through read operations. Note that by /// using [`as_ref`][as-ref] on a reader you discard the lifetime information of /// the underlying buffer for the returned reference. /// /// # Examples /// /// Reading from a slice: /// /// ``` /// use byteio::ReadBytes; /// /// fn main() { /// let mut buf = &[1, 2, 3, 4, 5][..]; /// /// let sub_slice = buf.read_exact(2); /// assert_eq!(sub_slice, &[1, 2][..]); /// /// let sub_slice = buf.read_exact(3); /// assert_eq!(sub_slice, &[3, 4, 5][..]); /// /// assert!(buf.is_empty()); /// } /// ``` /// /// Building a structure using borrowed data: /// /// ``` /// use core::str; /// /// use byteio::ReadBytes; /// /// /// A packet whose payload is encoded as `[n, b0, b1, ..., bn-1]`. /// struct Packet<'a> { /// payload: &'a [u8], /// } /// /// impl<'a> Packet<'a> { /// pub fn new<R: ReadBytes<'a>>(mut r: R) -> byteio::Result<Self> { /// let len: usize = r.try_read_exact(1)?[0].into(); /// let payload = r.try_read_exact(len)?; /// /// Ok(Self { payload }) /// } /// } /// /// fn main() -> byteio::Result<()> { /// let buf = b"\x05hello"; /// /// let packet = Packet::new(&buf[..])?; /// assert_eq!(str::from_utf8(packet.payload).unwrap(), "hello"); /// /// Ok(()) /// } /// ``` /// /// [read-exact]: trait.ReadBytes.html#tymethod.read_exact /// [as-ref-u8]: https://doc.rust-lang.org/core/convert/trait.AsRef.html /// [as-ref]: https://doc.rust-lang.org/core/convert/trait.AsRef.html#tymethod.as_ref pub trait ReadBytes<'a>: AsRef<[u8]> { /// Forcibly attempts to read exactly `n` bytes from the buffer. /// /// # Panics /// /// Panics if there are not enough bytes in `self`. fn read_exact(&mut self, n: usize) -> &'a [u8]; /// Attempts to read exactly `n` bytes from the buffer. /// /// If there are not enough bytes in `self` this function will return /// `Error::EndOfStream`. fn try_read_exact(&mut self, n: usize) -> crate::Result<&'a [u8]> { if n > self.as_ref().len() { Err(Error::EndOfStream) } else { Ok(self.read_exact(n)) } } } impl<'a> ReadBytes<'a> for &'a [u8] { fn read_exact(&mut self, n: usize) -> &'a [u8] { let (a, b) = self.split_at(n); *self = b; a } } impl<'a> ReadBytes<'a> for &'a mut [u8] { fn read_exact(&mut self, n: usize) -> &'a [u8] { let (a, b) = mem::replace(self, &mut []).split_at_mut(n); *self = b; a } } /* * * ReadBytesExt * */ macro_rules! impl_read { ($doc:literal, $ty:ty, $fn:ident, $byteorder:ident $( , )?) => { #[doc = $doc] #[inline] fn $fn<E: ByteOrder>(&mut self) -> $ty { E::$byteorder(self.read_exact(mem::size_of::<$ty>())) } } } macro_rules! impl_try_read { ($doc:literal, $ty:ty, $fn:ident, $byteorder:ident $( , )?) => { #[doc = $doc] #[inline] fn $fn<E: ByteOrder>(&mut self) -> crate::Result<$ty> { Ok(E::$byteorder(self.try_read_exact(mem::size_of::<$ty>())?)) } } } /// Extends `ReadBytes` with functions for reading numbers. /// /// # Examples /// /// Read `u16`s from a buffer using native endianness: /// /// ``` /// use byteio::ReadBytesExt; /// use byteorder::NativeEndian; /// /// fn main() { /// let mut buf = &[0_u8, 1, 1, 0][..]; /// /// let a = buf.read_u16::<NativeEndian>(); /// let b = buf.read_u16::<NativeEndian>(); /// /// assert!(buf.is_empty()); /// } /// ``` /// /// Try to read `u16`s from a buffer using a specific endianness: /// /// ``` /// use byteio::ReadBytesExt; /// use byteorder::{BigEndian, LittleEndian}; /// /// fn main() -> byteio::Result<()> { /// let mut buf = &[0_u8, 1, 1, 0][..]; /// /// let a = buf.try_read_u16::<BigEndian>()?; /// let b = buf.try_read_u16::<LittleEndian>()?; /// /// assert_eq!(a, 1); /// assert_eq!(b, 1); /// /// assert!(buf.is_empty()); /// /// Ok(()) /// } /// ``` pub trait ReadBytesExt<'a>: ReadBytes<'a> { /// Reads a `u8` from the underlying buffer. /// /// # Panics /// /// Panics if there are not enough bytes in `self`. fn read_u8(&mut self) -> u8 { self.read_exact(1)[0] } /// Attempts to read a `u8` from the underlying buffer. /// /// If there are not enough bytes in `self` this function will return /// `Error::EndOfStream`. fn try_read_u8(&mut self) -> crate::Result<u8> { Ok(self.try_read_exact(1)?[0]) } /// Reads an `i8` from the underlying buffer. /// /// # Panics /// /// Panics if there are not enough bytes in `self`. fn read_i8(&mut self) -> i8 { self.read_exact(1)[0] as _ } /// Attempts to read an `i8` from the underlying buffer. /// /// If there are not enough bytes in `self` this function will return /// `Error::EndOfStream`. fn try_read_i8(&mut self) -> crate::Result<i8> { Ok(self.try_read_exact(1)?[0] as _) } impl_read! { "Reads a `u16` from the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", u16, read_u16, read_u16, } impl_try_read! { "Attempts to read a `u16` from the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", u16, try_read_u16, read_u16, } impl_read! { "Reads an `i16` from the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", i16, read_i16, read_i16, } impl_try_read! { "Attempts to read an `i16` from the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", i16, try_read_i16, read_i16, } impl_read! { "Reads a `u32` from the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", u32, read_u32, read_u32, } impl_try_read! { "Attempts to read a `u32` from the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", u32, try_read_u32, read_u32, } impl_read! { "Reads an `i32` from the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", i32, read_i32, read_i32, } impl_try_read! { "Attempts to read an `i32` from the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", i32, try_read_i32, read_i32, } impl_read! { "Reads a `u64` from the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", u64, read_u64, read_u64, } impl_try_read! { "Attempts to read a `u64` from the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", u64, try_read_u64, read_u64, } impl_read! { "Reads an `i64` from the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", i64, read_i64, read_i64, } impl_try_read! { "Attempts to read an `i64` from the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", i64, try_read_i64, read_i64, } impl_read! { "Reads a `u128` from the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", u128, read_u128, read_u128, } impl_try_read! { "Attempts to read a `u128` from the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", u128, try_read_u128, read_u128, } impl_read! { "Reads an `i128` from the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", i128, read_i128, read_i128, } impl_try_read! { "Attempts to read an `i128` from the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", i128, try_read_i128, read_i128, } impl_read! { "Reads an IEEE754 `f32` from the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", f32, read_f32, read_f32, } impl_try_read! { "Attempts to read an IEEE754 `f32` from the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", f32, try_read_f32, read_f32, } impl_read! { "Reads an IEEE754 `f64` from the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", f64, read_f64, read_f64, } impl_try_read! { "Attempts to read an IEEE754 `f64` from the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", f64, try_read_f64, read_f64, } } impl<'a, R: ReadBytes<'a>> ReadBytesExt<'a> for R {} /* * * Reader * */ /// A convenience structure used for counting the number of bytes read. /// /// This structure wraps an implementation of [`ReadBytes`][readbytes]. It /// forwards read operations to the inner type while also maintaining a count /// of the number of bytes that pass through it. /// /// When you have finished with it, you can return the original type via the /// [`into_inner`][into-inner] method. /// /// # Examples /// /// ``` /// use byteio::{ReadBytes, ReadBytesExt, Reader}; /// use byteorder::BigEndian; /// /// fn main() -> byteio::Result<()> { /// let buf: &[u8] = &[1, 0, 2, 0, 0, 0, 3]; /// /// let mut reader = Reader::new(buf); /// /// assert_eq!(reader.try_read_u8()?, 1); /// assert_eq!(reader.try_read_u16::<BigEndian>()?, 2); /// assert_eq!(reader.try_read_u32::<BigEndian>()?, 3); /// /// assert_eq!(reader.num_bytes_read(), 7); /// /// let inner = reader.into_inner(); /// assert!(inner.is_empty()); /// /// Ok(()) /// } /// ``` /// /// [readbytes]: trait.ReadBytes.html /// [into-inner]: struct.Reader.html#method.into_inner #[derive(Debug, Clone, Eq, PartialEq)] pub struct Reader<'a, R: ReadBytes<'a>>(R, usize, PhantomData<&'a ()>); impl<'a, R: ReadBytes<'a>> Reader<'a, R> { /// Creates a new `Reader` by wrapping a [`ReadBytes`][readbytes] /// implementor. /// /// # Examples /// /// ``` /// use byteio::Reader; /// /// let buf = [0_u8; 2]; /// let mut reader = Reader::new(&buf[..]); /// ``` /// /// [readbytes]: trait.ReadBytes.html #[inline] pub fn new(reader: R) -> Self { Self(reader, 0, PhantomData) } /// Retrieves the number of bytes that have been read by this `Reader`. /// /// # Examples /// /// ``` /// use byteio::{ReadBytes, Reader}; /// /// let buf = [0_u8; 2]; /// let mut reader = Reader::new(&buf[..]); /// let _ = reader.read_exact(1); /// let _ = reader.read_exact(1); /// /// assert_eq!(reader.num_bytes_read(), 2); /// ``` #[inline] pub fn num_bytes_read(&self) -> usize { self.1 } /// Consumes this `Reader` and returns the original [`ReadBytes`][readbytes] /// implementor. /// /// # Examples /// /// ``` /// use byteio::{ReadBytes, Reader}; /// /// let buf = [0_u8; 2]; /// let mut reader = Reader::new(&buf[..]); /// let _ = reader.read_exact(1); /// let inner = reader.into_inner(); /// /// assert_eq!(inner.len(), 1); // the reader consumed one byte from its view of the slice /// ``` /// /// [readbytes]: trait.ReadBytes.html #[inline] pub fn into_inner(self) -> R { self.0 } } impl<'a, R: ReadBytes<'a>> AsRef<[u8]> for Reader<'a, R> { fn as_ref(&self) -> &[u8] { self.0.as_ref() } } impl<'a, R: ReadBytes<'a>> ReadBytes<'a> for Reader<'a, R> { fn read_exact(&mut self, n: usize) -> &'a [u8] { self.1 += n; self.0.read_exact(n) } } /* * * WriteBytes * */ /// Write a slice of bytes into a buffer. /// /// Writers can be thought of as mutable cursors that only allow you to seek /// forward from the current position. They can be implemented with one method; /// [`write_exact`][write-exact]. This forcibly attempts to writer the bytes /// to the underlying buffer, and advance the buffer forward such that the next /// call to [`write_exact`][write-exact] will commit the bytes directly after /// those previously written. /// /// `WriteBytes` uses [`AsMut<[u8]>`][as-mut-u8] as a supertrait. This means /// that a generic writer can obtain its current length or mutably peek at the /// underlying bytes without advancing the cursor through write operations. /// /// # Examples /// /// Writing into a slice: /// /// ``` /// use byteio::WriteBytes; /// /// fn main() -> byteio::Result<()> { /// let mut buf = [0; 8]; /// /// { /// let mut buf = &mut buf[..]; /// /// buf.try_write_exact(&[1, 2])?; /// assert_eq!(buf.len(), 6); /// /// buf.try_write_exact(&[3, 4, 5, 6, 7])?; /// assert_eq!(buf.len(), 1); /// /// buf.try_write_exact(&[8])?; /// assert!(buf.is_empty()); /// } /// /// assert_eq!(buf, [1, 2, 3, 4, 5, 6, 7, 8]); /// Ok(()) /// } /// ``` /// /// [write-exact]: trait.WriteBytes.html#tymethod.write_exact /// [as-mut-u8]: https://doc.rust-lang.org/core/convert/trait.AsMut.html pub trait WriteBytes: AsMut<[u8]> { /// Forcibly attempts to write the exact slice into the buffer. /// /// # Panics /// /// Panics if there are not enough bytes in `self`. fn write_exact(&mut self, buf: &[u8]); /// Attempts to write the exact slice into the buffer. /// /// If there are not enough bytes in `self` this function will return /// `Error::EndOfStream`. fn try_write_exact(&mut self, buf: &[u8]) -> crate::Result<()> { if buf.len() > self.as_mut().len() { Err(Error::EndOfStream) } else { self.write_exact(buf); Ok(()) } } } impl<'a> WriteBytes for &'a mut [u8] { fn write_exact(&mut self, buf: &[u8]) { let (a, b) = mem::replace(self, &mut []).split_at_mut(buf.len()); a.copy_from_slice(&buf); *self = b; } } #[cfg(any(feature = "std", feature = "alloc"))] impl<'a> WriteBytes for &'a mut Vec<u8> { fn write_exact(&mut self, buf: &[u8]) { self.extend_from_slice(buf); } fn try_write_exact(&mut self, buf: &[u8]) -> crate::Result<()> { self.write_exact(buf); Ok(()) } } /* * * WriteBytesExt * */ macro_rules! impl_write { ($doc:literal, $ty:ty, $fn:ident, $byteorder:ident $( , )?) => { #[doc = $doc] #[inline] fn $fn<E: ByteOrder>(&mut self, n: $ty) { let mut buf = [0; mem::size_of::<$ty>()]; E::$byteorder(&mut buf, n); self.write_exact(&buf); } } } macro_rules! impl_try_write { ($doc:literal, $ty:ty, $fn:ident, $byteorder:ident $( , )?) => { #[doc = $doc] #[inline] fn $fn<E: ByteOrder>(&mut self, n: $ty) -> crate::Result<()> { let mut buf = [0; mem::size_of::<$ty>()]; E::$byteorder(&mut buf, n); self.try_write_exact(&buf)?; Ok(()) } } } /// Extends `WriteBytes` with functions for writing numbers. /// /// # Examples /// /// Write `u16`s into a buffer using native endianness: /// /// ``` /// use byteio::WriteBytesExt; /// use byteorder::NativeEndian; /// /// fn main() { /// let mut buf = [0; 4]; /// /// { /// let mut buf = &mut buf[..]; /// /// buf.write_u16::<NativeEndian>(256); /// buf.write_u16::<NativeEndian>(1); /// /// assert!(buf.is_empty()); /// } /// } /// ``` /// /// Try to write `u16`s into a buffer using a specific endianness: /// /// ``` /// use byteio::WriteBytesExt; /// use byteorder::{BigEndian, LittleEndian}; /// /// fn main() -> byteio::Result<()> { /// let mut buf = [0; 4]; /// /// { /// let mut buf = &mut buf[..]; /// /// buf.try_write_u16::<BigEndian>(1)?; /// buf.try_write_u16::<LittleEndian>(1)?; /// /// assert!(buf.is_empty()); /// } /// /// assert_eq!(buf, [0, 1, 1, 0]); /// /// Ok(()) /// } /// ``` pub trait WriteBytesExt: WriteBytes { /// Writes a `u8` into the underlying buffer. /// /// # Panics /// /// Panics if there are not enough bytes in `self`. #[inline] fn write_u8(&mut self, n: u8) { self.write_exact(&[n]); } /// Attempts to write a `u8` into the underlying buffer. /// /// If there are not enough bytes in `self` this function will return /// `Error::EndOfStream`. #[inline] fn try_write_u8(&mut self, n: u8) -> crate::Result<()> { self.try_write_exact(&[n])?; Ok(()) } /// Writes an `i8` into the underlying buffer. /// /// # Panics /// /// Panics if there are not enough bytes in `self`. #[inline] fn write_i8(&mut self, n: i8) { self.write_exact(&[n as _]); } /// Attempts to write an `i8` into the underlying buffer. /// /// If there are not enough bytes in `self` this function will return /// `Error::EndOfStream`. #[inline] fn try_write_i8(&mut self, n: i8) -> crate::Result<()> { self.try_write_exact(&[n as _])?; Ok(()) } impl_write! { "Writes a `u16` into the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", u16, write_u16, write_u16, } impl_try_write! { "Attempts to write a `u16` into the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", u16, try_write_u16, write_u16, } impl_write! { "Writes an `i16` into the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", i16, write_i16, write_i16, } impl_try_write! { "Attempts to write an `i16` into the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", i16, try_write_i16, write_i16, } impl_write! { "Writes a `u32` into the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", u32, write_u32, write_u32, } impl_try_write! { "Attempts to write a `u32` into the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", u32, try_write_u32, write_u32, } impl_write! { "Writes an `i32` into the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", i32, write_i32, write_i32, } impl_try_write! { "Attempts to write an `i32` into the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", i32, try_write_i32, write_i32, } impl_write! { "Writes a `u64` into the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", u64, write_u64, write_u64, } impl_try_write! { "Attempts to write a `u64` into the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", u64, try_write_u64, write_u64, } impl_write! { "Writes an `i64` into the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", i64, write_i64, write_i64, } impl_try_write! { "Attempts to write an `i64` into the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", i64, try_write_i64, write_i64, } impl_write! { "Writes a `u128` into the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", u128, write_u128, write_u128, } impl_try_write! { "Attempts to write a `u128` into the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", u128, try_write_u128, write_u128, } impl_write! { "Writes an `i128` into the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", i128, write_i128, write_i128, } impl_try_write! { "Attempts to write an `i128` into the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", i128, try_write_i128, write_i128, } impl_write! { "Writes an IEEE754 `f32` into the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", f32, write_f32, write_f32, } impl_try_write! { "Attempts to write an IEEE754 `f32` into the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", f32, try_write_f32, write_f32, } impl_write! { "Writes an IEEE754 `f64` into the underlying buffer. # Panics Panics if there are not enough bytes in `self`.", f64, write_f64, write_f64, } impl_try_write! { "Attempts to write an IEEE754 `f64` into the underlying buffer. If there are not enough bytes in `self` this function will return `Error::EndOfStream`.", f64, try_write_f64, write_f64, } } impl<W: WriteBytes> WriteBytesExt for W {} /* * * Writer * */ /// A convenience structure used for counting the number of bytes written. /// /// This structure wraps an implementation of [`WriteBytes`][writebytes]. It /// forwards write operations to the inner type while also maintaining a count /// of the number of bytes that pass through it. /// /// When you have finished with it, you can return the original type via the /// [`into_inner`][into-inner] method. /// /// # Examples /// /// ``` /// use byteio::{WriteBytes, WriteBytesExt, Writer}; /// use byteorder::BigEndian; /// /// fn main() -> byteio::Result<()> { /// let mut buf = [0; 7]; /// /// { /// let mut writer = Writer::new(&mut buf[..]); /// /// writer.try_write_u8(1)?; /// writer.try_write_u16::<BigEndian>(2)?; /// writer.try_write_u32::<BigEndian>(3)?; /// /// assert_eq!(writer.num_bytes_written(), 7); /// /// let inner = writer.into_inner(); /// assert!(inner.is_empty()); /// } /// /// assert_eq!(buf, [1, 0, 2, 0, 0, 0, 3]); /// /// Ok(()) /// } /// ``` /// /// [writebytes]: trait.WriteBytes.html /// [into-inner]: struct.Writer.html#method.into_inner #[derive(Debug, Clone, Eq, PartialEq, Hash)] pub struct Writer<W: WriteBytes>(W, usize); impl<W: WriteBytes> Writer<W> { /// Creates a new `Writer` by wrapping a [`WriteBytes`][writebytes] /// implementor. /// /// # Examples /// /// ``` /// use byteio::Writer; /// /// let mut buf = [0_u8; 2]; /// let mut writer = Writer::new(&mut buf[..]); /// ``` /// /// [writebytes]: trait.WriteBytes.html #[inline] pub fn new(writer: W) -> Self { Self(writer, 0) } /// Retrieves the number of bytes that have been written by this `Writer`. /// /// # Examples /// /// ``` /// use byteio::{WriteBytes, Writer}; /// /// let mut buf = [0_u8; 2]; /// let mut writer = Writer::new(&mut buf[..]); /// writer.write_exact(&[1]); /// writer.write_exact(&[1]); /// /// assert_eq!(writer.num_bytes_written(), 2); /// ``` #[inline] pub fn num_bytes_written(&self) -> usize { self.1 } /// Consumes this `Writer` and returns the original /// [`WriteBytes`][writebytes] implementor. /// /// ``` /// use byteio::{WriteBytes, Writer}; /// /// let mut buf = [0_u8; 2]; /// let mut writer = Writer::new(&mut buf[..]); /// writer.write_exact(&[1]); /// let inner = writer.into_inner(); /// /// assert_eq!(inner.len(), 1); // the writer consumed one byte from its view of the slice /// ``` /// /// [writebytes]: trait.WriteBytes.html #[inline] pub fn into_inner(self) -> W { self.0 } } impl<W: WriteBytes> AsMut<[u8]> for Writer<W> { fn as_mut(&mut self) -> &mut [u8] { self.0.as_mut() } } impl<W: WriteBytes> WriteBytes for Writer<W> { fn write_exact(&mut self, buf: &[u8]) { self.0.write_exact(buf); self.1 += buf.len(); } // NOTE: we can't rely on the default implementation here because the // underlying writer may be able to reallocate fn try_write_exact(&mut self, buf: &[u8]) -> crate::Result<()> { match self.0.try_write_exact(buf) { res @ Ok(_) => { self.1 += buf.len(); res } res @ Err(_) => res, } } } /* * * Unit tests * * For the full test suite, see $CARGO_MANIFEST_DIR/tests * */ #[cfg(test)] mod test { use super::*; #[cfg(feature = "std")] #[test] fn io_error_from_error_end_of_stream() { let err: io::Error = Error::EndOfStream.into(); assert_eq!(err.kind(), io::ErrorKind::UnexpectedEof); } #[cfg(feature = "std")] #[test] #[should_panic] fn io_error_from_error_nonexhaustive() { let _: io::Error = Error::_nonexhaustive(()).into(); } #[cfg(feature = "std")] #[test] fn display_error_end_of_stream() { use std::string::ToString; assert_eq!(Error::EndOfStream.to_string(), "unexpected end of stream"); } #[cfg(feature = "std")] #[test] #[should_panic] fn display_error_nonexhaustive() { use std::string::ToString; let _ = Error::_nonexhaustive(()).to_string(); } }