Added documentation for the src/de module

This commit is contained in:
Victor Koenders 2021-10-14 17:30:52 +02:00
parent 84344af2c6
commit ea75220cd0
3 changed files with 330 additions and 261 deletions

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@ -1,215 +1,234 @@
use super::{ use super::{
read::{BorrowReader, Reader}, read::{BorrowReader, Reader},
BorrowDecode, Decode, BorrowDecode, Decode,
}; };
use crate::{ use crate::{
config::{Config, Endian, IntEncoding}, config::{Config, Endian, IntEncoding},
error::DecodeError, error::DecodeError,
}; };
use core::marker::PhantomData; use core::marker::PhantomData;
pub struct Decoder<R, C: Config> { /// A Decoder that reads bytes from a given reader `R`.
reader: R, ///
config: PhantomData<C>, /// This struct should rarely be used.
} /// In most cases, prefer any of the `decode` functions.
///
impl<'de, R: Reader<'de>, C: Config> Decoder<R, C> { /// The ByteOrder that is chosen will impact the endianness that
pub fn new(reader: R, _config: C) -> Decoder<R, C> { /// is used to read integers out of the reader.
Decoder { ///
reader, /// ```
config: PhantomData, /// # let slice: &[u8] = &[0, 0, 0, 0];
} /// # let some_reader = bincode::de::read::SliceReader::new(slice);
} /// use bincode::de::{Decoder, Decodable};
/// use bincode::config;
pub fn into_reader(self) -> R { /// let mut decoder = Decoder::new(some_reader, config::Default);
self.reader /// // this u32 can be any Decodable
} /// let value = u32::decode(&mut decoder).unwrap();
} /// ```
pub struct Decoder<R, C: Config> {
impl<'a, 'de, R: BorrowReader<'de>, C: Config> BorrowDecode<'de> for &'a mut Decoder<R, C> { reader: R,
fn decode_slice(&mut self, len: usize) -> Result<&'de [u8], DecodeError> { config: PhantomData<C>,
self.reader.take_bytes(len) }
}
} impl<'de, R: Reader<'de>, C: Config> Decoder<R, C> {
/// Construct a new Decoder
impl<'a, 'de, R: Reader<'de>, C: Config> Decode for &'a mut Decoder<R, C> { pub fn new(reader: R, _config: C) -> Decoder<R, C> {
fn decode_u8(&mut self) -> Result<u8, DecodeError> { Decoder {
let mut bytes = [0u8; 1]; reader,
self.reader.read(&mut bytes)?; config: PhantomData,
Ok(bytes[0]) }
} }
fn decode_u16(&mut self) -> Result<u16, DecodeError> { /// Consume the decoder and return the inner reader
match C::INT_ENCODING { pub fn into_reader(self) -> R {
IntEncoding::Variable => crate::varint::varint_decode_u16(&mut self.reader, C::ENDIAN), self.reader
IntEncoding::Fixed => { }
let mut bytes = [0u8; 2]; }
self.reader.read(&mut bytes)?;
Ok(match C::ENDIAN { impl<'a, 'de, R: BorrowReader<'de>, C: Config> BorrowDecode<'de> for &'a mut Decoder<R, C> {
Endian::Little => u16::from_le_bytes(bytes), fn decode_slice(&mut self, len: usize) -> Result<&'de [u8], DecodeError> {
Endian::Big => u16::from_be_bytes(bytes), self.reader.take_bytes(len)
}) }
} }
}
} impl<'a, 'de, R: Reader<'de>, C: Config> Decode for &'a mut Decoder<R, C> {
fn decode_u8(&mut self) -> Result<u8, DecodeError> {
fn decode_u32(&mut self) -> Result<u32, DecodeError> { let mut bytes = [0u8; 1];
match C::INT_ENCODING { self.reader.read(&mut bytes)?;
IntEncoding::Variable => crate::varint::varint_decode_u32(&mut self.reader, C::ENDIAN), Ok(bytes[0])
IntEncoding::Fixed => { }
let mut bytes = [0u8; 4];
self.reader.read(&mut bytes)?; fn decode_u16(&mut self) -> Result<u16, DecodeError> {
Ok(match C::ENDIAN { match C::INT_ENCODING {
Endian::Little => u32::from_le_bytes(bytes), IntEncoding::Variable => crate::varint::varint_decode_u16(&mut self.reader, C::ENDIAN),
Endian::Big => u32::from_be_bytes(bytes), IntEncoding::Fixed => {
}) let mut bytes = [0u8; 2];
} self.reader.read(&mut bytes)?;
} Ok(match C::ENDIAN {
} Endian::Little => u16::from_le_bytes(bytes),
Endian::Big => u16::from_be_bytes(bytes),
fn decode_u64(&mut self) -> Result<u64, DecodeError> { })
match C::INT_ENCODING { }
IntEncoding::Variable => crate::varint::varint_decode_u64(&mut self.reader, C::ENDIAN), }
IntEncoding::Fixed => { }
let mut bytes = [0u8; 8];
self.reader.read(&mut bytes)?; fn decode_u32(&mut self) -> Result<u32, DecodeError> {
Ok(match C::ENDIAN { match C::INT_ENCODING {
Endian::Little => u64::from_le_bytes(bytes), IntEncoding::Variable => crate::varint::varint_decode_u32(&mut self.reader, C::ENDIAN),
Endian::Big => u64::from_be_bytes(bytes), IntEncoding::Fixed => {
}) let mut bytes = [0u8; 4];
} self.reader.read(&mut bytes)?;
} Ok(match C::ENDIAN {
} Endian::Little => u32::from_le_bytes(bytes),
Endian::Big => u32::from_be_bytes(bytes),
fn decode_u128(&mut self) -> Result<u128, DecodeError> { })
match C::INT_ENCODING { }
IntEncoding::Variable => crate::varint::varint_decode_u128(&mut self.reader, C::ENDIAN), }
IntEncoding::Fixed => { }
let mut bytes = [0u8; 16];
self.reader.read(&mut bytes)?; fn decode_u64(&mut self) -> Result<u64, DecodeError> {
Ok(match C::ENDIAN { match C::INT_ENCODING {
Endian::Little => u128::from_le_bytes(bytes), IntEncoding::Variable => crate::varint::varint_decode_u64(&mut self.reader, C::ENDIAN),
Endian::Big => u128::from_be_bytes(bytes), IntEncoding::Fixed => {
}) let mut bytes = [0u8; 8];
} self.reader.read(&mut bytes)?;
} Ok(match C::ENDIAN {
} Endian::Little => u64::from_le_bytes(bytes),
Endian::Big => u64::from_be_bytes(bytes),
fn decode_usize(&mut self) -> Result<usize, DecodeError> { })
match C::INT_ENCODING { }
IntEncoding::Variable => { }
crate::varint::varint_decode_usize(&mut self.reader, C::ENDIAN) }
}
IntEncoding::Fixed => { fn decode_u128(&mut self) -> Result<u128, DecodeError> {
let mut bytes = [0u8; 8]; match C::INT_ENCODING {
self.reader.read(&mut bytes)?; IntEncoding::Variable => crate::varint::varint_decode_u128(&mut self.reader, C::ENDIAN),
Ok(match C::ENDIAN { IntEncoding::Fixed => {
Endian::Little => u64::from_le_bytes(bytes), let mut bytes = [0u8; 16];
Endian::Big => u64::from_be_bytes(bytes), self.reader.read(&mut bytes)?;
} as usize) Ok(match C::ENDIAN {
} Endian::Little => u128::from_le_bytes(bytes),
} Endian::Big => u128::from_be_bytes(bytes),
} })
}
fn decode_i8(&mut self) -> Result<i8, DecodeError> { }
let mut bytes = [0u8; 1]; }
self.reader.read(&mut bytes)?;
Ok(bytes[0] as i8) fn decode_usize(&mut self) -> Result<usize, DecodeError> {
} match C::INT_ENCODING {
IntEncoding::Variable => {
fn decode_i16(&mut self) -> Result<i16, DecodeError> { crate::varint::varint_decode_usize(&mut self.reader, C::ENDIAN)
match C::INT_ENCODING { }
IntEncoding::Variable => crate::varint::varint_decode_i16(&mut self.reader, C::ENDIAN), IntEncoding::Fixed => {
IntEncoding::Fixed => { let mut bytes = [0u8; 8];
let mut bytes = [0u8; 2]; self.reader.read(&mut bytes)?;
self.reader.read(&mut bytes)?; Ok(match C::ENDIAN {
Ok(match C::ENDIAN { Endian::Little => u64::from_le_bytes(bytes),
Endian::Little => i16::from_le_bytes(bytes), Endian::Big => u64::from_be_bytes(bytes),
Endian::Big => i16::from_be_bytes(bytes), } as usize)
}) }
} }
} }
}
fn decode_i8(&mut self) -> Result<i8, DecodeError> {
fn decode_i32(&mut self) -> Result<i32, DecodeError> { let mut bytes = [0u8; 1];
match C::INT_ENCODING { self.reader.read(&mut bytes)?;
IntEncoding::Variable => crate::varint::varint_decode_i32(&mut self.reader, C::ENDIAN), Ok(bytes[0] as i8)
IntEncoding::Fixed => { }
let mut bytes = [0u8; 4];
self.reader.read(&mut bytes)?; fn decode_i16(&mut self) -> Result<i16, DecodeError> {
Ok(match C::ENDIAN { match C::INT_ENCODING {
Endian::Little => i32::from_le_bytes(bytes), IntEncoding::Variable => crate::varint::varint_decode_i16(&mut self.reader, C::ENDIAN),
Endian::Big => i32::from_be_bytes(bytes), IntEncoding::Fixed => {
}) let mut bytes = [0u8; 2];
} self.reader.read(&mut bytes)?;
} Ok(match C::ENDIAN {
} Endian::Little => i16::from_le_bytes(bytes),
Endian::Big => i16::from_be_bytes(bytes),
fn decode_i64(&mut self) -> Result<i64, DecodeError> { })
match C::INT_ENCODING { }
IntEncoding::Variable => crate::varint::varint_decode_i64(&mut self.reader, C::ENDIAN), }
IntEncoding::Fixed => { }
let mut bytes = [0u8; 8];
self.reader.read(&mut bytes)?; fn decode_i32(&mut self) -> Result<i32, DecodeError> {
Ok(match C::ENDIAN { match C::INT_ENCODING {
Endian::Little => i64::from_le_bytes(bytes), IntEncoding::Variable => crate::varint::varint_decode_i32(&mut self.reader, C::ENDIAN),
Endian::Big => i64::from_be_bytes(bytes), IntEncoding::Fixed => {
}) let mut bytes = [0u8; 4];
} self.reader.read(&mut bytes)?;
} Ok(match C::ENDIAN {
} Endian::Little => i32::from_le_bytes(bytes),
Endian::Big => i32::from_be_bytes(bytes),
fn decode_i128(&mut self) -> Result<i128, DecodeError> { })
match C::INT_ENCODING { }
IntEncoding::Variable => crate::varint::varint_decode_i128(&mut self.reader, C::ENDIAN), }
IntEncoding::Fixed => { }
let mut bytes = [0u8; 16];
self.reader.read(&mut bytes)?; fn decode_i64(&mut self) -> Result<i64, DecodeError> {
Ok(match C::ENDIAN { match C::INT_ENCODING {
Endian::Little => i128::from_le_bytes(bytes), IntEncoding::Variable => crate::varint::varint_decode_i64(&mut self.reader, C::ENDIAN),
Endian::Big => i128::from_be_bytes(bytes), IntEncoding::Fixed => {
}) let mut bytes = [0u8; 8];
} self.reader.read(&mut bytes)?;
} Ok(match C::ENDIAN {
} Endian::Little => i64::from_le_bytes(bytes),
Endian::Big => i64::from_be_bytes(bytes),
fn decode_isize(&mut self) -> Result<isize, DecodeError> { })
match C::INT_ENCODING { }
IntEncoding::Variable => { }
crate::varint::varint_decode_isize(&mut self.reader, C::ENDIAN) }
}
IntEncoding::Fixed => { fn decode_i128(&mut self) -> Result<i128, DecodeError> {
let mut bytes = [0u8; 8]; match C::INT_ENCODING {
self.reader.read(&mut bytes)?; IntEncoding::Variable => crate::varint::varint_decode_i128(&mut self.reader, C::ENDIAN),
Ok(match C::ENDIAN { IntEncoding::Fixed => {
Endian::Little => i64::from_le_bytes(bytes), let mut bytes = [0u8; 16];
Endian::Big => i64::from_be_bytes(bytes), self.reader.read(&mut bytes)?;
} as isize) Ok(match C::ENDIAN {
} Endian::Little => i128::from_le_bytes(bytes),
} Endian::Big => i128::from_be_bytes(bytes),
} })
}
fn decode_f32(&mut self) -> Result<f32, DecodeError> { }
let mut bytes = [0u8; 4]; }
self.reader.read(&mut bytes)?;
Ok(match C::ENDIAN { fn decode_isize(&mut self) -> Result<isize, DecodeError> {
Endian::Little => f32::from_le_bytes(bytes), match C::INT_ENCODING {
Endian::Big => f32::from_be_bytes(bytes), IntEncoding::Variable => {
}) crate::varint::varint_decode_isize(&mut self.reader, C::ENDIAN)
} }
IntEncoding::Fixed => {
fn decode_f64(&mut self) -> Result<f64, DecodeError> { let mut bytes = [0u8; 8];
let mut bytes = [0u8; 8]; self.reader.read(&mut bytes)?;
self.reader.read(&mut bytes)?; Ok(match C::ENDIAN {
Ok(match C::ENDIAN { Endian::Little => i64::from_le_bytes(bytes),
Endian::Little => f64::from_le_bytes(bytes), Endian::Big => i64::from_be_bytes(bytes),
Endian::Big => f64::from_be_bytes(bytes), } as isize)
}) }
} }
}
fn decode_array<const N: usize>(&mut self) -> Result<[u8; N], DecodeError> {
let mut array = [0u8; N]; fn decode_f32(&mut self) -> Result<f32, DecodeError> {
self.reader.read(&mut array)?; let mut bytes = [0u8; 4];
Ok(array) self.reader.read(&mut bytes)?;
} Ok(match C::ENDIAN {
} Endian::Little => f32::from_le_bytes(bytes),
Endian::Big => f32::from_be_bytes(bytes),
})
}
fn decode_f64(&mut self) -> Result<f64, DecodeError> {
let mut bytes = [0u8; 8];
self.reader.read(&mut bytes)?;
Ok(match C::ENDIAN {
Endian::Little => f64::from_le_bytes(bytes),
Endian::Big => f64::from_be_bytes(bytes),
})
}
fn decode_array<const N: usize>(&mut self) -> Result<[u8; N], DecodeError> {
let mut array = [0u8; N];
self.reader.read(&mut array)?;
Ok(array)
}
}

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@ -1,45 +1,75 @@
use crate::error::DecodeError; use crate::error::DecodeError;
mod decoder; mod decoder;
mod impls; mod impls;
pub mod read; pub mod read;
pub use self::decoder::Decoder; pub use self::decoder::Decoder;
pub trait Decodable: for<'de> BorrowDecodable<'de> { /// Trait that makes a type able to be decoded, akin to serde's `DeserializeOwned` trait.
fn decode<D: Decode>(decoder: D) -> Result<Self, DecodeError>; ///
} /// This trait should be implemented for types which do not have references to data in the reader. For types that contain e.g. `&str` and `&[u8]`, implement [BorrowDecodable] instead.
///
pub trait BorrowDecodable<'de>: Sized { /// Whenever you implement `Decodable` for your type, the base trait `BorrowDecodable` is automatically implemented.
fn borrow_decode<D: BorrowDecode<'de>>(decoder: D) -> Result<Self, DecodeError>; pub trait Decodable: for<'de> BorrowDecodable<'de> {
} /// Attempt to decode this type with the given [Decode].
fn decode<D: Decode>(decoder: D) -> Result<Self, DecodeError>;
impl<'de, T: Decodable> BorrowDecodable<'de> for T { }
fn borrow_decode<D: Decode>(decoder: D) -> Result<Self, DecodeError> {
Decodable::decode(decoder) /// Trait that makes a type able to be decoded, akin to serde's `Deserialize` trait.
} ///
} /// This trait should be implemented for types that contain borrowed data, like `&str` and `&[u8]`. If your type does not have borrowed data, consider implementing [Decodable] instead.
pub trait BorrowDecodable<'de>: Sized {
pub trait Decode { /// Attempt to decode this type with the given [BorrowDecode].
fn decode_u8(&mut self) -> Result<u8, DecodeError>; fn borrow_decode<D: BorrowDecode<'de>>(decoder: D) -> Result<Self, DecodeError>;
fn decode_u16(&mut self) -> Result<u16, DecodeError>; }
fn decode_u32(&mut self) -> Result<u32, DecodeError>;
fn decode_u64(&mut self) -> Result<u64, DecodeError>; impl<'de, T: Decodable> BorrowDecodable<'de> for T {
fn decode_u128(&mut self) -> Result<u128, DecodeError>; fn borrow_decode<D: Decode>(decoder: D) -> Result<Self, DecodeError> {
fn decode_usize(&mut self) -> Result<usize, DecodeError>; Decodable::decode(decoder)
}
fn decode_i8(&mut self) -> Result<i8, DecodeError>; }
fn decode_i16(&mut self) -> Result<i16, DecodeError>;
fn decode_i32(&mut self) -> Result<i32, DecodeError>; /// Any source that can decode basic types. This type is most notably implemented for [Decoder].
fn decode_i64(&mut self) -> Result<i64, DecodeError>; pub trait Decode {
fn decode_i128(&mut self) -> Result<i128, DecodeError>; /// Attempt to decode a `u8`
fn decode_isize(&mut self) -> Result<isize, DecodeError>; fn decode_u8(&mut self) -> Result<u8, DecodeError>;
/// Attempt to decode a `u16`
fn decode_f32(&mut self) -> Result<f32, DecodeError>; fn decode_u16(&mut self) -> Result<u16, DecodeError>;
fn decode_f64(&mut self) -> Result<f64, DecodeError>; /// Attempt to decode a `u32`
fn decode_array<const N: usize>(&mut self) -> Result<[u8; N], DecodeError>; fn decode_u32(&mut self) -> Result<u32, DecodeError>;
} /// Attempt to decode a `u64`
fn decode_u64(&mut self) -> Result<u64, DecodeError>;
pub trait BorrowDecode<'de>: Decode { /// Attempt to decode a `u128`
fn decode_slice(&mut self, len: usize) -> Result<&'de [u8], DecodeError>; fn decode_u128(&mut self) -> Result<u128, DecodeError>;
} /// Attempt to decode a `usize`
fn decode_usize(&mut self) -> Result<usize, DecodeError>;
/// Attempt to decode a `i8`
fn decode_i8(&mut self) -> Result<i8, DecodeError>;
/// Attempt to decode a `i16`
fn decode_i16(&mut self) -> Result<i16, DecodeError>;
/// Attempt to decode a `i32`
fn decode_i32(&mut self) -> Result<i32, DecodeError>;
/// Attempt to decode a `i64`
fn decode_i64(&mut self) -> Result<i64, DecodeError>;
/// Attempt to decode a `i128`
fn decode_i128(&mut self) -> Result<i128, DecodeError>;
/// Attempt to decode a `isize`
fn decode_isize(&mut self) -> Result<isize, DecodeError>;
/// Attempt to decode a `f32`
fn decode_f32(&mut self) -> Result<f32, DecodeError>;
/// Attempt to decode a `f64`
fn decode_f64(&mut self) -> Result<f64, DecodeError>;
/// Attempt to decode an array of `N` entries.
fn decode_array<const N: usize>(&mut self) -> Result<[u8; N], DecodeError>;
}
/// Any source that can decode basic types. This type is most notably implemented for [Decoder].
///
/// This is an extension of [Decode] that can also return borrowed data.
pub trait BorrowDecode<'de>: Decode {
/// Decode `len` bytes, returning the slice as borrowed data.
fn decode_slice(&mut self, len: usize) -> Result<&'de [u8], DecodeError>;
}

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@ -1,20 +1,40 @@
//! This module contains reader-based structs and traits.
//!
//! Because `std::io::Read` is only limited to `std` and not `core`, we provide 2 alternative readers.
//!
//! [Reader] is a reader for sources that do not own their data. It is assumed that the reader's data is dropped after the `read` method is called. This reader is incapable of reading borrowed data, like `&str` and `&[u8]`.
//!
//! [BorrowReader] is an extension of `Reader` that also allows returning borrowed data. A `BorrowReader` allows reading `&str` and `&[u8]`.
//!
//! Specifically the `Reader` trait is used by [Decodable] and the `BorrowReader` trait is used by `[BorrowDecodable]`.
//!
//! [Decodable]: ../trait.Decodable.html
//! [BorrowDecodable]: ../trait.BorrowDecodable.html
use crate::error::DecodeError; use crate::error::DecodeError;
/// A reader for owned data. See the module documentation for more information.
pub trait Reader<'storage> { pub trait Reader<'storage> {
/// Fill the given `bytes` argument with values. Exactly the length of the given slice must be filled, or else an error must be returned.
fn read(&mut self, bytes: &mut [u8]) -> Result<(), DecodeError>; fn read(&mut self, bytes: &mut [u8]) -> Result<(), DecodeError>;
} }
/// A reader for borrowed data. Implementors of this must also implement the [Reader] trait. See the module documentation for more information.
pub trait BorrowReader<'storage>: Reader<'storage> { pub trait BorrowReader<'storage>: Reader<'storage> {
/// Read exactly `length` bytes and return a slice to this data. If not enough bytes could be read, an error should be returned.
///
/// *note*: Exactly `length` bytes must be returned. If less bytes are returned, bincode may panic. If more bytes are returned, the excess bytes may be discarded.
fn take_bytes(&mut self, length: usize) -> Result<&'storage [u8], DecodeError>; fn take_bytes(&mut self, length: usize) -> Result<&'storage [u8], DecodeError>;
} }
/// A reader type for `&[u8]` slices. Implements both [Reader] and [BorrowReader], and thus can be used for borrowed data.
pub struct SliceReader<'storage> { pub struct SliceReader<'storage> {
slice: &'storage [u8], slice: &'storage [u8],
} }
impl<'storage> SliceReader<'storage> { impl<'storage> SliceReader<'storage> {
/// Constructs a slice reader /// Constructs a slice reader
pub(crate) fn new(bytes: &'storage [u8]) -> SliceReader<'storage> { pub fn new(bytes: &'storage [u8]) -> SliceReader<'storage> {
SliceReader { slice: bytes } SliceReader { slice: bytes }
} }