diff options
Diffstat (limited to 'src/deserialise')
| -rw-r--r-- | src/deserialise/mod.rs | 92 | ||||
| -rw-r--r-- | src/deserialise/test.rs | 16 |
2 files changed, 82 insertions, 26 deletions
diff --git a/src/deserialise/mod.rs b/src/deserialise/mod.rs index 59e2b69..eaebe2b 100644 --- a/src/deserialise/mod.rs +++ b/src/deserialise/mod.rs @@ -22,20 +22,25 @@ #[cfg(test)] mod test; -use crate::{Dstream, Error, Serialise}; - -use std::convert::Infallible; -use std::error::Error as StdError; -use std::mem::size_of; -use std::num::NonZero; - -/// Denotes a type capable of being deserialised. -pub trait Deserialise: Serialise + Sized { +use crate::{Error, Dstream}; + +use alloc::boxed::Box; +use core::convert::Infallible; +use core::error::Error as StdError; +use core::mem::{MaybeUninit, size_of}; +use core::num::NonZero; +use core::ptr::read; + +/// Types capable of being deserialised. +pub trait Deserialise: Sized { + /// The error of deserialisation. + /// + /// Use [`Infallible`] if **all** deserialisations are infallible, as is the case of zero-length types. type Error; /// Deserialises the byte stream to an object. /// - /// This function should not take *more* bytes than specified by [`SERIALISE_LIMIT`](Serialise::SERIALISE_LIMIT). + /// This function should **not** take more bytes than specified by [`T::SERIALISE_LIMIT`](crate::Serialise::SERIALISE_LIMIT). /// Doing so is considered a logic error. /// /// # Errors @@ -75,7 +80,11 @@ macro_rules! impl_int { Ok(Self::from_be_bytes(data)) } } + }; +} +macro_rules! impl_non_zero { + ($type:ty) => { impl Deserialise for NonZero<$type> { type Error = Error; @@ -353,19 +362,33 @@ where } } -impl<T: Deserialise<Error: StdError + 'static>, const N: usize> Deserialise for [T; N] { +impl<T, const N: usize> Deserialise for [T; N] +where + T: Default + Deserialise<Error: StdError + 'static>, { type Error = Box<dyn StdError>; fn deserialise(stream: &mut Dstream) -> Result<Self, Self::Error> { - let len = usize::try_from(u64::deserialise(stream)?).unwrap(); + let len = usize::deserialise(stream)?; + if len != N { return Err(Box::new(Error::ArrayTooShort { req: len, len: N })) }; - let mut buf = Vec::with_capacity(len); - for _ in 0x0..len { buf.push(Deserialise::deserialise(stream)?); } + let mut buf: [MaybeUninit<T>; N] = unsafe { MaybeUninit::uninit().assume_init() }; - // If we had used the checked unwrap, we would also - // have to require `T: Debug`. - Ok(unsafe { buf.try_into().unwrap_unchecked() }) + // Deserialise t + for item in buf.iter_mut().take(len) { + item.write(Deserialise::deserialise(stream)?); + } + + for item in buf.iter_mut().skip(len) { + item.write(Default::default()); + } + + // This should be safe as `MaybeUninit<T>` is + // transparent to `T`. The original buffer is + // NOT dropped automatically, so we can just + // forget about it from this point on. + let buf = unsafe { read(core::ptr::from_ref(&buf).cast::<[T; N]>()) }; + Ok(buf) } } @@ -406,6 +429,17 @@ impl Deserialise for Infallible { fn deserialise(_stream: &mut Dstream) -> Result<Self, Self::Error> { unreachable!() } } +impl Deserialise for isize { + type Error = Error; + + fn deserialise(stream: &mut Dstream) -> Result<Self, Self::Error> { + let value = i16::deserialise(stream)? + .into(); + + Ok(value) + } +} + impl<T: Deserialise<Error: StdError + 'static>> Deserialise for Option<T> { type Error = Box<dyn StdError>; @@ -439,6 +473,17 @@ where } } +impl Deserialise for usize { + type Error = Error; + + fn deserialise(stream: &mut Dstream) -> Result<Self, Self::Error> { + let value = u16::deserialise(stream)? + .into(); + + Ok(value) + } +} + impl_float!(f32); impl_float!(f64); @@ -452,3 +497,16 @@ impl_int!(u16); impl_int!(u32); impl_int!(u64); impl_int!(u8); + +impl_non_zero!(i128); +impl_non_zero!(i16); +impl_non_zero!(i32); +impl_non_zero!(i64); +impl_non_zero!(i8); +impl_non_zero!(isize); +impl_non_zero!(u128); +impl_non_zero!(u16); +impl_non_zero!(u32); +impl_non_zero!(u64); +impl_non_zero!(u8); +impl_non_zero!(usize); diff --git a/src/deserialise/test.rs b/src/deserialise/test.rs index 27acfda..70293cb 100644 --- a/src/deserialise/test.rs +++ b/src/deserialise/test.rs @@ -19,23 +19,21 @@ // er General Public License along with bzipper. If // not, see <https://www.gnu.org/licenses/>. -use crate::{Deserialise, Dstream, FixedString}; +use crate::{Deserialise, FixedString}; #[test] fn test_deserialise() { let data = [ 0x00, 0xFF, 0xFF, 0x0F, 0xEF, 0x1F, 0xDF, 0x2F, 0xCF, 0x3F, 0xBF, 0x4F, 0xAF, 0x5F, 0x9F, 0x6F, - 0x8F, 0x7F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - 0x00, 0x09, 0x6D, 0xC3, 0xA1, 0x6E, 0x61, 0xC3, - 0xB0, 0x75, 0x72, 0x00, 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x05, 0x00, 0x00, 0x03, 0xBB, 0x00, - 0x00, 0x03, 0x91, 0x00, 0x00, 0x03, 0xBC, 0x00, - 0x00, 0x03, 0x94, 0x00, 0x00, 0x03, 0xB1, 0x01, - 0x00, 0x00, 0x01, 0x80, + 0x8F, 0x7F, 0x00, 0x09, 0x6D, 0xC3, 0xA1, 0x6E, + 0x61, 0xC3, 0xB0, 0x75, 0x72, 0x00, 0x05, 0x00, + 0x00, 0x03, 0xBB, 0x00, 0x00, 0x03, 0x91, 0x00, + 0x00, 0x03, 0xBC, 0x00, 0x00, 0x03, 0x94, 0x00, + 0x00, 0x03, 0xB1, 0x01, 0x00, 0x00, 0x01, 0x80, ]; - let mut stream = Dstream::from(&data); + let mut stream = From::from(&data); assert_eq!( u8::deserialise(&mut stream).unwrap(), |