1 files changed, 164 insertions, 6 deletions
diff --git a/src/deserialise/mod.rs b/src/deserialise/mod.rs
index cd0889a..2678670 100644
--- a/src/deserialise/mod.rs
+++ b/src/deserialise/mod.rs
@@ -19,11 +19,169 @@
 // er General Public License along with bzipper. If
 // not, see <https://www.gnu.org/licenses/>.
 
-//! Deserialisation utilities.
-
-use crate::use_mod;
-use_mod!(pub d_stream);
-use_mod!(pub deserialise);
-
 #[cfg(test)]
 mod test;
+
+use crate::{DStream, Error};
+
+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: Sized {
+ type Error;
+
+ /// Deserialises the byte stream to an object.
+ ///
+ /// # Errors
+ ///
+ /// If deserialisation failed, e.g. by an invalid value being found, an error is returned.
+ fn deserialise(stream: &mut DStream) -> Result<Self, Self::Error>;
+}
+
+macro_rules! impl_float {
+ ($type:ty) => {
+ impl Deserialise for $type {
+ type Error = Error;
+
+ fn deserialise(stream: &mut DStream) -> Result<Self, Self::Error> {
+ let data = stream
+ .take(size_of::<Self>())?
+ .try_into()
+ .unwrap();
+
+ Ok(Self::from_be_bytes(data))
+ }
+ }
+ };
+}
+
+macro_rules! impl_int {
+ ($type:ty) => {
+ impl Deserialise for $type {
+ type Error = Error;
+
+ fn deserialise(stream: &mut DStream) -> Result<Self, Self::Error> {
+ let data = stream
+ .take(size_of::<Self>())?
+ .try_into()
+ .unwrap();
+
+ Ok(Self::from_be_bytes(data))
+ }
+ }
+
+ impl Deserialise for NonZero<$type> {
+ type Error = Error;
+
+ fn deserialise(stream: &mut DStream) -> Result<Self, Self::Error> {
+ let value = <$type>::deserialise(stream)?;
+
+ NonZero::new(value)
+ .ok_or(Error::NullInteger)
+ }
+ }
+ };
+}
+
+impl<T: Deserialise<Error: StdError + 'static>, const N: usize> Deserialise for [T; N] {
+ type Error = Box<dyn StdError>;
+
+ fn deserialise(stream: &mut DStream) -> Result<Self, Self::Error> {
+ let len = usize::try_from(u64::deserialise(stream)?).unwrap();
+ if len != N { return Err(Box::new(Error::ArrayLengthMismatch { len, ok_len: N })) };
+
+ let mut buf = Vec::with_capacity(len);
+ for _ in 0x0..len { buf.push(Deserialise::deserialise(stream)?); }
+
+ // If we had used the checked unwrap, we would also
+ // have to require `T: Debug`.
+ Ok(unsafe { buf.try_into().unwrap_unchecked() })
+ }
+}
+
+impl Deserialise for () {
+ type Error = Error;
+
+ fn deserialise(_stream: &mut DStream) -> Result<Self, Self::Error> { Ok(()) }
+}
+
+impl Deserialise for bool {
+ type Error = Error;
+
+ fn deserialise(stream: &mut DStream) -> Result<Self, Self::Error> {
+ let value = u8::deserialise(stream)?;
+
+ match value {
+ 0x00 => Ok(false),
+ 0x01 => Ok(true),
+ _ => Err(Error::InvalidBoolean { value })
+ }
+ }
+}
+
+impl Deserialise for char {
+ type Error = Error;
+
+ fn deserialise(stream: &mut DStream) -> Result<Self, Self::Error> {
+ let value = u32::deserialise(stream)?;
+
+ Self::from_u32(value)
+ .ok_or(Error::InvalidCodePoint { value })
+ }
+}
+
+impl Deserialise for Infallible {
+ type Error = Error;
+
+ fn deserialise(_stream: &mut DStream) -> Result<Self, Self::Error> { unreachable!() }
+}
+
+impl<T: Deserialise<Error: StdError + 'static>> Deserialise for Option<T> {
+ type Error = Box<dyn StdError>;
+
+ fn deserialise(stream: &mut DStream) -> Result<Self, Self::Error> {
+ let sign = bool::deserialise(stream)?;
+
+ if sign {
+ Ok(Some(T::deserialise(stream)?))
+ } else {
+ Ok(None)
+ }
+ }
+}
+
+impl<T: Deserialise, E: Deserialise> Deserialise for Result<T, E>
+where
+ <T as Deserialise>::Error: StdError + 'static,
+ <E as Deserialise>::Error: StdError + 'static, {
+ type Error = Box<dyn StdError>;
+
+ fn deserialise(stream: &mut DStream) -> Result<Self, Self::Error> {
+ let sign = bool::deserialise(stream)?;
+
+ let value = if sign {
+ Err(E::deserialise(stream)?)
+ } else {
+ Ok(T::deserialise(stream)?)
+ };
+
+ Ok(value)
+ }
+}
+
+impl_float!(f32);
+impl_float!(f64);
+
+impl_int!(i128);
+impl_int!(i16);
+impl_int!(i32);
+impl_int!(i64);
+impl_int!(i8);
+impl_int!(u128);
+impl_int!(u16);
+impl_int!(u32);
+impl_int!(u64);
+impl_int!(u8);