1 files changed, 61 insertions, 0 deletions
diff --git a/src/deserialise/d_stream/mod.rs b/src/deserialise/d_stream/mod.rs
new file mode 100644
index 0000000..f6adbd9
--- /dev/null
+++ b/src/deserialise/d_stream/mod.rs
@@ -0,0 +1,61 @@
+// Copyright 2022-2024 Gabriel Bjørnager Jensen.
+
+use crate::error::{Error, Result};
+
+use std::fmt::{Debug, Formatter};
+
+/// A byte stream for deserialisation.
+///
+/// This type borrows a byte slice (hence [`new`](DStream::new)), keeping track internally of the used bytes.
+#[derive(Clone)]
+pub struct DStream<'a> {
+	data: &'a [u8],
+	len:  usize,
+}
+
+impl<'a> DStream<'a> {
+	/// Constructs a new byte stream.
+	pub fn new<T: AsRef<[u8]> + ?Sized>(buf: &'a T) -> Self { Self {
+		data: buf.as_ref(),
+		len:  buf.as_ref().len(),
+	} }
+
+	/// Takes bytes from the stream.
+	///
+	/// # Errors
+	///
+	/// If the internal buffer doesn't hold at least the requested ammount of bytes, an [`EndOfDStream`](Error::EndOfDStream) error is returned.
+	pub fn take(&mut self, len: usize) -> Result<&[u8]> {
+		if self.len < len { return Err(Error::EndOfDStream { len: self.len, ok_len: len } ) }
+
+		let start = self.data.len() - self.len;
+		let stop  = start + len;
+
+		self.len -= len;
+
+		Ok(&self.data[start..stop])
+	}
+}
+
+impl Debug for DStream<'_> {
+	fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
+		let stop  = self.data.len();
+		let start = self.data.len() - self.len;
+
+		write!(f, "[")?;
+
+		for v in &self.data[start..stop] { write!(f, "{v:#02X},")? };
+
+		write!(f, "]")?;
+
+		Ok(())
+	}
+}
+
+impl<'a> From<&'a [u8]> for DStream<'a> {
+	fn from(value: &'a [u8]) -> Self { Self::new(value) }
+}
+
+impl<'a, const N: usize> From<&'a [u8; N]> for DStream<'a> {
+	fn from(value: &'a [u8; N]) -> Self { Self::new(value) }
+}