Big refactor.

substrate/wasm-runtime/polkadot/src/streamreader.rs

@@ -0,0 +1,63 @@
+use slicable::Slicable;
+
+pub struct StreamReader<'a> {
+	data: &'a[u8],
+	offset: usize,
+}
+
+impl<'a> StreamReader<'a> {
+	pub fn new(data: &'a[u8]) -> Self {
+		StreamReader {
+			data: data,
+			offset: 0,
+		}
+	}
+	pub fn read<T: Slicable>(&mut self) -> Option<T> {
+		let size = T::size_of(&self.data[self.offset..])?;
+		let new_offset = self.offset + size;
+		let slice = &self.data[self.offset..new_offset];
+		self.offset = new_offset;
+		Slicable::from_slice(slice)
+	}
+}
+
+pub trait Joiner {
+	fn join<T: Slicable + Sized>(self, value: &T) -> Self;
+}
+
+impl Joiner for Vec<u8> {
+	fn join<T: Slicable + Sized>(mut self, value: &T) -> Vec<u8> {
+		value.as_slice_then(|s| self.extend_from_slice(s));
+		self
+	}
+}
+/*
+// Not in use yet
+// TODO: introduce fn size_will_be(&self) -> usize; to Slicable trait and implement
+struct StreamWriter<'a> {
+	data: &'a mut[u8],
+	offset: usize,
+}
+
+impl<'a> StreamWriter<'a> {
+	pub fn new(data: &'a mut[u8]) -> Self {
+		StreamWriter {
+			data: data,
+			offset: 0,
+		}
+	}
+	pub fn write<T: Slicable>(&mut self, value: &T) -> bool {
+		value.as_slice_then(|s| {
+			let new_offset = self.offset + s.len();
+			if self.data.len() <= new_offset {
+				let slice = &mut self.data[self.offset..new_offset];
+				self.offset = new_offset;
+				slice.copy_from_slice(s);
+				true
+			} else {
+				false
+			}
+		})
+	}
+}
+*/