add methods to consume Bytes as Packed... things

triblespace · Sep 26, 2024 · a5425be · a5425be
1 parent 9da557b
commit a5425be
Showing 1 changed file with 77 additions and 0 deletions.
diff --git a/src/packed.rs b/src/packed.rs
@@ -2,11 +2,88 @@ mod packedscalar;
 mod packedslice;
 mod packedstr;
 
+use std::mem::replace;
+
 pub use packedscalar::Packed;
 pub use packedslice::PackedSlice;
 pub use packedstr::PackedStr;
+use zerocopy::FromBytes;
+
+use crate::Bytes;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum PackError {
     BadLayout,
 }
+
+impl Bytes {
+    pub fn packed_prefix<T>(&mut self) -> Option<Packed<T>>
+    where T: FromBytes {
+        let slice = self.as_slice();
+        let size = size_of::<T>();
+        let (data, rest) = slice.split_at(size);
+        let data = self.slice_to_bytes(data)?;
+        let rest = self.slice_to_bytes(rest)?;
+        let packed: Packed<T> = data.try_into().ok()?;
+        _ = replace(self, rest);
+        Some(packed)
+    }
+
+    pub fn packedslice_prefix<T>(&mut self, count: usize) -> Option<PackedSlice<T>>
+    where T: FromBytes {
+        let slice = self.as_slice();
+        let size = size_of::<T>() * count;
+        let (data, rest) = slice.split_at(size);
+        let data = self.slice_to_bytes(data)?;
+        let rest = self.slice_to_bytes(rest)?;
+        let packedslice: PackedSlice<T> = data.try_into().ok()?;
+        _ = replace(self, rest);
+        Some(packedslice)
+    }
+
+    pub fn packedstr_prefix<T>(&mut self, count: usize) -> Option<PackedStr>
+    where T: FromBytes {
+        let slice = self.as_slice();
+        let size = size_of::<T>() * count;
+        let (data, rest) = slice.split_at(size);
+        let data = self.slice_to_bytes(data)?;
+        let rest = self.slice_to_bytes(rest)?;
+        let packedstr: PackedStr = data.try_into().ok()?;
+        _ = replace(self, rest);
+        Some(packedstr)
+    }
+
+    pub fn packed_suffix<T>(&mut self) -> Option<Packed<T>>
+    where T: FromBytes {
+        let slice = self.as_slice();
+        let size = size_of::<T>();
+        let (data, rest) = slice.split_at(slice.len() - size);
+        let data = self.slice_to_bytes(data)?;
+        let rest = self.slice_to_bytes(rest)?;
+        let packed: Packed<T> = data.try_into().ok()?;
+        _ = replace(self, rest);
+        Some(packed)
+    }
+
+    pub fn packedslice_suffix<T>(&mut self, count: usize) -> Option<PackedSlice<T>>
+    where T: FromBytes {
+        let slice = self.as_slice();
+        let size = size_of::<T>() * count;
+        let (data, rest) = slice.split_at(slice.len() - size);
+        let data = self.slice_to_bytes(data)?;
+        let rest = self.slice_to_bytes(rest)?;
+        let packedslice: PackedSlice<T> = data.try_into().ok()?;
+        _ = replace(self, rest);
+        Some(packedslice)
+    }
+
+    pub fn packedstr_suffix(&mut self, size: usize) -> Option<PackedStr> {
+        let slice = self.as_slice();
+        let (data, rest) = slice.split_at(slice.len() - size);
+        let data = self.slice_to_bytes(data)?;
+        let rest = self.slice_to_bytes(rest)?;
+        let packedstr: PackedStr = data.try_into().ok()?;
+        _ = replace(self, rest);
+        Some(packedstr)
+    }
+}