1 files changed, 75 insertions, 0 deletions
diff --git a/third_party/rust/wast/src/encode.rs b/third_party/rust/wast/src/encode.rs
new file mode 100644
index 0000000000..3fc932690e
--- /dev/null
+++ b/third_party/rust/wast/src/encode.rs
@@ -0,0 +1,75 @@
+pub(crate) trait Encode {
+    fn encode(&self, e: &mut Vec<u8>);
+}
+
+impl<T: Encode + ?Sized> Encode for &'_ T {
+    fn encode(&self, e: &mut Vec<u8>) {
+        T::encode(self, e)
+    }
+}
+
+impl<T: Encode> Encode for [T] {
+    fn encode(&self, e: &mut Vec<u8>) {
+        self.len().encode(e);
+        for item in self {
+            item.encode(e);
+        }
+    }
+}
+
+impl<T: Encode> Encode for Vec<T> {
+    fn encode(&self, e: &mut Vec<u8>) {
+        <[T]>::encode(self, e)
+    }
+}
+
+impl Encode for str {
+    fn encode(&self, e: &mut Vec<u8>) {
+        self.len().encode(e);
+        e.extend_from_slice(self.as_bytes());
+    }
+}
+
+impl Encode for usize {
+    fn encode(&self, e: &mut Vec<u8>) {
+        assert!(*self <= u32::max_value() as usize);
+        (*self as u32).encode(e)
+    }
+}
+
+impl Encode for u8 {
+    fn encode(&self, e: &mut Vec<u8>) {
+        e.push(*self);
+    }
+}
+
+impl Encode for u32 {
+    fn encode(&self, e: &mut Vec<u8>) {
+        leb128::write::unsigned(e, (*self).into()).unwrap();
+    }
+}
+
+impl Encode for i32 {
+    fn encode(&self, e: &mut Vec<u8>) {
+        leb128::write::signed(e, (*self).into()).unwrap();
+    }
+}
+
+impl Encode for u64 {
+    fn encode(&self, e: &mut Vec<u8>) {
+        leb128::write::unsigned(e, *self).unwrap();
+    }
+}
+
+impl Encode for i64 {
+    fn encode(&self, e: &mut Vec<u8>) {
+        leb128::write::signed(e, *self).unwrap();
+    }
+}
+
+impl<T: Encode, U: Encode> Encode for (T, U) {
+    fn encode(&self, e: &mut Vec<u8>) {
+        self.0.encode(e);
+        self.1.encode(e);
+    }
+}