Speed up Vec<u8> [d]e[n]code operations by dropping the generic

src/consensus/encode.rs

@@ -45,6 +45,10 @@ use secp256k1;
 use util::base58;
 use util::psbt;
 
+use blockdata::transaction::{TxOut, Transaction, TxIn};
+use network::message_blockdata::Inventory;
+use network::address::Address;
+
 /// Encoding error
 #[derive(Debug)]
 pub enum Error {
@@ -551,21 +555,23 @@ impl<S: Encoder> Encodable<S> for [u16; 8] {
 }
 
 // Vectors
-impl<S: Encoder, T: Encodable<S>> Encodable<S> for Vec<T> {
+macro_rules! impl_vec {
+    ($type: ty) => {
+        impl<S: Encoder> Encodable<S> for Vec<$type> {
             #[inline]
             fn consensus_encode(&self, s: &mut S) -> Result<(), self::Error> {
                 VarInt(self.len() as u64).consensus_encode(s)?;
                 for c in self.iter() { c.consensus_encode(s)?; }
                 Ok(())
             }
-}
+        }
 
-impl<D: Decoder, T: Decodable<D>> Decodable<D> for Vec<T> {
+        impl<D: Decoder> Decodable<D> for Vec<$type> {
             #[inline]
-    fn consensus_decode(d: &mut D) -> Result<Vec<T>, self::Error> {
+            fn consensus_decode(d: &mut D) -> Result<Vec<$type>, self::Error> {
                 let len = VarInt::consensus_decode(d)?.0;
                 let byte_size = (len as usize)
-                            .checked_mul(mem::size_of::<T>())
+                                    .checked_mul(mem::size_of::<$type>())
                                     .ok_or(self::Error::ParseFailed("Invalid length"))?;
                 if byte_size > MAX_VEC_SIZE {
                     return Err(self::Error::OversizedVectorAllocation { requested: byte_size, max: MAX_VEC_SIZE })
@@ -574,6 +580,39 @@ impl<D: Decoder, T: Decodable<D>> Decodable<D> for Vec<T> {
                 for _ in 0..len { ret.push(Decodable::consensus_decode(d)?); }
                 Ok(ret)
             }
+        }
+    }
+}
+impl_vec!(sha256d::Hash);
+impl_vec!(Transaction);
+impl_vec!(TxOut);
+impl_vec!(TxIn);
+impl_vec!(Inventory);
+impl_vec!(Vec<u8>);
+impl_vec!((u32, Address));
+impl_vec!(u64);
+
+impl<S: Encoder> Encodable<S> for Vec<u8> {
+    #[inline]
+    fn consensus_encode(&self, s: &mut S) -> Result<(), self::Error> {
+        VarInt(self.len() as u64).consensus_encode(s)?;
+        s.emit_slice(&self)
+    }
+}
+
+impl<D: Decoder> Decodable<D> for Vec<u8> {
+    #[inline]
+    fn consensus_decode(d: &mut D) -> Result<Vec<u8>, self::Error> {
+        let len = VarInt::consensus_decode(d)?.0;
+        let len = len as usize;
+        if len > MAX_VEC_SIZE {
+            return Err(self::Error::OversizedVectorAllocation { requested: len, max: MAX_VEC_SIZE })
+        }
+        let mut ret = Vec::with_capacity(len);
+        ret.resize(len, 0);
+        d.read_slice(&mut ret)?;
+        Ok(ret)
+    }
 }
 
 impl<S: Encoder> Encodable<S> for Box<[u8]> {