From 0f65a0df8a88efbf4e4fb46788c036fdb9e16899 Mon Sep 17 00:00:00 2001
From: Martin Hoffmann <martin@nlnetlabs.nl>
Date: Thu, 5 Dec 2019 11:48:14 +0100
Subject: [PATCH] Add octets traits for SmallVec.

---
 domain-core/Cargo.toml    | 12 ++++---
 domain-core/src/octets.rs | 67 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 5 deletions(-)

diff --git a/domain-core/Cargo.toml b/domain-core/Cargo.toml
index 41b184b8..6f54c5de 100644
--- a/domain-core/Cargo.toml
+++ b/domain-core/Cargo.toml
@@ -16,12 +16,14 @@ name = "domain_core"
 path = "src/lib.rs"
 
 [dependencies]
+chrono         = "0.4"
+derive_more    = "0.99.1"
+rand           = "0.7"
+unwrap         = "1.2"
+void           = "1.0"
+
 bytes          = { version = "^0.4", optional = true }
-chrono         = { version = "^0.4", optional = true }
-derive_more    = { version = "0.15.1-pre", git = "https://github.com/JelteF/derive_more.git" }
-rand           = "^0.7"
-unwrap         = "^1.2"
-void           = "^1.0"
+smallvec       = { version = "1.0", optional = true }
 
 [features]
 default = ["std"]
diff --git a/domain-core/src/octets.rs b/domain-core/src/octets.rs
index ca737942..c542261f 100644
--- a/domain-core/src/octets.rs
+++ b/domain-core/src/octets.rs
@@ -5,6 +5,7 @@ use core::cmp::Ordering;
 use core::convert::TryFrom;
 #[cfg(feature = "std")] use std::vec::Vec;
 #[cfg(feature = "bytes")] use bytes::{Bytes, BytesMut};
+#[cfg(feature = "smallvec")] use smallvec::{Array, SmallVec};
 use derive_more::Display;
 use crate::name::ToDname;
 use crate::net::{Ipv4Addr, Ipv6Addr};
@@ -37,6 +38,13 @@ impl OctetsExt for Bytes {
     }
 }
 
+#[cfg(feature = "smallvec")]
+impl<A: Array<Item = u8>> OctetsExt for SmallVec<A> {
+    fn truncate(&mut self, len: usize) {
+        self.truncate(len)
+    }
+}
+
 
 //------------ OctetsRef -----------------------------------------------------
 
@@ -91,6 +99,15 @@ impl<'a> OctetsRef for &'a Bytes  {
     }
 }
 
+#[cfg(feature = "smallvec")]
+impl<'a, A: Array<Item = u8>> OctetsRef for &'a SmallVec<A> {
+    type Range = &'a [u8];
+
+    fn range(self, start: usize, end: usize) -> Self::Range {
+        &self.as_slice()[start..end]
+    }
+}
+
 
 //------------ OctetsBuilder -------------------------------------------------
 
@@ -187,6 +204,18 @@ impl OctetsBuilder for BytesMut {
 
 }
 
+#[cfg(feature = "smallvec")]
+impl<A: Array<Item = u8>> OctetsBuilder for SmallVec<A> {
+    fn append_slice(&mut self, slice: &[u8]) -> Result<(), ShortBuf> {
+        self.extend_from_slice(slice);
+        Ok(())
+    }
+
+    fn truncate(&mut self, len: usize) {
+        SmallVec::truncate(self, len)
+    }
+}
+
 
 //------------ EmptyBuilder --------------------------------------------------
 
@@ -218,6 +247,17 @@ impl EmptyBuilder for BytesMut {
     }
 }
 
+#[cfg(feature = "smallvec")]
+impl<A: Array<Item = u8>> EmptyBuilder for SmallVec<A> {
+    fn empty() -> Self {
+        SmallVec::new()
+    }
+
+    fn with_capacity(capacity: usize) -> Self {
+        SmallVec::with_capacity(capacity)
+    }
+}
+
 
 //------------ IntoOctets ----------------------------------------------------
 
@@ -245,6 +285,15 @@ impl IntoOctets for BytesMut {
     }
 }
 
+#[cfg(feature = "smallvec")]
+impl<A: Array<Item = u8>> IntoOctets for SmallVec<A> {
+    type Octets = Self;
+
+    fn into_octets(self) -> Self::Octets {
+        self
+    }
+}
+
 
 //------------ IntoBuilder ---------------------------------------------------
 
@@ -281,6 +330,15 @@ impl IntoBuilder for Bytes {
     }
 }
 
+#[cfg(feature = "smallvec")]
+impl<A: Array<Item = u8>> IntoBuilder for SmallVec<A> {
+    type Builder = Self;
+
+    fn into_builder(self) -> Self::Builder {
+        self
+    }
+}
+
 
 //------------ FromBuilder ---------------------------------------------------
 
@@ -308,6 +366,15 @@ impl FromBuilder for Bytes {
     }
 }
 
+#[cfg(feature = "smallvec")]
+impl<A: Array<Item = u8>> FromBuilder for SmallVec<A> {
+    type Builder = Self;
+
+    fn from_builder(builder: Self) -> Self {
+        builder
+    }
+}
+
 
 //------------ Compose -------------------------------------------------------