From adc4f10d4c86c8919e46d0469258e5084fde68e1 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Wed, 13 Jul 2022 14:09:21 +0200
Subject: [PATCH] Small win for writing large integers

---
 .../rust/preserves/src/value/packed/writer.rs | 22 +++++++++----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/implementations/rust/preserves/src/value/packed/writer.rs b/implementations/rust/preserves/src/value/packed/writer.rs
index 7d46659..b6fae48 100644
--- a/implementations/rust/preserves/src/value/packed/writer.rs
+++ b/implementations/rust/preserves/src/value/packed/writer.rs
@@ -66,13 +66,13 @@ impl<W: io::Write> PackedWriter<W> {
     }
 
     #[inline(always)]
-    pub fn write_all(&mut self, bs: &[u8]) {
-        self.buffer.write_all(Cow::Borrowed(bs))
+    pub fn write_all(&mut self, bs: Cow<'_, [u8]>) {
+        self.buffer.write_all(bs)
     }
 
     #[inline(always)]
     pub fn write_integer(&mut self, bs: &[u8]) -> io::Result<()> {
-        self.write_atom(Tag::SignedInteger, bs)
+        self.write_atom(Tag::SignedInteger, Cow::Borrowed(bs))
     }
 
     #[inline(always)]
@@ -81,7 +81,7 @@ impl<W: io::Write> PackedWriter<W> {
     }
 
     #[inline(always)]
-    pub fn write_atom(&mut self, tag: Tag, bs: &[u8]) -> io::Result<()> {
+    pub fn write_atom(&mut self, tag: Tag, bs: Cow<'_, [u8]>) -> io::Result<()> {
         self.write_tag(tag);
         self.write_all(bs);
         self.finish_item_if_toplevel()
@@ -182,14 +182,14 @@ impl<W: io::Write> Writer for PackedWriter<W>
     #[inline(always)]
     fn write_f32(&mut self, v: f32) -> io::Result<()> {
         self.write_tag(Tag::Float);
-        self.write_all(&u32::to_be_bytes(f32::to_bits(v)));
+        self.write_all(Cow::Borrowed(&u32::to_be_bytes(f32::to_bits(v))));
         self.finish_item_if_toplevel()
     }
 
     #[inline(always)]
     fn write_f64(&mut self, v: f64) -> io::Result<()> {
         self.write_tag(Tag::Float);
-        self.write_all(&u64::to_be_bytes(f64::to_bits(v)));
+        self.write_all(Cow::Borrowed(&u64::to_be_bytes(f64::to_bits(v))));
         self.finish_item_if_toplevel()
     }
 
@@ -315,7 +315,7 @@ impl<W: io::Write> Writer for PackedWriter<W>
         let bs: [u8; 16] = v.to_be_bytes();
         self.write_tag(Tag::SignedInteger);
         self.write_byte(0);
-        self.write_all(&bs);
+        self.write_all(Cow::Borrowed(&bs));
         Ok(())
     }
 
@@ -326,7 +326,7 @@ impl<W: io::Write> Writer for PackedWriter<W>
             None => {
                 match v.to_i128() {
                     Some(n) => self.write_i128(n),
-                    None => self.write_atom(Tag::SignedInteger, &v.to_signed_bytes_be()),
+                    None => self.write_atom(Tag::SignedInteger, Cow::Owned(v.to_signed_bytes_be())),
                 }
             }
         }
@@ -335,19 +335,19 @@ impl<W: io::Write> Writer for PackedWriter<W>
     #[inline(always)]
     fn write_string(&mut self, v: &str) -> io::Result<()> {
         self.write_tag(Tag::String);
-        self.write_all(v.as_bytes());
+        self.write_all(Cow::Borrowed(v.as_bytes()));
         self.write_byte(0);
         self.finish_item_if_toplevel()
     }
 
     #[inline(always)]
     fn write_bytes(&mut self, v: &[u8]) -> io::Result<()> {
-        self.write_atom(Tag::ByteString, v)
+        self.write_atom(Tag::ByteString, Cow::Borrowed(v))
     }
 
     #[inline(always)]
     fn write_symbol(&mut self, v: &str) -> io::Result<()> {
-        self.write_atom(Tag::Symbol, v.as_bytes())
+        self.write_atom(Tag::Symbol, Cow::Borrowed(v.as_bytes()))
     }
 
     #[inline(always)]