Minor refactors

The slight changes to read_atom_header led to a very minor speed up on
serialization.

benchmarks/benches/benchmarks.rs

@@ -211,8 +211,7 @@ fn bench_logs(c: &mut Criterion) {
 }
 
 fn pot_serialize_into(logs: &LogArchive, buffer: &mut Vec<u8>) {
-    logs.serialize(&mut pot::ser::Serializer::new(buffer).unwrap())
-        .unwrap();
+    pot::to_writer(logs, buffer).unwrap();
 }
 
 fn cbor_serialize_into(logs: &LogArchive, buffer: &mut Vec<u8>) {

pot/src/format.rs

@@ -127,15 +127,16 @@ pub fn read_atom_header<R: ReadBytesExt>(reader: &mut R) -> Result<(Kind, u64),
     let first_byte = reader.read_u8()?;
     let kind = Kind::from_u8(first_byte >> 5)?;
     let mut arg = u64::from(first_byte & 0b1111);
-    if first_byte & 0b10000 > 0 {
-        let mut bytes_read = 1;
+    if first_byte & 0b10000 != 0 {
+        let mut bytes_remaining = 9;
         let mut offset = 4;
         loop {
             let byte = reader.read_u8()?;
-            bytes_read += 1;
-            arg |= u64::from(byte & 0x7f) << offset;
+            let data = byte & 0x7f;
+            arg |= u64::from(data) << offset;
             offset += 7;
-            if byte < 128 || bytes_read == 10 {
+            bytes_remaining -= 1;
+            if data == byte || bytes_remaining == 0 {
                 break;
             }
         }

pot/src/lib.rs

@@ -164,11 +164,10 @@ impl Config {
     }
 
     /// Serializes a value to a `Vec` using the configured options.
-    #[allow(clippy::unused_self)]
+    #[inline]
     pub fn serialize<T: Serialize>(&self, value: &T) -> Result<Vec<u8>> {
-        let mut output = Vec::default();
-        let mut serializer = ser::Serializer::new(&mut output)?;
-        value.serialize(&mut serializer)?;
+        let mut output = Vec::new();
+        self.serialize_into(value, &mut output)?;
         Ok(output)
     }
 

pot/src/ser.rs

@@ -495,21 +495,11 @@ impl<'de, 'a: 'de, W: WriteBytesExt + 'a> ser::SerializeStructVariant
 }
 
 /// A list of previously serialized symbols.
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct SymbolMap {
     symbols: Vec<(usize, u32)>,
 }
 
-impl Default for SymbolMap {
-    #[inline]
-    fn default() -> Self {
-        let mut symbols = Vec::default();
-        // TODO make this configurable
-        symbols.reserve(1024);
-        Self { symbols }
-    }
-}
-
 struct RegisteredSymbol {
     id: u32,
     new: bool,