Faster encoded_varint64_len

stepancheg · Feb 25, 2024 · 0083c42 · 0083c42
1 parent c1c937b
commit 0083c42
Showing 1 changed file with 4 additions and 6 deletions.
diff --git a/protobuf/src/varint/encode.rs b/protobuf/src/varint/encode.rs
@@ -92,12 +92,10 @@ pub(crate) fn encode_varint32(mut value: u32, buf: &mut [MaybeUninit<u8>]) -> us
 /// Encoded size of u64 value.
 #[inline]
 pub(crate) fn encoded_varint64_len(value: u64) -> usize {
-    if value == 0 {
-        1
-    } else {
-        let significant_bits = 64 - value.leading_zeros();
-        (significant_bits + 6) as usize / 7
-    }
+    // Bitwise-or'ing by 1 allows the `value = zero` case to work without
+    // affecting other cases.
+    let significant_bits = 64 - (value | 1).leading_zeros();
+    (significant_bits + 6) as usize / 7
 }
 
 #[cfg(test)]