From 95966fa0d47eee3c503e8943472ecf0dd2518ff4 Mon Sep 17 00:00:00 2001
From: Siim Kallas <siimkallas@gmail.com>
Date: Mon, 22 Aug 2022 16:24:34 +0300
Subject: [PATCH] perf: hexToBase64: use preallocated buffer

---
 .../src/platform/node/hex-to-base64.ts               | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/packages/opentelemetry-core/src/platform/node/hex-to-base64.ts b/packages/opentelemetry-core/src/platform/node/hex-to-base64.ts
index 31fd1890c1..66d4ad0fe9 100644
--- a/packages/opentelemetry-core/src/platform/node/hex-to-base64.ts
+++ b/packages/opentelemetry-core/src/platform/node/hex-to-base64.ts
@@ -28,8 +28,18 @@ function intValue(charCode: number): number {
   return charCode - 55;
 }
 
+const buf8 = Buffer.alloc(8);
+const buf16 = Buffer.alloc(16);
+
 export function hexToBase64(hexStr: string): string {
-  const buf = Buffer.alloc(hexStr.length / 2);
+  let buf;
+  if (hexStr.length === 16) {
+    buf = buf8;
+  } else if (hexStr.length === 32) {
+    buf = buf16;
+  } else {
+    buf = Buffer.alloc(hexStr.length / 2);
+  }
   let offset = 0;
 
   for (let i = 0; i < hexStr.length; i += 2) {