crypto: avoid temporary Uint8Array in BufferSource normalization

Replace TypedArrayPrototypeSlice(new Uint8Array(buf, off, len)) with
new Uint8Array(ArrayBufferPrototypeSlice(buf, off, off + len)) in
normalizeAlgorithm. This eliminates a throwaway view allocation per
BufferSource member during algorithm normalization.

Signed-off-by: Filip Skokan <panva.ip@gmail.com>

Author: panva

lib/internal/crypto/util.js

@@ -3,6 +3,7 @@
 const {
   ArrayBufferIsView,
   ArrayBufferPrototypeGetByteLength,
+  ArrayBufferPrototypeSlice,
   ArrayPrototypeIncludes,
   ArrayPrototypePush,
   BigInt,
@@ -22,7 +23,6 @@ const {
   TypedArrayPrototypeGetBuffer,
   TypedArrayPrototypeGetByteLength,
   TypedArrayPrototypeGetByteOffset,
-  TypedArrayPrototypeSlice,
   Uint8Array,
 } = primordials;
 
@@ -606,12 +606,13 @@ function normalizeAlgorithm(algorithm, op) {
       // 3.
       if (idlType === 'BufferSource' && idlValue) {
         const isView = ArrayBufferIsView(idlValue);
-        normalizedAlgorithm[member] = TypedArrayPrototypeSlice(
-          new Uint8Array(
-            isView ? getDataViewOrTypedArrayBuffer(idlValue) : idlValue,
-            isView ? getDataViewOrTypedArrayByteOffset(idlValue) : 0,
-            isView ? getDataViewOrTypedArrayByteLength(idlValue) : ArrayBufferPrototypeGetByteLength(idlValue),
-          ),
+        const buffer = isView ? getDataViewOrTypedArrayBuffer(idlValue) : idlValue;
+        const offset = isView ? getDataViewOrTypedArrayByteOffset(idlValue) : 0;
+        const length = isView ?
+          getDataViewOrTypedArrayByteLength(idlValue) :
+          ArrayBufferPrototypeGetByteLength(idlValue);
+        normalizedAlgorithm[member] = new Uint8Array(
+          ArrayBufferPrototypeSlice(buffer, offset, offset + length),
         );
       } else if (idlType === 'HashAlgorithmIdentifier') {
         normalizedAlgorithm[member] = normalizeAlgorithm(idlValue, 'digest');