implement optimizations

src/commonMain/kotlin/com/infendro/mac/HMAC.kt

@@ -1,6 +1,6 @@
 package com.infendro.mac
 
-import com.infendro.bytearray.padEnd
+import com.infendro.bytes.bytearray.xorInto
 import com.infendro.hash.HashFunction
 
 class HMAC(
@@ -9,25 +9,24 @@ class HMAC(
     override val bytes: Int
         get() = function.bytes
 
-    override fun hash(
-        key: UByteArray,
-        value: UByteArray,
-    ): UByteArray {
+    override fun hashInto(key: ByteArray, value: ByteArray, destination: ByteArray, destinationOffset: Int) {
         val paddedKey = pad(key)
-
-        val innerKey = paddedKey.map { it xor 0x36U }.toUByteArray()
-        val outerKey = paddedKey.map { it xor 0x5CU }.toUByteArray()
-
-        return function.hash(outerKey + function.hash(innerKey + value))
-    }
-
-    private fun pad(
-        key: UByteArray,
-    ): UByteArray {
-        return when {
-            key.size > function.block -> function.hash(key)
-            key.size < function.block -> key.padEnd(function.block, 0x00U)
-            else -> key
+        val inner = ByteArray(function.block + value.size).also {
+            paddedKey.xorInto(0x36, it)
+            value.copyInto(it, function.block)
         }
+        val outer = ByteArray(function.block + function.bytes).also {
+            paddedKey.xorInto(0x5C, it)
+            function.hashInto(inner, it, function.block)
+        }
+        function.hashInto(outer, destination, destinationOffset)
     }
+
+    private fun pad(key: ByteArray): ByteArray =
+        ByteArray(function.block).also {
+            when {
+                key.size > function.block -> function.hashInto(key, it)
+                else -> key.copyInto(it)
+            }
+        }
 }