refactor SHA1 and SHA2

src/commonMain/kotlin/com/infendro/hash/sha2/SHA-384.kt

@@ -45,43 +45,45 @@ object `SHA-384` : HashFunction() {
         value: UByteArray,
     ): UByteArray {
         val h = initial.copyOf()
-        val l = value.size.toULong() * 8UL
 
-        // padding
-        val paddedValue = buildList {
+        val blocks = pad(value)
+            .chunked(128) { it.toUByteArray() }
+        for (block in blocks) {
+            process(h, block)
+        }
+
+        return h.sliceArray(0..5).toUByteArray()
+    }
+
+    private fun pad(
+        value: UByteArray,
+    ): UByteArray {
+        val l = value.size.toULong() * 8UL
+        return buildList {
             addAll(value)
             add(0x80U)
             while (size % 128 != 120) {
                 add(0x00U)
             }
             addAll(l.toUByteArray())
-        }
-
-        // process
-        val blocks = paddedValue
-            .chunked(128) { it.toUByteArray() }
-        for (block in blocks) {
-            val w = buildList {
-                addAll(block.toULongArray())
-                for (i in 16..<80) {
-                    val s0 = get(i - 15).rotateRight(1) xor get(i - 15).rotateRight(8) xor (get(i - 15) shr 7)
-                    val s1 = get(i - 2).rotateRight(19) xor get(i - 2).rotateRight(61) xor (get(i - 2) shr 6)
-                    add(get(i - 16) + s0 + get(i - 7) + s1)
-                }
-            }.toULongArray()
-            process(h, w)
-        }
-
-        return h.sliceArray(0..5).toUByteArray()
+        }.toUByteArray()
     }
 
     private fun process(
         h: ULongArray,
-        w: ULongArray,
+        block: UByteArray,
     ) {
+        val w = buildList {
+            addAll(block.toULongArray())
+            for (i in 16..79) {
+                val s0 = get(i - 15).rotateRight(1) xor get(i - 15).rotateRight(8) xor (get(i - 15) shr 7)
+                val s1 = get(i - 2).rotateRight(19) xor get(i - 2).rotateRight(61) xor (get(i - 2) shr 6)
+                add(get(i - 16) + s0 + get(i - 7) + s1)
+            }
+        }.toULongArray()
         val v = h.copyOf()
 
-        for (i in 0..<80) {
+        repeat(80) { i ->
             val s0 = v[0].rotateRight(28) xor v[0].rotateRight(34) xor v[0].rotateRight(39)
             val s1 = v[4].rotateRight(14) xor v[4].rotateRight(18) xor v[4].rotateRight(41)
             val ch = (v[4] and v[5]) xor (v[4].inv() and v[6])