refactor Blake and Blake2

src/commonMain/kotlin/com/infendro/hash/blake2/Blake2s.kt

@@ -36,40 +36,40 @@ class Blake2s(
     )
 
     override fun hash(value: UByteArray): UByteArray {
+        val l = value.size.toULong()
         val h = initial.copyOf()
         h[0] = h[0] xor (0x01010000U or bytes.toUInt())
         var t = 0U
-        val l = value.size.toULong()
 
-        // padding
-        val paddedValue = buildList {
+        val blocks = pad(value)
+            .chunked(64) { it.toUByteArray() }
+        for ((i, block) in blocks.withIndex()) {
+            t += minOf(l - t, 64UL).toUInt()
+            compress(h, block, t, i == blocks.lastIndex)
+        }
+
+        return h.toUByteArray(LITTLE_ENDIAN).sliceArray(0..<bytes)
+    }
+
+    private fun pad(
+        value: UByteArray,
+    ): UByteArray {
+        return buildList {
             addAll(value)
             if (isEmpty()) add(0x00U)
             while (size % 64 != 0) {
                 add(0x00U)
             }
         }.toUByteArray()
-
-        // compress
-        val blocks = paddedValue
-            .chunked(64) { it.toUByteArray() }
-        for ((i, block) in blocks.withIndex()) {
-            t += minOf(l - t, 64U).toUInt()
-
-            val m = block.toUIntArray()
-            compress(h, m, t, i == blocks.lastIndex)
-        }
-
-        return h.toUByteArray(LITTLE_ENDIAN).sliceArray(0..<bytes)
     }
 
     private fun compress(
         h: UIntArray,
-        m: UIntArray,
+        block: UByteArray,
         t: UInt,
         last: Boolean,
     ) {
-        // initialization
+        val m = block.toUIntArray()
         val v = UIntArray(16)
         for (i in 0..<8) v[i] = h[i]
         for (i in 0..<8) v[i + 8] = initial[i]
@@ -77,24 +77,20 @@ class Blake2s(
         v[12] = v[12] xor t
         if (last) v[14] = v[14].inv()
 
-        // rounds
-        for (r in 0..<10) {
+        repeat(10) { r ->
             val s = sigma[r]
 
-            // column
             mix(v, 0, 4, 8, 12, m[s[0]], m[s[1]])
             mix(v, 1, 5, 9, 13, m[s[2]], m[s[3]])
             mix(v, 2, 6, 10, 14, m[s[4]], m[s[5]])
             mix(v, 3, 7, 11, 15, m[s[6]], m[s[7]])
 
-            // diagonal
             mix(v, 0, 5, 10, 15, m[s[8]], m[s[9]])
             mix(v, 1, 6, 11, 12, m[s[10]], m[s[11]])
             mix(v, 2, 7, 8, 13, m[s[12]], m[s[13]])
             mix(v, 3, 4, 9, 14, m[s[14]], m[s[15]])
         }
 
-        // finalization
         for (i in 0..7) {
             h[i] = h[i] xor v[i] xor v[i + 8]
         }