Move MAC utils to MacAddressCompat

mobile/src/main/java/be/mygod/vpnhotspot/net/MacAddressCompat.kt

@@ -0,0 +1,45 @@
+package be.mygod.vpnhotspot.net
+
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+
+inline class MacAddressCompat(val addr: Long) {
+    companion object {
+        private const val ETHER_ADDR_LEN = 6
+        /**
+         * The MacAddress zero MAC address.
+         *
+         * Not publicly exposed or treated specially since the OUI 00:00:00 is registered.
+         * @hide
+         */
+        val ALL_ZEROS_ADDRESS = MacAddressCompat(0)
+
+        fun bytesToString(addr: ByteArray): String {
+            require(addr.size == ETHER_ADDR_LEN) { addr.contentToString() + " was not a valid MAC address" }
+            return addr.joinToString(":") { "%02x".format(it) }
+        }
+        fun bytesToString(addr: Collection<Byte>): String {
+            require(addr.size == ETHER_ADDR_LEN) { addr.joinToString() + " was not a valid MAC address" }
+            return addr.joinToString(":") { "%02x".format(it) }
+        }
+
+        @Throws(IllegalArgumentException::class)
+        fun fromString(addr: String) = MacAddressCompat(ByteBuffer.allocate(8).run {
+            order(ByteOrder.LITTLE_ENDIAN)
+            mark()
+            try {
+                put(addr.split(':').map { Integer.parseInt(it, 16).toByte() }.toByteArray())
+            } catch (e: NumberFormatException) {
+                throw IllegalArgumentException(e)
+            }
+            reset()
+            long
+        })
+    }
+
+    override fun toString() = ByteBuffer.allocate(8).run {
+        order(ByteOrder.LITTLE_ENDIAN)
+        putLong(addr)
+        bytesToString(array().take(6))
+    }
+}