Trim leading zeros from ipv4 addrs.

Underlying libraries will interpret leading zeros as octal values and
fail.

bug:5262995
Change-Id: Iff949225bb6b941f7274ee81754e1f41ed719a6c

core/java/android/net/NetworkUtils.java

@@ -250,4 +250,31 @@ public class NetworkUtils {
         }
         return result;
     }
+
+    /**
+     * Trim leading zeros from IPv4 address strings
+     * Our base libraries will interpret that as octel..
+     * Must leave non v4 addresses and host names alone.
+     * For example, 192.168.000.010 -> 192.168.0.10
+     * TODO - fix base libraries and remove this function
+     * @param addr a string representing an ip addr
+     * @return a string propertly trimmed
+     */
+    public static String trimV4AddrZeros(String addr) {
+        String[] octets = addr.split("\\.");
+        if (octets.length != 4) return addr;
+        StringBuilder builder = new StringBuilder(16);
+        String result = null;
+        for (int i = 0; i < 4; i++) {
+            try {
+                if (octets[i].length > 3) return addr;
+                builder.append(Integer.parseInt(octets[i]));
+            } catch (NumberFormatException e) {
+                return addr;
+            }
+            if (i < 3) builder.append('.');
+        }
+        result = builder.toString();
+        return result;
+    }
 }