Add a method to parse a binary string to a Prefix.
This enables us to get human-readable output out of the radix tress.
Addresses ONOS-1957.
Change-Id: Ia28f6e56e7067bfe447423ba8451d762c4baa49c
diff --git a/src/main/java/net/onrc/onos/apps/sdnip/Prefix.java b/src/main/java/net/onrc/onos/apps/sdnip/Prefix.java
index 81010d6..489beda 100644
--- a/src/main/java/net/onrc/onos/apps/sdnip/Prefix.java
+++ b/src/main/java/net/onrc/onos/apps/sdnip/Prefix.java
@@ -1,7 +1,9 @@
package net.onrc.onos.apps.sdnip;
+import java.math.BigInteger;
import java.net.InetAddress;
import java.net.UnknownHostException;
+import java.nio.ByteBuffer;
import java.util.Arrays;
import com.google.common.net.InetAddresses;
@@ -28,6 +30,8 @@
public static final int MIN_PREFIX_LENGTH = 0;
+ private static final int BINARY_RADIX = 2;
+
private final int prefixLength;
private final byte[] address;
private final String binaryString;
@@ -237,23 +241,46 @@
}
/**
- * Print the prefix to a String showing the bits of the address.
+ * Creates a Prefix object from a binary string.
+ * <p/>
+ * This is the reverse operation of {@link Prefix#toBinaryString()}. It
+ * takes a binary string (a String containing only '0' and '1'
+ * characters) and parses it to create a corresponding Prefix object.
*
- * @return the bit-string of the prefix
+ * @param binaryString the binary string to convert to Prefix
+ * @return a Prefix object representing the same prefix as the input string
*/
- public String printAsBits() {
- StringBuilder result = new StringBuilder();
- for (int i = 0; i < address.length; i++) {
- byte b = address[i];
- for (int j = 0; j < Byte.SIZE; j++) {
- byte mask = (byte) (0x80 >>> j);
- result.append(((b & mask) == 0) ? "0" : "1");
- if (i * Byte.SIZE + j == prefixLength - 1) {
- return result.toString();
- }
- }
- result.append(' ');
+ public static Prefix fromBinaryString(String binaryString) {
+ if (binaryString.length() > MAX_PREFIX_LENGTH) {
+ throw new IllegalArgumentException(
+ "Binary string length must not be greater than "
+ + MAX_PREFIX_LENGTH);
}
- return result.substring(0, result.length() - 1);
+
+ for (int i = 0; i < binaryString.length(); i++) {
+ char character = binaryString.charAt(i);
+ if (character != '0' && character != '1') {
+ throw new IllegalArgumentException(
+ "Binary string may only contain the characters "
+ + "\'0\' or \'1\'");
+ }
+ }
+
+ // Pad the binary string out to be MAX_PREFIX_LENGTH bits long
+ StringBuilder paddedBinaryString = new StringBuilder(MAX_PREFIX_LENGTH);
+ paddedBinaryString.append(binaryString);
+ for (int i = binaryString.length(); i < MAX_PREFIX_LENGTH; i++) {
+ paddedBinaryString.append('0');
+ }
+
+ // BigInteger will parse the binary string to an integer using radix 2
+ BigInteger bigInteger =
+ new BigInteger(paddedBinaryString.toString(), BINARY_RADIX);
+
+ // Convert the integer to a byte array
+ ByteBuffer bb = ByteBuffer.allocate(ADDRESS_LENGTH_BYTES);
+ bb.putInt(bigInteger.intValue());
+
+ return new Prefix(bb.array(), binaryString.length());
}
}