1 files changed, 213 insertions, 0 deletions
diff --git a/src/org/xbill/DNS/utils/base32.java b/src/org/xbill/DNS/utils/base32.java
new file mode 100644
index 0000000..a2f26ea
--- /dev/null
+++ b/src/org/xbill/DNS/utils/base32.java
@@ -0,0 +1,213 @@
+// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)
+
+package org.xbill.DNS.utils;
+
+import java.io.*;
+
+/**
+ * Routines for converting between Strings of base32-encoded data and arrays
+ * of binary data.  This currently supports the base32 and base32hex alphabets
+ * specified in RFC 4648, sections 6 and 7.
+ * 
+ * @author Brian Wellington
+ */
+
+public class base32 {
+
+public static class Alphabet {
+	private Alphabet() {}
+
+	public static final String BASE32 =
+		"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567=";
+	public static final String BASE32HEX =
+		"0123456789ABCDEFGHIJKLMNOPQRSTUV=";
+};
+
+private String alphabet;
+private boolean padding, lowercase;
+
+/**
+ * Creates an object that can be used to do base32 conversions.
+ * @param alphabet Which alphabet should be used
+ * @param padding Whether padding should be used
+ * @param lowercase Whether lowercase characters should be used.
+ * default parameters (The standard base32 alphabet, no padding, uppercase)
+ */
+public
+base32(String alphabet, boolean padding, boolean lowercase) {
+	this.alphabet = alphabet;
+	this.padding = padding;
+	this.lowercase = lowercase;
+}
+
+static private int
+blockLenToPadding(int blocklen) {
+	switch (blocklen) {
+	case 1:
+		return 6;
+	case 2:
+		return 4;
+	case 3:
+		return 3;
+	case 4:
+		return 1;
+	case 5:
+		return 0;
+	default:
+		return -1;
+	}
+}
+
+static private int
+paddingToBlockLen(int padlen) {
+	switch (padlen) {
+	case 6:
+		return 1;
+	case 4:
+		return 2;
+	case 3:
+		return 3;
+	case 1:
+		return 4;
+	case 0:
+		return 5;
+	default :
+		return -1;
+	}
+}
+
+/**
+ * Convert binary data to a base32-encoded String
+ * 
+ * @param b An array containing binary data
+ * @return A String containing the encoded data
+ */
+public String
+toString(byte [] b) {
+	ByteArrayOutputStream os = new ByteArrayOutputStream();
+
+	for (int i = 0; i < (b.length + 4) / 5; i++) {
+		short s[] = new short[5];
+		int t[] = new int[8];
+
+		int blocklen = 5;
+		for (int j = 0; j < 5; j++) {
+			if ((i * 5 + j) < b.length)
+				s[j] = (short) (b[i * 5 + j] & 0xFF);
+			else {
+				s[j] = 0;
+				blocklen--;
+			}
+		}
+		int padlen = blockLenToPadding(blocklen);
+
+		// convert the 5 byte block into 8 characters (values 0-31).
+
+		// upper 5 bits from first byte
+		t[0] = (byte) ((s[0] >> 3) & 0x1F);
+		// lower 3 bits from 1st byte, upper 2 bits from 2nd.
+		t[1] = (byte) (((s[0] & 0x07) << 2) | ((s[1] >> 6) & 0x03));
+		// bits 5-1 from 2nd.
+		t[2] = (byte) ((s[1] >> 1) & 0x1F);
+		// lower 1 bit from 2nd, upper 4 from 3rd
+		t[3] = (byte) (((s[1] & 0x01) << 4) | ((s[2] >> 4) & 0x0F));
+		// lower 4 from 3rd, upper 1 from 4th.
+		t[4] = (byte) (((s[2] & 0x0F) << 1) | ((s[3] >> 7) & 0x01));
+		// bits 6-2 from 4th
+		t[5] = (byte) ((s[3] >> 2) & 0x1F);
+		// lower 2 from 4th, upper 3 from 5th;
+		t[6] = (byte) (((s[3] & 0x03) << 3) | ((s[4] >> 5) & 0x07));
+		// lower 5 from 5th;
+		t[7] = (byte) (s[4] & 0x1F);
+
+		// write out the actual characters.
+		for (int j = 0; j < t.length - padlen; j++) {
+			char c = alphabet.charAt(t[j]);
+			if (lowercase)
+				c = Character.toLowerCase(c);
+			os.write(c);
+		}
+
+		// write out the padding (if any)
+		if (padding) {
+			for (int j = t.length - padlen; j < t.length; j++)
+				os.write('=');
+		}
+	}
+
+    return new String(os.toByteArray());
+}
+
+/**
+ * Convert a base32-encoded String to binary data
+ * 
+ * @param str A String containing the encoded data
+ * @return An array containing the binary data, or null if the string is invalid
+ */
+public byte[]
+fromString(String str) {
+	ByteArrayOutputStream bs = new ByteArrayOutputStream();
+	byte [] raw = str.getBytes();
+	for (int i = 0; i < raw.length; i++)
+	{
+		char c = (char) raw[i];
+		if (!Character.isWhitespace(c)) {
+			c = Character.toUpperCase(c);
+			bs.write((byte) c);
+		}
+	}
+
+	if (padding) {
+		if (bs.size() % 8 != 0)
+			return null;
+	} else {
+		while (bs.size() % 8 != 0)
+			bs.write('=');
+	}
+
+	byte [] in = bs.toByteArray();
+
+	bs.reset();
+	DataOutputStream ds = new DataOutputStream(bs);
+
+	for (int i = 0; i < in.length / 8; i++) {
+		short[] s = new short[8];
+		int[] t = new int[5];
+
+		int padlen = 8;
+		for (int j = 0; j < 8; j++) {
+			char c = (char) in[i * 8 + j];
+			if (c == '=')
+				break;
+			s[j] = (short) alphabet.indexOf(in[i * 8 + j]);
+			if (s[j] < 0)
+				return null;
+			padlen--;
+		}
+		int blocklen = paddingToBlockLen(padlen);
+		if (blocklen < 0)
+			return null;
+
+		// all 5 bits of 1st, high 3 (of 5) of 2nd
+		t[0] = (s[0] << 3) | s[1] >> 2;
+		// lower 2 of 2nd, all 5 of 3rd, high 1 of 4th
+		t[1] = ((s[1] & 0x03) << 6) | (s[2] << 1) | (s[3] >> 4);
+		// lower 4 of 4th, high 4 of 5th
+		t[2] = ((s[3] & 0x0F) << 4) | ((s[4] >> 1) & 0x0F);
+		// lower 1 of 5th, all 5 of 6th, high 2 of 7th
+		t[3] = (s[4] << 7) | (s[5] << 2) | (s[6] >> 3);
+		// lower 3 of 7th, all of 8th
+		t[4] = ((s[6] & 0x07) << 5) | s[7];
+
+		try {
+			for (int j = 0; j < blocklen; j++)
+				ds.writeByte((byte) (t[j] & 0xFF));
+		}
+		catch (IOException e) {
+		}
+	}
+
+    return bs.toByteArray();
+}
+
+}