SMACK-361 Added support for Entity Capabilities.

git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/branches/smack_3_3_0@13560 b35dd754-fafc-0310-a699-88a17e54d16e

source/org/jivesoftware/smack/util/Base32Encoder.java

@@ -0,0 +1,187 @@
+/**
+ * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jivesoftware.smack.util;
+
+
+import java.io.ByteArrayOutputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+/**
+ * Base32 string encoding is useful for when filenames case-insensitive filesystems are encoded.
+ * Base32 representation takes roughly 20% more space then Base64.
+ * 
+ * @author Florian Schmaus
+ * Based on code by Brian Wellington (bwelling@xbill.org)
+ * @see <a href="http://en.wikipedia.org/wiki/Base32">Base32 Wikipedia entry<a>
+ *
+ */
+public class Base32Encoder implements StringEncoder {
+
+    private static Base32Encoder instance;
+    private static final String ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ2345678";
+
+    private Base32Encoder() {
+        // Use getInstance()
+    }
+
+    public static Base32Encoder getInstance() {
+        if (instance == null) {
+            instance = new Base32Encoder();
+        }
+        return instance;
+    }
+
+    @Override
+    public String decode(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);
+            }
+        }
+
+        while (bs.size() % 8 != 0)
+            bs.write('8');
+
+        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 == '8')
+                    break;
+                s[j] = (short) ALPHABET.indexOf(in[i * 8 + j]);
+                if (s[j] < 0)
+                    return null;
+                padlen--;
+            }
+            int blocklen = paddingToLen(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 new String(bs.toByteArray());
+    }
+
+    @Override
+    public String encode(String str) {
+        byte[] b = str.getBytes();
+        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 = lenToPadding(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]);
+                os.write(c);
+            }
+        }
+        return new String(os.toByteArray());
+    }
+
+    private static int lenToPadding(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;
+        }
+    }
+
+    private static int paddingToLen(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;
+        }
+    }
+
+}