From 8f98f71ecbb18f833f74bd408c11df520a55af28 Mon Sep 17 00:00:00 2001
From: Gaston Dombiak <gaston@jivesoftware.com>
Date: Sun, 3 Sep 2006 03:10:15 +0000
Subject: [PATCH] Added JID escaping support. SMACK-167

git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/trunk@5195 b35dd754-fafc-0310-a699-88a17e54d16e
---
 .../jivesoftware/smack/util/StringUtils.java  | 141 ++++++++++++++++++
 1 file changed, 141 insertions(+)

diff --git a/source/org/jivesoftware/smack/util/StringUtils.java b/source/org/jivesoftware/smack/util/StringUtils.java
index d0d685788..7e9e1aa69 100644
--- a/source/org/jivesoftware/smack/util/StringUtils.java
+++ b/source/org/jivesoftware/smack/util/StringUtils.java
@@ -127,6 +127,147 @@ public class StringUtils {
         }
     }
 
+    /**
+     * Escapes the node portion of a JID according to "JID Escaping" (JEP-0106).
+     * Escaping replaces characters prohibited by node-prep with escape sequences,
+     * as follows:<p>
+     *
+     * <table border="1">
+     * <tr><td><b>Unescaped Character</b></td><td><b>Encoded Sequence</b></td></tr>
+     * <tr><td>&lt;space&gt;</td><td>\20</td></tr>
+     * <tr><td>"</td><td>\22</td></tr>
+     * <tr><td>&</td><td>\26</td></tr>
+     * <tr><td>'</td><td>\27</td></tr>
+     * <tr><td>/</td><td>\2f</td></tr>
+     * <tr><td>:</td><td>\3a</td></tr>
+     * <tr><td>&lt;</td><td>\3c</td></tr>
+     * <tr><td>&gt;</td><td>\3e</td></tr>
+     * <tr><td>@</td><td>\40</td></tr>
+     * <tr><td>\</td><td>\5c</td></tr>
+     * </table><p>
+     *
+     * This process is useful when the node comes from an external source that doesn't
+     * conform to nodeprep. For example, a username in LDAP may be "Joe Smith". Because
+     * the &lt;space&gt; character isn't a valid part of a node, the username should
+     * be escaped to "Joe\20Smith" before being made into a JID (e.g. "joe\20smith@example.com"
+     * after case-folding, etc. has been applied).<p>
+     *
+     * All node escaping and un-escaping must be performed manually at the appropriate
+     * time; the JID class will not escape or un-escape automatically.
+     *
+     * @param node the node.
+     * @return the escaped version of the node.
+     */
+    public static String escapeNode(String node) {
+        if (node == null) {
+            return null;
+        }
+        StringBuilder buf = new StringBuilder(node.length() + 8);
+        for (int i=0, n=node.length(); i<n; i++) {
+            char c = node.charAt(i);
+            switch (c) {
+                case '"': buf.append("\\22"); break;
+                case '&': buf.append("\\26"); break;
+                case '\'': buf.append("\\27"); break;
+                case '/': buf.append("\\2f"); break;
+                case ':': buf.append("\\3a"); break;
+                case '<': buf.append("\\3c"); break;
+                case '>': buf.append("\\3e"); break;
+                case '@': buf.append("\\40"); break;
+                case '\\': buf.append("\\5c"); break;
+                default: {
+                    if (Character.isWhitespace(c)) {
+                        buf.append("\\20");
+                    }
+                    else {
+                        buf.append(c);
+                    }
+                }
+            }
+        }
+        return buf.toString();
+    }
+
+    /**
+     * Un-escapes the node portion of a JID according to "JID Escaping" (JEP-0106).<p>
+     * Escaping replaces characters prohibited by node-prep with escape sequences,
+     * as follows:<p>
+     *
+     * <table border="1">
+     * <tr><td><b>Unescaped Character</b></td><td><b>Encoded Sequence</b></td></tr>
+     * <tr><td>&lt;space&gt;</td><td>\20</td></tr>
+     * <tr><td>"</td><td>\22</td></tr>
+     * <tr><td>&</td><td>\26</td></tr>
+     * <tr><td>'</td><td>\27</td></tr>
+     * <tr><td>/</td><td>\2f</td></tr>
+     * <tr><td>:</td><td>\3a</td></tr>
+     * <tr><td>&lt;</td><td>\3c</td></tr>
+     * <tr><td>&gt;</td><td>\3e</td></tr>
+     * <tr><td>@</td><td>\40</td></tr>
+     * <tr><td>\</td><td>\5c</td></tr>
+     * </table><p>
+     *
+     * This process is useful when the node comes from an external source that doesn't
+     * conform to nodeprep. For example, a username in LDAP may be "Joe Smith". Because
+     * the &lt;space&gt; character isn't a valid part of a node, the username should
+     * be escaped to "Joe\20Smith" before being made into a JID (e.g. "joe\20smith@example.com"
+     * after case-folding, etc. has been applied).<p>
+     *
+     * All node escaping and un-escaping must be performed manually at the appropriate
+     * time; the JID class will not escape or un-escape automatically.
+     *
+     * @param node the escaped version of the node.
+     * @return the un-escaped version of the node.
+     */
+    public static String unescapeNode(String node) {
+        if (node == null) {
+            return null;
+        }
+        char [] nodeChars = node.toCharArray();
+        StringBuilder buf = new StringBuilder(nodeChars.length);
+        for (int i=0, n=nodeChars.length; i<n; i++) {
+            compare: {
+                char c = node.charAt(i);
+                if (c == '\\' && i+2<n) {
+                    char c2 = nodeChars[i+1];
+                    char c3 = nodeChars[i+2];
+                    if (c2 == '2') {
+                        switch (c3) {
+                            case '0': buf.append(' '); i+=2; break compare;
+                            case '2': buf.append('"'); i+=2; break compare;
+                            case '6': buf.append('&'); i+=2; break compare;
+                            case '7': buf.append('\''); i+=2; break compare;
+                            case 'f': buf.append('/'); i+=2; break compare;
+                        }
+                    }
+                    else if (c2 == '3') {
+                        switch (c3) {
+                            case 'a': buf.append(':'); i+=2; break compare;
+                            case 'c': buf.append('<'); i+=2; break compare;
+                            case 'e': buf.append('>'); i+=2; break compare;
+                        }
+                    }
+                    else if (c2 == '4') {
+                        if (c3 == '0') {
+                            buf.append("@");
+                            i+=2;
+                            break compare;
+                        }
+                    }
+                    else if (c2 == '5') {
+                        if (c3 == 'c') {
+                            buf.append("\\");
+                            i+=2;
+                            break compare;
+                        }
+                    }
+                }
+                buf.append(c);
+            }
+        }
+        return buf.toString();
+    }
+
     /**
      * Escapes all necessary characters in the String so that it can be used
      * in an XML doc.