chore: Added escape() function

Added `escape()` function that escapes non-ISO8859-1 chars.
Also made `unescape()`, `rawKey()` and `rawValue()` public.

Author: quintesse

src/main/java/org/codejive/properties/Properties.java

@@ -296,11 +296,11 @@ public String put(String key, String value) {
         if (key == null || value == null) {
             throw new NullPointerException();
         }
-        String rawValue = escape(value, false);
+        String rawValue = rawValue(value);
         if (values.containsKey(key)) {
             replaceValue(key, rawValue, value);
         } else {
-            String rawKey = escape(key, true);
+            String rawKey = rawKey(key);
             addNewKeyValue(rawKey, key, rawValue, value);
         }
         return values.put(key, value);
@@ -575,19 +575,50 @@ private Cursor indexOf(String key) {
         return index(
                 tokens.indexOf(
                         new PropertiesParser.Token(
-                                PropertiesParser.Type.KEY, escape(key, true), key)));
+                                PropertiesParser.Type.KEY, rawKey(key), key)));
     }
 
-    private String escape(String raw, boolean forKey) {
-        raw = raw.replace("\\", "\\\\");
-        raw = raw.replace("\n", "\\n");
-        raw = raw.replace("\r", "\\r");
-        raw = raw.replace("\t", "\\t");
-        raw = raw.replace("\f", "\\f");
-        if (forKey) {
-            raw = raw.replace(" ", "\\ ");
-        }
-        return raw;
+    /**
+     * Returns a copy of the given string that can be used to
+     * prepare values before passing them to methods like
+     * code>putRaw()</code>.
+     *
+     * @param value Input value
+     * @return Encoded value
+     */
+    public static String rawValue(String value) {
+        return value
+                .replace("\\", "\\\\")
+                .replace("\n", "\\n")
+                .replace("\r", "\\r")
+                .replace("\t", "\\t")
+                .replace("\f", "\\f");
+    }
+
+    /**
+     * Returns a copy of the given string that can be used to
+     * prepare keys before passing them to methods like
+     * code>putRaw()</code>.
+     *
+     * @param key Input key
+     * @return Encoded key
+     */
+    public static String rawKey(String key) {
+        return rawValue(key).replace(" ", "\\ ");
+    }
+
+    /**
+     * Returns a copy of the given string where all non-ISO8859-1
+     * characters have been encoded using \u0000 escape sequences.
+     *
+     * @param text Input string
+     * @return Encoded string
+     */
+    public static String escape(String text) {
+        return replace(
+                text,
+                "[^\\x{0000}-\\x{00FF}]",
+                m -> "\\\\u" + String.format("%04x", (int)m.group(0).charAt(0)));
     }
 
     private static String replace(String input, String regex, Function<Matcher, String> callback) {

src/main/java/org/codejive/properties/PropertiesParser.java

@@ -293,7 +293,14 @@ private String string() {
         return result;
     }
 
-    static String unescape(String escape) {
+    /**
+     * Returns a copy of the given string where all escape sequences
+     * have been turned into their representative values.
+     *
+     * @param escape Input string
+     * @return Decoded string
+     */
+    public static String unescape(String escape) {
         StringBuilder txt = new StringBuilder();
         for (int i = 0; i < escape.length(); i++) {
             char ch = escape.charAt(i);