Add 'src/be/nikiroo/utils/' from commit '46add0670fdee4bd936a13fe2448c5e20a7ffd0a'
[nikiroo-utils.git] / src / be / nikiroo / utils / serial / SerialUtils.java
index c28faeddebd86cd783e4924460aa01cb749f4b83..ad3b5d4da2a8dae4955e12ce28f2cfd9a51fc5f7 100644 (file)
@@ -1,23 +1,55 @@
 package be.nikiroo.utils.serial;
 
-import java.awt.image.BufferedImage;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.NotSerializableException;
+import java.io.OutputStream;
 import java.lang.reflect.Array;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.lang.reflect.Modifier;
+import java.net.URL;
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.UnknownFormatConversionException;
 
+import be.nikiroo.utils.IOUtils;
+import be.nikiroo.utils.Image;
 import be.nikiroo.utils.StringUtils;
+import be.nikiroo.utils.streams.Base64InputStream;
+import be.nikiroo.utils.streams.Base64OutputStream;
+import be.nikiroo.utils.streams.BufferedInputStream;
+import be.nikiroo.utils.streams.NextableInputStream;
+import be.nikiroo.utils.streams.NextableInputStreamStep;
 
 /**
  * Small class to help with serialisation.
  * <p>
  * Note that we do not support inner classes (but we do support nested classes)
  * and all objects require an empty constructor to be deserialised.
+ * <p>
+ * It is possible to add support to custom types (both the encoder and the
+ * decoder will require the custom classes) -- see {@link CustomSerializer}.
+ * <p>
+ * Default supported types are:
+ * <ul>
+ * <li>NULL (as a null value)</li>
+ * <li>String</li>
+ * <li>Boolean</li>
+ * <li>Byte</li>
+ * <li>Character</li>
+ * <li>Short</li>
+ * <li>Long</li>
+ * <li>Float</li>
+ * <li>Double</li>
+ * <li>Integer</li>
+ * <li>Enum (any enum whose name and value is known by the caller)</li>
+ * <li>java.awt.image.BufferedImage (as a {@link CustomSerializer})</li>
+ * <li>An array of the above (as a {@link CustomSerializer})</li>
+ * <li>URL</li>
+ * </ul>
  * 
  * @author niki
  */
@@ -30,79 +62,133 @@ public class SerialUtils {
                // Array types:
                customTypes.put("[]", new CustomSerializer() {
                        @Override
-                       protected String toString(Object value) {
+                       protected void toStream(OutputStream out, Object value)
+                                       throws IOException {
+
                                String type = value.getClass().getCanonicalName();
                                type = type.substring(0, type.length() - 2); // remove the []
 
-                               StringBuilder builder = new StringBuilder();
-                               builder.append(type).append("\n");
+                               write(out, type);
                                try {
                                        for (int i = 0; true; i++) {
                                                Object item = Array.get(value, i);
+
                                                // encode it normally if direct value
-                                               if (!SerialUtils.encode(builder, item)) {
+                                               write(out, "\r");
+                                               if (!SerialUtils.encode(out, item)) {
                                                        try {
-                                                               // use ZIP: if not
-                                                               builder.append(new Exporter().append(item)
-                                                                               .toString(true));
+                                                               write(out, "B64:");
+                                                               OutputStream out64 = new Base64OutputStream(
+                                                                               out, true);
+                                                               new Exporter(out64).append(item);
+                                                               out64.flush();
                                                        } catch (NotSerializableException e) {
                                                                throw new UnknownFormatConversionException(e
                                                                                .getMessage());
                                                        }
                                                }
-                                               builder.append("\n");
                                        }
                                } catch (ArrayIndexOutOfBoundsException e) {
                                        // Done.
                                }
+                       }
+
+                       @Override
+                       protected Object fromStream(InputStream in) throws IOException {
+                               NextableInputStream stream = new NextableInputStream(in,
+                                               new NextableInputStreamStep('\r'));
+
+                               try {
+                                       List<Object> list = new ArrayList<Object>();
+                                       stream.next();
+                                       String type = IOUtils.readSmallStream(stream);
+
+                                       while (stream.next()) {
+                                               Object value = new Importer().read(stream).getValue();
+                                               list.add(value);
+                                       }
+
+                                       Object array = Array.newInstance(
+                                                       SerialUtils.getClass(type), list.size());
+                                       for (int i = 0; i < list.size(); i++) {
+                                               Array.set(array, i, list.get(i));
+                                       }
 
-                               return builder.toString();
+                                       return array;
+                               } catch (Exception e) {
+                                       if (e instanceof IOException) {
+                                               throw (IOException) e;
+                                       }
+                                       throw new IOException(e.getMessage());
+                               }
                        }
 
                        @Override
                        protected String getType() {
                                return "[]";
                        }
+               });
 
+               // URL:
+               customTypes.put("java.net.URL", new CustomSerializer() {
                        @Override
-                       protected Object fromString(String content) {
-                               String[] tab = content.split("\n");
+                       protected void toStream(OutputStream out, Object value)
+                                       throws IOException {
+                               String val = "";
+                               if (value != null) {
+                                       val = ((URL) value).toString();
+                               }
 
-                               try {
-                                       Object array = Array.newInstance(
-                                                       SerialUtils.getClass(tab[0]), tab.length - 1);
-                                       for (int i = 1; i < tab.length; i++) {
-                                               Object value = new Importer().read(tab[i]).getValue();
-                                               Array.set(array, i - 1, value);
-                                       }
+                               out.write(StringUtils.getBytes(val));
+                       }
 
-                                       return array;
-                               } catch (Exception e) {
-                                       throw new UnknownFormatConversionException(e.getMessage());
+                       @Override
+                       protected Object fromStream(InputStream in) throws IOException {
+                               String val = IOUtils.readSmallStream(in);
+                               if (!val.isEmpty()) {
+                                       return new URL(val);
                                }
+
+                               return null;
+                       }
+
+                       @Override
+                       protected String getType() {
+                               return "java.net.URL";
                        }
                });
 
                // Images (this is currently the only supported image type by default)
-               customTypes.put("java.awt.image.BufferedImage", new CustomSerializer() {
+               customTypes.put("be.nikiroo.utils.Image", new CustomSerializer() {
                        @Override
-                       protected String toString(Object value) {
+                       protected void toStream(OutputStream out, Object value)
+                                       throws IOException {
+                               Image img = (Image) value;
+                               OutputStream encoded = new Base64OutputStream(out, true);
                                try {
-                                       return StringUtils.fromImage((BufferedImage) value);
-                               } catch (IOException e) {
-                                       throw new UnknownFormatConversionException(e.getMessage());
+                                       InputStream in = img.newInputStream();
+                                       try {
+                                               IOUtils.write(in, encoded);
+                                       } finally {
+                                               in.close();
+                                       }
+                               } finally {
+                                       encoded.flush();
+                                       // Cannot close!
                                }
                        }
 
                        @Override
                        protected String getType() {
-                               return "java.awt.image.BufferedImage";
+                               return "be.nikiroo.utils.Image";
                        }
 
                        @Override
-                       protected Object fromString(String content) {
+                       protected Object fromStream(InputStream in) throws IOException {
                                try {
-                                       return StringUtils.toImage(content);
+                                       // Cannot close it!
+                                       InputStream decoded = new Base64InputStream(in, false);
+                                       return new Image(decoded);
                                } catch (IOException e) {
                                        throw new UnknownFormatConversionException(e.getMessage());
                                }
@@ -126,27 +212,68 @@ public class SerialUtils {
        public static Object createObject(String type)
                        throws ClassNotFoundException, NoSuchMethodException {
 
+               String desc = null;
                try {
                        Class<?> clazz = getClass(type);
                        String className = clazz.getName();
-                       Object[] args = null;
+                       List<Object> args = new ArrayList<Object>();
+                       List<Class<?>> classes = new ArrayList<Class<?>>();
                        Constructor<?> ctor = null;
                        if (className.contains("$")) {
-                               Object javaParent = createObject(className.substring(0,
-                                               className.lastIndexOf('$')));
-                               args = new Object[] { javaParent };
-                               ctor = clazz.getDeclaredConstructor(new Class[] { javaParent
-                                               .getClass() });
+                               for (String parentName = className.substring(0,
+                                               className.lastIndexOf('$'));; parentName = parentName
+                                               .substring(0, parentName.lastIndexOf('$'))) {
+                                       Object parent = createObject(parentName);
+                                       args.add(parent);
+                                       classes.add(parent.getClass());
+
+                                       if (!parentName.contains("$")) {
+                                               break;
+                                       }
+                               }
+
+                               // Better error description in case there is no empty
+                               // constructor:
+                               desc = "";
+                               String end = "";
+                               for (Class<?> parent = clazz; parent != null
+                                               && !parent.equals(Object.class); parent = parent
+                                               .getSuperclass()) {
+                                       if (!desc.isEmpty()) {
+                                               desc += " [:";
+                                               end += "]";
+                                       }
+                                       desc += parent;
+                               }
+                               desc += end;
+                               //
+
+                               try {
+                                       ctor = clazz.getDeclaredConstructor(classes
+                                                       .toArray(new Class[] {}));
+                               } catch (NoSuchMethodException nsme) {
+                                       // TODO: it seems we do not always need a parameter for each
+                                       // level, so we currently try "ALL" levels or "FIRST" level
+                                       // only -> we should check the actual rule and use it
+                                       ctor = clazz.getDeclaredConstructor(classes.get(0));
+                                       Object firstParent = args.get(0);
+                                       args.clear();
+                                       args.add(firstParent);
+                               }
+                               desc = null;
                        } else {
-                               args = new Object[] {};
                                ctor = clazz.getDeclaredConstructor();
                        }
 
                        ctor.setAccessible(true);
-                       return ctor.newInstance(args);
+                       return ctor.newInstance(args.toArray());
                } catch (ClassNotFoundException e) {
                        throw e;
                } catch (NoSuchMethodException e) {
+                       if (desc != null) {
+                               throw new NoSuchMethodException("Empty constructor not found: "
+                                               + desc);
+                       }
                        throw e;
                } catch (Exception e) {
                        throw new NoSuchMethodException("Cannot instantiate: " + type);
@@ -165,14 +292,14 @@ public class SerialUtils {
        }
 
        /**
-        * Serialise the given object into this {@link StringBuilder}.
+        * Serialise the given object into this {@link OutputStream}.
         * <p>
         * <b>Important: </b>If the operation fails (with a
         * {@link NotSerializableException}), the {@link StringBuilder} will be
         * corrupted (will contain bad, most probably not importable data).
         * 
-        * @param builder
-        *            the output {@link StringBuilder} to serialise to
+        * @param out
+        *            the output {@link OutputStream} to serialise to
         * @param o
         *            the object to serialise
         * @param map
@@ -184,9 +311,11 @@ public class SerialUtils {
         *             if the object cannot be serialised (in this case, the
         *             {@link StringBuilder} can contain bad, most probably not
         *             importable data)
+        * @throws IOException
+        *             in case of I/O errors
         */
-       static void append(StringBuilder builder, Object o, Map<Integer, Object> map)
-                       throws NotSerializableException {
+       static void append(OutputStream out, Object o, Map<Integer, Object> map)
+                       throws NotSerializableException, IOException {
 
                Field[] fields = new Field[] {};
                String type = "";
@@ -197,10 +326,8 @@ public class SerialUtils {
                        fields = o.getClass().getDeclaredFields();
                        type = o.getClass().getCanonicalName();
                        if (type == null) {
-                               throw new NotSerializableException(
-                                               String.format(
-                                                               "Cannot find the class for this object: %s (it could be an inner class, which is not supported)",
-                                                               o));
+                               // Anonymous inner classes support
+                               type = o.getClass().getName();
                        }
                        id = Integer.toString(hash);
                        if (map.containsKey(hash)) {
@@ -210,9 +337,13 @@ public class SerialUtils {
                        }
                }
 
-               builder.append("{\nREF ").append(type).append("@").append(id)
-                               .append(":");
-               if (!encode(builder, o)) { // check if direct value
+               write(out, "{\nREF ");
+               write(out, type);
+               write(out, "@");
+               write(out, id);
+               write(out, ":");
+
+               if (!encode(out, o)) { // check if direct value
                        try {
                                for (Field field : fields) {
                                        field.setAccessible(true);
@@ -226,16 +357,15 @@ public class SerialUtils {
                                                continue;
                                        }
 
-                                       builder.append("\n");
-                                       builder.append(field.getName());
-                                       builder.append(":");
-                                       Object value;
+                                       write(out, "\n^");
+                                       write(out, field.getName());
+                                       write(out, ":");
 
-                                       value = field.get(o);
+                                       Object value = field.get(o);
 
-                                       if (!encode(builder, value)) {
-                                               builder.append("\n");
-                                               append(builder, value, map);
+                                       if (!encode(out, value)) {
+                                               write(out, "\n");
+                                               append(out, value, map);
                                        }
                                }
                        } catch (IllegalArgumentException e) {
@@ -245,42 +375,74 @@ public class SerialUtils {
                                e.printStackTrace(); // should not happen (see
                                                                                // setAccessible)
                        }
+
+                       write(out, "\n}");
                }
-               builder.append("\n}");
        }
 
-       // return true if encoded (supported)
-       static boolean encode(StringBuilder builder, Object value) {
+       /**
+        * Encode the object into the given {@link OutputStream} if possible and if
+        * supported.
+        * <p>
+        * A supported object in this context means an object we can directly
+        * encode, like an Integer or a String. Custom objects and arrays are also
+        * considered supported, but <b>compound objects are not supported here</b>.
+        * <p>
+        * For compound objects, you should use {@link Exporter}.
+        * 
+        * @param out
+        *            the {@link OutputStream} to append to
+        * @param value
+        *            the object to encode (can be NULL, which will be encoded)
+        * 
+        * @return TRUE if success, FALSE if not (the content of the
+        *         {@link OutputStream} won't be changed in case of failure)
+        * 
+        * @throws IOException
+        *             in case of I/O error
+        */
+       static boolean encode(OutputStream out, Object value) throws IOException {
                if (value == null) {
-                       builder.append("NULL");
-               } else if (value.getClass().getCanonicalName().endsWith("[]")) {
-                       customTypes.get("[]").encode(builder, value);
+                       write(out, "NULL");
+               } else if (value.getClass().getSimpleName().endsWith("[]")) {
+                       // Simple name does support [] suffix and do not return NULL for
+                       // inner anonymous classes
+                       customTypes.get("[]").encode(out, value);
                } else if (customTypes.containsKey(value.getClass().getCanonicalName())) {
                        customTypes.get(value.getClass().getCanonicalName())//
-                                       .encode(builder, value);
+                                       .encode(out, value);
                } else if (value instanceof String) {
-                       encodeString(builder, (String) value);
+                       encodeString(out, (String) value);
                } else if (value instanceof Boolean) {
-                       builder.append(value);
+                       write(out, value);
                } else if (value instanceof Byte) {
-                       builder.append(value).append('b');
+                       write(out, "b");
+                       write(out, value);
                } else if (value instanceof Character) {
-                       encodeString(builder, "" + value);
-                       builder.append('c');
+                       write(out, "c");
+                       encodeString(out, "" + value);
                } else if (value instanceof Short) {
-                       builder.append(value).append('s');
+                       write(out, "s");
+                       write(out, value);
                } else if (value instanceof Integer) {
-                       builder.append(value);
+                       write(out, "i");
+                       write(out, value);
                } else if (value instanceof Long) {
-                       builder.append(value).append('L');
+                       write(out, "l");
+                       write(out, value);
                } else if (value instanceof Float) {
-                       builder.append(value).append('F');
+                       write(out, "f");
+                       write(out, value);
                } else if (value instanceof Double) {
-                       builder.append(value).append('d');
+                       write(out, "d");
+                       write(out, value);
                } else if (value instanceof Enum) {
+                       write(out, "E:");
                        String type = value.getClass().getCanonicalName();
-                       builder.append(type).append(".").append(((Enum<?>) value).name())
-                                       .append(";");
+                       write(out, type);
+                       write(out, ".");
+                       write(out, ((Enum<?>) value).name());
+                       write(out, ";");
                } else {
                        return false;
                }
@@ -288,48 +450,153 @@ public class SerialUtils {
                return true;
        }
 
-       static Object decode(String encodedValue) {
-               String cut = "";
-               if (encodedValue.length() > 1) {
-                       cut = encodedValue.substring(0, encodedValue.length() - 1);
+       static boolean isDirectValue(BufferedInputStream encodedValue)
+                       throws IOException {
+               if (CustomSerializer.isCustom(encodedValue)) {
+                       return false;
+               }
+
+               for (String fullValue : new String[] { "NULL", "null", "true", "false" }) {
+                       if (encodedValue.is(fullValue)) {
+                               return true;
+                       }
                }
 
+               for (String prefix : new String[] { "c\"", "\"", "b", "s", "i", "l",
+                               "f", "d", "E:" }) {
+                       if (encodedValue.startsWith(prefix)) {
+                               return true;
+                       }
+               }
+
+               return false;
+       }
+
+       /**
+        * Decode the data into an equivalent supported source object.
+        * <p>
+        * A supported object in this context means an object we can directly
+        * encode, like an Integer or a String (see
+        * {@link SerialUtils#decode(String)}.
+        * <p>
+        * Custom objects and arrays are also considered supported here, but
+        * <b>compound objects are not</b>.
+        * <p>
+        * For compound objects, you should use {@link Importer}.
+        * 
+        * @param encodedValue
+        *            the encoded data, cannot be NULL
+        * 
+        * @return the object (can be NULL for NULL encoded values)
+        * 
+        * @throws IOException
+        *             if the content cannot be converted
+        */
+       static Object decode(BufferedInputStream encodedValue) throws IOException {
                if (CustomSerializer.isCustom(encodedValue)) {
-                       // custom:TYPE_NAME:"content is String-encoded"
-                       String type = CustomSerializer.typeOf(encodedValue);
-                       if (customTypes.containsKey(type)) {
-                               return customTypes.get(type).decode(encodedValue);
+                       // custom^TYPE^ENCODED_VALUE
+                       NextableInputStream content = new NextableInputStream(encodedValue,
+                                       new NextableInputStreamStep('^'));
+                       try {
+                               content.next();
+                               @SuppressWarnings("unused")
+                               String custom = IOUtils.readSmallStream(content);
+                               content.next();
+                               String type = IOUtils.readSmallStream(content);
+                               content.nextAll();
+                               if (customTypes.containsKey(type)) {
+                                       return customTypes.get(type).decode(content);
+                               }
+                               content.end();
+                               throw new IOException("Unknown custom type: " + type);
+                       } finally {
+                               content.close(false);
+                               encodedValue.end();
+                       }
+               }
+
+               String encodedString = IOUtils.readSmallStream(encodedValue);
+               return decode(encodedString);
+       }
+
+       /**
+        * Decode the data into an equivalent supported source object.
+        * <p>
+        * A supported object in this context means an object we can directly
+        * encode, like an Integer or a String.
+        * <p>
+        * For custom objects and arrays, you should use
+        * {@link SerialUtils#decode(InputStream)} or directly {@link Importer}.
+        * <p>
+        * For compound objects, you should use {@link Importer}.
+        * 
+        * @param encodedValue
+        *            the encoded data, cannot be NULL
+        * 
+        * @return the object (can be NULL for NULL encoded values)
+        * 
+        * @throws IOException
+        *             if the content cannot be converted
+        */
+       static Object decode(String encodedValue) throws IOException {
+               try {
+                       String cut = "";
+                       if (encodedValue.length() > 1) {
+                               cut = encodedValue.substring(1);
+                       }
+
+                       if (encodedValue.equals("NULL") || encodedValue.equals("null")) {
+                               return null;
+                       } else if (encodedValue.startsWith("\"")) {
+                               return decodeString(encodedValue);
+                       } else if (encodedValue.equals("true")) {
+                               return true;
+                       } else if (encodedValue.equals("false")) {
+                               return false;
+                       } else if (encodedValue.startsWith("b")) {
+                               return Byte.parseByte(cut);
+                       } else if (encodedValue.startsWith("c")) {
+                               return decodeString(cut).charAt(0);
+                       } else if (encodedValue.startsWith("s")) {
+                               return Short.parseShort(cut);
+                       } else if (encodedValue.startsWith("l")) {
+                               return Long.parseLong(cut);
+                       } else if (encodedValue.startsWith("f")) {
+                               return Float.parseFloat(cut);
+                       } else if (encodedValue.startsWith("d")) {
+                               return Double.parseDouble(cut);
+                       } else if (encodedValue.startsWith("i")) {
+                               return Integer.parseInt(cut);
+                       } else if (encodedValue.startsWith("E:")) {
+                               cut = cut.substring(1);
+                               return decodeEnum(cut);
                        } else {
-                               throw new UnknownFormatConversionException(
-                                               "Unknown custom type: " + type);
+                               throw new IOException("Unrecognized value: " + encodedValue);
                        }
-               } else if (encodedValue.equals("NULL") || encodedValue.equals("null")) {
-                       return null;
-               } else if (encodedValue.endsWith("\"")) {
-                       return decodeString(encodedValue);
-               } else if (encodedValue.equals("true")) {
-                       return true;
-               } else if (encodedValue.equals("false")) {
-                       return false;
-               } else if (encodedValue.endsWith("b")) {
-                       return Byte.parseByte(cut);
-               } else if (encodedValue.endsWith("c")) {
-                       return decodeString(cut).charAt(0);
-               } else if (encodedValue.endsWith("s")) {
-                       return Short.parseShort(cut);
-               } else if (encodedValue.endsWith("L")) {
-                       return Long.parseLong(cut);
-               } else if (encodedValue.endsWith("F")) {
-                       return Float.parseFloat(cut);
-               } else if (encodedValue.endsWith("d")) {
-                       return Double.parseDouble(cut);
-               } else if (encodedValue.endsWith(";")) {
-                       return decodeEnum(encodedValue);
-               } else {
-                       return Integer.parseInt(encodedValue);
+               } catch (Exception e) {
+                       if (e instanceof IOException) {
+                               throw (IOException) e;
+                       }
+                       throw new IOException(e.getMessage(), e);
                }
        }
 
+       /**
+        * Write the given {@link String} into the given {@link OutputStream} in
+        * UTF-8.
+        * 
+        * @param out
+        *            the {@link OutputStream}
+        * @param data
+        *            the data to write, cannot be NULL
+        * 
+        * @throws IOException
+        *             in case of I/O error
+        */
+       static void write(OutputStream out, Object data) throws IOException {
+               out.write(StringUtils.getBytes(data.toString()));
+       }
+
        /**
         * Return the corresponding class or throw an {@link Exception} if it
         * cannot.
@@ -381,7 +648,7 @@ public class SerialUtils {
        }
 
        @SuppressWarnings({ "unchecked", "rawtypes" })
-       private static Enum<?> decodeEnum(String escaped) {
+       static private Enum<?> decodeEnum(String escaped) {
                // escaped: be.xxx.EnumType.VALUE;
                int pos = escaped.lastIndexOf(".");
                String type = escaped.substring(0, pos);
@@ -390,39 +657,48 @@ public class SerialUtils {
                try {
                        return Enum.valueOf((Class<Enum>) getClass(type), name);
                } catch (Exception e) {
-                       e.printStackTrace();
                        throw new UnknownFormatConversionException("Unknown enum: <" + type
                                        + "> " + name);
                }
        }
 
        // aa bb -> "aa\tbb"
-       private static void encodeString(StringBuilder builder, String raw) {
-               builder.append('\"');
+       static void encodeString(OutputStream out, String raw) throws IOException {
+               // TODO: not. efficient.
+               out.write('\"');
                for (char car : raw.toCharArray()) {
-                       switch (car) {
-                       case '\\':
-                               builder.append("\\\\");
-                               break;
-                       case '\r':
-                               builder.append("\\r");
-                               break;
-                       case '\n':
-                               builder.append("\\n");
-                               break;
-                       case '"':
-                               builder.append("\\\"");
-                               break;
-                       default:
-                               builder.append(car);
-                               break;
-                       }
+                       encodeString(out, car);
+               }
+               out.write('\"');
+       }
+
+       // for encoding string, NOT to encode a char by itself!
+       static void encodeString(OutputStream out, char raw) throws IOException {
+               switch (raw) {
+               case '\\':
+                       out.write('\\');
+                       out.write('\\');
+                       break;
+               case '\r':
+                       out.write('\\');
+                       out.write('r');
+                       break;
+               case '\n':
+                       out.write('\\');
+                       out.write('n');
+                       break;
+               case '"':
+                       out.write('\\');
+                       out.write('\"');
+                       break;
+               default:
+                       out.write(raw);
+                       break;
                }
-               builder.append('\"');
        }
 
        // "aa\tbb" -> aa bb
-       private static String decodeString(String escaped) {
+       static String decodeString(String escaped) {
                StringBuilder builder = new StringBuilder();
 
                boolean escaping = false;
@@ -452,6 +728,6 @@ public class SerialUtils {
                        }
                }
 
-               return builder.substring(1, builder.length() - 1).toString();
+               return builder.substring(1, builder.length() - 1);
        }
 }