Index: src/OFMutableString.h
==================================================================
--- src/OFMutableString.h
+++ src/OFMutableString.h
@@ -27,10 +27,26 @@
  * @param index The index where to set the character
  */
 - (void)setCharacter: (of_unichar_t)character
 	     atIndex: (size_t)index;
 
+/*!
+ * @brief Appends another OFString to the OFMutableString.
+ *
+ * @param string An OFString to append
+ */
+- (void)appendString: (OFString*)string;
+
+/*!
+ * @brief Appends the specified characters to the OFMutableString.
+ *
+ * @param characters An array of characters to append
+ * @param length The length of the array of characters
+ */
+- (void)appendCharacters: (of_unichar_t*)characters
+		  length: (size_t)length;
+
 /*!
  * @brief Appends a UTF-8 encoded C string to the OFMutableString.
  *
  * @param UTF8String A UTF-8 encoded C string to append
  */
@@ -65,17 +81,10 @@
  */
 - (void)appendCString: (const char*)cString
 	     encoding: (of_string_encoding_t)encoding
 	       length: (size_t)cStringLength;
 
-/*!
- * @brief Appends another OFString to the OFMutableString.
- *
- * @param string An OFString to append
- */
-- (void)appendString: (OFString*)string;
-
 /*!
  * @brief Appends a formatted string to the OFMutableString.
  *
  * See printf for the format syntax. As an addition, %@ is available as format
  * specifier for objects.

Index: src/OFMutableString.m
==================================================================
--- src/OFMutableString.m
+++ src/OFMutableString.m
@@ -284,10 +284,27 @@
 	[self replaceCharactersInRange: of_range(index, 1)
 			    withString: string];
 
 	objc_autoreleasePoolPop(pool);
 }
+
+- (void)appendString: (OFString*)string
+{
+	return [self insertString: string
+			  atIndex: [self length]];
+}
+
+- (void)appendCharacters: (of_unichar_t*)characters
+		  length: (size_t)length
+{
+	void *pool = objc_autoreleasePoolPush();
+
+	return [self appendString: [OFString stringWithCharacters: characters
+							   length: length]];
+
+	objc_autoreleasePoolPop(pool);
+}
 
 - (void)appendUTF8String: (const char*)UTF8String
 {
 	void *pool = objc_autoreleasePoolPush();
 
@@ -329,16 +346,10 @@
 						 length: cStringLength]];
 
 	objc_autoreleasePoolPop(pool);
 }
 
-- (void)appendString: (OFString*)string
-{
-	return [self insertString: string
-			  atIndex: [self length]];
-}
-
 - (void)appendFormat: (OFConstantString*)format, ...
 {
 	va_list arguments;
 
 	va_start(arguments, format);

Index: src/OFMutableString_UTF8.m
==================================================================
--- src/OFMutableString_UTF8.m
+++ src/OFMutableString_UTF8.m
@@ -388,10 +388,71 @@
 		if (((OFString_UTF8*)string)->s->isUTF8)
 			s->isUTF8 = YES;
 	} else
 		s->isUTF8 = YES;
 }
+
+- (void)appendCharacters: (of_unichar_t*)characters
+		  length: (size_t)length
+{
+	char *tmp;
+
+	tmp = [self allocMemoryWithSize: (length * 4) + 1];
+	@try {
+		size_t i, j = 0;
+		BOOL isUTF8 = NO;
+
+		for (i = 0; i < length; i++) {
+			char buffer[4];
+
+			switch (of_string_utf8_encode(characters[i], buffer)) {
+			case 1:
+				tmp[j++] = buffer[0];
+				break;
+			case 2:
+				isUTF8 = YES;
+
+				memcpy(tmp + j, buffer, 2);
+				j += 2;
+
+				break;
+			case 3:
+				isUTF8 = YES;
+
+				memcpy(tmp + j, buffer, 3);
+				j += 3;
+
+				break;
+			case 4:
+				isUTF8 = YES;
+
+				memcpy(tmp + j, buffer, 4);
+				j += 4;
+
+				break;
+			default:
+				@throw [OFInvalidEncodingException
+				    exceptionWithClass: [self class]];
+			}
+		}
+
+		tmp[j] = '\0';
+
+		s->hashed = NO;
+		s->cString = [self resizeMemory: s->cString
+					   size: s->cStringLength + j + 1];
+		memcpy(s->cString + s->cStringLength, tmp, j + 1);
+
+		s->cStringLength += j;
+		s->length += length;
+
+		if (isUTF8)
+			s->isUTF8 = YES;
+	} @finally {
+		[self freeMemory: tmp];
+	}
+}
 
 - (void)appendFormat: (OFConstantString*)format
 	   arguments: (va_list)arguments
 {
 	char *UTF8String;

Index: src/OFString_UTF8.m
==================================================================
--- src/OFString_UTF8.m
+++ src/OFString_UTF8.m
@@ -422,11 +422,10 @@
 		} else if (byteOrder != OF_BYTE_ORDER_NATIVE)
 			swap = YES;
 
 		s = &s_store;
 
-		s->cStringLength = length;
 		s->cString = [self allocMemoryWithSize: (length * 4) + 1];
 		s->length = length;
 
 		for (i = 0; i < length; i++) {
 			char buffer[4];
@@ -438,27 +437,24 @@
 			case 1:
 				s->cString[j++] = buffer[0];
 				break;
 			case 2:
 				s->isUTF8 = YES;
-				s->cStringLength++;
 
 				memcpy(s->cString + j, buffer, 2);
 				j += 2;
 
 				break;
 			case 3:
 				s->isUTF8 = YES;
-				s->cStringLength += 2;
 
 				memcpy(s->cString + j, buffer, 3);
 				j += 3;
 
 				break;
 			case 4:
 				s->isUTF8 = YES;
-				s->cStringLength += 3;
 
 				memcpy(s->cString + j, buffer, 4);
 				j += 4;
 
 				break;
@@ -467,14 +463,15 @@
 				    exceptionWithClass: [self class]];
 			}
 		}
 
 		s->cString[j] = '\0';
+		s->cStringLength = j;
 
 		@try {
 			s->cString = [self resizeMemory: s->cString
-						   size: s->cStringLength + 1];
+						   size: j + 1];
 		} @catch (OFOutOfMemoryException *e) {
 			/* We don't care, as we only tried to make it smaller */
 		}
 	} @catch (id e) {
 		[self release];

Index: tests/OFStringTests.m
==================================================================
--- tests/OFStringTests.m
+++ tests/OFStringTests.m
@@ -116,10 +116,14 @@
 
 	TEST(@"-[appendString:] and -[appendUTF8String:]",
 	    R([s[1] appendUTF8String: "1𝄞"]) && R([s[1] appendString: @"3"]) &&
 	    R([s[0] appendString: s[1]]) && [s[0] isEqual: @"täs€1𝄞3"])
 
+	TEST(@"-[appendCharacters:length:]",
+	    R([s[1] appendCharacters: ucstr + 6
+			      length: 2]) && [s[1] isEqual: @"1𝄞3r🀺"])
+
 	TEST(@"-[length]", [s[0] length] == 7)
 	TEST(@"-[UTF8StringLength]", [s[0] UTF8StringLength] == 13)
 	TEST(@"-[hash]", [s[0] hash] == 0x705583C0)
 
 	TEST(@"-[characterAtIndex:]", [s[0] characterAtIndex: 0] == 't' &&