@@ -56,10 +56,17 @@
 
 + (instancetype)dataArrayWithItemSize: (size_t)itemSize
 {
 	return [[[self alloc] initWithItemSize: itemSize] autorelease];
 }
+
++ (instancetype)dataArrayWithItemSize: (size_t)itemSize
+			     capacity: (size_t)capacity
+{
+	return [[[self alloc] initWithItemSize: itemSize
+				      capacity: capacity] autorelease];
+}
 
 + (instancetype)dataArrayWithContentsOfFile: (OFString*)path
 {
 	return [[[self alloc] initWithContentsOfFile: path] autorelease];
 }
@@ -80,18 +87,22 @@
 	return [[[self alloc] initWithBase64EncodedString: string] autorelease];
 }
 
 - init
 {
-	self = [super init];
+	return [self initWithItemSize: 1
+			     capacity: 0];
+}
 
-	_itemSize = 1;
-
-	return self;
+- initWithItemSize: (size_t)itemSize
+{
+	return [self initWithItemSize: itemSize
+			     capacity: 0];
 }
 
 - initWithItemSize: (size_t)itemSize
+	  capacity: (size_t)capacity
 {
 	self = [super init];
 
 	if (itemSize == 0) {
 		Class c = [self class];
@@ -98,24 +109,32 @@
 		[self release];
 		@throw [OFInvalidArgumentException exceptionWithClass: c
 							     selector: _cmd];
 	}
 
+	_items = [self allocMemoryWithSize: itemSize
+				     count: capacity];
+
 	_itemSize = itemSize;
+	_capacity = capacity;
 
 	return self;
 }
 
 - initWithContentsOfFile: (OFString*)path
 {
-	self = [super init];
-
 	@try {
 		OFFile *file = [[OFFile alloc] initWithPath: path
 						       mode: @"rb"];
+		off_t size = [OFFile sizeOfFileAtPath: path];
 
-		_itemSize = 1;
+		if (size > SIZE_MAX)
+			@throw [OFOutOfRangeException
+			    exceptionWithClass: [self class]];
+
+		self = [self initWithItemSize: 1
+				     capacity: size];
 
 		@try {
 			size_t pageSize = [OFSystemInfo pageSize];
 			char *buffer = [self allocMemoryWithSize: pageSize];
 
@@ -169,10 +188,14 @@
 		@throw [OFHTTPRequestFailedException
 		    exceptionWithClass: [request class]
 			       request: request
 				 reply: reply];
 
+	/*
+	 * TODO: This can be optimized by allocating a data array with the
+	 * capacity from the Content-Length header.
+	 */
 	self = [[reply readDataArrayTillEndOfStream] retain];
 
 	headers = [reply headers];
 	if ((contentLength = [headers objectForKey: @"Content-Length"]) != nil)
 		if ([self count] != (size_t)[contentLength decimalValue])
@@ -240,15 +263,14 @@
 	return self;
 }
 
 - initWithBase64EncodedString: (OFString*)string
 {
-	self = [super init];
+	self = [self initWithItemSize: 1
+			     capacity: [string length] / 3];
 
 	@try {
-		_itemSize = 1;
-
 		if (!of_base64_decode(self, [string cStringWithEncoding:
 		    OF_STRING_ENCODING_ASCII], [string
 		    cStringLengthWithEncoding: OF_STRING_ENCODING_ASCII])) {
 			Class c = [self class];
 			[self release];
@@ -262,14 +284,10 @@
 	return self;
 }
 
 - initWithSerialization: (OFXMLElement*)element
 {
-	self = [super init];
-
-	_itemSize = 1;
-
 	@try {
 		void *pool = objc_autoreleasePoolPush();
 		OFString *stringValue;
 
 		if (![[element name] isEqual: [self className]] ||
@@ -278,16 +296,11 @@
 			    exceptionWithClass: [self class]
 				      selector: _cmd];
 
 		stringValue = [element stringValue];
 
-		if (!of_base64_decode(self, [stringValue
-		    cStringWithEncoding: OF_STRING_ENCODING_ASCII],
-		    [stringValue cStringLengthWithEncoding:
-		    OF_STRING_ENCODING_ASCII]))
-			@throw [OFInvalidFormatException
-			    exceptionWithClass: [self class]];
+		self = [self initWithBase64EncodedString: stringValue];
 
 		objc_autoreleasePoolPop(pool);
 	} @catch (id e) {
 		[self release];
 		@throw e;
@@ -338,13 +351,16 @@
 - (void)addItem: (const void*)item
 {
 	if (SIZE_MAX - _count < 1)
 		@throw [OFOutOfRangeException exceptionWithClass: [self class]];
 
-	_items = [self resizeMemory: _items
-			       size: _itemSize
-			      count: _count + 1];
+	if (_count + 1 > _capacity) {
+		_items = [self resizeMemory: _items
+				       size: _itemSize
+				      count: _count + 1];
+		_capacity = _count + 1;
+	}
 
 	memcpy(_items + _count * _itemSize, item, _itemSize);
 
 	_count++;
 }
@@ -361,13 +377,16 @@
 	   count: (size_t)count
 {
 	if (count > SIZE_MAX - count)
 		@throw [OFOutOfRangeException exceptionWithClass: [self class]];
 
-	_items = [self resizeMemory: _items
-			       size: _itemSize
-			      count: _count + count];
+	if (_count + count > _capacity) {
+		_items = [self resizeMemory: _items
+				       size: _itemSize
+				      count: _count + count];
+		_capacity = _count + count;
+	}
 
 	memcpy(_items + _count * _itemSize, items, count * _itemSize);
 	_count += count;
 }
 
@@ -376,13 +395,16 @@
 	      count: (size_t)count
 {
 	if (count > SIZE_MAX - _count || index > _count)
 		@throw [OFOutOfRangeException exceptionWithClass: [self class]];
 
-	_items = [self resizeMemory: _items
-			       size: _itemSize
-			      count: _count + count];
+	if (_count + count > _capacity) {
+		_items = [self resizeMemory: _items
+				       size: _itemSize
+				      count: _count + count];
+		_capacity = _count + count;
+	}
 
 	memmove(_items + (index + count) * _itemSize,
 	    _items + index * _itemSize, (_count - index) * _itemSize);
 	memcpy(_items + index * _itemSize, items, count * _itemSize);
 
@@ -407,10 +429,11 @@
 	_count -= range.length;
 	@try {
 		_items = [self resizeMemory: _items
 				       size: _itemSize
 				      count: _count];
+		_capacity = _count;
 	} @catch (OFOutOfMemoryException *e) {
 		/* We don't really care, as we only made it smaller */
 	}
 }
 
@@ -422,10 +445,11 @@
 	_count--;
 	@try {
 		_items = [self resizeMemory: _items
 				       size: _itemSize
 				      count: _count];
+		_capacity = _count;
 	} @catch (OFOutOfMemoryException *e) {
 		/* We don't care, as we only made it smaller */
 	}
 }
 
@@ -433,15 +457,17 @@
 {
 	[self freeMemory: _items];
 
 	_items = NULL;
 	_count = 0;
+	_capacity = 0;
 }
 
 - copy
 {
-	OFDataArray *copy = [[[self class] alloc] initWithItemSize: _itemSize];
+	OFDataArray *copy = [[[self class] alloc] initWithItemSize: _itemSize
+							  capacity: _count];
 
 	[copy addItems: _items
 		 count: _count];
 
 	return copy;
@@ -590,10 +616,21 @@
 	return [element autorelease];
 }
 @end
 
 @implementation OFBigDataArray
+- initWithItemSize: (size_t)itemSize
+	  capacity: (size_t)capacity
+{
+	size_t lastPageByte = [OFSystemInfo pageSize] - 1;
+
+	capacity = (capacity * itemSize + lastPageByte) & ~lastPageByte;
+
+	return [super initWithItemSize: itemSize
+			      capacity: capacity];
+}
+
 - (void)addItem: (const void*)item
 {
 	size_t size, lastPageByte;
 
 	if (SIZE_MAX - _count < 1 || _count + 1 > SIZE_MAX / _itemSize)
@@ -600,13 +637,15 @@
 		@throw [OFOutOfRangeException exceptionWithClass: [self class]];
 
 	lastPageByte = [OFSystemInfo pageSize] - 1;
 	size = ((_count + 1) * _itemSize + lastPageByte) & ~lastPageByte;
 
-	if (_size != size)
+	if (size > _capacity) {
 		_items = [self resizeMemory: _items
 				       size: size];
+		_capacity = size;
+	}
 
 	memcpy(_items + _count * _itemSize, item, _itemSize);
 
 	_count++;
 	_size = size;
@@ -621,13 +660,15 @@
 		@throw [OFOutOfRangeException exceptionWithClass: [self class]];
 
 	lastPageByte = [OFSystemInfo pageSize] - 1;
 	size = ((_count + count) * _itemSize + lastPageByte) & ~lastPageByte;
 
-	if (_size != size)
+	if (size > _capacity) {
 		_items = [self resizeMemory: _items
 				       size: size];
+		_capacity = size;
+	}
 
 	memcpy(_items + _count * _itemSize, items, count * _itemSize);
 
 	_count += count;
 	_size = size;
@@ -644,13 +685,15 @@
 		@throw [OFOutOfRangeException exceptionWithClass: [self class]];
 
 	lastPageByte = [OFSystemInfo pageSize] - 1;
 	size = ((_count + count) * _itemSize + lastPageByte) & ~lastPageByte;
 
-	if (_size != size)
+	if (size > _capacity) {
 		_items = [self resizeMemory: _items
 				       size: size];
+		_capacity = size;
+	}
 
 	memmove(_items + (index + count) * _itemSize,
 	    _items + index * _itemSize, (_count - index) * _itemSize);
 	memcpy(_items + index * _itemSize, items, count * _itemSize);
 
@@ -676,10 +719,11 @@
 
 	if (_size != size && size >= pageSize) {
 		@try {
 			_items = [self resizeMemory: _items
 					       size: size];
+			_capacity = size;
 		} @catch (OFOutOfMemoryException *e) {
 			/* We don't care, as we only made it smaller */
 		}
 
 		_size = size;
@@ -699,10 +743,11 @@
 
 	if (_size != size && size >= pageSize) {
 		@try {
 			_items = [self resizeMemory: _items
 					       size: size];
+			_capacity = size;
 		} @catch (OFOutOfMemoryException *e) {
 			/* We don't care, as we only made it smaller */
 		}
 
 		_size = size;
@@ -714,13 +759,14 @@
 	size_t pageSize = [OFSystemInfo pageSize];
 
 	@try {
 		_items = [self resizeMemory: _items
 				       size: pageSize];
+		_capacity = pageSize;
 		_size = pageSize;
 	} @catch (OFOutOfMemoryException *e) {
 		/* We don't care, as we only made it smaller */
 	}
 
 	_count = 0;
 }
 @end