Add initial iOS application

This is already in a working state, but is still missing a few things.
For example, there is no proper progress indication during generation
and the UI just hangs and there's no way to delete a site yet.

iOS/SiteStorage.m

@@ -0,0 +1,159 @@
+/*
+ * Copyright (c) 2016, Jonathan Schleifer <js@heap.zone>
+ *
+ * https://heap.zone/git/?p=scrypt-pwgen.git
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice is present in all copies.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+@import ObjFW;
+
+/* For literals and boxing. */
+@compatibility_alias NSDictionary OFDictionary;
+@compatibility_alias NSNumber OFNumber;
+
+#import "SiteStorage.h"
+
+@interface SiteStorage ()
+- (void)_update;
+@end
+
+static OFNumber *lengthField, *legacyField;
+
+@implementation SiteStorage
++ (void)initialize
+{
+	lengthField = [@(UINT8_C(0)) retain];
+	legacyField = [@(UINT8_C(1)) retain];
+}
+
+- init
+{
+	self = [super init];
+
+	@try {
+		void *pool = objc_autoreleasePoolPush();
+		OFFileManager *fileManager = [OFFileManager defaultManager];
+		OFString *userDataPath = [OFSystemInfo userDataPath];
+
+		if (![fileManager directoryExistsAtPath: userDataPath])
+			[fileManager createDirectoryAtPath: userDataPath];
+
+		_path = [[userDataPath stringByAppendingPathComponent:
+		    @"sites.msgpack"] retain];
+
+		@try {
+			_storage = [[[OFDataArray
+			    dataArrayWithContentsOfFile: _path]
+			    messagePackValue] mutableCopy];
+		} @catch (id e) {
+			_storage = [[OFMutableDictionary alloc] init];
+		}
+
+		_sites = [[[_storage allKeys] sortedArray] retain];
+
+		objc_autoreleasePoolPop(pool);
+	} @catch (id e) {
+		[self release];
+		@throw e;
+	}
+
+	return self;
+}
+
+- (void)dealloc
+{
+	[_path release];
+	[_storage release];
+	[_sites release];
+
+	[super dealloc];
+}
+
+- (OFArray*)sites
+{
+	void *pool = objc_autoreleasePoolPush();
+	OFArray *sites = [[_storage allKeys] sortedArray];
+
+	[sites retain];
+	objc_autoreleasePoolPop(pool);
+	return [sites autorelease];
+}
+
+- (size_t)sitesCount
+{
+	return [_storage count];
+}
+
+- (bool)hasSite: (OFString*)name
+{
+	return (_storage[name] != nil);
+}
+
+- (size_t)lengthForSite: (OFString*)name
+{
+	OFDictionary *site = _storage[name];
+
+	if (site == nil)
+		@throw [OFInvalidArgumentException exception];
+
+	return [site[lengthField] sizeValue];
+}
+
+- (bool)isSiteLegacy: (OFString*)name
+{
+	OFDictionary *site = _storage[name];
+
+	if (site == nil)
+		@throw [OFInvalidArgumentException exception];
+
+	return [site[legacyField] boolValue];
+}
+
+- (void)setSite: (OFString*)site
+	 length: (size_t)length
+	 legacy: (bool)legacy
+{
+	void *pool = objc_autoreleasePoolPush();
+
+	_storage[site] = @{
+		lengthField: @(length),
+		legacyField: @(legacy)
+	};
+	[self _update];
+
+	objc_autoreleasePoolPop(pool);
+}
+
+- (void)removeSite: (OFString*)name
+{
+	[_storage removeObjectForKey: name];
+	[self _update];
+}
+
+- (void)_update
+{
+	void *pool = objc_autoreleasePoolPush();
+
+	[[_storage messagePackRepresentation] writeToFile: _path];
+
+	[_sites release];
+	_sites = [[[_storage allKeys] sortedArray] retain];
+
+	objc_autoreleasePoolPop(pool);
+}
+@end