dhoerl

// Based on https://gist.github.com/schickling/b5d86cb070130f80bb40#gistcomment-2894406
func image(data: Data, orientation: UIImage.Orientation = .up) -> UIImage? {
    let context: CGContext
    let width: CGFloat
    let height: CGFloat

    func defaultImage() -> UIImage? {
        return UIImage(data: data)
    }

dhoerl

struct UpperCasePublisher: Publisher {
    typealias Output = [Character]
    typealias Failure = Error

    let upstreamPublisher: AnyPublisher<Output, Error>

    init(upstream: AnyPublisher<Output, Error>) {
        self.upstreamPublisher = upstream
    }

dhoerl

final class StringSubscriber: Subscriber {
    typealias Input = [Character]
    typealias Failure = Error

    var subscription: Subscription?
    var count = 0

    func receive(subscription: Subscription) {
        self.subscription = subscription
        self.subscription?.request(.max(1))

dhoerl

enum SPErrors: Error {
    case inputStringWasEmpty
}

struct StringPublisher: Publisher {
    typealias Output = [Character]
    typealias Failure = Error

    private let data: [Character]

dhoerl

// Inspired by https://gist.github.com/nitrag/b3117a4b6b8e89fdbc12b98029cf98f8

+ (UIImage *)imageFromView:(UIView *)view subsection:(CGRect)subRect
{
    // Image will be sized to the smaller rectangle
    UIGraphicsBeginImageContextWithOptions(subRect.size, YES, 0);

    // The primary view needs to shift up and left so the desired rect is visible
    // But the rect passed below needs to be sized to the view, otherwise the image is compressed
    CGRect drawRect = CGRectMake(-subRect.origin.x, -subRect.origin.x, view.bounds.size.width, view.bounds.size.height);

dhoerl

//
//  Asymmetric.swift
//
//  Created by David Hoerl on 12/23/18.
//  Copyright © 2018 David Hoerl. All rights reserved.
//

/*
  This is the portion you need in the distributed app, which uses the public key that can appear in plain text
*/

dhoerl

David's Top 10: Do That When Writing Swift

1) Purchase Dash (OS X and iOS) and get Swift from SwiftDoc.org (invaluable reference, I use it daily!)

2) Use Enums for UIView tags and SegmentedControl segments;

   enum MyViews: Int { case OKButton=1...} then switch MyViews(rawValue: view.tag)
   
 also for states (somewhat replaces C's X-Macros, helps during debugging)
 

dhoerl

static NSString *kcIdentifier = @"MyApp";

@implementation LTAppDelegate (KeyChain)

- (void)keychainInit
{
	self.keychainDict = [NSMutableDictionary dictionaryWithCapacity:7];
	KeychainItemWrapper *item = [[KeychainItemWrapper alloc] initWithIdentifier:kcIdentifier accessGroup:nil];
	
	[self.keychainDict setObject:@"" forKey:kcEmailAddress];

dhoerl

- (uint64_t)freeDiskspace
{
	uint64_t totalFreeSpace = 0;

	__autoreleasing NSError *error = nil;  
	NSString *path = [self applicationDocumentsDirectory];  
	NSDictionary *dictionary = [[NSFileManager defaultManager] attributesOfFileSystemForPath:path error: &error];  

	if (dictionary) {  
		NSNumber *freeFileSystemSizeInBytes = [dictionary objectForKey:NSFileSystemFreeSize];

dhoerl

Prefer printf to the C++ iosstream methods? Now you can create a string using printf style format strings, and also append formatted string to existing strings.

Inspired by: http://stackoverflow.com/questions/2342162