mayoff

• http://courses.cms.caltech.edu/cs179/
• http://www.amd.com/Documents/GCN_Architecture_whitepaper.pdf
• https://community.arm.com/graphics/b/blog
• http://cdn.imgtec.com/sdk-documentation/PowerVR+Hardware.Architecture+Overview+for+Developers.pdf
• http://cdn.imgtec.com/sdk-documentation/PowerVR+Series5.Architecture+Guide+for+Developers.pdf
• https://www.imgtec.com/blog/a-look-at-the-powervr-graphics-architecture-tile-based-rendering/
• https://www.imgtec.com/blog/the-dr-in-tbdr-deferred-rendering-in-rogue/
• http://developer.amd.com/tools-and-sdks/opencl-zone/amd-accelerated-parallel-processing-app-sdk/opencl-optimization-guide/#50401334_pgfId-412605
• https://fgiesen.wordpress.com/2011/07/09/a-trip-through-the-graphics-pipeline-2011-index/
• https://community.arm.com/graphics/b/documents/posts/moving-mobile-graphics#siggraph2015

mayoff

import UIKit

class FloatingButtonController: UIViewController {

    private(set) var button: UIButton!

    required init?(coder aDecoder: NSCoder) {
        fatalError()
    }

mayoff

(* To the extent possible under law, Rob Mayoff has waived all copyright and related or neighboring rights to “AppleScript to make Google Chrome open/reload a URL”. This work is published from: United States. https://creativecommons.org/publicdomain/zero/1.0/ *)
tell application "Google Chrome"
	activate
	set theUrl to "http://tycho.usno.navy.mil/cgi-bin/timer.pl"
	
	if (count every window) = 0 then
		make new window
	end if
	
	set found to false

mayoff

import Cocoa
import MetalKit

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate, MTKViewDelegate {
    weak var window: NSWindow!
    weak var metalView: MTKView!
    let device = MTLCreateSystemDefaultDevice()!
    var commandQueue: MTLCommandQueue!
    var pipelineState: MTLRenderPipelineState!

mayoff

The attached lldb command pblock command lets you peek inside an Objective-C block. It tries to tell you where to find the source code for the block, and the values captured by the block when it was created.

Consider this example program:

#import <Foundation/Foundation.h>

@interface Foo: NSObject
@end

@implementation Foo

mayoff

#import <UIKit/UIKit.h>

@interface UIBezierPath (forEachElement)

- (void)forEachElement:(void (^)(CGPathElement const *element))block;

@end

mayoff

import SwiftUI

extension UnitPoint {
    /// - returns: The point on the perimeter of the unit square that is at angle `angle` relative to the center of the unit square.
    init(_ angle: Angle) {
        // Inspired by https://math.stackexchange.com/a/4041510/399217
        // Also see https://www.desmos.com/calculator/k13553cbgk

        let s = sin(angle.radians)
        let c = cos(angle.radians)

mayoff

Using LLVM's libfuzzer with Swift

Background

Of the many tools available for fuzzing, I've found that LLVM's libfuzzer is the easiest to use for Swift on macOS. Other tools seem to have a list of requirements taht are difficult to meet. libfuzzer on the other hand is built into LLVM and is available on macOS in the custom Swift toolchains: https://www.swift.org/download/

In this document I'll describe how to use libfuzzer with Swift and Swift Packages.

I used this setup to fuzz an SVG Renderer package that I am building. I was able to find and fix a number of bugs in my SVG parsing code using libfuzzer in basically no time at all.

mayoff

// See https://stackoverflow.com/q/59367202/77567

import Combine
import Foundation

extension Publisher {
    func step(with stepper: @escaping (SteppingSubscriber<Output, Failure>.Event) -> ()) -> AnyCancellable {
        let subscriber = SteppingSubscriber<Output, Failure>(stepper: stepper)
        self.subscribe(subscriber)
        return .init(subscriber)

mayoff

#import <UIKit/UIKit.h>
#import <ImageIO/ImageIO.h>
#import <MobileCoreServices/MobileCoreServices.h>

static UIImage *frameImage(CGSize size, CGFloat radians) {
    UIGraphicsBeginImageContextWithOptions(size, YES, 1); {
        [[UIColor whiteColor] setFill];
        UIRectFill(CGRectInfinite);
        CGContextRef gc = UIGraphicsGetCurrentContext();
        CGContextTranslateCTM(gc, size.width / 2, size.height / 2);