mayoff’s gists

mayoff / parser.c

Last active December 11, 2017 15:48

recursive descent parser for a very simple tree grammar; see http://stackoverflow.com/questions/14085626

	#include <stdio.h>
	#include <stdlib.h>

	typedef struct BinaryTree {
	char info;
	struct BinaryTree left, right, *father;
	} BinaryTree;

	typedef struct {
	BinaryTree *node;

mayoff / curveArea.m

Created January 11, 2013 22:30

Compute the area of a closed curve by counting pixels. http://stackoverflow.com/questions/14220719/ios-how-to-calculate-number-of-pixels-area-enclosed-by-a-curve

	static CGPathRef createClosedPathWithPoints(const CGPoint *points, size_t count) {
	CGMutablePathRef path = CGPathCreateMutable();
	CGPathAddLines(path, NULL, points, count);
	CGPathCloseSubpath(path);
	return path;
	}

	static CGRect integralFrameForPath(CGPathRef path) {
	CGRect frame = CGPathGetBoundingBox(path);
	return CGRectIntegral(frame);

mayoff / makeAnimatedGif.m

Created February 16, 2013 23:00

Example of creating an animated GIF on iOS, with no 3rd-party code required. This should also be easy to port to OS X.

	#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);

mayoff / longDecimalToHex.mm

Created March 13, 2013 21:30

Test program that converts an arbitrary-precision decimal digit string to a hex digit string.

	#import <Foundation/Foundation.h>
	#import <vector>

	// index 0 is the least significant digit
	typedef std::vector<uint16_t> BigInt;

	static void insertDecimalDigit(BigInt &b, uint16_t decimalDigit) {
	uint32_t carry = decimalDigit;
	for (size_t i = 0; i < b.size(); ++i) {
	uint32_t product = b[i] * (uint32_t)10 + carry;

mayoff / drawArc.m

Created April 7, 2013 22:07

Use Core Graphics to draw an arc with a gradient fill, a stroked outline, and a shadow. http://stackoverflow.com/questions/15866179/draw-segments-from-a-circle-or-donut

	static UIImage *imageWithSize(CGSize size) {
	static CGFloat const kThickness = 20;
	static CGFloat const kLineWidth = 1;
	static CGFloat const kShadowWidth = 8;

	UIGraphicsBeginImageContextWithOptions(size, NO, 0); {
	CGContextRef gc = UIGraphicsGetCurrentContext();
	CGContextAddArc(gc, size.width / 2, size.height / 2,
	(size.width - kThickness - kLineWidth) / 2,
	-M_PI / 4, -3 * M_PI / 4, YES);

mayoff / open.sh

Last active April 5, 2018 23:46

bash completion for the `-a` and `-b` flags of the Mac OS X `open` command

	#
	# This is a set of bash function definitions, and a bash command, that
	# set up bash completion for the Mac OS X "open" command.
	#
	# HOW TO USE
	#
	# Add this command to your .bashrc:
	#
	# . open.sh
	#

mayoff / ViewController.m

Created June 14, 2013 23:53

Example of using auto layout to make a container view as tall as its tallest subview, but no taller. For http://stackoverflow.com/q/17117799/77567 .


	#import "ViewController.h"

	@interface ViewController ()

	@end

	@implementation ViewController {
	UIView *containerView;
	NSArray *subviews;

mayoff / .lldbinit

Created June 18, 2013 04:58

An lldb command that prints the description of the exception being raised, when run while the target is stopped at the first instruction of objc_exception_throw. Many thanks to Enrico Granata and Sean Callanan for basically writing this to my specifications at WWDC 2013.

command script import ~/Library/lldb/sniff_objc_exception_throw.py

mayoff / .lldbinit

Created July 12, 2013 05:05

My .lldbinit for Cocoa Coders

	# command alias rd expression -o -- [[UIApp keyWindow] recursiveDescription]

	command regex rd 's/^[[:space:]]*$/po [[UIApp keyWindow] recursiveDescription]/' 's/^(.+)$/po [%1 recursiveDescription]/'

	command regex rsd 's/.*/po [UIApp Rob_recursiveSceneDescription]/'

	command script import ~/.../lldb/sniff_objc_exception_throw.py

	command regex hcons 's/^(.+)$/po [(id)%1 constraintsAffectingLayoutForAxis:0]/'
	command regex vcons 's/^(.+)$/po [(id)%1 constraintsAffectingLayoutForAxis:1]/'

mayoff / GenericPrepareForSegue.m

Created August 10, 2013 05:52

This is a generic implementation of prepareForSegue:sender: that calls a segue-specific method based on the segue identifier. There's also a similar implementation of shouldPerformSegueWithIdentifier:sender:.

	- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
	NSString *identifier = segue.identifier;
	if (identifier.length == 0)
	return;
	NSString *selectorString = [NSString stringWithFormat:@"prepareFor%@Segue:sender:", identifier];
	SEL selector = NSSelectorFromString(selectorString);
	if (!selector \|\| ![self respondsToSelector:selector])
	return;
	void (method)(id, SEL, id, id) = (void ()(id, SEL, id, id))[self methodForSelector:selector];
	method(self, selector, segue, sender);

Rob Mayoff mayoff