dmaclach’s gists

dmaclach / gist:a0f51212e871e19165c6b970bc7158fb

Created April 23, 2025 02:27

Code snippet for converting between OpenSSL types and SecKeyRefs. Hacky, but it worked for my needs.

	uint8_t get_EC_curve(const EC_key_t ec)
	{
	int nid;

	nid = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
	return get_ec_curve_type(nid);
	}

	static EC_KEY *SecKeyToOpenSSLKey(SecKeyRef secKey, int public) {
	CFErrorRef error;

dmaclach / main.m

Last active December 3, 2022 22:49

Apple Archive Example In Objective-C

	int main(int argc, const char * argv[]) {
	@autoreleasepool {
	NSString *dst =
	[NSHomeDirectory() stringByAppendingPathComponent:@"Desktop/file.aar"];
	AAByteStream fileStream = AAFileStreamOpenWithPath(dst.UTF8String,
	O_CREAT \| O_WRONLY, 0644);

	AAByteStream compressionStream = AACompressionOutputStreamOpen(fileStream,
	AA_COMPRESSION_ALGORITHM_LZFSE, 1<<20, AA_FLAG_VERBOSITY_3, 0);
	AAArchiveStream encodeStream = AAEncodeArchiveOutputStreamOpen(compressionStream,

dmaclach / MisalignedRead.m

Last active August 9, 2020 16:44

Compile this with Xcode 11 "release" and it will crash on ARMv7 due to misaligned read. Use a "single view" iOS App as your template, and replace AppDelegate.m with this code.

	#import <UIKit/UIKit.h>

	@interface AppDelegate : UIResponder <UIApplicationDelegate>
	@end

	__attribute__((noinline)) double GPBCodedInputStreamReadDouble(uint8_t *buf) {
	int64_t value = OSReadLittleInt64(buf, 0);
	double result;
	memcpy(&result, &value, sizeof(result));
	return result;

dmaclach / Instrument.xml

Created January 8, 2019 16:55

	<?xml version="1.0" encoding="UTF-8" ?>
	<package>
	<id>com.google.ImageMapper</id>
	<title>ImageMapper</title>
	<owner>
	<name>Dave MacLachlan</name>
	</owner>
	<import-schema>kdebug-strings</import-schema>
	<ktrace-interval-schema>
	<id>com-google-dyld-map-image-schema</id>

dmaclach / dyld details.txt

Last active January 6, 2019 01:19

	total time: 635.49 milliseconds (100.0%)
	total images loaded: 457 (451 from dyld shared cache)
	total segments mapped: 15, into 3756 pages with 408 pages pre-fetched
	total images loading time: 376.31 milliseconds (59.2%)
	total load time in ObjC: 64.57 milliseconds (10.1%)
	total debugger pause time: 0.00 milliseconds (0.0%)
	total dtrace DOF registration time: 0.11 milliseconds (0.0%)
	total rebase fixups: 1,164,368
	total rebase fixups time: 76.51 milliseconds (12.0%)
	total binding fixups: 83,028

dmaclach / AppLaunchTime.c

Created January 5, 2019 00:49

	#include <sys/sysctl.h>

	struct timeval AppLaunchTimeRelativeTo1970(void) {
	id_t pid = getpid();
	int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, (int)pid };
	const size_t mibSize = sizeof(mib) / sizeof(mib[0]);
	size_t infoSize = 0;

	// Get initial size of KERN_PROC data structure.
	if (sysctl(mib, mibSize, NULL, &infoSize, NULL, 0) != 0) {

dmaclach / property_encoding.csv

Last active December 10, 2018 17:39

Objective C property encodings

	code	meaning
	R	read-only
	C	by-copy
	&	by-reference
	D	dynamic
	G	getter (followed by selector name)
	S	setter (followed by selector name)
	V	instance variable (followed by variable name)
	T	type encoding (followed by old-style type encoding)
	W	weak

dmaclach / objc_metadata_hider.h

Last active May 19, 2023 20:34

	/**
	* Wraps C++ classes (ptrs and refs) so that they can be passed around in
	* Objective-C++ programs without generating a lot of useless Objective-C
	* runtime metadata.
	* Use objc_metadata_hider_ptr for ptrs and objc_metadata_hider_ref for refs.
	* Example use:
	* ```
	* class Foo {
	* public:
	* ....

dmaclach / main.mm

Last active November 29, 2018 21:59

ObjectiveC wrapping C++

	#import <Foundation/Foundation.h>
	#include <map>
	#include <string>

	struct CppType {
	std::map<std::string, std::string> myMap;
	};

	@interface ObjCType : NSObject {
	CppType map;

dmaclach / main.m

Last active November 29, 2018 05:55

Create an Objective C Class at runtime

	#import <Foundation/Foundation.h>
	#import <objc/runtime.h>

	int main(int argc, const char * argv[]) {
	@autoreleasepool {
	Class myClass = objc_allocateClassPair([NSObject class], "MyClass", 0);
	IMP methodIMP = imp_implementationWithBlock(^(id self) {
	return @"Hello";
	});
	if (!class_addMethod(myClass, @selector(description), methodIMP, "@@:")) {

dmaclach dmaclach