MemPatcher magic lines itself

MemPatcher.m

#import "MemPatcher.h"

vm_object_offset_t calcAddress(vm_object_offset_t offset)
{
	const struct mach_header *mach;
	mach = _dyld_get_image_header(0);

	if (mach->flags & MH_PIE)
	{
		vm_object_offset_t slide = _dyld_get_image_vmaddr_slide(0);
		return (slide + offset);
	}
	else
		return offset;
}

kern_return_t readAddress(vm_object_offset_t address, unsigned char *outData, size_t size)
{
	address &= ~1;
	mach_port_t port = mach_task_self();
	vm_size_t sz;
	return vm_read_overwrite(port, address, size, (vm_object_offset_t)outData, &sz);
}

kern_return_t writeAddress(vm_object_offset_t address, unsigned char *inData, size_t size)
{
	kern_return_t status;
	mach_port_t port = mach_task_self();

	address &= ~1;

	vm_object_offset_t text_base = address;

	status = vm_protect(port, text_base, size, false, VM_PROT_READ | VM_PROT_WRITE | VM_PROT_COPY);

	if (status != KERN_SUCCESS)
		return status;

	status = vm_write(port, address, (vm_object_offset_t)inData, size);

	if (status != KERN_SUCCESS)
		return status;

	return vm_protect(port, text_base, size, false, VM_PROT_READ | VM_PROT_EXECUTE);
}

@implementation MemPatcher
- (id) initAddress:(vm_object_offset_t)addr data:(uint)data
{
	self = [super init];
	if (self)
	{
		patchAddr = calcAddress(addr);

		if (!(((data & 0xFFFF8000) + 0x8000) & 0xFFFF7FFF)) {
			patchSize = sizeof(unsigned short);
			data = OSSwapInt16(data);
		}
		else {
			data = OSSwapInt32(data);
			patchSize = sizeof(int);
		}

		patchData = (unsigned char*)malloc(sizeof(unsigned char) * patchSize);
		origData  = (unsigned char*)malloc(sizeof(unsigned char) * patchSize);

		memcpy(patchData, &data, patchSize);
		readAddress(patchAddr, origData, patchSize);
	}
	return self;
}

+ (instancetype) patch:(vm_object_offset_t)addr data:(uint)data
{
	MemPatcher *mp = [[MemPatcher alloc] initAddress:addr data:data];
	return mp;
}

- (bool) apply
{
	return writeAddress(patchAddr, patchData, patchSize);
}

- (bool) reset
{
	return writeAddress(patchAddr, origData, patchSize);
}

+ (vm_object_offset_t)calculate:(vm_object_offset_t)offset
{
	return calcAddress(offset);
}

- (void)dealloc
{
    free(patchData);
    free(origData);
}
@end

patchAddr, patchSize, origData are not declared :/ @arthurdapaz