Hack to choose the displayed carrier name in the iOS simulator

XCDFakeCarrier.m

//
// Copyright (c) 2012-2015 Cédric Luthi / @0xced. All rights reserved.
//

#import <Foundation/Foundation.h>

#if TARGET_OS_SIMULATOR

static const char *fakeCarrier;
static const char *fakeTime;

#import <objc/runtime.h>

@interface XCDFakeCarrier : NSObject
@end

@implementation XCDFakeCarrier

/*
  Runtime offsets for the -[UIStatusBarComposedData rawData] struct
  struct {
    BOOL itemIsEnabled[27];
    BOOL timeString[64];
    int gsmSignalStrengthRaw;
    int gsmSignalStrengthBars;
    BOOL serviceString[100];
    ...
  }
 
  See https://github.com/nst/iOS-Runtime-Headers/blob/master/Frameworks/UIKit.framework/UIStatusBarComposedData.h
*/
static NSUInteger timeStringOffset;
static NSUInteger timeStringSize;
static NSUInteger gsmSignalStrengthBarsOffset;
static NSUInteger gsmSignalStrengthBarsSize;
static NSUInteger serviceStringOffset;
static NSUInteger serviceStringSize;

+ (void) load
{
	fakeCarrier = getenv("FAKE_CARRIER");
	if (!fakeCarrier)
	{
		NSLog(@"You must set the FAKE_CARRIER environment variable");
		return;
	}
	fakeTime = getenv("FAKE_TIME");
	
	const Class UIStatusBarComposedData = objc_getClass("UIStatusBarComposedData");
	const Method rawData = class_getInstanceMethod(UIStatusBarComposedData, sel_getUid("rawData"));
	const char *typeEncoding = method_getTypeEncoding(rawData);
	
	if (typeEncoding)
	{
		NSRegularExpression *typeEncodingRegularExpression = [NSRegularExpression regularExpressionWithPattern:@"\\^(\\{\\?=\\[\\d+[Bc]\\]\\[\\d+c\\]ii\\[\\d+c\\])" options:(NSRegularExpressionOptions)0 error:NULL];
		NSString *typeEncodingString = @(typeEncoding);
		NSTextCheckingResult *typeEncodingMatch = [typeEncodingRegularExpression firstMatchInString:typeEncodingString options:(NSMatchingOptions)0 range:NSMakeRange(0, typeEncodingString.length)];
		if (typeEncodingMatch.numberOfRanges > 1)
		{
			NSString *partialTypeEncoding = [[typeEncodingString substringWithRange:[typeEncodingMatch rangeAtIndex:1]] stringByAppendingString:@"}"];
			NSMethodSignature *methodSignature = [NSMethodSignature signatureWithObjCTypes:partialTypeEncoding.UTF8String];
			NSString *parsedTypeEncoding = methodSignature.debugDescription;
			NSRegularExpression *parsedTypeEncodingRegularExpression = [NSRegularExpression regularExpressionWithPattern:@"^            memory \\{offset = (\\d+), size = (\\d+)\\}" options:NSRegularExpressionAnchorsMatchLines error:NULL];
			NSArray<NSTextCheckingResult *> *offsetMatches = [parsedTypeEncodingRegularExpression matchesInString:parsedTypeEncoding options:(NSMatchingOptions)0 range:NSMakeRange(0, parsedTypeEncoding.length)];
			if (offsetMatches.count == 5)
			{
				timeStringOffset =            [[parsedTypeEncoding substringWithRange:[offsetMatches[1] rangeAtIndex:1]] integerValue];
				timeStringSize =              [[parsedTypeEncoding substringWithRange:[offsetMatches[1] rangeAtIndex:2]] integerValue];
				gsmSignalStrengthBarsOffset = [[parsedTypeEncoding substringWithRange:[offsetMatches[3] rangeAtIndex:1]] integerValue];
				gsmSignalStrengthBarsSize =   [[parsedTypeEncoding substringWithRange:[offsetMatches[3] rangeAtIndex:2]] integerValue];
				serviceStringOffset =         [[parsedTypeEncoding substringWithRange:[offsetMatches[4] rangeAtIndex:1]] integerValue];
				serviceStringSize =           [[parsedTypeEncoding substringWithRange:[offsetMatches[4] rangeAtIndex:2]] integerValue];
				
				BOOL isTimeStringOK = timeStringOffset > 0 && timeStringSize > 0;
				BOOL isSignalStrengthBarsOK = gsmSignalStrengthBarsOffset > 0 && gsmSignalStrengthBarsSize == sizeof(int);
				BOOL isServiceStringOK = serviceStringOffset > 0 && serviceStringSize > 0;
				if (isTimeStringOK && isSignalStrengthBarsOK && isServiceStringOK)
				{
					const SEL fakeSelector = @selector(fake_rawData);
					const Method fakeRawData = class_getInstanceMethod(self, fakeSelector);
					if (class_addMethod(UIStatusBarComposedData, fakeSelector, method_getImplementation(fakeRawData), typeEncoding))
					{
						method_exchangeImplementations(rawData, class_getInstanceMethod(UIStatusBarComposedData, fakeSelector));
						NSLog(@"Using \"%s\" fake carrier", fakeCarrier);
						return;
					}
				}
			}
		}
	}
	
	NSLog(@"XCDFakeCarrier failed to initialize");
}

- (void *) fake_rawData
{
	char *rawData = [self fake_rawData];
	
	BOOL isEmptyCarrier = [@(fakeCarrier ?: "") stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]].length == 0;
	BOOL isEmptyTime = [@(fakeTime ?: "") stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]].length == 0;
	
	if (isEmptyCarrier && isEmptyTime)
	{
		bzero(rawData, serviceStringOffset + serviceStringSize);
		return rawData;
	}
	
	strlcpy(rawData + serviceStringOffset, fakeCarrier, serviceStringSize);
	
	if (fakeTime)
		strlcpy(rawData + timeStringOffset, fakeTime, timeStringSize);
	
	int gsmSignalStrengthBars = 5;
	memcpy(rawData + gsmSignalStrengthBarsOffset, &gsmSignalStrengthBars, gsmSignalStrengthBarsSize);
	
	BOOL enableSignalBars = YES;
	memcpy(rawData + 3, &enableSignalBars, sizeof(enableSignalBars));

	BOOL enableBatteryLevelPercentage = YES;
	memcpy(rawData + 8, &enableBatteryLevelPercentage, sizeof(enableBatteryLevelPercentage));
	
	/*
	  0  center  Time
	  1  right   Do not Sisturb
	  2  left    Airplane
	  3  left    Signal Bars
	  4  left    Carrier
	  5  left    Wi-Fi
	  6  right   Time
	  7  right   Battery Logo
	  8  right   Battery Level Percentage
	  9  right   Battery Level Percentage
	 10  right   Bluetooth Battery
	 11  right   Bluetooth
	 12  right   TTY
	 13  right   Alarm
	 14  right   Plus
	 15          unknown
	 16  right   Location Service
	 17  right   Rotation Lock
	 18          unknown
	 19  right   AirPlay
	 20  right   Siri
	 21  left    Play
	 22  left    VPN
	 23  left    Call Forward
	 24  left    Network Activity Indicator
	 25  left    Black Square
	*/
	return rawData;
}

@end

#endif