How can I calculate polynomial coefficients for Tone Curve points:
// • Red channel: (0, 0), (60, 39), (128, 128), (255, 255)
// • Green channel: (0, 0), (63, 50), (128, 128), (255, 255)
// • Blue channel: (0, 0), (60, 47), (119, 119), (255, 255)
CIFilter:
func colorCrossPolynomial(inputImage: CIImage) -> CIImage? {
let colorCrossPolynomial = CIFilter.colorCrossPolynomial()
let redfloatArr: [CGFloat] = [1, 1, 1, 1, 0, 0, 0, 0, 0, 0]
let greenfloatArr: [CGFloat] = [0, 1, 1, 0, 0, 0, 0, 0, 0, 1]
let bluefloatArr: [CGFloat] = [0, 0, 1, 0, 0, 0, 0, 1, 1, 0]
colorCrossPolynomial.inputImage = inputImage
colorCrossPolynomial.blueCoefficients = CIVector(values: bluefloatArr, count: bluefloatArr.count)
colorCrossPolynomial.redCoefficients = CIVector(values: redfloatArr, count: redfloatArr.count)
colorCrossPolynomial.greenCoefficients = CIVector(values: greenfloatArr, count: greenfloatArr.count)
return colorCrossPolynomial.outputImage
}
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I wonder if this is correct behavior. I was surprised to get this result when compiling and running the following C code with Apple clang version 14.0.0 (clang-1400.0.29.102) target arm64-apple-darwin21.6.0 on a M1 Pro 12.7.6 with cc -O2 file.c:
#include <stdio.h>
#include <stdlib.h>
unsigned long long factorial(int n)
{
unsigned long long fac = 1;
while (n > 0)
fac *= n;
return fac;
}
int main()
{
return factorial(1);
}
Compiling with -O2 and running this code gives "Trace/BPT trap".
Checking with LLDB:
$ lldb ./a.out
(lldb) target create "./a.out"
Current executable set to '/Users/engelen/Projects/Euler/a.out' (arm64).
(lldb) run
Process 79580 launched: '/Users/engelen/Projects/Euler/a.out' (arm64)
Process 79580 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BREAKPOINT (code=1, subcode=0x100003fb4)
frame #0: 0x0000000100003fb4 a.out`main at 20.c:9:3 [opt]
6 unsigned long long fac = 1;
7 while (n > 0)
8 fac *= n;
-> 9 return fac;
10 }
11
12 int main()
The loop is non-terminating. But a breakpoint trap is triggered at the return statement. The code should just hang in the loop IMO, not trap, because it never updates variable n (a correct factorial function should decrement n). Never seen this before (not since I started wiring C code in the 80s.)
If I change the update *= into += then there is no trap.
Topic:
Programming Languages
SubTopic:
General
Here is my code:
`
// A 3rd-party class I must use.
class MySession{
init() async throws {
// ..
}
}
actor SessionManager{
private var mySession: MySession? // The MySession is not Sendable
func createSession() async {
do {
mySession = try await MySession()
log("getOrCreateSession() End, success.")
} catch {
log("getOrCreateSession() End, failure.")
}
}
}`
I get this warning: "Non-sendable type 'MySession' returned by implicitly asynchronous call to a nonisolated function cannot cross the actor boundary."
How can this be fixed?
Sometimes when my app crashes I get an exception like this: EXC_BREAKPOINT (SIGTRAP).
But I don't know how to catch it. Is there a way in Swift to catch such exceptions?
I have a class that I want to custom encode into JSON:
class Declination: Decodable, Encodable {
var asString: String
var asDouble: Double
init(_ asString: String) {
self.asString = asString
self.asDouble = raToDouble(asString)
}
required init(from decoder: Decoder) throws {
let value = try decoder.singleValueContainer()
self.asString = try value.decode(String.self)
self.asDouble = declinationToDouble(asString)
}
}
As you can see, I calculate the double form of the declination when I decode a JSON file containing the data. What I want to do now is ENCODE the class back out as a single string.
Currently the standard JSON encode in Swift produces the following:
"declination":{"asDouble":18.26388888888889,"asString":"+18:15:50.00"}
what I want to produce is:
declination:"+18:15:50.00"
How can I easily do that? I've read up about custom encoders and such, and I get confused about the containers and what keys are being used. I think there might be a simple answer where I could just code:
extension Coordinate: Encodable {
func encode(to encoder: Encoder) throws {
return encoder.encode(self.asString)
}
}
But experienced Swift developers will immediately see that won't work. Should I do JSONSerialization instead? Can I just write a toString() extension and have JSON pick that up?
Any help would be appreciated.
Thanks,
Robert
Topic:
Programming Languages
SubTopic:
Swift
I have an old app that I just got a notice will be pulled form the App Store if I don't upgrade. I tried to open in Xcode but it says I need to use Xcode 10.1 to convert to Swift 4.
Exact message - "Use Xcode 10.1 to migrate the code to Swift 4."
I downloaded Xcode 10.1 , now the OS (Sequoia ) says can't do it, have to use the latest version of Xcode.
Exact message - "The version of Xcode installed on this Mac is not compatible with macOS Sequoia. Download the latest version for free from the App Store."
Any experience with this and suggestions would be greatly appreciated.
decidePolicyFor delegate method:
import WebKit
@objc extension DocumentationVC
{
func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void)
Being called just alright in swift 5 minimal concurrency.
Raising concurrency to complete with swift 5 or swift 6. Changing the code to avoid warnings:
@preconcurrency import WebKit
@objc extension DocumentationVC
{
func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
The delegate method is not being called. Changing back to swift 5 concurrency minimal - it is called.
Looking at WKNavigationDelegate:
WK_SWIFT_UI_ACTOR
@protocol WKNavigationDelegate <NSObject>
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(WK_SWIFT_UI_ACTOR void (^)(WKNavigationActionPolicy))decisionHandler WK_SWIFT_ASYNC(3);
Changing the delegate method to:
func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping @MainActor (WKNavigationActionPolicy) -> Void) {
And it is called across swift 5 concurrency minimal to complete to swift 6.
I thought, the meaning of @preconcurrency import WebKit was to keep the delegate without @MainActor before the (WKNavigationActionPolicy) still matching regardless the swift concurrency mode?
My point is - this can introduce hidden breaking changes? I didn't see this documented anyhow at: https://www.swift.org/migration/documentation/migrationguide/.
decidePolicyFor is an optional method - so if signature 'mismatches' - there will be no warning on not-implementing the delegate method.
How do we catch or diagnose irregularities like this? Is it something @preconcurrency import WebKit should be ensuring and it is not?
Is this delegate mismatch a bug on swift side or something we should be taking care of while migrating? If it is on us, how do we diagnose these potential mismatches?
thread #1, stop reason = signal SIGABRT
frame #0: 0x00000001a95985a8 dyld__abort_with_payload + 8 frame #1: 0x00000001a959f208 dyldabort_with_payload_wrapper_internal + 104
frame #2: 0x00000001a959f23c dyldabort_with_payload + 16 frame #3: 0x00000001a95364c8 dylddyld4::halt(char const*, dyld4::StructuredError const*) + 300
frame #4: 0x00000001a9541f60 dylddyld4::prepare(dyld4::APIs&, dyld3::MachOAnalyzer const*) + 4124 frame #5: 0x00000001a95667a8 dylddyld4::start(dyld4::KernelArgs*, void*, void*)::$_0::operator()() const + 544
frame #6: 0x00000001a955fb1c dyld`start + 2188
Topic:
Programming Languages
SubTopic:
Swift
Hi I'm new here - I'm trying to learn Swift and SwiftUI.
Tried on PluralSight and Udemy but they have been outdated and thus hard to follow.
So after finding Apples own guides I felt relieved and happy, but now I'm stuck again.
After they've updated Xcode to use #Preview instead of PreviewProvider it's hard to follow along on their tutorial.
Does anyone know of good resources to study SwiftUI? Or know if apple plan to update their tutorials any time soon?
I'm here now if anyone's interested or it's useful information: https://developer.apple.com/tutorials/app-dev-training/managing-state-and-life-cycle
When Xcode is connected to the mobile phone for debugging, the app that contains the logic of executing machine code runs normally, but if Xcode is disconnected and the app is run alone, it will crash.
First use the xcode-run execution function to start the app
The machine code logic executes normally
Disconnect the phone from xcode
Start the app
5.Crash
Here is the test code:https://gitee.com/FanChiang_admin/demo.git
Topic:
Programming Languages
SubTopic:
General
Hello,
I have integrated LZMA2 compression into my iOS app, Hogs, and successfully implemented compression. However, when attempting to upload the app for TestFlight, I encountered an error:
"The app references non-public symbols in Payload/Hogs.app/Hogs: _lzma_code, _lzma_end."
These functions are part of the LZMA compression library (specifically LZMA2). Here's a detailed description of the issue:
What I Have Done:
LZMA2 Integration: I integrated LZMA2 compression into the app and created a wrapper around the LZMA functions (_lzma_code, _lzma_end) to prevent direct references.
App Build Configuration:
I ensured the LZMA2 library is linked correctly with the -lzma flag in the linker settings.
I wrapped the LZMA functions in custom functions (my_lzma_code, my_lzma_end) in an attempt to avoid using the non-public symbols directly.
Error Message:
During the app submission process, I received the following error:
"The app references non-public symbols in Payload/Hogs.app/Hogs: _lzma_code, _lzma_end."
Steps Taken to Resolve:
Checked if any LZMA functions were exposed incorrectly.
Ensured that all non-public symbols were properly encapsulated in a wrapper.
Verified linker settings to ensure the proper inclusion of the LZMA2 library.
Request:
Could anyone provide suggestions or best practices to resolve this issue and avoid references to non-public symbols? Should I use a different method for linking LZMA2 or encapsulating these symbols?
Thank You:
I appreciate your help in resolving this issue so I can move forward with submitting the app for TestFlight.
Topic:
Programming Languages
SubTopic:
Swift
Tags:
Swift Packages
Apple Archive
Compression
TestFlight
I notice that Swift Data type's hashValue collision when first 80 byte of data and data length are same because of the Implementation only use first 80 bytes to compute the hash.
https://web.archive.org/web/20120605052030/https://opensource.apple.com/source/CF/CF-635.21/CFData.c
also, even if hash collision on the situation like this, I can check data is really equal or not by ==
does there any reason for this implementation(only use 80 byte of data to make hashValue)?
test code is under below
let dataArray: [UInt8] = [
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00
]
var dataArray1: [UInt8] = dataArray
var dataArray2: [UInt8] = dataArray
dataArray1.append(contentsOf: [0x00, 0x00, 0x00, 0x00])
dataArray2.append(contentsOf: [0xff, 0xff, 0xff, 0xff])
let data1 = Data(dataArray1)
let data2 = Data(dataArray2) // Only last 4 byte differs
print(data1.hashValue)
print(data2.hashValue)
print(data1.hashValue == data2.hashValue) // true
print(data1 == data2) // false
In my project, i have a Swift class with a class level property of type string. Like this :
class TWSwiftString {
var pString:String!
init(_ pString: String) {
self.pString = pString
}
}
I am creating intance of this class and then creating a opaque pointer to this intance. Like this :
let str = TWSwiftString("World")
// Increasing RC by 1
strptr = Unmanaged.passRetained(str).toOpaque()
Now using this opaque pointer i want to modify the value of pString by directly operating on memory. Like this:
withUnsafeMutablePointer(to: &strptr.pString) { strPointer in
strPointer.pointee = "World"
}
Although i am able to modify pString like this and print. Lets assume i have a approach to make sure memory remains valid when it is operated on and freeing of memory is also handled somehow .
Will this approach work if i have 100s of intance of this string which are being operated in this manner ? What if the size of new value is greater than existing string value ? For this i am thinking of chunk of memory initially and then keep on increasing size of it as bigger string then this chunk comes. Does this approach seems feasible ? Any other problems i can encounter by using this approach ?
Chatgpt gave this answer :
To directly update the memory of a Swift class’s property, particularly to alter a String property, is generally discouraged due to Swift's memory safety model. However, if we want to access and modify a class property directly, the best practice is to use a property accessor, as manually altering memory could lead to undefined behavior or even crashes. Why Direct Memory Manipulation Is Risky When you attempt to manipulate memory directly, especially with Swift’s memory model, you might alter not only the value but also the memory layout of Swift’s String type, which could break things internally. The Swift compiler may store String differently based on the internal structure, so even if we manage to locate the correct memory address, directly modifying it is unreliable.
do you have any opinion around chatgpt resoponse ?
Topic:
Programming Languages
SubTopic:
Swift
Tags:
Foundation
Swift Packages
Inter-process communication
I recently submitted my app, Hogs, to the App Store, but it was rejected due to references to non-public symbols:
_lzma_code
_lzma_end
I am using the LZMA compression library in my app, and these functions are part of that implementation. Here's a breakdown of my usage:
Library Used: liblzma (custom wrapper around LZMA functions)
Error Message: "The app references non-public symbols in Payload/Hogs.app/Hogs: _lzma_code, _lzma_end."
Steps I’ve Taken:
I’ve wrapped the LZMA functions in my own functions (my_lzma_code, my_lzma_end) to prevent direct references.
I have checked the build settings and included -lzma in the linker flags.
I’ve tried using a custom framework to encapsulate LZMA, but the issue persists.
I would greatly appreciate any help or suggestions on how to resolve this issue and get my app approved. Is there any workaround or adjustment I can make to avoid using these non-public symbols?
Thank you in advance for your assistance.
❌ Could not find email_ai.py in the app bundle. Available files: []
The error above is what I’m encountering.
I’ve placed the referenced file both in the project directory and inside the app. However, every time I remove and reinsert the file into the folder within the app, it prompts me to designate the targets—I select all, but this doesn’t resolve the issue.
I’m unsure how to properly reference the file so that it is recognised and included in the bundle. Any guidance would be greatly appreciated.
this is my build phase:
#!/bin/sh
set -x # Prints each command before running it (for debugging)
pwd # Shows the current working directory
echo "$SRCROOT" # Shows what Xcode thinks is the project root
ls -l "$SRCROOT/EmailAssistant/EmailAssistant/PythonScripts" # Lists files in the script folder
export PYTHONPATH="/Users/caesar/.pyenv/versions/3.11.6/bin"
/Users/caesar/.pyenv/versions/3.11.6/bin/python3 "$SRCROOT/EmailAssistant/EmailAssistant/PythonScripts/email_ai.py"
echo "Script completed."
I'll describe my crash with an example, looking for some insights into the reason why this is happening.
@objc public protocol LauncherContainer {
var launcher: Launcher { get }
}
@objc public protocol Launcher: UIViewControllerTransitioningDelegate {
func initiateLaunch(url: URL, launchingHotInstance: Bool)
}
@objc final class LauncherContainer: NSObject, LauncherContainer, TabsContentCellTapHandler {
...
init(
...
) {
...
super.init()
}
...
//
// ContentCellTapHandler
//
public func tabContentCellItemDidTap(
tabId: String
) {
...
launcher.initiateNewTabNavigation(
tabId: tabId // Crash happens here
)
}
public class Launcher: NSObject, Launcher, FooterPillTapHandler {
public func initiateNewTabNavigation(tabId: String) {
...
}
}
public protocol TabsContentCellTapHandler: NSObject {
func tabContentCellItemDidTap(
tabId: String,
}
Crash stack last 2 lines are- libswiftCore.dylib swift_unknownObjectRetain libswiftCore.dylib String._bridgeToObjectiveCImpl()
String._bridgeToObjectiveCImpl() gets called when the caller and implementation is in Swift file
I believe due to @objc class LauncherContainer there'd be bridging header generated. Does that mean tabId passed to tabContentCellItemDidTap is a String but the one passed to initiateNewTabNavigation is NSString?
TabId is UUID().uuidString if that helps. Wondering if UUID().uuidString has something to do with this.
Thanks a ton for helping. Please find attached screenshot of the stack trace.
I am porting an old app from ObjC. The app uses many defined constants such as:
#define COM_OFFSET 12.5
and many variables that are read and/or written throughout the App, such as:
PCDate* Dates[367];
@class PCMainView;
PCMainView* MainView;
in one file called "PCCommon.h"
How do I duplicate this function in Swift? I have looked around and have found no help.
Thanks in advance.
For my app I've created a Dictionary that I want to persist using AppStorage
In order to be able to do this, I added RawRepresentable conformance for my specific type of Dictionary. (see code below)
typealias ScriptPickers = [Language: Bool]
extension ScriptPickers: @retroactive RawRepresentable where Key == Language, Value == Bool {
public init?(rawValue: String) {
guard let data = rawValue.data(using: .utf8),
let result = try? JSONDecoder().decode(ScriptPickers.self, from: data)
else {
return nil
}
self = result
}
public var rawValue: String {
guard let data = try? JSONEncoder().encode(self), // data is Data type
let result = String(data: data, encoding: .utf8) // coerce NSData to String
else {
return "{}" // empty Dictionary represented as String
}
return result
}
}
public enum Language: String, Codable, {
case en = "en"
case fr = "fr"
case ja = "ja"
case ko = "ko"
case hr = "hr"
case de = "de"
}
This all works fine in my app, however trying to run any tests, the build fails with the following:
Conflicting conformance of 'Dictionary<Key, Value>' to protocol 'RawRepresentable'; there cannot be more than one conformance, even with different conditional bounds
But then when I comment out my RawRepresentable implementation, I get the following error when attempting to run tests:
Value of type 'ScriptPickers' (aka 'Dictionary<Language, Bool>') has no member 'rawValue'
I hope Joseph Heller is out there somewhere chuckling at my predicament
any/all ideas greatly appreciated
I use Kotlin Multiplayer Development to develop iOS applications. I access the methods in the Kotlin class of the shared module in the ContentView.swift file. Functions without parameters can be used normally, but functions with parameters cannot. For example, the 78th line of code on the left side of the screenshot works, but the 79th line does not. Can someone please tell me the reason? Thank you!
I have configured DateFormatter in the following way:
let df = DateFormatter()
df.dateFormat = "yyyy-MM-dd'T'HH:mm:ss'Z'"
df.locale = .init(identifier: "en")
df.timeZone = .init(secondsFromGMT: 0)
in some user devices instead of ISO8601 style it returns date like 09/25/2024 12:00:34
Tried to change date format from settings, changed calendar and I think that checked everything that can cause the problem, but nothing helped to reproduce this issue, but actually this issue exists and consumers complain about not working date picker.
Is there any information what can cause such problem? May be there is some bug in iOS itself?