dchen23 / PrimeNumbersCalculator

PrimeNumbersCalculator

A cross-platform library and an Android app that can calculate the N:th prime number based on user input.

APK: Download

adb install app-debug.apk

Environment

• Android Studio Hedgehog | 2023.1.1 Canary 16
  • NDK 25.1.8937393
  • cmake 3.22.1
• Test Device: OnePlus 7 Pro (Android 11)

Usage

1. Type anything you like inside INPUT text box;

   NOTE: Only intergers in range (0, 50000] will return proper result, non-calculable input will always return 0 !

2. Click the RUN button to calculate all prime numbers;
3. If input sequence has large value (like 20,000), the process will take longer, and all button will be unclickable. Just wait for few seconds;
4. The result of N:th prime numbers will display on the OUTPUT textview;
5. Click the CLR buttorn, both the INPUT text box and OUTPUT textview will reset;
6. Start forn 1st step.

The Examples of Input/Ouput

• Sample Input #1

  Hello 2, 4, 7.5
  

• Sample Output #1

  3, 7, 17
  

• Sample Input #2

  0 1 -10 +34.5 12000
  

• Sample Output #2

  0, 2, 0, 139, 128189
  

• Sample Input #3

  -+abc123 #$-345 7 "!$[phone]
  

• Sample Output #3

  677, 0, 17, 611953, 0
  

Documentation

The core cross-plarform library can be delievered as .so/.h files:

• PrimeNumbersAPI.so: PrimeNumbersAPI.cpp, prime.cpp, prime.h, threadpool.h
• PrimeNumbersAPI.h: PrimeNumbersAPI.h.

The functionality can be divided into four main parts:

1. Numeric Sequence Pharser: Use regex to find all matched numeric inputs
2. Prime Calculator: A brute force approaching to find N:th prime number is less than or equal to 50,000 in order
3. C-style API Wrapper: A C API layer provides better compatibility and interoperability, while also avoiding C++ feature conflicts and ensuring API stability
4. Thread Pool Utility: A thread pool manages a fixed set of threads, improving resource utilizaion and enbaling efficient concurrent task execution
5. Hybird Lifetime Control: An objects and resources manager for both Kotlin and C++ languages, considering their distinct memory management and lifetime paradigms within a single application
6. Android App: A Kotlin frontend can communicate with native libraries using the Java Native Interface (JNI).

Achievements

• Application responsiveness & edge cases
• Cross platform compatibility
• Multithreading support
• Memory management
• Library API design
• Code readability
• Threads/resources should be properly terminated/released after UI has been closed.

Screenshots

1. Display result on output textview

2. Buttons are unclickable during calculation

3. Each workflow process in a threaded operation, different tid under same pid

4. Threads are released when UI is inactive.

TODO

• Utilize a hash table to store calculated order, prime_number pairs
• Apply less time-consuming prime number calculation algorithm, like Sieve of Eratosthenes or Sieve of Atkin
• Support more numeric input format, such as scientific notation, arithmetic calculation and so on
• Change application frontend to compose UI framework.