g4n - Cross-Platform Math Library

A professional Go module implemented using Domain-Driven Design (DDD) that provides basic mathematical operations as a dynamic library for Visual Basic and other applications on both Windows and Linux platforms.

Features

• Basic Arithmetic Operations: Addition, Subtraction, Multiplication, Division
• Advanced Mathematical Functions: Power, Square Root, Natural Logarithm
• Trigonometric Functions: Sine, Cosine, Tangent (input in radians)
• Error Handling: Proper error handling for invalid operations
• Cross-Platform: Builds for both Windows (.dll) and Linux (.so)
• Visual Basic Compatible: C-compatible exports for easy integration
• DDD Architecture: Clean, maintainable code structure
• History Management: Optional operation history tracking

Architecture

This project follows Domain-Driven Design principles:

├── internal/
│   ├── domain/math/          # Domain layer - business logic and entities
│   ├── application/math/     # Application layer - use cases and services
│   └── infrastructure/math/  # Infrastructure layer - implementations
├── cmd/library/              # Main entry point for library build
├── include/                  # C header files for external integration
├── examples/                 # Usage examples for different platforms
└── build/                    # Generated build artifacts

Building the Library

Prerequisites

• Go 1.24+ installed
• For Windows cross-compilation on Linux: MinGW-w64 toolchain

Installing MinGW-w64 (for Windows builds on Linux)

Ubuntu/Debian:

sudo apt-get install gcc-mingw-w64

CentOS/RHEL:

sudo yum install mingw64-gcc

Arch Linux:

sudo pacman -S mingw-w64-gcc

Build Commands

Build for all platforms

make all

Build for specific platforms

make linux    # Build for Linux (.so)
make windows  # Build for Windows (.dll)
make local    # Build for current platform only

Other useful commands

make test     # Run unit tests
make clean    # Clean build artifacts
make package  # Create package with headers
make help     # Show all available commands

Build Output

• Linux: build/libcommon4n.so
• Windows: build/g4n.dll
• Headers: include/g4n.h

Usage Examples

Visual Basic .NET

Imports System.Runtime.InteropServices

Public Class MathLibrary
    <DllImport("g4n.dll", CallingConvention:=CallingConvention.Cdecl)>
    Public Shared Function Add(a As Double, b As Double) As Double
    End Function
    
    <DllImport("g4n.dll", CallingConvention:=CallingConvention.Cdecl)>
    Public Shared Function Divide(a As Double, b As Double, ByRef hasError As Integer) As Double
    End Function
End Class

' Usage
Dim result As Double = MathLibrary.Add(10.5, 5.3)
Console.WriteLine($"Result: {result}")

Visual Basic 6

Private Declare Function Add Lib "g4n.dll" (ByVal a As Double, ByVal b As Double) As Double
Private Declare Function Divide Lib "g4n.dll" (ByVal a As Double, ByVal b As Double, ByRef hasError As Long) As Double

' Usage
Dim result As Double
result = Add(10.5, 5.3)
MsgBox "Result: " & CStr(result)

C/C++

#include "g4n.h"

int main() {
    double result = Add(10.5, 5.3);
    printf("Result: %f\n", result);
    
    int hasError = 0;
    double divResult = Divide(15.0, 3.0, &hasError);
    if (hasError == 0) {
        printf("Division result: %f\n", divResult);
    }
    
    return 0;
}

API Reference

Basic Arithmetic Operations

• double Add(double a, double b) - Addition
• double Subtract(double a, double b) - Subtraction
• double Multiply(double a, double b) - Multiplication
• double Divide(double a, double b, int* hasError) - Division with error handling

Advanced Mathematical Functions

• double Power(double base, double exponent) - Power calculation
• double SquareRoot(double x, int* hasError) - Square root with error handling
• double Logarithm(double x, int* hasError) - Natural logarithm with error handling

Trigonometric Functions

• double Sine(double x) - Sine (input in radians)
• double Cosine(double x) - Cosine (input in radians)
• double Tangent(double x) - Tangent (input in radians)

Utility Functions

• int ClearHistory() - Clear calculation history
• char* GetLastErrorMessage() - Get last error message
• void FreeErrorMessage(char* msg) - Free error message memory

Error Handling

Functions that can fail (like division by zero) use an int* hasError parameter:

• 0 = Success
• 1 = Error occurred

For trigonometric functions, all angles should be provided in radians.

Development

Running Tests

make test

Project Structure

g4n/
├── cmd/library/main.go               # C exports and main entry point
├── internal/
│   ├── domain/math/
│   │   ├── entities.go               # Domain entities
│   │   └── interfaces.go             # Domain interfaces
│   ├── application/math/
│   │   └── service.go                # Application services
│   └── infrastructure/math/
│       ├── calculator.go             # Calculator implementation
│       └── repository.go             # Repository implementation
├── include/g4n.h                # C header file
├── examples/                         # Usage examples
├── Makefile                          # Build configuration
└── README.md                         # This file

Contributing

1. Fork the repository
2. Create a feature branch
3. Write tests for new functionality
4. Ensure all tests pass
5. Submit a pull request

License

This project is available under the MIT License. See the LICENSE file for more details.

Platform Support

• Windows: x64 (64-bit)
• Linux: x64 (64-bit)
• Visual Basic: VB6, VB.NET
• Other: Any language that can call C functions from dynamic libraries

Troubleshooting

Common Issues

1. Missing MinGW-w64: Install the MinGW-w64 toolchain for Windows cross-compilation
2. CGO Disabled: Ensure CGO_ENABLED=1 environment variable is set
3. Library Not Found: Make sure the library is in your system's library path or the same directory as your executable

Getting Help

• Check the examples in the examples/ directory
• Review the test files for usage patterns
• Open an issue on GitHub for bug reports or feature requests