Hi. How can I convert this C++ code to Kotlin nati...

# multiplatform

[Giorgi]

Hi. How can I convert this C++ code to Kotlin native?

#include <iostream>
#include <windows.h>
#include <Commdlg.h>

//
// Gobal Variables and declarations.
//
OPENFILENAME ofn ;


// a another memory buffer to contain the file name
char szFile[100] ;

int main() {
    ZeroMemory( &ofn , sizeof( ofn));
    ofn.lStructSize = sizeof ( ofn );
    ofn.hwndOwner = NULL  ;
    ofn.lpstrFile = szFile ;
    ofn.lpstrFile[0] = '\0';
    ofn.nMaxFile = sizeof( szFile );
    ofn.lpstrFilter = "All\0*.*\0Text\0*.TXT\0";
    ofn.nFilterIndex =1;
    ofn.lpstrFileTitle = NULL ;
    ofn.nMaxFileTitle = 0 ;
    ofn.lpstrInitialDir=NULL ;
    ofn.Flags = OFN_PATHMUSTEXIST|OFN_FILEMUSTEXIST ;

    GetOpenFileName( &ofn );

    // Now simpley display the file name
    MessageBox ( NULL , ofn.lpstrFile , "File Name" , MB_OK);
    return 0;
}

Currently, Im strugling with creating OPENFILENAME object. It is alias of tagOFNA, and it takes rawPtr: kotlinx.cinterop.NativePtr in its constructor. How do I create NativePtr ?

[Giorgi]

okay I figured out how to create OPENFILENAME. Here is my progress

fun main(args: Array<String>) {
    memScoped {
        val result = alloc<tagOFNA>()
        SecureZeroMemory?.invoke(result.ptr, sizeOf<tagOFNA>().toULong())

        val szFile = ByteArray(100)

        alloc<CHARVar>()


        result.apply {
            hwndOwner = null
            lpstrFile = szFile
        }
        
        GetOpenFileNameA(result.ptr)
    }
}

Now I need help with creating _char_ szFile[100] ; and its pointer for ofn.lpstrFile

[Giorgi]

A bit more progress

fun main(args: Array<String>) {
    memScoped {
        val result = alloc<tagOFNA>()
        SecureZeroMemory?.invoke(result.ptr, sizeOf<tagOFNA>().toULong())

        val szFile = ByteArray(100)
//        szFile[0] = '\0'
        val pinnedSzFile = szFile.pin()
        val filter = "All\0*.*\0Text\0*.TXT\0".encodeToByteArray().pin()

        result.apply {
            hwndOwner = null
            lpstrFile = pinnedSzFile.addressOf(0)
//                nMaxFile = pinnedSzFile
            //    ofn.lpstrFilter = "All\0*.*\0Text\0*.TXT\0";
            lpstrFilter = filter.addressOf(0)
            nFilterIndex = 1u;
            lpstrFileTitle = null
            nMaxFileTitle = 0u
            lpstrInitialDir = null
            Flags = (OFN_PATHMUSTEXIST or OFN_FILEMUSTEXIST).toUInt()

        }

        GetOpenFileNameA(result.ptr)
    }
}

Need help with _val_ filter = "All\0*.*\0Text\0*.TXT\0".encodeToByteArray().pin() it says illegal escape \0

[Giorgi]

AHAHAHA, I did it

[Giorgi]

here is the code:

import kotlinx.cinterop.*
import platform.windows.*
import kotlin.native.concurrent.freeze

fun main(args: Array<String>) {
    memScoped {
        val result = alloc<tagOFNA>()
        SecureZeroMemory?.invoke(result.ptr, sizeOf<tagOFNA>().toULong())

        val szFile = ByteArray(100)
        szFile[0] = 0
        val pinnedSzFile = szFile.pin()
        val filter = "All$NUL*.*${NUL}Text$NUL*.TXT$NUL".encodeToByteArray().pin()

        result.apply {
            lStructSize = sizeOf<tagOFNA>().toUInt()
            hwndOwner = null
            lpstrFile = pinnedSzFile.addressOf(0)
            nMaxFile = szFile.size.toUInt()
            lpstrFilter = filter.addressOf(0)
            nFilterIndex = 1u;
            lpstrFileTitle = null
            nMaxFileTitle = 0u
            lpstrInitialDir = null
            Flags = (OFN_PATHMUSTEXIST or OFN_FILEMUSTEXIST).toUInt()

        }

        GetOpenFileNameA(result.ptr)
    }
}

const val NUL = '\u0000'

[Giorgi]

I dont know if its correct, but it works 🔥