Sparked x86 loadpack (wip)

dim as long level
level=4

declare sub loadpack(level as long) as string
declare function nconcat(n as long,d as long) as string
declare Sub Intro(level as long)

function nconcat(n as long,d as long) as string
    dim as string sn
    sn=str(n)
    while left(sn,1)=chr(32):sn=right(sn,len(sn)-1):wend
    if len(sn)<d then sn=string(d-len(sn),"0")+sn
    nconcat=sn
end function

Sub Intro(level as long)
    color 15,1
    dim as string gamename,levelname,rating,datapack
    dim as long levelnum,packexists

    dim as long filemode
    datapack="./datapack/level-"+nconcat(level,2)

    filemode=freefile
    packexists=open(datapack+"/summary.txt" for input as #filemode)

    if packexists then
        gamename="Sparked x86"
        levelnum=0
        levelname="Placeholder"
        rating="Debug Mode"
    else
        input #filemode,gamename
        input #filemode,levelnum,levelname
        input #filemode,rating
    end if

    close #filemode

    cls : randomize()

    locate 1,1 : print datapack

    locate  5,34 : print gamename;
    locate  7,28 : print "LEVEL "+nconcat(levelnum,2)+": "+levelname;
    locate  9,28 : print "RATING: "+rating;
    locate 15,24 : print "PUSH THE <ENTER> KEY TO START";

    while getkey()<>13 : wend

end sub

function loadpack(level as long) as string
    dim as string gamename,levelname,rating,datapack
    dim as long levelnum,packexists

    dim as string head,buffer,handle,pix
    dim as long o

    dim as long filemode

    dim as long wid,hei


    pix=space(0)
    wid=0
    hei=0

    buffer=space(0)
    o=0
    filemode=0
    head=space(0)

    datapack="./datapack/level-"+nconcat(level,2)

    filemode=freefile
    packexists=open(datapack+"/sprites.txt" for input as #filemode)

    if packexists then
        gamename="Sparked x86"
        levelnum=0
        levelname="Placeholder"
        rating="Debug Mode"
    else
        do while not(eof(filemode))
            line input #filemode,buffer
            o=instr(1,buffer,"( ")
            if o>0 then
                head=left(buffer,o-1)
                if head="DeclareGlobalImage" then
                    buffer=mid(buffer,len(head)+2)

                    o=instr(1,buffer," , ")
                    handle=left(buffer,o-1)
                    buffer=mid(buffer,len(handle)+3)

                    o=instr(1,buffer," , ")
                    wid=left(buffer,o-1)
                    pix=pix+nconcat(wid,2)
                    buffer=mid(buffer,len(wid)+3)

                    o=instr(1,buffer," , ")
                    hei=left(buffer,o-1)
                    pix=pix+nconcat(hei,2)
                    buffer=mid(buffer,len(hei)+3)

                    if buffer="_" then exit do
                else
                    do while len(buffer)>0
                        o=instr(1,buffer,space(2))
                        if o=1 then
                            buffer=mid$(buffer,o+1)
                        else
                            exit do
                        end if

                        o=instr(1,buffer,",")
                        if o>0 then
                            pix=pix+lnconcat(left(buffer,o-1),1)
                            buffer=mid(buffer,len(pix)+1)
                        elseif buffer=" , _"
                            buffer=space(0)
                        elseif buffer="  )"
                            buffer=space(0)
                        end if
                    loop
                end if
            end if
        loop

        loadpack=pix

    end if

    close #filemode

end function