const { uint8array, array } = require("jszip/lib/support")

exports.newPacket=function(cmd,payload)
{
    if (!cmd)
    {
        return -1;
    }
    
    if (payload)
    {
        var p=2;
        var bf=new Uint8Array(payload.length+3);       
        bf[0]=0xFE;
        bf[1]=cmd;
        
        payload.forEach((element,index) => {
            bf[p]=element;
            p=p+1;
        });
        bf[p]=0xFD;
    }

    return bf;
}

exports.parsePacket=function(data)
{
    if (!data)
    {
        return -1;
    }
    var len=data.length;
    if (data[0]!=0xFE || data[len-1]!=0xFD)
    {
        return -2
    }
        var cmd=data[1];
        var p=0;
        var bf=new Uint8Array(len-4);       
        
        data.forEach((element,index) => {
            if (index>1 && index<len-1)
            {
                bf[p]=element;
                p=p+1;
            }
        });

    

    return {'cmd':cmd,'payload':bf};
}