lua-protobuf: encode fields in sequential order

ordered-encode.lua

local function pbOrderedEncode(type, data)
    -- Check type
    if pb.type(type) == nil then
        return nil, string.format("type '%s' does not exists", type)
    end
    -- List type fields
    local typeFields = {}
    for name, number, type, defval, flags in pb.fields(type) do
        typeFields[name] = {
            name = name,
            number = number,
            type = type,
            flags = flags
        }
    end
    -- List data fields
    local dataFields = {}
    for k,v in pairs(data) do
        -- ignore fields that don't belong to the type
        if typeFields[k] ~= nil then
            table.insert(dataFields, k)
        end
    end
    -- Sort data fields by number
    table.sort(dataFields, function (a, b)
        return typeFields[a].number < typeFields[b].number
    end)

    -- Encode message
    local buffer = pb.buffer();
    for i, fieldName in ipairs(dataFields) do
        local typeField = typeFields[fieldName]
        local value = data[fieldName]
        -- TODO encode
        
    end
    return buffer:result(), nil
end