function init()
    assert(chainhelper:is_owner(),'no auth')
    chainhelper:read_chain()
    if public_data == nil then
        public_data = {}
        public_data.bancor1_table={}
        public_data.product1_table={}
    end
    public_data.a=5
    chainhelper:write_chain()
end

function add_bancor1_pair(ratio,main_supply,main_sym,main_unit,main_fee, sub_supply,sub_sym,sub_unit,sub_fee)
    chainhelper:read_chain()
    for inx,trade_pair in pairs(public_data.bancor1_table) do
        if(trade_pair.main_sym==main_sym and trade_pair.sub_sym==sub_sym) then
            assert(false,'pair already exists')
        end
        if(trade_pair.main_sym==sub_sym and trade_pair.sub_sym==main_sym) then
            assert(false,'pair already exists')
        end
    end
    trade_pair = {}
    trade_pair.ratio=ratio
    trade_pair.price=main_supply/(sub_supply*ratio)
    trade_pair.main_supply=main_supply
    trade_pair.main_sym=main_sym
    trade_pair.main_unit=main_unit
    trade_pair.main_fee=main_fee
    trade_pair.sub_supply=sub_supply
    trade_pair.sub_sym=sub_sym
    trade_pair.sub_unit=sub_unit
    trade_pair.sub_fee=sub_fee
    trade_pair.main_mask=0
    trade_pair.sub_mask=0
    trade_pair.share_keys=0
    table.insert(public_data.bancor1_table, trade_pair)
    chainhelper:write_chain()
end

function add_product_pair()

end

local function test1(a)
    public_data.a=public_data.a+a
end

local function test2(a)
    public_data.a=public_data.a+a
end


function rm_pair(a,b,c)
    chainhelper:read_chain()
    public_data.a=a
    for i = 1, 10 do
        chainhelper:read_chain()
        test1(b)
        test2(c)
        chainhelper:write_chain()
    end
    chainhelper:write_chain()
end




function swap_bancor1_pair(from_sym,from_amount,to_sym,to_amount)

end

function swap_product_pair(from_sym,from_amount,to_sym,to_amount)

end