wallet-core/contrib/coinsim.ts
Florian Dold 003fb34971
coinsim
2018-08-24 17:30:47 +02:00

153 lines
3.4 KiB
TypeScript

/*
This file is part of GNU Taler
(C) 2018 GNUnet e.V.
GNU Taler is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
function getRandomInt(min, max) {
return Math.floor(Math.random() * (max - min + 1)) + min;
}
const denoms = [512, 256, 128, 64, 32, 16, 8, 4, 2, 1];
// mapping from denomination index to count
const wallet = denoms.map(() => 0);
const trans_max = 1000;
const trans_min = 2;
const withdraw_max = 5000;
const num_transactions = parseInt(process.argv[2]);
// Refresh or withdraw operations
let ops = 0;
function withdraw(amount) {
while (amount != 0) {
for (let i = 0; i < denoms.length; i++) {
let d = denoms[i];
if (d <= amount) {
amount -= d;
wallet[i]++;
ops++;
break;
}
}
}
}
function spendSmallestFirst(cost) {
while (cost != 0) {
for (let j = 0; j < denoms.length; j++) {
const k = denoms.length - j - 1;
const d = denoms[k];
const w = wallet[k];
if (w == 0) {
continue;
}
if (d <= cost) {
// spend
wallet[k]--;
cost -= d;
ops++;
break;
}
// partially spend and then refresh
ops++;
let r = d - cost;
wallet[k]--;
withdraw(r);
cost = 0;
}
}
}
function spendLargestFirst(cost) {
while (cost != 0) {
for (let j = 0; j < denoms.length; j++) {
const d = denoms[j];
const w = wallet[j];
if (w == 0) {
continue;
}
if (d <= cost) {
// spend
wallet[j]--;
cost -= d;
ops++;
break;
}
// partially spend and then refresh
ops++;
let r = d - cost;
wallet[j]--;
withdraw(r);
cost = 0;
}
}
}
function spendHybrid(cost) {
for (let j = 0; j < denoms.length; j++) {
const k = denoms.length - j - 1;
const d = denoms[k];
const w = wallet[k];
if (w == 0) {
continue;
}
if (d < cost) {
continue;
}
// partially spend and then refresh
ops++;
let r = d - cost;
wallet[k]--;
withdraw(r);
cost = 0;
}
spendSmallestFirst(cost);
}
for (let i = 0; i < num_transactions; i++) {
// check existing wallet balance
let balance = 0;
for (let j = 0; j < denoms.length; j++) {
balance += wallet[j] * denoms[j]
}
// choose how much we want to spend
let cost = getRandomInt(trans_min, trans_max);
if (balance < cost) {
// we need to withdraw
let amount = getRandomInt(cost - balance, withdraw_max);
withdraw(amount);
}
// check that we now have enough balance
balance = 0;
for (let j = 0; j < denoms.length; j++) {
balance += wallet[j] * denoms[j]
}
if (balance < cost) {
throw Error("not enough balance");
}
// now we spend
spendHybrid(cost);
}
console.log(ops / num_transactions);