// SPDX-License-Identifier: GPL-3.0-only
pragma solidity 0.7.4;
library SafeMathLib {
function times(uint a, uint b) public pure returns (uint) {
uint c = a * b;
require(a == 0 || c / a == b, 'Overflow detected');
return c;
}
function minus(uint a, uint b) public pure returns (uint) {
require(b <= a, 'Underflow detected');
return a - b;
}
function plus(uint a, uint b) public pure returns (uint) {
uint c = a + b;
require(c>=a && c>=b, 'Overflow detected');
return c;
}
}
contract Token {
using SafeMathLib for uint;
mapping (address => uint) balances;
mapping (address => mapping (address => uint)) allowed;
mapping (uint => FrozenTokens) public frozenTokensMap;
event Transfer(address indexed sender, address indexed receiver, uint value);
event Approval(address approver, address spender, uint value);
event TokensFrozen(address indexed freezer, uint amount, uint id, uint lengthFreezeDays);
event TokensUnfrozen(address indexed unfreezer, uint amount, uint id);
event TokensBurned(address burner, uint amount);
event TokensMinted(address recipient, uint amount);
event BankUpdated(address oldBank, address newBank);
uint8 constant public decimals = 18;
string constant public symbol = "FVT";
string constant public name = "Finance.Vote Token";
uint public totalSupply;
uint numFrozenStructs;
address public bank;
struct FrozenTokens {
uint id;
uint dateFrozen;
uint lengthFreezeDays;
uint amount;
bool frozen;
address owner;
}
// simple initialization, giving complete token supply to one address
constructor(address _bank) {
bank = _bank;
require(bank != address(0), 'Must initialize with nonzero address');
uint totalInitialBalance = 1e9 * 1 ether;
balances[bank] = totalInitialBalance;
totalSupply = totalInitialBalance;
emit Transfer(address(0), bank, totalInitialBalance);
}
modifier bankOnly() {
require (msg.sender == bank, 'Only bank address may call this');
_;
}
function setBank(address newBank) public bankOnly {
address oldBank = bank;
bank = newBank;
emit BankUpdated(oldBank, newBank);
}
// freeze tokens for a certain number of days
function freeze(uint amount, uint freezeDays) public {
require(amount > 0, 'Cannot freeze 0 tokens');
// move tokens into this contract's address from sender
balances[msg.sender] = balances[msg.sender].minus(amount);
balances[address(this)] = balances[address(this)].plus(amount);
numFrozenStructs = numFrozenStructs.plus(1);
frozenTokensMap[numFrozenStructs] = FrozenTokens(numFrozenStructs, block.timestamp, freezeDays, amount, true, msg.sender);
emit Transfer(msg.sender, address(this), amount);
emit TokensFrozen(msg.sender, amount, numFrozenStructs, freezeDays);
}
// unfreeze frozen tokens
function unFreeze(uint id) public {
FrozenTokens storage f = frozenTokensMap[id];
require(f.dateFrozen + (f.lengthFreezeDays * 1 days) < block.timestamp, 'May not unfreeze until freeze time is up');
require(f.frozen, 'Can only unfreeze frozen tokens');
f.frozen = false;
// move tokens back into owner's address from this contract's address
balances[f.owner] = balances[f.owner].plus(f.amount);
balances[address(this)] = balances[address(this)].minus(f.amount);
emit Transfer(address(this), msg.sender, f.amount);
emit TokensUnfrozen(f.owner, f.amount, id);
}
// burn tokens, taking them out of supply
function burn(uint amount) public {
balances[msg.sender] = balances[msg.sender].minus(amount);
totalSupply = totalSupply.minus(amount);
emit Transfer(msg.sender, address(0), amount);
emit TokensBurned(msg.sender, amount);
}
function mint(address recipient, uint amount) public bankOnly {
uint totalAmount = amount * 1 ether;
balances[recipient] = balances[recipient].plus(totalAmount);
totalSupply = totalSupply.plus(totalAmount);
emit Transfer(address(0), recipient, totalAmount);
emit TokensMinted(recipient, totalAmount);
}
// burn tokens for someone else, subject to approval
function burnFor(address burned, uint amount) public {
uint currentAllowance = allowed[burned][msg.sender];
// deduct
balances[burned] = balances[burned].minus(amount);
// adjust allowance
allowed[burned][msg.sender] = currentAllowance.minus(amount);
totalSupply = totalSupply.minus(amount);
emit Transfer(burned, address(0), amount);
emit TokensBurned(burned, amount);
}
// transfer tokens
function transfer(address to, uint value) public returns (bool success)
{
if (to == address(0)) {
burn(value);
} else {
// deduct
balances[msg.sender] = balances[msg.sender].minus(value);
// add
balances[to] = balances[to].plus(value);
emit Transfer(msg.sender, to, value);
}
return true;
}
// transfer someone else's tokens, subject to approval
function transferFrom(address from, address to, uint value) public returns (bool success)
{
if (to == address(0)) {
burnFor(from, value);
} else {
uint currentAllowance = allowed[from][msg.sender];
// deduct
balances[from] = balances[from].minus(value);
// add
balances[to] = balances[to].plus(value);
// adjust allowance
allowed[from][msg.sender] = currentAllowance.minus(value);
emit Transfer(from, to, value);
}
return true;
}
// retrieve the balance of address
function balanceOf(address owner) public view returns (uint balance) {
return balances[owner];
}
// approve another address to transfer a specific amount of tokens
function approve(address spender, uint value) public returns (bool success) {
allowed[msg.sender][spender] = value;
emit Approval(msg.sender, spender, value);
return true;
}
// incrementally increase approval, see https://github.com/ethereum/EIPs/issues/738
function increaseApproval(address spender, uint value) public returns (bool success) {
allowed[msg.sender][spender] = allowed[msg.sender][spender].plus(value);
emit Approval(msg.sender, spender, allowed[msg.sender][spender]);
return true;
}
// incrementally decrease approval, see https://github.com/ethereum/EIPs/issues/738
function decreaseApproval(address spender, uint decreaseValue) public returns (bool success) {
uint oldValue = allowed[msg.sender][spender];
// allow decreasing too much, to prevent griefing via front-running
if (decreaseValue >= oldValue) {
allowed[msg.sender][spender] = 0;
} else {
allowed[msg.sender][spender] = oldValue.minus(decreaseValue);
}
emit Approval(msg.sender, spender, allowed[msg.sender][spender]);
return true;
}
// retrieve allowance for a given owner, spender pair of addresses
function allowance(address owner, address spender) public view returns (uint remaining) {
return allowed[owner][spender];
}
function numCoinsFrozen() public view returns (uint) {
return balances[address(this)];
}}
{
"compilationTarget": {
"Token.sol": "Token"
},
"evmVersion": "istanbul",
"libraries": {},
"metadata": {
"bytecodeHash": "ipfs"
},
"optimizer": {
"enabled": false,
"runs": 200
},
"remappings": []
}
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:"string"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"numCoinsFrozen","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"newBank","type":"address"}],"name":"setBank","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"symbol","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"totalSupply","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"}],"name":"transfer","outputs":[{"internalType":"bool","name":"success","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"from","type":"address"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"}],"name":"transferFrom","outputs":[{"internalType":"bool","name":"success","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"id","type":"uint256"}],"name":"unFreeze","outputs":[],"stateMutability":"nonpayable","type":"function"}]