pragmasolidity ^0.5.13;import"./SafeMath.sol";
/**
* @title Standard ERC20 token
*
* @dev Implementation of the basic standard token.
* https://eips.ethereum.org/EIPS/eip-20
* Originally based on code by FirstBlood:
* https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
*
* This implementation emits additional Approval events, allowing applications to reconstruct the allowance status for
* all accounts just by listening to said events. Note that this isn't required by the specification, and other
* compliant implementations may not do it.
*/contractERC20{
usingSafeMathforuint256;
mapping(address=>uint256) private _balances;
mapping(address=>mapping(address=>uint256)) private _allowed;
uint256private _totalSupply;
stringpublic name;
stringpublic symbol;
uint8public decimals;
eventTransfer(addressindexedfrom, addressindexed to, uint256 value);
eventApproval(addressindexed owner,
addressindexed spender,
uint256 value
);
constructor(stringmemory _name, stringmemory _symbol, uint8 _decimals) public{
name = _name;
symbol = _symbol;
decimals = _decimals;
}
/**
* @dev Total number of tokens in existence.
*/functiontotalSupply() publicviewreturns (uint256) {
return _totalSupply;
}
/**
* @dev Gets the balance of the specified address.
* @param owner The address to query the balance of.
* @return A uint256 representing the amount owned by the passed address.
*/functionbalanceOf(address owner) publicviewreturns (uint256) {
return _balances[owner];
}
/**
* @dev Function to check the amount of tokens that an owner allowed to a spender.
* @param owner address The address which owns the funds.
* @param spender address The address which will spend the funds.
* @return A uint256 specifying the amount of tokens still available for the spender.
*/functionallowance(address owner, address spender)
publicviewreturns (uint256)
{
return _allowed[owner][spender];
}
/**
* @dev Transfer token to a specified address.
* @param to The address to transfer to.
* @param value The amount to be transferred.
*/functiontransfer(address to, uint256 value) publicreturns (bool) {
_transfer(msg.sender, to, value);
returntrue;
}
/**
* @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
* Beware that changing an allowance with this method brings the risk that someone may use both the old
* and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
* race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
* @param spender The address which will spend the funds.
* @param value The amount of tokens to be spent.
*/functionapprove(address spender, uint256 value) publicreturns (bool) {
_approve(msg.sender, spender, value);
returntrue;
}
/**
* @dev Transfer tokens from one address to another.
* Note that while this function emits an Approval event, this is not required as per the specification,
* and other compliant implementations may not emit the event.
* @param from address The address which you want to send tokens from
* @param to address The address which you want to transfer to
* @param value uint256 the amount of tokens to be transferred
*/functiontransferFrom(addressfrom, address to, uint256 value)
publicreturns (bool)
{
_transfer(from, to, value);
_approve(from, msg.sender, _allowed[from][msg.sender].sub(value));
returntrue;
}
/**
* @dev Increase the amount of tokens that an owner allowed to a spender.
* approve should be called when _allowed[msg.sender][spender] == 0. To increment
* allowed value is better to use this function to avoid 2 calls (and wait until
* the first transaction is mined)
* From MonolithDAO Token.sol
* Emits an Approval event.
* @param spender The address which will spend the funds.
* @param addedValue The amount of tokens to increase the allowance by.
*/functionincreaseAllowance(address spender, uint256 addedValue)
publicreturns (bool)
{
_approve(
msg.sender,
spender,
_allowed[msg.sender][spender].add(addedValue)
);
returntrue;
}
/**
* @dev Decrease the amount of tokens that an owner allowed to a spender.
* approve should be called when _allowed[msg.sender][spender] == 0. To decrement
* allowed value is better to use this function to avoid 2 calls (and wait until
* the first transaction is mined)
* From MonolithDAO Token.sol
* Emits an Approval event.
* @param spender The address which will spend the funds.
* @param subtractedValue The amount of tokens to decrease the allowance by.
*/functiondecreaseAllowance(address spender, uint256 subtractedValue)
publicreturns (bool)
{
_approve(
msg.sender,
spender,
_allowed[msg.sender][spender].sub(subtractedValue)
);
returntrue;
}
/**
* @dev Transfer token for a specified addresses.
* @param from The address to transfer from.
* @param to The address to transfer to.
* @param value The amount to be transferred.
*/function_transfer(addressfrom, address to, uint256 value) internal{
require(to !=address(0), "ERC20: transfer to the zero address");
_balances[from] = _balances[from].sub(value);
_balances[to] = _balances[to].add(value);
emit Transfer(from, to, value);
}
/**
* @dev Internal function that mints an amount of the token and assigns it to
* an account. This encapsulates the modification of balances such that the
* proper events are emitted.
* @param account The account that will receive the created tokens.
* @param value The amount that will be created.
*/function_mint(address account, uint256 value) internal{
require(account !=address(0), "ERC20: mint to the zero address");
_totalSupply = _totalSupply.add(value);
_balances[account] = _balances[account].add(value);
emit Transfer(address(0), account, value);
}
/**
* @dev Internal function that burns an amount of the token of a given
* account.
* @param account The account whose tokens will be burnt.
* @param value The amount that will be burnt.
*/function_burn(address account, uint256 value) internal{
require(account !=address(0), "ERC20: burn from the zero address");
_totalSupply = _totalSupply.sub(value);
_balances[account] = _balances[account].sub(value);
emit Transfer(account, address(0), value);
}
/**
* @dev Approve an address to spend another addresses' tokens.
* @param owner The address that owns the tokens.
* @param spender The address that will spend the tokens.
* @param value The number of tokens that can be spent.
*/function_approve(address owner, address spender, uint256 value) internal{
require(owner !=address(0), "ERC20: approve from the zero address");
require(spender !=address(0), "ERC20: approve to the zero address");
_allowed[owner][spender] = value;
emit Approval(owner, spender, value);
}
/**
* @dev Internal function that burns an amount of the token of a given
* account, deducting from the sender's allowance for said account. Uses the
* internal burn function.
* Emits an Approval event (reflecting the reduced allowance).
* @param account The account whose tokens will be burnt.
* @param value The amount that will be burnt.
*/function_burnFrom(address account, uint256 value) internal{
_burn(account, value);
_approve(account, msg.sender, _allowed[account][msg.sender].sub(value));
}
}
Contract Source Code
File 3 of 5: Ownable.sol
pragmasolidity ^0.5.13;/**
* @title Ownable
* @dev The Ownable contract has an owner address, and provides basic authorization control
* functions, this simplifies the implementation of "user permissions".
*/contractOwnable{
addressprivate _owner;
eventOwnershipTransferred(addressindexed previousOwner,
addressindexed newOwner
);
/**
* @dev The Ownable constructor sets the original `owner` of the contract to the sender
* account.
*/constructor() internal{
_owner =msg.sender;
emit OwnershipTransferred(address(0), _owner);
}
/**
* @return the address of the owner.
*/functionowner() publicviewreturns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/modifieronlyOwner() {
require(isOwner(), "Ownable: caller is not the owner");
_;
}
/**
* @return true if `msg.sender` is the owner of the contract.
*/functionisOwner() publicviewreturns (bool) {
returnmsg.sender== _owner;
}
/**
* @dev Allows the current owner to relinquish control of the contract.
* It will not be possible to call the functions with the `onlyOwner`
* modifier anymore.
* @notice Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/functionrenounceOwnership() publiconlyOwner{
emit OwnershipTransferred(_owner, address(0));
_owner =address(0);
}
/**
* @dev Allows the current owner to transfer control of the contract to a newOwner.
* @param newOwner The address to transfer ownership to.
*/functiontransferOwnership(address newOwner) publiconlyOwner{
_transferOwnership(newOwner);
}
/**
* @dev Transfers control of the contract to a newOwner.
* @param newOwner The address to transfer ownership to.
*/function_transferOwnership(address newOwner) internal{
require(
newOwner !=address(0),
"Ownable: new owner is the zero address"
);
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
Contract Source Code
File 4 of 5: SafeMath.sol
pragmasolidity ^0.5.13;/**
* @title SafeMath
* @dev Unsigned math operations with safety checks that revert on error.
*/librarySafeMath{
/**
* @dev Multiplies two unsigned integers, reverts on overflow.
*/functionmul(uint256 a, uint256 b) internalpurereturns (uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the// benefit is lost if 'b' is also tested.// See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522if (a ==0) {
return0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
*/functiondiv(uint256 a, uint256 b) internalpurereturns (uint256) {
// Solidity only automatically asserts when dividing by 0require(b >0, "SafeMath: division by zero");
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't holdreturn c;
}
/**
* @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
*/functionsub(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b <= a, "SafeMath: subtraction overflow");
uint256 c = a - b;
return c;
}
/**
* @dev Adds two unsigned integers, reverts on overflow.
*/functionadd(uint256 a, uint256 b) internalpurereturns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
* reverts when dividing by zero.
*/functionmod(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b !=0, "SafeMath: modulo by zero");
return a % b;
}
}
Contract Source Code
File 5 of 5: StableCoin.sol
pragmasolidity ^0.5.13;import"./ERC20.sol";
import"./DateTime.sol";
import"./Ownable.sol";
contractStableCoinisERC20, DateTime, Ownable{
usingSafeMathforuint256;
addresspublic tokenIssuer;
uint256public lastOxydationDate;
eventOxydated(address holder, uint256 amount);
eventTimestampComparaison(uint256 newTimestamp, uint256 oldTimestamp);
constructor(stringmemory _tokenName,
stringmemory _tokenSymbol,
uint8 _decimals,
address _tokenIssuer
) publicERC20(_tokenName, _tokenSymbol, _decimals) Ownable() {
lastOxydationDate =now;
tokenIssuer = _tokenIssuer;
}
// change address that get fees from oxydationfunctionsetTokenIssuer(address _addressVeraOneFees) publiconlyOwner{
tokenIssuer = _addressVeraOneFees;
}
functionmint(address _to, uint256 _tokenAmount) publiconlyOwner{
_mint(_to, _tokenAmount);
}
//Mint tokens to each each beneficiaryfunctionmints(address[] calldata _recipients, uint256[] calldata _values) externalonlyOwner{
for (uint256 i =0; i < _recipients.length; i++) {
mint(_recipients[i], _values[i]);
}
}
functionburn(address _account, uint256 _value) publiconlyOwner{
_burn(_account, _value);
}
//Burn tokens to each each beneficiaryfunctionburns(address[] calldata _recipients, uint256[] calldata _values) externalonlyOwner{
for (uint256 i =0; i < _recipients.length; i++) {
burn(_recipients[i], _values[i]);
}
}
// can accept etherfunction() externalpayable{}
// give number of ether owned by smart contractfunctiongetBalanceEthSmartContract() publicviewreturns (uint256) {
returnaddress(this).balance;
}
// transfer smart contract balance to ownerfunctionwithdrawEther(uint256 amount) publiconlyOwner{
addresspayable ownerPayable =address(uint160(Ownable.owner()));
ownerPayable.transfer(amount);
}
// monthly oxydation for all investorsfunctionoxydation(address[] calldata holders) external{
for (uint256 i =0; i < holders.length; i++) {
emit TimestampComparaison(getMonth(lastOxydationDate), getMonth(now));
if (getMonth(lastOxydationDate) != getMonth(now)) {
// once a monthuint256 balanceCurrent = balanceOf(holders[i]);
uint256 toOxyde = balanceCurrent.div(1200); // 1% annual over 12 months
_burn(holders[i], toOxyde);
_mint(tokenIssuer, toOxyde);
emit Oxydated(holders[i], toOxyde);
}
}
lastOxydationDate =now;
}
functionNow() externalviewreturns (uint256){
return (now);
}
}