Contract Source Code:
File 1 of 1 : GERA
/**
*Submitted for verification at Etherscan.io on 2020-10-30
*/
pragma solidity ^0.5.0;
library SafeMath{
/**
* Returns the addition of two unsigned integers, reverting on
* overflow.
*
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, errorMessage);
return c;
}
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
}
contract owned {
address public owner;
constructor() public {
owner = msg.sender;
}
modifier onlyOwner {
require(msg.sender == owner,"ERC20: Required Owner !");
_;
}
function transferOwnership(address newOwner) onlyOwner public {
require (newOwner != address(0),"ERC20 New Owner cannot be zero address");
owner = newOwner;
}
}
interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes calldata _extraData) external ; }
contract TOKENERC20 {
using SafeMath for uint256;
event TransferEnabled (bool);
event TransferDisabled (bool);
// Public variables of the token
string public name;
string public symbol;
uint8 public decimals = 18;
// 18 decimals is the strongly suggested default, avoid changing it
uint256 public totalSupply;
/* This generates a public event on the blockchain that will notify clients */
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
event Mint(address indexed from, uint256 value);
constructor(
uint256 initialSupply,
string memory tokenName,
string memory tokenSymbol
) public {
totalSupply = initialSupply * 10 ** uint256(decimals); // Update total supply with the decimal amount
balanceOf[msg.sender] = totalSupply; // Give the creator all initial tokens
name = tokenName; // Set the name for display purposes
symbol = tokenSymbol; // Set the symbol for display purposes
TransferAllowed = true;
}
// This creates an array with all balances
mapping (address => uint256) public balanceOf;
mapping (address => mapping (address => uint256)) private _allowance;
mapping (address => bool) public LockList;
mapping (address => uint256) public LockedTokens;
bool public TransferAllowed;
// This generates a public event on the blockchain that will notify clients
event Transfer(address indexed from, address indexed to, uint256 value);
// This notifies clients about the amount burnt
event Burn(address indexed from, uint256 value);
/* Internal transfer, only can be called by this contract */
function _transfer(address _from, address _to, uint256 _value) internal {
uint256 stage;
require(_from != address(0), "ERC20: transfer from the zero address");
require(_to != address(0), "ERC20: transfer to the zero address"); // Prevent transfer to 0x0 address. Use burn() instead
require (LockList[msg.sender] == false,"ERC20: Caller Locked !"); // Check if msg.sender is locked or not
require (LockList[_from] == false, "ERC20: Sender Locked !");
require (LockList[_to] == false,"ERC20: Receipient Locked !");
require (TransferAllowed == true,"ERC20: Transfer enabled false !");
// Check if sender balance is locked
stage=balanceOf[_from].sub(_value, "ERC20: transfer amount exceeds balance");
require (stage >= LockedTokens[_from],"ERC20: transfer amount exceeds Senders Locked Amount");
//Deduct and add balance
balanceOf[_from]=stage;
balanceOf[_to]=balanceOf[_to].add(_value,"ERC20: Addition overflow");
//emit Transfer event
emit Transfer(_from, _to, _value);
}
/**
* Sets `amount` as the allowance of `spender` over the `owner`s tokens.
*
* This is internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(address owner, address _spender, uint256 amount) internal {
require(owner != address(0), "ERC20: approve from the zero address");
require(_spender != address(0), "ERC20: approve to the zero address");
_allowance[owner][_spender] = amount;
emit Approval(owner, _spender, amount);
}
/**
* Transfer tokens
*
* Send `_value` tokens to `_to` from your account
*
* @param _to The address of the recipient
* @param _value the amount to send
*/
function transfer(address _to, uint256 _value) public returns(bool){
_transfer(msg.sender, _to, _value);
return true;
}
function burn(uint256 _value) public returns(bool){
require (LockList[msg.sender] == false,"ERC20: User Locked !");
uint256 stage;
stage=balanceOf[msg.sender].sub(_value, "ERC20: transfer amount exceeds balance");
require (stage >= LockedTokens[msg.sender],"ERC20: transfer amount exceeds Senders Locked Amount");
balanceOf[msg.sender]=balanceOf[msg.sender].sub(_value,"ERC20: Burn amount exceeds balance.");
totalSupply=totalSupply.sub(_value,"ERC20: Burn amount exceeds total supply");
emit Burn(msg.sender, _value);
emit Transfer(msg.sender, address(0), _value);
return true;
}
/**
* Destroy tokens
*
* Remove `_value` tokens from the system irreversibly
*
* @param Account address
*
* @param _value the amount of money to burn
*
* Safely check if total supply is not overdrawn
*/
function burnFrom(address Account, uint256 _value) public returns (bool success) {
require (LockList[msg.sender] == false,"ERC20: User Locked !");
require (LockList[Account] == false,"ERC20: Owner Locked !");
uint256 stage;
require(Account != address(0), "ERC20: Burn from the zero address");
_approve(Account, msg.sender, _allowance[Account][msg.sender].sub(_value,"ERC20: burn amount exceeds allowance"));
//Do not allow burn if Accounts tokens are locked.
stage=balanceOf[Account].sub(_value,"ERC20: Transfer amount exceeds allowance");
require(stage>=LockedTokens[Account],"ERC20: Burn amount exceeds accounts locked amount");
balanceOf[Account] =stage ; // Subtract from the sender
//Deduct burn amount from totalSupply
totalSupply=totalSupply.sub(_value,"ERC20: Burn Amount exceeds totalSupply");
emit Burn(Account, _value);
emit Transfer(Account, address(0), _value);
return true;
}
/**
* Transfer tokens from other address
*
* Send `_value` tokens to `_to` on behalf of `_from`
*
* @param _from The address of the sender
* @param _to The address of the recipient
* @param _value the amount to send
*/
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
_transfer(_from, _to, _value);
_approve(_from,msg.sender,_allowance[_from][msg.sender].sub(_value,"ERC20: transfer amount exceeds allowance"));
return true;
}
/**
* Set allowance for other address
*
* Allows `_spender` to spend no more than `_value` tokens in your behalf
* Emits Approval Event
* @param _spender The address authorized to spend
* @param _value the max amount they can spend
*/
function approve(address _spender, uint256 _value) public
returns (bool success) {
uint256 unapprovbal;
// Do not allow approval if amount exceeds locked amount
unapprovbal=balanceOf[msg.sender].sub(_value,"ERC20: Allowance exceeds balance of approver");
require(unapprovbal>=LockedTokens[msg.sender],"ERC20: Approval amount exceeds locked amount ");
_allowance[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
/**
* Set allowance for other address and notify
*
* Allows `_spender` to spend no more than `_value` tokens in your behalf, and then ping the contract about it
*
* @param _spender The address authorized to spend
* @param _value the max amount they can spend
* @param _extraData some extra information to send to the approved contract
*/
function approveAndCall(address _spender, uint256 _value, bytes memory _extraData)
public
returns (bool success) {
tokenRecipient spender = tokenRecipient(_spender);
if (approve(_spender, _value)) {
spender.receiveApproval(msg.sender, _value, address(this), _extraData);
return true;
}
}
function allowance(address _owner,address _spender) public view returns(uint256){
return _allowance[_owner][_spender];
}
}
contract GERA is owned, TOKENERC20 {
/* Initializes contract with initial supply tokens to the creator of the contract */
constructor () TOKENERC20(
8800000000 * 1 ** uint256(decimals),
"Gera",
"GERA") public {
}
/**
* User Lock
*
* @param Account the address of account to lock for transaction
*
* @param mode true or false for lock mode
*
*/
function UserLock(address Account, bool mode) onlyOwner public {
LockList[Account] = mode;
}
/**
* Lock tokens
*
* @param Account the address of account to lock
*
* @param amount the amount of money to lock
*
*
*/
function LockTokens(address Account, uint256 amount) onlyOwner public{
LockedTokens[Account]=amount;
}
function UnLockTokens(address Account) onlyOwner public{
LockedTokens[Account]=0;
}
/**
* Mintable, Destroy tokens
*
* Remove `_value` tokens from the system irreversibly
*
* @param _value the amount of money to burn
*/
function mint(uint256 _value) onlyOwner public returns (bool success) {
require(balanceOf[msg.sender] >= _value);
require(balanceOf[msg.sender] != 0x0); // Check if the sender has enough
balanceOf[msg.sender]=balanceOf[msg.sender].add(_value,"ERC20: Addition overflow"); // Subtract from the sender
totalSupply=totalSupply.add(_value,"ERC20: totalSupply increased ");
emit Mint(msg.sender, _value);
return true;
}
/**
* Airdrop tokens
*
* Remove `_value` tokens from the system irreversibly
*
* @param _value the amount with decimals(18)
*
*/
mapping (address => uint256) public airDropHistory;
event AirDrop(address _receiver, uint256 _amount);
function dropToken(address[] memory receivers, uint256[] memory values) onlyOwner public {
require(receivers.length != 0);
require(receivers.length == values.length);
for (uint256 i = 0; i < receivers.length; i++) {
address receiver = receivers[i];
uint256 amount = values[i];
transfer(receiver, amount);
airDropHistory[receiver] += amount;
emit AirDrop(receiver, amount);
}
}
/// Set whether transfer is enabled or disabled
function enableTokenTransfer() onlyOwner public {
TransferAllowed = true;
emit TransferEnabled (true);
}
function disableTokenTransfer() onlyOwner public {
TransferAllowed = false;
emit TransferDisabled (true);
}
}