pragma solidity 0.5.6; /*
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// ----------------------------------------------------------------------------
// 'DlikeToken' contract with following features
// => ERC20 Compliance
// => Higher degree of control by owner - safeguard functionality
// => SafeMath implementation
// => Burnable and minting
// => in-built buy/sell functions (owner can control buying/selling process)
//
// Name : DlikeToken
// Symbol : DLIKE
// Total supply: 800,000,000 (800 Million)
// Decimals : 18
//
// Copyright 2019 onwards - Dlike ( https://dlike.io )
// Contract designed and audited by EtherAuthority ( https://EtherAuthority.io )
// Special thanks to openzeppelin for inspiration: ( https://github.com/OpenZeppelin )
// ----------------------------------------------------------------------------
*/
//*******************************************************************//
//------------------------ SafeMath Library -------------------------//
//*******************************************************************//
/**
* @title SafeMath
* @dev Math operations with safety checks that throw on error
*/
library SafeMath {
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
uint256 c = a * b;
assert(c / a == b);
return c;
}
function div(uint256 a, uint256 b) internal pure returns (uint256) {
// assert(b > 0); // Solidity automatically throws when dividing by 0
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
assert(b <= a);
return a - b;
}
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
assert(c >= a);
return c;
}
}
//*******************************************************************//
//------------------ Contract to Manage Ownership -------------------//
//*******************************************************************//
contract owned {
address payable internal owner;
constructor () public {
owner = msg.sender;
}
modifier onlyOwner {
require(msg.sender == owner);
_;
}
function transferOwnership(address payable newOwner) onlyOwner public {
owner = newOwner;
}
}
//****************************************************************************//
//--------------------- MAIN CODE STARTS HERE ---------------------//
//****************************************************************************//
contract DlikeToken is owned {
/*===============================
= DATA STORAGE =
===============================*/
// Public variables of the token
using SafeMath for uint256;
string constant public name = "DlikeToken";
string constant public symbol = "DLIKE";
uint256 constant public decimals = 18;
uint256 public totalSupply = 800000000 * (10**decimals); //800 million tokens
uint256 public maximumMinting;
bool public safeguard = false; //putting safeguard on will halt all non-owner functions
// This creates a mapping with all data storage
mapping (address => uint256) internal _balanceOf;
mapping (address => mapping (address => uint256)) internal _allowance;
mapping (address => bool) internal _frozenAccount;
/*===============================
= PUBLIC EVENTS =
===============================*/
// This generates a public event of token transfer
event Transfer(address indexed from, address indexed to, uint256 value);
// This will log approval of token Transfer
event Approval(address indexed from, address indexed spender, uint256 value);
// This notifies clients about the amount burnt
event Burn(address indexed from, uint256 value);
// This generates a public event for frozen (blacklisting) accounts
event FrozenFunds(address indexed target, bool indexed frozen);
/*======================================
= STANDARD ERC20 FUNCTIONS =
======================================*/
/**
* Check token balance of any user
*/
function balanceOf(address owner) public view returns (uint256) {
return _balanceOf[owner];
}
/**
* Check allowance of any spender versus owner
*/
function allowance(address owner, address spender) public view returns (uint256) {
return _allowance[owner][spender];
}
/**
* Check if particular user address is frozen or not
*/
function frozenAccount(address owner) public view returns (bool) {
return _frozenAccount[owner];
}
/**
* Internal transfer, only can be called by this contract
*/
function _transfer(address _from, address _to, uint _value) internal {
//checking conditions
require(!safeguard);
require (_to != address(0)); // Prevent transfer to 0x0 address. Use burn() instead
require(!_frozenAccount[_from]); // Check if sender is frozen
require(!_frozenAccount[_to]); // Check if recipient is frozen
// overflow and undeflow checked by SafeMath Library
_balanceOf[_from] = _balanceOf[_from].sub(_value); // Subtract from the sender
_balanceOf[_to] = _balanceOf[_to].add(_value); // Add the same to the recipient
// emit Transfer event
emit Transfer(_from, _to, _value);
}
/**
* 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 success) {
//no need to check for input validations, as that is ruled by SafeMath
_transfer(msg.sender, _to, _value);
return true;
}
/**
* Transfer tokens from other address
*
* Send `_value` tokens to `_to` in 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) {
require(_value <= _allowance[_from][msg.sender]); // Check _allowance
_allowance[_from][msg.sender] = _allowance[_from][msg.sender].sub(_value);
_transfer(_from, _to, _value);
return true;
}
/**
* Set _allowance for other address
*
* Allows `_spender` to spend no more than `_value` tokens in your behalf
*
* @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) {
require(!safeguard);
_allowance[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
/**
* @dev Increase the amount of tokens that an owner allowed to a spender.
* approve should be called when allowed_[_spender] == 0. To increment
* allowed value is better to use this function to avoid 2 calls (and wait until
* the first transaction is mined)
* Emits an Approval event.
* @param spender The address which will spend the funds.
* @param value The amount of tokens to increase the _allowance by.
*/
function increase_allowance(address spender, uint256 value) public returns (bool) {
require(spender != address(0));
_allowance[msg.sender][spender] = _allowance[msg.sender][spender].add(value);
emit Approval(msg.sender, spender, _allowance[msg.sender][spender]);
return true;
}
/**
* @dev Decrease the amount of tokens that an owner allowed to a spender.
* approve should be called when allowed_[_spender] == 0. To decrement
* allowed value is better to use this function to avoid 2 calls (and wait until
* the first transaction is mined)
* Emits an Approval event.
* @param spender The address which will spend the funds.
* @param value The amount of tokens to decrease the _allowance by.
*/
function decrease_allowance(address spender, uint256 value) public returns (bool) {
require(spender != address(0));
_allowance[msg.sender][spender] = _allowance[msg.sender][spender].sub(value);
emit Approval(msg.sender, spender, _allowance[msg.sender][spender]);
return true;
}
/*=====================================
= CUSTOM PUBLIC FUNCTIONS =
======================================*/
constructor() public{
//sending all the tokens to Owner
_balanceOf[owner] = totalSupply;
//maximum minting set to totalSupply
maximumMinting = totalSupply;
//firing event which logs this transaction
emit Transfer(address(0), owner, totalSupply);
}
/* No need for empty fallback function as contract without it will automatically rejects incoming ether */
//function () external payable { revert; }
/**
* Destroy tokens
*
* Remove `_value` tokens from the system irreversibly
*
* @param _value the amount of money to burn
*/
function burn(uint256 _value) public returns (bool success) {
require(!safeguard);
//checking of enough token balance is done by SafeMath
_balanceOf[msg.sender] = _balanceOf[msg.sender].sub(_value); // Subtract from the sender
totalSupply = totalSupply.sub(_value); // Updates totalSupply
emit Burn(msg.sender, _value);
return true;
}
/**
* Destroy tokens from other account
*
* Remove `_value` tokens from the system irreversibly on behalf of `_from`.
*
* @param _from the address of the sender
* @param _value the amount of money to burn
*/
function burnFrom(address _from, uint256 _value) public returns (bool success) {
require(!safeguard);
//checking of _allowance and token value is done by SafeMath
_balanceOf[_from] = _balanceOf[_from].sub(_value); // Subtract from the targeted balance
_allowance[_from][msg.sender] = _allowance[_from][msg.sender].sub(_value); // Subtract from the sender's _allowance
totalSupply = totalSupply.sub(_value); // Update totalSupply
emit Burn(_from, _value);
return true;
}
/**
* @notice `freeze? Prevent | Allow` `target` from sending & receiving tokens
* @param target Address to be frozen
* @param freeze either to freeze it or not
*/
function freezeAccount(address target, bool freeze) onlyOwner public {
_frozenAccount[target] = freeze;
emit FrozenFunds(target, freeze);
}
/**
* @notice Create `mintedAmount` tokens and send it to `target`
* @param target Address to receive the tokens
* @param mintedAmount the amount of tokens it will receive
*/
function mintToken(address target, uint256 mintedAmount) onlyOwner public {
totalSupply = totalSupply.add(mintedAmount);
//owner can not mint more than max supply of tokens, to prevent 'Evil Mint' issue!!
require(totalSupply <= maximumMinting, 'Minting reached its maximum minting limit' );
_balanceOf[target] = _balanceOf[target].add(mintedAmount);
emit Transfer(address(0), target, mintedAmount);
}
/**
* Owner can transfer tokens from contract to owner address
*
* When safeguard is true, then all the non-owner functions will stop working.
* When safeguard is false, then all the functions will resume working back again!
*/
function manualWithdrawTokens(uint256 tokenAmount) public onlyOwner{
// no need for overflow checking as that will be done in transfer function
_transfer(address(this), owner, tokenAmount);
}
//Just in rare case, owner wants to transfer Ether from contract to owner address
function manualWithdrawEther()onlyOwner public{
address(owner).transfer(address(this).balance);
}
/**
* Change safeguard status on or off
*
* When safeguard is true, then all the non-owner functions will stop working.
* When safeguard is false, then all the functions will resume working back again!
*/
function changeSafeguardStatus() onlyOwner public{
if (safeguard == false){
safeguard = true;
}
else{
safeguard = false;
}
}
}
{
"compilationTarget": {
"DlikeToken.sol": "DlikeToken"
},
"evmVersion": "petersburg",
"libraries": {},
"optimizer": {
"enabled": true,
"runs": 200
},
"remappings": []
}
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