Contract Name:
FairExchange
Contract Source Code:
File 1 of 1 : FairExchange
pragma solidity ^0.4.25;
/*
*
* https://fairdapp.com/exchange/ https://fairdapp.com/exchange/ https://fairdapp.com/exchange/
*
* _______ _ ______ _______ ______ ______
* (_______) (_) (______)(_______|_____ (_____ \
* _____ _____ _ ____ _ _ _______ _____) )____) )
* | ___|____ | |/ ___) | | | ___ | ____/ ____/
* | | / ___ | | | | |__/ /| | | | | | |
* |_| \_____|_|_| |_____/ |_| |_|_| |_|
*
* _______ _
* (_______) | |
* _____ _ _ ____| |__ _____ ____ ____ _____
* | ___) ( \ / ) ___) _ \(____ | _ \ / _ | ___ |
* | |_____ ) X ( (___| | | / ___ | | | ( (_| | ____|
* |_______|_/ \_)____)_| |_\_____|_| |_|\___ |_____)
* (_____|
* Warning:
*
* This contract is intended to link DAPPs on the FairDAPP platform.
* All could be lost by sending anything to this contract address.
* All users are prohibited to interact with this contract if this
* contract is in conflict with user’s local regulations or laws.
*
* Original code by TEAM JUST
* Original concept by Dr. Jochen Hoenicke
* Modified by the FairDAPP community with more scalable and fairer settings.
*
*/
contract FairExchange {
using NameFilter for string;
/*=================================
= MODIFIERS =
=================================*/
// only people with tokens
modifier onlyBagholders() {
require(myTokens() > 0);
_;
}
// only people with profits
modifier onlyStronghands() {
require(myDividends(true) > 0);
_;
}
// administrators can:
// -> change the name of the contract
// -> change the name of the token
// -> Allow contracts to use transfer functions
// they CANNOT:
// -> take funds
// -> disable withdrawals
// -> kill the contract
// -> change the price of tokens
modifier onlyAdministrator(){
address _customerAddress = msg.sender;
require(administrators[keccak256(abi.encodePacked(_customerAddress))]);
_;
}
modifier buyVerify(uint256 _amountOfEthereum){
if((totalEthereumBalance() - _amountOfEthereum) < whaleBalanceLimit)
require(tx.gasprice <= gaspriceMax);
address _customerAddress = msg.sender;
if(onlyAmbassadors && now <= startTime)
require(ambassadors_[_customerAddress]);
else{
if(onlyAmbassadors)
onlyAmbassadors = false;
if((totalEthereumBalance() - _amountOfEthereum) < whaleBalanceLimit)
require(_amountOfEthereum <= maxEarlyStake);
}
_;
}
/*==============================
= EVENTS =
==============================*/
event onTokenPurchase(
address indexed customerAddress,
uint256 incomingEthereum,
uint256 tokensMinted,
address indexed referredBy
);
event onTokenSell(
address indexed customerAddress,
uint256 tokensBurned,
uint256 ethereumEarned
);
event onReinvestment(
address indexed customerAddress,
uint256 ethereumReinvested,
uint256 tokensMinted
);
event onWithdraw(
address indexed customerAddress,
uint256 ethereumWithdrawn
);
// ERC223
event Transfer(
address indexed from,
address indexed to,
uint256 tokens,
bytes data
);
/*=====================================
= CONFIGURABLES =
=====================================*/
string public name = "FairExchange";
string public symbol = "Fair";
uint8 constant public decimals = 18;
uint8 constant internal dividendFee_ = 10;
uint256 constant internal tokenPriceInitial_ = 0.0001 ether;
uint256 constant internal tokenPriceIncremental_ = 0.000000005 ether;
uint256 constant internal magnitude = 2**64;
uint256 public gaspriceMax = 20000000000;
uint256 public startTime = 1539478800;
/// @dev anti-early-whale
uint256 public maxEarlyStake = 2.5 ether;
uint256 public whaleBalanceLimit = 250 ether;
// private offering program
mapping(address => bool) internal ambassadors_;
/*================================
= DATASETS =
================================*/
// amount of shares for each address (scaled number)
mapping(address => uint256) internal tokenBalanceLedger_;
mapping(address => uint256) internal referralBalance_;
mapping(address => int256) internal payoutsTo_;
uint256 internal tokenSupply_ = 0;
uint256 internal profitPerShare_;
// administrator list (see above on what they can do)
mapping(bytes32 => bool) public administrators;
// when this is set to true, only ambassadors can purchase tokens (this prevents a whale premine, it ensures a fairly distributed upper pyramid)
bool public onlyAmbassadors = true;
mapping (address => bytes32) public register;
mapping (bytes32 => address) public userName;
mapping (address => bool) public user;
/*=======================================
= PUBLIC FUNCTIONS =
=======================================*/
/*
* -- APPLICATION ENTRY POINTS --
*/
constructor()
public
{
// add administrators here
administrators[0x851d084c805eabf5ec90588a0f5cade287038d80d52c510eefe81f320e97cdcc] = true;
// add the ambassadors here.
// max 113 ETH, 40% to developer, 60% to limited quota private sales
ambassadors_[0xbC817A495f0114755Da5305c5AA84fc5ca7ebaBd] = true;
}
function registered(string _userName)
public
{
address _customerAddress = msg.sender;
bytes32 _name = _userName.nameFilter();
require (_customerAddress == tx.origin, "sender does not meet the rules");
require(_name != bytes32(0), "name cannot be empty");
require(userName[_name] == address(0), "this name has already been registered");
require(register[_customerAddress] == bytes32(0), "please do not repeat registration");
userName[_name] = _customerAddress;
register[_customerAddress] = _name;
if(!user[_customerAddress])
user[_customerAddress] = true;
}
/**
* Converts all incoming ethereum to tokens for the caller, and passes down the referral addy (if any)
*/
function buy(address _referredBy)
buyVerify(msg.value)
public
payable
returns(uint256)
{
purchaseTokens(msg.value, _referredBy);
}
/**
* Converts all incoming ethereum to tokens for the caller, and passes down the referral addy (if any)
*/
function buyXname(string _referredName)
buyVerify(msg.value)
public
payable
returns(uint256)
{
purchaseTokens(msg.value, userName[_referredName.nameFilter()]);
}
/**
* Fallback function to handle ethereum that was send straight to the contract
* Unfortunately we cannot use a referral address this way.
*/
function()
buyVerify(msg.value)
payable
public
{
purchaseTokens(msg.value, 0x0);
}
/**
* Converts all of caller's dividends to tokens.
*/
function reinvest()
onlyStronghands()
public
{
// fetch dividends
uint256 _dividends = myDividends(false); // retrieve ref. bonus later in the code
// pay out the dividends virtually
address _customerAddress = msg.sender;
payoutsTo_[_customerAddress] += (int256) (_dividends * magnitude);
// retrieve ref. bonus
_dividends += referralBalance_[_customerAddress];
referralBalance_[_customerAddress] = 0;
// dispatch a buy order with the virtualized "withdrawn dividends"
uint256 _tokens = purchaseTokens(_dividends, 0x0);
// fire event
emit onReinvestment(_customerAddress, _dividends, _tokens);
}
/**
* Alias of sell() and withdraw().
*/
function exit()
public
{
// get token count for caller & sell them all
address _customerAddress = msg.sender;
uint256 _tokens = tokenBalanceLedger_[_customerAddress];
if(_tokens > 0) sell(_tokens);
// lambo delivery service
withdraw();
}
/**
* Withdraws all of the callers earnings.
*/
function withdraw()
onlyStronghands()
public
{
// setup data
address _customerAddress = msg.sender;
uint256 _dividends = myDividends(false); // get ref. bonus later in the code
// update dividend tracker
payoutsTo_[_customerAddress] += (int256) (_dividends * magnitude);
// add ref. bonus
_dividends += referralBalance_[_customerAddress];
referralBalance_[_customerAddress] = 0;
// lambo delivery service
_customerAddress.transfer(_dividends);
// fire event
emit onWithdraw(_customerAddress, _dividends);
}
/**
* Liquifies tokens to ethereum.
*/
function sell(uint256 _amountOfTokens)
onlyBagholders()
public
{
// setup data
address _customerAddress = msg.sender;
// russian hackers BTFO
require(_amountOfTokens <= tokenBalanceLedger_[_customerAddress]);
uint256 _tokens = _amountOfTokens;
uint256 _ethereum = tokensToEthereum_(_tokens);
uint256 _dividends = SafeMath.div(_ethereum, dividendFee_);
uint256 _taxedEthereum = SafeMath.sub(_ethereum, _dividends);
// burn the sold tokens
tokenSupply_ = SafeMath.sub(tokenSupply_, _tokens);
tokenBalanceLedger_[_customerAddress] = SafeMath.sub(tokenBalanceLedger_[_customerAddress], _tokens);
// update dividends tracker
int256 _updatedPayouts = (int256) (profitPerShare_ * _tokens + (_taxedEthereum * magnitude));
payoutsTo_[_customerAddress] -= _updatedPayouts;
// dividing by zero is a bad idea
if (tokenSupply_ > 0) {
// update the amount of dividends per token
profitPerShare_ = SafeMath.add(profitPerShare_, (_dividends * magnitude) / tokenSupply_);
}
// fire event
emit onTokenSell(_customerAddress, _tokens, _taxedEthereum);
}
/**
* ERC20 Transfer
* Contract address is blocked from using the transfer function
* Contact us to approve contracts for transfer
* Contracts will not be a registered user by default
* All contracts will be approved unless the contract is malicious
*/
function transfer(address _toAddress, uint256 _amountOfTokens)
onlyBagholders()
public
returns(bool)
{
// setup
address _customerAddress = msg.sender;
require(_amountOfTokens <= tokenBalanceLedger_[_customerAddress]);
require(user[_customerAddress]);
// withdraw all outstanding dividends first
if(myDividends(true) > 0) withdraw();
// exchange tokens
tokenBalanceLedger_[_customerAddress] = SafeMath.sub(tokenBalanceLedger_[_customerAddress], _amountOfTokens);
tokenBalanceLedger_[_toAddress] = SafeMath.add(tokenBalanceLedger_[_toAddress], _amountOfTokens);
// update dividend trackers
payoutsTo_[_customerAddress] -= (int256) (profitPerShare_ * _amountOfTokens);
payoutsTo_[_toAddress] += (int256) (profitPerShare_ * _amountOfTokens);
bytes memory _empty;
uint256 codeLength;
assembly {
codeLength := extcodesize(_toAddress)
}
if(codeLength > 0){
ERC223ReceivingContract receiver = ERC223ReceivingContract(_toAddress);
receiver.tokenFallback(_customerAddress, _amountOfTokens, _empty);
}
// fire event
emit Transfer(_customerAddress, _toAddress, _amountOfTokens, _empty);
// ERC20
return true;
}
/**
* ERC223 Transfer
* Contract address is blocked from using the transfer function
* Contact us to approve contracts for transfer
* Contracts will not be a registered user by default
* All contracts will be approved unless the contract is malicious
*/
function transfer(address _toAddress, uint256 _amountOfTokens, bytes _data)
onlyBagholders()
public
returns(bool)
{
// setup
address _customerAddress = msg.sender;
require(_amountOfTokens <= tokenBalanceLedger_[_customerAddress]);
require(user[_customerAddress]);
// withdraw all outstanding dividends first
if(myDividends(true) > 0) withdraw();
// exchange tokens
tokenBalanceLedger_[_customerAddress] = SafeMath.sub(tokenBalanceLedger_[_customerAddress], _amountOfTokens);
tokenBalanceLedger_[_toAddress] = SafeMath.add(tokenBalanceLedger_[_toAddress], _amountOfTokens);
// update dividend trackers
payoutsTo_[_customerAddress] -= (int256) (profitPerShare_ * _amountOfTokens);
payoutsTo_[_toAddress] += (int256) (profitPerShare_ * _amountOfTokens);
uint256 codeLength;
assembly {
codeLength := extcodesize(_toAddress)
}
if(codeLength > 0){
ERC223ReceivingContract receiver = ERC223ReceivingContract(_toAddress);
receiver.tokenFallback(_customerAddress, _amountOfTokens, _data);
}
// fire event
emit Transfer(_customerAddress, _toAddress, _amountOfTokens, _data);
// ERC223
return true;
}
/*---------- ADMINISTRATOR ONLY FUNCTIONS ----------*/
/**
* In case one of us dies, we need to replace ourselves.
*/
function setAdministrator(bytes32 _identifier, bool _status)
onlyAdministrator()
public
{
administrators[_identifier] = _status;
}
/**
* If we want to rebrand, we can.
*/
function setName(string _name)
onlyAdministrator()
public
{
name = _name;
}
/**
* If we want to rebrand, we can.
*/
function setSymbol(string _symbol)
onlyAdministrator()
public
{
symbol = _symbol;
}
/**
* Change start time.
*/
function setTimestamp(uint256 _timestamp)
onlyAdministrator()
public
{
require(now < 1541001600);
startTime = _timestamp;
}
/**
* Manually add a user to contract for transfer.
*/
function setUser(address[] _userAddress)
onlyAdministrator()
public
{
uint256 _length = _userAddress.length;
require(_length > 0);
for(uint256 i = 0; i < _length; i++){
if(!user[_userAddress[i]])
user[_userAddress[i]] = true;
}
}
/*---------- HELPERS AND CALCULATORS ----------*/
/**
* Method to view the current Ethereum stored in the contract
* Example: totalEthereumBalance()
*/
function totalEthereumBalance()
public
view
returns(uint)
{
return address(this).balance;
}
/**
* Retrieve the total token supply.
*/
function totalSupply()
public
view
returns(uint256)
{
return tokenSupply_;
}
/**
* Retrieve the tokens owned by the caller.
*/
function myTokens()
public
view
returns(uint256)
{
address _customerAddress = msg.sender;
return balanceOf(_customerAddress);
}
/**
* Retrieve the dividends owned by the caller.
* If `_includeReferralBonus` is to to 1/true, the referral bonus will be included in the calculations.
* The reason for this, is that in the frontend, we will want to get the total divs (global + ref)
* But in the internal calculations, we want them separate.
*/
function myDividends(bool _includeReferralBonus)
public
view
returns(uint256)
{
address _customerAddress = msg.sender;
return _includeReferralBonus ? dividendsOf(_customerAddress) + referralBalance_[_customerAddress] : dividendsOf(_customerAddress) ;
}
/**
* Retrieve the token balance of any single address.
*/
function balanceOf(address _customerAddress)
view
public
returns(uint256)
{
return tokenBalanceLedger_[_customerAddress];
}
/**
* Retrieve the dividend balance of any single address.
*/
function dividendsOf(address _customerAddress)
view
public
returns(uint256)
{
return (uint256) ((int256)(profitPerShare_ * tokenBalanceLedger_[_customerAddress]) - payoutsTo_[_customerAddress]) / magnitude;
}
/**
* Return the buy price of 1 individual token.
*/
function sellPrice()
public
view
returns(uint256)
{
// our calculation relies on the token supply, so we need supply. Doh.
if(tokenSupply_ == 0){
return tokenPriceInitial_ - tokenPriceIncremental_;
} else {
uint256 _ethereum = tokensToEthereum_(1e18);
uint256 _dividends = SafeMath.div(_ethereum, dividendFee_ );
uint256 _taxedEthereum = SafeMath.sub(_ethereum, _dividends);
return _taxedEthereum;
}
}
/**
* Return the sell price of 1 individual token.
*/
function buyPrice()
public
view
returns(uint256)
{
// our calculation relies on the token supply, so we need supply. Doh.
if(tokenSupply_ == 0){
return tokenPriceInitial_ + tokenPriceIncremental_;
} else {
uint256 _ethereum = tokensToEthereum_(1e18);
uint256 _dividends = SafeMath.div(_ethereum, dividendFee_ );
uint256 _taxedEthereum = SafeMath.add(_ethereum, _dividends);
return _taxedEthereum;
}
}
/**
* Function for the frontend to dynamically retrieve the price scaling of buy orders.
*/
function calculateTokensReceived(uint256 _ethereumToSpend)
public
view
returns(uint256)
{
uint256 _dividends = SafeMath.div(_ethereumToSpend, dividendFee_);
uint256 _taxedEthereum = SafeMath.sub(_ethereumToSpend, _dividends);
uint256 _amountOfTokens = ethereumToTokens_(_taxedEthereum);
return _amountOfTokens;
}
/**
* Function for the frontend to dynamically retrieve the price scaling of sell orders.
*/
function calculateEthereumReceived(uint256 _tokensToSell)
public
view
returns(uint256)
{
require(_tokensToSell <= tokenSupply_);
uint256 _ethereum = tokensToEthereum_(_tokensToSell);
uint256 _dividends = SafeMath.div(_ethereum, dividendFee_);
uint256 _taxedEthereum = SafeMath.sub(_ethereum, _dividends);
return _taxedEthereum;
}
/*==========================================
= INTERNAL FUNCTIONS =
==========================================*/
function purchaseTokens(uint256 _incomingEthereum, address _referredBy)
internal
returns(uint256)
{
// data setup
address _customerAddress = msg.sender;
uint256 _undividedDividends = SafeMath.div(_incomingEthereum, dividendFee_);
uint256 _referralBonus = SafeMath.div(_undividedDividends, 3);
uint256 _dividends = SafeMath.sub(_undividedDividends, _referralBonus);
uint256 _taxedEthereum = SafeMath.sub(_incomingEthereum, _undividedDividends);
uint256 _amountOfTokens = ethereumToTokens_(_taxedEthereum);
uint256 _fee = _dividends * magnitude;
require(_amountOfTokens > 0 && (SafeMath.add(_amountOfTokens,tokenSupply_) > tokenSupply_));
// is the user referred by a masternode?
if(
_referredBy != 0x0000000000000000000000000000000000000000 &&
_referredBy != _customerAddress &&
register[_referredBy] != bytes32(0)
){
// wealth redistribution
referralBalance_[_referredBy] = SafeMath.add(referralBalance_[_referredBy], _referralBonus);
} else {
// no ref purchase
// add the referral bonus back to the global dividends cake
_dividends = SafeMath.add(_dividends, _referralBonus);
_fee = _dividends * magnitude;
}
// we can't give people infinite ethereum
if(tokenSupply_ > 0){
// add tokens to the pool
tokenSupply_ = SafeMath.add(tokenSupply_, _amountOfTokens);
// take the amount of dividends gained through this transaction, and allocates them evenly to each shareholder
profitPerShare_ += (_dividends * magnitude / (tokenSupply_));
// calculate the amount of tokens the customer receives over his purchase
_fee = _fee - (_fee-(_amountOfTokens * (_dividends * magnitude / (tokenSupply_))));
} else {
// add tokens to the pool
tokenSupply_ = _amountOfTokens;
}
// update circulating supply & the ledger address for the customer
tokenBalanceLedger_[_customerAddress] = SafeMath.add(tokenBalanceLedger_[_customerAddress], _amountOfTokens);
// Tells the contract that the buyer doesn't deserve dividends for the tokens before they owned them;
//really i know you think you do but you don't
int256 _updatedPayouts = (int256) ((profitPerShare_ * _amountOfTokens) - _fee);
payoutsTo_[_customerAddress] += _updatedPayouts;
if(_customerAddress == tx.origin && !user[_customerAddress])
user[_customerAddress] = true;
// fire event
emit onTokenPurchase(_customerAddress, _incomingEthereum, _amountOfTokens, _referredBy);
return _amountOfTokens;
}
/**
* Calculate Token price based on an amount of incoming ethereum
* It's an algorithm, hopefully we gave you the whitepaper with it in scientific notation;
* Some conversions occurred to prevent decimal errors or underflows / overflows in solidity code.
*/
function ethereumToTokens_(uint256 _ethereum)
public
view
returns(uint256)
{
uint256 _tokenPriceInitial = tokenPriceInitial_ * 1e18;
uint256 _tokensReceived =
(
(
// underflow attempts BTFO
SafeMath.sub(
(sqrt
(
(_tokenPriceInitial**2)
+
(2*(tokenPriceIncremental_ * 1e18)*(_ethereum * 1e18))
+
(((tokenPriceIncremental_)**2)*(tokenSupply_**2))
+
(2*(tokenPriceIncremental_)*_tokenPriceInitial*tokenSupply_)
)
), _tokenPriceInitial
)
)/(tokenPriceIncremental_)
)-(tokenSupply_)
;
return _tokensReceived;
}
/**
* Calculate token sell value.
* It's an algorithm, hopefully we gave you the whitepaper with it in scientific notation;
* Some conversions occurred to prevent decimal errors or underflows / overflows in solidity code.
*/
function tokensToEthereum_(uint256 _tokens)
internal
view
returns(uint256)
{
uint256 tokens_ = (_tokens + 1e18);
uint256 _tokenSupply = (tokenSupply_ + 1e18);
uint256 _etherReceived =
(
// underflow attempts BTFO
SafeMath.sub(
(
(
(
tokenPriceInitial_ +(tokenPriceIncremental_ * (_tokenSupply/1e18))
)-tokenPriceIncremental_
)*(tokens_ - 1e18)
),(tokenPriceIncremental_*((tokens_**2-tokens_)/1e18))/2
)
/1e18);
return _etherReceived;
}
function sqrt(uint x) internal pure returns (uint y) {
uint z = (x + 1) / 2;
y = x;
while (z < y) {
y = z;
z = (x / z + z) / 2;
}
}
}
contract ERC223ReceivingContract {
function tokenFallback(address _from, uint256 _amountOfTokens, bytes _data) public returns (bool);
}
/**
* @title SafeMath
* @dev Math operations with safety checks that throw on error
*/
library SafeMath {
/**
* @dev Multiplies two numbers, throws on overflow.
*/
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;
}
/**
* @dev Integer division of two numbers, truncating the quotient.
*/
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;
}
/**
* @dev Substracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
assert(b <= a);
return a - b;
}
/**
* @dev Adds two numbers, throws on overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
assert(c >= a);
return c;
}
}
library NameFilter {
function nameFilter(string _input)
internal
pure
returns(bytes32)
{
bytes memory _temp = bytes(_input);
uint256 _length = _temp.length;
//sorry limited to 32 characters
require (_length <= 32 && _length > 3, "string must be between 4 and 32 characters");
// make sure first two characters are not 0x
if (_temp[0] == 0x30)
{
require(_temp[1] != 0x78, "string cannot start with 0x");
require(_temp[1] != 0x58, "string cannot start with 0X");
}
for (uint256 i = 0; i < _length; i++)
{
require
(
// OR uppercase A-Z
(_temp[i] > 0x40 && _temp[i] < 0x5b) ||
// OR lowercase a-z
(_temp[i] > 0x60 && _temp[i] < 0x7b) ||
// or 0-9
(_temp[i] > 0x2f && _temp[i] < 0x3a),
"string contains invalid characters"
);
}
bytes32 _ret;
assembly {
_ret := mload(add(_temp, 32))
}
return (_ret);
}
}