Contract Source Code:
File 1 of 1 : OceanToken
pragma solidity 0.5.3;
/**
* @title ERC20 interface
* @dev see https://github.com/ethereum/EIPs/issues/20
*/
interface IERC20 {
function transfer(address to, uint256 value) external returns (bool);
function approve(address spender, uint256 value) external returns (bool);
function transferFrom(address from, address to, uint256 value) external returns (bool);
function totalSupply() external view returns (uint256);
function balanceOf(address who) external view returns (uint256);
function allowance(address owner, address spender) external view returns (uint256);
event Transfer(address indexed from, address indexed to, uint256 value);
event Approval(address indexed owner, address indexed spender, uint256 value);
}
/**
* @title SafeMath
* @dev Unsigned math operations with safety checks that revert on error
*/
library SafeMath {
/**
* @dev Multiplies two unsigned integers, reverts on overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (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/522
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b);
return c;
}
/**
* @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
require(b <= a);
uint256 c = a - b;
return c;
}
/**
* @dev Adds two unsigned integers, reverts on overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a);
return c;
}
/**
* @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
* reverts when dividing by zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
require(b != 0);
return a % b;
}
}
/**
* @title Standard ERC20 token
*
* @dev Implementation of the basic standard token.
* https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
* 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.
*/
contract ERC20 is IERC20 {
using SafeMath for uint256;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowed;
uint256 private _totalSupply;
/**
* @dev Total number of tokens in existence
*/
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
/**
* @dev Gets the balance of the specified address.
* @param owner The address to query the balance of.
* @return An uint256 representing the amount owned by the passed address.
*/
function balanceOf(address owner) public view returns (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.
*/
function allowance(address owner, address spender) public view returns (uint256) {
return _allowed[owner][spender];
}
/**
* @dev Transfer token for a specified address
* @param to The address to transfer to.
* @param value The amount to be transferred.
*/
function transfer(address to, uint256 value) public returns (bool) {
_transfer(msg.sender, to, value);
return true;
}
/**
* @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.
*/
function approve(address spender, uint256 value) public returns (bool) {
require(spender != address(0));
_allowed[msg.sender][spender] = value;
emit Approval(msg.sender, spender, value);
return true;
}
/**
* @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
*/
function transferFrom(address from, address to, uint256 value) public returns (bool) {
_allowed[from][msg.sender] = _allowed[from][msg.sender].sub(value);
_transfer(from, to, value);
emit Approval(from, msg.sender, _allowed[from][msg.sender]);
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)
* 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.
*/
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
require(spender != address(0));
_allowed[msg.sender][spender] = _allowed[msg.sender][spender].add(addedValue);
emit Approval(msg.sender, spender, _allowed[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)
* 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.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
require(spender != address(0));
_allowed[msg.sender][spender] = _allowed[msg.sender][spender].sub(subtractedValue);
emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
return true;
}
/**
* @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(address from, address to, uint256 value) internal {
require(to != address(0));
_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));
_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));
_totalSupply = _totalSupply.sub(value);
_balances[account] = _balances[account].sub(value);
emit Transfer(account, address(0), 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 {
_allowed[account][msg.sender] = _allowed[account][msg.sender].sub(value);
_burn(account, value);
emit Approval(account, msg.sender, _allowed[account][msg.sender]);
}
}
/**
* @title Roles
* @dev Library for managing addresses assigned to a Role.
*/
library Roles {
struct Role {
mapping (address => bool) bearer;
}
/**
* @dev give an account access to this role
*/
function add(Role storage role, address account) internal {
require(account != address(0));
require(!has(role, account));
role.bearer[account] = true;
}
/**
* @dev remove an account's access to this role
*/
function remove(Role storage role, address account) internal {
require(account != address(0));
require(has(role, account));
role.bearer[account] = false;
}
/**
* @dev check if an account has this role
* @return bool
*/
function has(Role storage role, address account) internal view returns (bool) {
require(account != address(0));
return role.bearer[account];
}
}
contract MinterRole {
using Roles for Roles.Role;
event MinterAdded(address indexed account);
event MinterRemoved(address indexed account);
Roles.Role private _minters;
constructor () internal {
_addMinter(msg.sender);
}
modifier onlyMinter() {
require(isMinter(msg.sender));
_;
}
function isMinter(address account) public view returns (bool) {
return _minters.has(account);
}
function addMinter(address account) public onlyMinter {
_addMinter(account);
}
function renounceMinter() public {
_removeMinter(msg.sender);
}
function _addMinter(address account) internal {
_minters.add(account);
emit MinterAdded(account);
}
function _removeMinter(address account) internal {
_minters.remove(account);
emit MinterRemoved(account);
}
}
/**
* @title ERC20Mintable
* @dev ERC20 minting logic
*/
contract ERC20Mintable is ERC20, MinterRole {
/**
* @dev Function to mint tokens
* @param to The address that will receive the minted tokens.
* @param value The amount of tokens to mint.
* @return A boolean that indicates if the operation was successful.
*/
function mint(address to, uint256 value) public onlyMinter returns (bool) {
_mint(to, value);
return true;
}
}
/**
* @title Capped token
* @dev Mintable token with a token cap.
*/
contract ERC20Capped is ERC20Mintable {
uint256 private _cap;
constructor (uint256 cap) public {
require(cap > 0);
_cap = cap;
}
/**
* @return the cap for the token minting.
*/
function cap() public view returns (uint256) {
return _cap;
}
function _mint(address account, uint256 value) internal {
require(totalSupply().add(value) <= _cap);
super._mint(account, value);
}
}
/**
* @title ERC20Detailed token
* @dev The decimals are only for visualization purposes.
* All the operations are done using the smallest and indivisible token unit,
* just as on Ethereum all the operations are done in wei.
*/
contract ERC20Detailed is IERC20 {
string private _name;
string private _symbol;
uint8 private _decimals;
constructor (string memory name, string memory symbol, uint8 decimals) public {
_name = name;
_symbol = symbol;
_decimals = decimals;
}
/**
* @return the name of the token.
*/
function name() public view returns (string memory) {
return _name;
}
/**
* @return the symbol of the token.
*/
function symbol() public view returns (string memory) {
return _symbol;
}
/**
* @return the number of decimals of the token.
*/
function decimals() public view returns (uint8) {
return _decimals;
}
}
contract PauserRole {
using Roles for Roles.Role;
event PauserAdded(address indexed account);
event PauserRemoved(address indexed account);
Roles.Role private _pausers;
constructor () internal {
_addPauser(msg.sender);
}
modifier onlyPauser() {
require(isPauser(msg.sender));
_;
}
function isPauser(address account) public view returns (bool) {
return _pausers.has(account);
}
function addPauser(address account) public onlyPauser {
_addPauser(account);
}
function renouncePauser() public {
_removePauser(msg.sender);
}
function _addPauser(address account) internal {
_pausers.add(account);
emit PauserAdded(account);
}
function _removePauser(address account) internal {
_pausers.remove(account);
emit PauserRemoved(account);
}
}
/**
* @title Pausable
* @dev Base contract which allows children to implement an emergency stop mechanism.
*/
contract Pausable is PauserRole {
event Paused(address account);
event Unpaused(address account);
bool private _paused;
constructor () internal {
_paused = false;
}
/**
* @return true if the contract is paused, false otherwise.
*/
function paused() public view returns (bool) {
return _paused;
}
/**
* @dev Modifier to make a function callable only when the contract is not paused.
*/
modifier whenNotPaused() {
require(!_paused);
_;
}
/**
* @dev Modifier to make a function callable only when the contract is paused.
*/
modifier whenPaused() {
require(_paused);
_;
}
/**
* @dev called by the owner to pause, triggers stopped state
*/
function pause() public onlyPauser whenNotPaused {
_paused = true;
emit Paused(msg.sender);
}
/**
* @dev called by the owner to unpause, returns to normal state
*/
function unpause() public onlyPauser whenPaused {
_paused = false;
emit Unpaused(msg.sender);
}
}
/**
* @title Pausable token
* @dev ERC20 modified with pausable transfers.
**/
contract ERC20Pausable is ERC20, Pausable {
function transfer(address to, uint256 value) public whenNotPaused returns (bool) {
return super.transfer(to, value);
}
function transferFrom(address from, address to, uint256 value) public whenNotPaused returns (bool) {
return super.transferFrom(from, to, value);
}
function approve(address spender, uint256 value) public whenNotPaused returns (bool) {
return super.approve(spender, value);
}
function increaseAllowance(address spender, uint addedValue) public whenNotPaused returns (bool success) {
return super.increaseAllowance(spender, addedValue);
}
function decreaseAllowance(address spender, uint subtractedValue) public whenNotPaused returns (bool success) {
return super.decreaseAllowance(spender, subtractedValue);
}
}
/**
* @title Ownable
* @dev The Ownable contract has an owner address, and provides basic authorization control
* functions, this simplifies the implementation of "user permissions".
*/
contract Ownable {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed 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.
*/
function owner() public view returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(isOwner());
_;
}
/**
* @return true if `msg.sender` is the owner of the contract.
*/
function isOwner() public view returns (bool) {
return msg.sender == _owner;
}
/**
* @dev Allows the current owner to relinquish control of the contract.
* @notice Renouncing to ownership will leave the contract without an owner.
* It will not be possible to call the functions with the `onlyOwner`
* modifier anymore.
*/
function renounceOwnership() public onlyOwner {
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.
*/
function transferOwnership(address newOwner) public onlyOwner {
_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));
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
/**
* @title Ocean Protocol ERC20 Token Contract
* @author Ocean Protocol Team
* @dev Implementation of the Ocean Token.
*/
contract OceanToken is Ownable, ERC20Pausable, ERC20Detailed, ERC20Capped {
using SafeMath for uint256;
uint8 constant DECIMALS = 18;
uint256 constant CAP = 1410000000;
uint256 TOTALSUPPLY = CAP.mul(uint256(10) ** DECIMALS);
// keep track token holders
address[] private accounts = new address[](0);
mapping(address => bool) private tokenHolders;
/**
* @dev Ocean Token constructor
* @param contractOwner refers to the owner of the contract
*/
constructor(
address contractOwner
)
public
ERC20Detailed('Ocean Token', 'OCEAN', DECIMALS)
ERC20Capped(TOTALSUPPLY)
Ownable()
{
addPauser(contractOwner);
renouncePauser();
addMinter(contractOwner);
renounceMinter();
transferOwnership(contractOwner);
}
/**
* @dev transfer tokens when not paused (pausable transfer function)
* @param _to receiver address
* @param _value amount of tokens
* @return true if receiver is illegible to receive tokens
*/
function transfer(
address _to,
uint256 _value
)
public
returns (bool)
{
bool success = super.transfer(_to, _value);
if (success) {
updateTokenHolders(msg.sender, _to);
}
return success;
}
/**
* @dev transferFrom transfers tokens only when token is not paused
* @param _from sender address
* @param _to receiver address
* @param _value amount of tokens
* @return true if receiver is illegible to receive tokens
*/
function transferFrom(
address _from,
address _to,
uint256 _value
)
public
returns (bool)
{
bool success = super.transferFrom(_from, _to, _value);
if (success) {
updateTokenHolders(_from, _to);
}
return success;
}
/**
* @dev retrieve the address & token balance of token holders (each time retrieve partial from the list)
* @param _start index
* @param _end index
* @return array of accounts and array of balances
*/
function getAccounts(
uint256 _start,
uint256 _end
)
external
view
onlyOwner
returns (address[] memory, uint256[] memory)
{
require(
_start <= _end && _end < accounts.length,
'Array index out of bounds'
);
uint256 length = _end.sub(_start).add(1);
address[] memory _tokenHolders = new address[](length);
uint256[] memory _tokenBalances = new uint256[](length);
for (uint256 i = _start; i <= _end; i++)
{
address account = accounts[i];
uint256 accountBalance = super.balanceOf(account);
if (accountBalance > 0)
{
_tokenBalances[i] = accountBalance;
_tokenHolders[i] = account;
}
}
return (_tokenHolders, _tokenBalances);
}
/**
* @dev get length of account list
*/
function getAccountsLength()
external
view
onlyOwner
returns (uint256)
{
return accounts.length;
}
/**
* @dev kill the contract and destroy all tokens
*/
function kill()
external
onlyOwner
{
selfdestruct(address(uint160(owner())));
}
/**
* @dev fallback function prevents ether transfer to this contract
*/
function()
external
payable
{
revert('Invalid ether transfer');
}
/*
* @dev tryToAddTokenHolder try to add the account to the token holders structure
* @param account address
*/
function tryToAddTokenHolder(
address account
)
private
{
if (!tokenHolders[account] && super.balanceOf(account) > 0)
{
accounts.push(account);
tokenHolders[account] = true;
}
}
/*
* @dev updateTokenHolders maintains the accounts array and set the address as a promising token holder
* @param sender address
* @param receiver address.
*/
function updateTokenHolders(
address sender,
address receiver
)
private
{
tryToAddTokenHolder(sender);
tryToAddTokenHolder(receiver);
}
}