本次的优化，增加了追加发币功能，和暂停交易功能（暂停所有用户的交易）。
pragma solidity ^0.4.24; /** * @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 c) { if (a == 0) { return 0; } 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) { return a / b; } /** * @dev Subtracts 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 c) { c = a + b; assert(c >= a); return c; }}/** * @title ERC20Basic * @dev Simpler version of ERC20 interface * @dev see https://github.com/ethereum/EIPs/issues/179 */contract ERC20Basic { uint256 public totalSupply; function balanceOf(address who) public view returns (uint256); function transfer(address to, uint256 value) public returns (bool); event Transfer(address indexed from, address indexed to, uint256 value);}/** * @title ERC20 interface * @dev see https://github.com/ethereum/EIPs/issues/20 */contract ERC20 is ERC20Basic { function allowance(address owner, address spender) public view returns (uint256); function transferFrom(address from, address to, uint256 value) public returns (bool); function approve(address spender, uint256 value) public returns (bool); event Approval(address indexed owner, address indexed spender, uint256 value);}/** * @title Basic token * @dev Basic version of StandardToken, with no allowances. */contract BasicToken is ERC20Basic { using SafeMath for uint256; mapping(address => uint256) balances; /** * @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) { require(_to != address(0)); require(_value <= balances[msg.sender]); uint previousBalances = balances[msg.sender] + balances[_to]; // SafeMath.sub will throw if there is not enough balance. balances[msg.sender] = balances[msg.sender].sub(_value); balances[_to] = balances[_to].add(_value); emit Transfer(msg.sender, _to, _value); assert(balances[msg.sender] + balances[_to] == previousBalances); return true; } /** * @dev Gets the balance of the specified address. * @param _owner The address to query the the balance of. * @return An uint256 representing the amount owned by the passed address. */ function balanceOf(address _owner) public view returns (uint256 balance) { return balances[_owner]; }}/** * @title Standard ERC20 token * * @dev Implementation of the basic standard token. * @dev https://github.com/ethereum/EIPs/issues/20 * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol */contract StandardToken is ERC20, BasicToken { mapping (address => mapping (address => uint256)) internal allowed; /** * @dev Transfer tokens from one address to another * @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) { require(_to != address(0)); require(_value <= balances[_from]); require(_value <= allowed[_from][msg.sender]); uint previousBalances = balances[_from] + balances[_to]; balances[_from] = balances[_from].sub(_value); balances[_to] = balances[_to].add(_value); allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value); emit Transfer(_from, _to, _value); assert(balances[_from] + balances[_to] == previousBalances); 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) { allowed[msg.sender][_spender] = _value; emit Approval(msg.sender, _spender, _value); return true; } /** * @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]; } /** * 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) */ function increaseApproval(address _spender, uint _addedValue) public returns (bool) { allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue); emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]); return true; } function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) { uint oldValue = allowed[msg.sender][_spender]; if (_subtractedValue > oldValue) { allowed[msg.sender][_spender] = 0; } else { allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue); } emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]); return true; }}/** * @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 public owner; /** * @dev The Ownable constructor sets the original `owner` of the contract to the sender * account. */ constructor() public{ owner = msg.sender; } /** * @dev Throws if called by any account other than the owner. */ modifier onlyOwner() { require(msg.sender == owner); _; }}/** * @title Pausable * @dev Base contract which allows children to implement an emergency stop mechanism. */contract Pausable is Ownable { event Pause(); event Unpause(); bool public paused = false; /** * @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() onlyOwner whenNotPaused public { paused = true; emit Pause(); } /** * @dev called by the owner to unpause, returns to normal state */ function unpause() onlyOwner whenPaused public { paused = false; emit Unpause(); }}/** * @title Mintable token * @dev Simple ERC20 Token example, with mintable token creation * Based on code by TokenMarketNet: https://github.com/TokenMarketNet/ico/blob/master/contracts/MintableToken.sol */contract MintableToken is StandardToken, Pausable { event Mint(address indexed to, uint256 amount); event MintFinished(); bool public mintingFinished = false; modifier canMint() { require(!mintingFinished); _; } modifier hasMintPermission() { require(msg.sender == owner); _; } /** * @dev Function to mint tokens * @param _to The address that will receive the minted tokens. * @param _amount The amount of tokens to mint. * @return A boolean that indicates if the operation was successful. */ function mint( address _to, uint256 _amount ) hasMintPermission canMint public returns (bool) { totalSupply = totalSupply.add(_amount); balances[_to] = balances[_to].add(_amount); emit Mint(_to, _amount); emit Transfer(address(0), _to, _amount); return true; } /** * @dev Function to stop minting new tokens. * @return True if the operation was successful. */ function finishMinting() onlyOwner canMint public returns (bool) { mintingFinished = true; emit MintFinished(); return true; }}/** * @title Burnable Token * @dev Token that can be irreversibly burned (destroyed). */contract BurnableToken is MintableToken { event Burn(address indexed burner, uint256 value); /** * @dev Burns a specific amount of tokens. * @param _value The amount of token to be burned. */ function burn(uint256 _value) public { _burn(msg.sender, _value); } function _burn(address _who, uint256 _value) internal { require(_value <= balances[_who]); // no need to require value <= totalSupply, since that would imply the // sender's balance is greater than the totalSupply, which *should* be an assertion failure balances[_who] = balances[_who].sub(_value); totalSupply = totalSupply.sub(_value); emit Burn(_who, _value); emit Transfer(_who, address(0), _value); }}/** * @title Pausable token * @dev StandardToken modified with pausable transfers. **/contract PausableToken is BurnableToken { 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 increaseApproval( address _spender, uint _addedValue ) public whenNotPaused returns (bool success) { return super.increaseApproval(_spender, _addedValue); } function decreaseApproval( address _spender, uint _subtractedValue ) public whenNotPaused returns (bool success) { return super.decreaseApproval(_spender, _subtractedValue); }}/** * @title RPHToken Token * * @dev Implementation of RPHToken Token based on the basic standard token. */contract RPHToken is PausableToken{ function () public { //if ether is sent to this address, send it back. revert(); } /** * Public variables of the token * The following variables are OPTIONAL vanities. One does not have to include them. * They allow one to customise the token contract & in no way influences the core functionality. * Some wallets/interfaces might not even bother to look at this information. */ string public name; uint8 public decimals=18; string public symbol; string public version = '1.0.0'; /** * @dev Function to check the amount of tokens that an owner allowed to a spender. * @param _totalSupply total supply of the token. * @param _name token name e.g RPHT Token. * @param _symbol token symbol e.g RPHT. */ constructor(uint256 _totalSupply, string _name, string _symbol) public { totalSupply = _totalSupply * 10 ** uint256(decimals); balances[msg.sender] = totalSupply; // Give the creator all initial tokens name = _name; symbol = _symbol; }}复制代码