pragma solidity ^0.5.0; // ---------------------------------------------------------------------------- // 'FIXED' 'Example Fixed Supply Token' token contract // // Symbol : FIXED // Name : Example Fixed Supply Token // Total supply: 1,000,000.000000000000000000 // Decimals : 18 // // Enjoy. // // (c) BokkyPooBah / Bok Consulting Pty Ltd 2018. The MIT Licence. // ---------------------------------------------------------------------------- // ---------------------------------------------------------------------------- // Safe maths // ---------------------------------------------------------------------------- library SafeMath { function add(uint a, uint b) internal pure returns (uint c) { c = a + b; require(c >= a); } function sub(uint a, uint b) internal pure returns (uint c) { require(b <= a); c = a - b; } function mul(uint a, uint b) internal pure returns (uint c) { c = a * b; require(a == 0 || c / a == b); } function div(uint a, uint b) internal pure returns (uint c) { require(b > 0); c = a / b; } } // ---------------------------------------------------------------------------- // ERC Token Standard #20 Interface // https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md // ---------------------------------------------------------------------------- contract ERC20Interface { function totalSupply() public view returns (uint); function balanceOf(address tokenOwner) public view returns (uint balance); function allowance(address tokenOwner, address spender) public view returns (uint remaining); function transfer(address to, uint tokens) public returns (bool success); function approve(address spender, uint tokens) public returns (bool success); function transferFrom(address from, address to, uint tokens) public returns (bool success); event Transfer(address indexed from, address indexed to, uint tokens); event Approval(address indexed tokenOwner, address indexed spender, uint tokens); } // ---------------------------------------------------------------------------- // Contract function to receive approval and execute function in one call // // Borrowed from MiniMeToken // ---------------------------------------------------------------------------- contract ApproveAndCallFallBack { function receiveApproval(address from, uint256 tokens, address token, bytes memory data) public; } // ---------------------------------------------------------------------------- // Owned contract // ---------------------------------------------------------------------------- contract Owned { address public owner; address public newOwner; event OwnershipTransferred(address indexed _from, address indexed _to); constructor() public { owner = msg.sender; } modifier onlyOwner { require(msg.sender == owner); _; } function transferOwnership(address _newOwner) public onlyOwner { newOwner = _newOwner; } function acceptOwnership() public { require(msg.sender == newOwner); emit OwnershipTransferred(owner, newOwner); owner = newOwner; newOwner = address(0); } } // ---------------------------------------------------------------------------- // ERC20 Token, with the addition of symbol, name and decimals and a // fixed supply // ---------------------------------------------------------------------------- contract FixedSupplyToken is ERC20Interface, Owned { using SafeMath for uint; string public symbol; string public name; uint8 public decimals; uint _totalSupply; mapping(address => uint) balances; mapping(address => mapping(address => uint)) allowed; // ------------------------------------------------------------------------ // Constructor // ------------------------------------------------------------------------ constructor() public { symbol = "FIXED"; name = "Example Fixed Supply Token"; decimals = 18; _totalSupply = 1000000 * 10**uint(decimals); balances[owner] = _totalSupply; emit Transfer(address(0), owner, _totalSupply); } // ------------------------------------------------------------------------ // Total supply // ------------------------------------------------------------------------ function totalSupply() public view returns (uint) { return _totalSupply.sub(balances[address(0)]); } // ------------------------------------------------------------------------ // Get the token balance for account `tokenOwner` // ------------------------------------------------------------------------ function balanceOf(address tokenOwner) public view returns (uint balance) { return balances[tokenOwner]; } // ------------------------------------------------------------------------ // Transfer the balance from token owner's account to `to` account // - Owner's account must have sufficient balance to transfer // - 0 value transfers are allowed // ------------------------------------------------------------------------ function transfer(address to, uint tokens) public returns (bool success) { balances[msg.sender] = balances[msg.sender].sub(tokens); balances[to] = balances[to].add(tokens); emit Transfer(msg.sender, to, tokens); return true; } // ------------------------------------------------------------------------ // Token owner can approve for `spender` to transferFrom(...) `tokens` // from the token owner's account // // https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md // recommends that there are no checks for the approval double-spend attack // as this should be implemented in user interfaces // ------------------------------------------------------------------------ function approve(address spender, uint tokens) public returns (bool success) { allowed[msg.sender][spender] = tokens; emit Approval(msg.sender, spender, tokens); return true; } // ------------------------------------------------------------------------ // Transfer `tokens` from the `from` account to the `to` account // // The calling account must already have sufficient tokens approve(...)-d // for spending from the `from` account and // - From account must have sufficient balance to transfer // - Spender must have sufficient allowance to transfer // - 0 value transfers are allowed // ------------------------------------------------------------------------ function transferFrom(address from, address to, uint tokens) public returns (bool success) { balances[from] = balances[from].sub(tokens); allowed[from][msg.sender] = allowed[from][msg.sender].sub(tokens); balances[to] = balances[to].add(tokens); emit Transfer(from, to, tokens); return true; } // ------------------------------------------------------------------------ // Returns the amount of tokens approved by the owner that can be // transferred to the spender's account // ------------------------------------------------------------------------ function allowance(address tokenOwner, address spender) public view returns (uint remaining) { return allowed[tokenOwner][spender]; } // ------------------------------------------------------------------------ // Token owner can approve for `spender` to transferFrom(...) `tokens` // from the token owner's account. The `spender` contract function // `receiveApproval(...)` is then executed // ------------------------------------------------------------------------ function approveAndCall(address spender, uint tokens, bytes memory data) public returns (bool success) { allowed[msg.sender][spender] = tokens; emit Approval(msg.sender, spender, tokens); ApproveAndCallFallBack(spender).receiveApproval(msg.sender, tokens, address(this), data); return true; } // ------------------------------------------------------------------------ // Don't accept ETH // ------------------------------------------------------------------------ function () external payable { revert(); } // ------------------------------------------------------------------------ // Owner can transfer out any accidentally sent ERC20 tokens // ------------------------------------------------------------------------ function transferAnyERC20Token(address tokenAddress, uint tokens) public onlyOwner returns (bool success) { return ERC20Interface(tokenAddress).transfer(owner, tokens); } }