pragma solidity ^ 0.4 .24;

// ----------------------------------------------------------------------------
// 'SLD' 'Solid Sources Token' contract
//
// Symbol      : SLD
// Name        : Solid Sources Token
// Total supply: 500,000,000.000000000000000000
// Decimals    : 18
//
// ----------------------------------------------------------------------------

// ----------------------------------------------------------------------------
// 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
// ----------------------------------------------------------------------------

contract ERC20Interface {
    function totalSupply() public constant returns(uint);

    function balanceOf(address tokenOwner) public constant returns(uint balance);

    function allowance(address tokenOwner, address spender) public constant 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
// ----------------------------------------------------------------------------

contract ApproveAndCallFallBack {
    function receiveApproval(address from, uint256 tokens, address token, bytes 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 SolidSourcesToken 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;

    event Burn(address indexed burner, uint256 value);

    // ------------------------------------------------------------------------
    // Constructor
    // ------------------------------------------------------------------------

    constructor() public {
        symbol = "SLD";
        name = "Solid Sources Token";
        decimals = 18;
        _totalSupply = 500000000 * 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
    // ------------------------------------------------------------------------

    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;
    }

    //Burn tokens

    function burn(uint256 _value) public returns (bool success) {
        require(balances[msg.sender] >= _value);   // Check if the sender has enough
        balances[msg.sender] -= _value;            // Subtract from the sender
        _totalSupply -= _value;                      // Updates totalSupply
        emit Burn(msg.sender, _value);
        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 data) public returns(bool success) {
        allowed[msg.sender][spender] = tokens;
        emit Approval(msg.sender, spender, tokens);
        ApproveAndCallFallBack(spender).receiveApproval(msg.sender, tokens, this, data);
        return true;
    }

    // ------------------------------------------------------------------------
    // Don't accept ETH
    // ------------------------------------------------------------------------

    function() public 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);
    }
}