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pragma solidity ^0.4.13; | |
library SafeMath { | |
function mul(uint256 a, uint256 b) internal constant returns (uint256) { | |
uint256 c = a * b; | |
assert(a == 0 || c / a == b); | |
return c; | |
} | |
function div(uint256 a, uint256 b) internal constant 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; | |
} | |
function sub(uint256 a, uint256 b) internal constant returns (uint256) { | |
assert(b <= a); | |
return a - b; | |
} | |
function add(uint256 a, uint256 b) internal constant returns (uint256) { | |
uint256 c = a + b; | |
assert(c >= a); | |
return c; | |
} | |
} | |
contract Ownable { | |
address public owner; | |
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner); | |
/** | |
* @dev The Ownable constructor sets the original `owner` of the contract to the sender | |
* account. | |
*/ | |
function Ownable() { | |
owner = msg.sender; | |
} | |
/** | |
* @dev Throws if called by any account other than the owner. | |
*/ | |
modifier onlyOwner() { | |
require(msg.sender == owner); | |
_; | |
} | |
/** | |
* @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) onlyOwner public { | |
require(newOwner != address(0)); | |
OwnershipTransferred(owner, newOwner); | |
owner = newOwner; | |
} | |
} | |
contract ERC20Basic { | |
uint256 public totalSupply; | |
function balanceOf(address who) public constant returns (uint256); | |
function transfer(address to, uint256 value) public returns (bool); | |
event Transfer(address indexed from, address indexed to, uint256 value); | |
} | |
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)); | |
// SafeMath.sub will throw if there is not enough balance. | |
balances[msg.sender] = balances[msg.sender].sub(_value); | |
balances[_to] = balances[_to].add(_value); | |
Transfer(msg.sender, _to, _value); | |
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 constant returns (uint256 balance) { | |
return balances[_owner]; | |
} | |
} | |
contract ERC20 is ERC20Basic { | |
function allowance(address owner, address spender) public constant 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); | |
} | |
contract StandardToken is ERC20, BasicToken { | |
mapping (address => mapping (address => uint256)) 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)); | |
uint256 _allowance = allowed[_from][msg.sender]; | |
// Check is not needed because sub(_allowance, _value) will already throw if this condition is not met | |
// require (_value <= _allowance); | |
balances[_from] = balances[_from].sub(_value); | |
balances[_to] = balances[_to].add(_value); | |
allowed[_from][msg.sender] = _allowance.sub(_value); | |
Transfer(_from, _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) { | |
allowed[msg.sender][_spender] = _value; | |
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 constant returns (uint256 remaining) { | |
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) | |
* From MonolithDAO Token.sol | |
*/ | |
function increaseApproval (address _spender, uint _addedValue) | |
returns (bool success) { | |
allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue); | |
Approval(msg.sender, _spender, allowed[msg.sender][_spender]); | |
return true; | |
} | |
function decreaseApproval (address _spender, uint _subtractedValue) | |
returns (bool success) { | |
uint oldValue = allowed[msg.sender][_spender]; | |
if (_subtractedValue > oldValue) { | |
allowed[msg.sender][_spender] = 0; | |
} else { | |
allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue); | |
} | |
Approval(msg.sender, _spender, allowed[msg.sender][_spender]); | |
return true; | |
} | |
} | |
contract VeTokenizedAsset is StandardToken, Ownable { | |
//--- Definitions | |
using SafeMath for uint256; | |
//--- Storage | |
bool public configured; | |
string public symbol; | |
string public name; | |
string public description; | |
uint256 public decimals; | |
string public source; | |
string public proof; | |
uint256 public totalSupply; | |
//--- Construction | |
function VeTokenizedAsset() { | |
// asset should be parametrized using `setup()` function | |
} | |
//--- Events | |
event SourceChanged(string newSource, string newProof, uint256 newTotalSupply); | |
event SupplyChanged(uint256 newTotalSupply); | |
//--- Public mutable functions | |
function setup( | |
string _symbol, | |
string _name, | |
string _description, | |
uint256 _decimals, | |
string _source, | |
string _proof, | |
uint256 _totalSupply | |
) | |
public | |
onlyOwner | |
{ | |
require(!configured); | |
require(bytes(_symbol).length > 0); | |
require(bytes(_name).length > 0); | |
require(_decimals > 0 && _decimals <= 32); | |
symbol = _symbol; | |
name = _name; | |
description = _description; | |
decimals = _decimals; | |
source = _source; | |
proof = _proof; | |
totalSupply = _totalSupply; | |
configured = true; | |
balances[owner] = _totalSupply; | |
SourceChanged(_source, _proof, _totalSupply); | |
} | |
function changeSource(string newSource, string newProof, uint256 newTotalSupply) onlyOwner { | |
uint256 prevBalance = balances[owner]; | |
if (newTotalSupply < totalSupply) { | |
uint256 decrease = totalSupply.sub(newTotalSupply); | |
balances[owner] = prevBalance.sub(decrease); // throws when balance is insufficient | |
} else if (newTotalSupply > totalSupply) { | |
uint256 increase = newTotalSupply.sub(totalSupply); | |
balances[owner] = prevBalance.add(increase); | |
} | |
source = newSource; | |
proof = newProof; | |
totalSupply = newTotalSupply; | |
SourceChanged(newSource, newProof, newTotalSupply); | |
} | |
function mint(uint256 amount) public onlyOwner { | |
require(amount > 0); | |
totalSupply = totalSupply.add(amount); | |
balances[owner] = balances[owner].add(amount); | |
SupplyChanged(totalSupply); | |
} | |
function burn(uint256 amount) public onlyOwner { | |
require(amount > 0); | |
require(amount <= balances[owner]); | |
totalSupply = totalSupply.sub(amount); | |
balances[owner] = balances[owner].sub(amount); // throws when balance is insufficient | |
SupplyChanged(totalSupply); | |
} | |
} | |
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