pragma solidity ^0.4.18;
contract ERC721 {
// Required methods
function approve(address _to, uint256 _tokenId) public;
function balanceOf(address _owner) public view returns (uint256 balance);
function implementsERC721() public pure returns (bool);
function ownerOf(uint256 _tokenId) public view returns (address addr);
function takeOwnership(uint256 _tokenId) public;
function totalSupply() public view returns (uint256 total);
function transferFrom(address _from, address _to, uint256 _tokenId) public;
function transfer(address _to, uint256 _tokenId) public;
event Transfer(address indexed from, address indexed to, uint256 tokenId);
event Approval(address indexed owner, address indexed approved, uint256 tokenId);
}
contract CodeToken is ERC721 {
/*** EVENTS ***/
/// @dev The Birth event is fired whenever a new codetoken comes into existence.
event Birth(uint256 tokenId, string name, address owner);
/// @dev The TokenSold event is fired whenever a token is sold.
event TokenSold(uint256 tokenId, uint256 oldPrice, uint256 newPrice, address prevOwner, address winner, string name);
/// @dev Transfer event as defined in current draft of ERC721.
/// ownership is assigned, including births.
event Transfer(address from, address to, uint256 tokenId);
/*** CONSTANTS ***/
/// @notice Name and symbol of the non fungible token, as defined in ERC721.
string public constant NAME = "CodeToken";
string public constant SYMBOL = "CT";
uint256 private startingPrice = 0.05 ether;
/*** STORAGE ***/
/// @dev A mapping from codetoken IDs to the address that owns them. All codetokens have
/// some valid owner address.
mapping (uint256 => address) public codetokenIndexToOwner;
// @dev A mapping from owner address to count of tokens that address owns.
// Used internally inside balanceOf() to resolve ownership count.
mapping (address => uint256) private ownershipTokenCount;
/// @dev A mapping from CodeIDs to an address that has been approved to call
/// transferFrom(). Each Code can only have one approved address for transfer
/// at any time. A zero value means no approval is outstanding.
mapping (uint256 => address) public codetokenIndexToApproved;
// @dev A mapping from CodeIDs to the price of the token.
mapping (uint256 => uint256) private codetokenIndexToPrice;
address public creator;
/*** DATATYPES ***/
struct Code {
string name;
}
Code[] private codetokens;
modifier onlyCreator() {
require(msg.sender == creator);
_;
}
function CodeToken() public {
creator = msg.sender;
}
/*** PUBLIC FUNCTIONS ***/
/// @notice Grant another address the right to transfer token via takeOwnership() and transferFrom().
/// @param _to The address to be granted transfer approval. Pass address(0) to
/// clear all approvals.
/// @param _tokenId The ID of the Token that can be transferred if this call succeeds.
/// @dev Required for ERC-721 compliance.
function approve(
address _to,
uint256 _tokenId
) public {
// Caller must own token.
require(_owns(msg.sender, _tokenId));
codetokenIndexToApproved[_tokenId] = _to;
Approval(msg.sender, _to, _tokenId);
}
/// For querying balance of a particular account
/// @param _owner The address for balance query
/// @dev Required for ERC-721 compliance.
function balanceOf(address _owner) public view returns (uint256 balance) {
return ownershipTokenCount[_owner];
}
function createCodeContract(string _name) public onlyCreator {
_createCode(_name, address(this), startingPrice);
}
/// @notice Returns all the relevant information about a specific codetoken.
/// @param _tokenId The tokenId of the codetoken of interest.
function getCodeToken(uint256 _tokenId) public view returns (
string codetokenName,
uint256 sellingPrice,
address owner
) {
Code storage codetoken = codetokens[_tokenId];
codetokenName = codetoken.name;
sellingPrice = codetokenIndexToPrice[_tokenId];
owner = codetokenIndexToOwner[_tokenId];
}
function implementsERC721() public pure returns (bool) {
return true;
}
/// @dev Required for ERC-721 compliance.
function name() public pure returns (string) {
return NAME;
}
/// For querying owner of token
/// @param _tokenId The tokenID for owner inquiry
/// @dev Required for ERC-721 compliance.
function ownerOf(uint256 _tokenId)
public
view
returns (address owner)
{
owner = codetokenIndexToOwner[_tokenId];
require(owner != address(0));
}
function payout(address _to) public onlyCreator {
_payout(_to);
}
// Allows someone to send ether and obtain the token
function purchase(uint256 _tokenId) public payable {
address oldOwner = codetokenIndexToOwner[_tokenId];
address newOwner = msg.sender;
uint256 sellingPrice = codetokenIndexToPrice[_tokenId];
// Making sure token owner is not sending to self
require(oldOwner != newOwner);
// Safety check to prevent against an unexpected 0x0 default.
require(_addressNotNull(newOwner));
// Making sure sent amount is greater than or equal to the sellingPrice
require(msg.value >= sellingPrice);
uint256 payment = uint256(SafeMath.div(SafeMath.mul(sellingPrice, 92), 100));
uint256 purchaseExcess = SafeMath.sub(msg.value, sellingPrice);
codetokenIndexToPrice[_tokenId] = SafeMath.div(SafeMath.mul(sellingPrice, 120), 92);
_transfer(oldOwner, newOwner, _tokenId);
// Pay previous tokenOwner if owner is not contract
if (oldOwner != address(this)) {
oldOwner.transfer(payment);
}
TokenSold(_tokenId, sellingPrice, codetokenIndexToPrice[_tokenId], oldOwner, newOwner, codetokens[_tokenId].name);
msg.sender.transfer(purchaseExcess);
}
function priceOf(uint256 _tokenId) public view returns (uint256 price) {
return codetokenIndexToPrice[_tokenId];
}
function setCreator(address _creator) public onlyCreator {
require(_creator != address(0));
creator = _creator;
}
/// @dev Required for ERC-721 compliance.
function symbol() public pure returns (string) {
return SYMBOL;
}
/// @notice Allow pre-approved user to take ownership of a token
/// @param _tokenId The ID of the Token that can be transferred if this call succeeds.
/// @dev Required for ERC-721 compliance.
function takeOwnership(uint256 _tokenId) public {
address newOwner = msg.sender;
address oldOwner = codetokenIndexToOwner[_tokenId];
// Safety check to prevent against an unexpected 0x0 default.
require(_addressNotNull(newOwner));
// Making sure transfer is approved
require(_approved(newOwner, _tokenId));
_transfer(oldOwner, newOwner, _tokenId);
}
/// For querying totalSupply of token
/// @dev Required for ERC-721 compliance.
function totalSupply() public view returns (uint256 total) {
return codetokens.length;
}
/// Owner initates the transfer of the token to another account
/// @param _to The address for the token to be transferred to.
/// @param _tokenId The ID of the Token that can be transferred if this call succeeds.
/// @dev Required for ERC-721 compliance.
function transfer(
address _to,
uint256 _tokenId
) public {
require(_owns(msg.sender, _tokenId));
require(_addressNotNull(_to));
_transfer(msg.sender, _to, _tokenId);
}
/// Third-party initiates transfer of token from address _from to address _to
/// @param _from The address for the token to be transferred from.
/// @param _to The address for the token to be transferred to.
/// @param _tokenId The ID of the Token that can be transferred if this call succeeds.
/// @dev Required for ERC-721 compliance.
function transferFrom(
address _from,
address _to,
uint256 _tokenId
) public {
require(_owns(_from, _tokenId));
require(_approved(_to, _tokenId));
require(_addressNotNull(_to));
_transfer(_from, _to, _tokenId);
}
/*** PRIVATE FUNCTIONS ***/
/// Safety check on _to address to prevent against an unexpected 0x0 default.
function _addressNotNull(address _to) private pure returns (bool) {
return _to != address(0);
}
/// For checking approval of transfer for address _to
function _approved(address _to, uint256 _tokenId) private view returns (bool) {
return codetokenIndexToApproved[_tokenId] == _to;
}
/// For creating Code Token
function _createCode(string _name, address _owner, uint256 _price) private {
Code memory _codetoken = Code({
name: _name
});
uint256 newCodeId = codetokens.push(_codetoken) - 1;
// It's probably never going to happen, 4 billion tokens are A LOT, but
// let's just be 100% sure we never let this happen.
require(newCodeId == uint256(uint32(newCodeId)));
Birth(newCodeId, _name, _owner);
codetokenIndexToPrice[newCodeId] = _price;
// This will assign ownership, and also emit the Transfer event as
// per ERC721 draft
_transfer(address(0), _owner, newCodeId);
}
/// Check for token ownership
function _owns(address claimant, uint256 _tokenId) private view returns (bool) {
return claimant == codetokenIndexToOwner[_tokenId];
}
/// For paying out balance on contract
function _payout(address _to) private {
if (_to == address(0)) {
creator.transfer(this.balance);
} else {
_to.transfer(this.balance);
}
}
/// @dev Assigns ownership of a specific Code to an address.
function _transfer(address _from, address _to, uint256 _tokenId) private {
// Since the number of codetokens is capped to 2^32 we can't overflow this
ownershipTokenCount[_to]++;
//transfer ownership
codetokenIndexToOwner[_tokenId] = _to;
// When creating new codetokens _from is 0x0, but we can't account that address.
if (_from != address(0)) {
ownershipTokenCount[_from]--;
// clear any previously approved ownership exchange
delete codetokenIndexToApproved[_tokenId];
}
// Emit the transfer event.
Transfer(_from, _to, _tokenId);
}
}
library SafeMath {
/**
* @dev Multiplies two numbers, throws on overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
uint256 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) {
// 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;
}
/**
* @dev Substracts 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) {
uint256 c = a + b;
assert(c >= a);
return c;
}
}
{
"compilationTarget": {
"CodeToken.sol": "CodeToken"
},
"libraries": {},
"optimizer": {
"enabled": false,
"runs": 200
},
"remappings": []
}
[{"constant":true,"inputs":[],"name":"creator","outputs":[{"name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"pure","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_tokenId","type":"uint256"}],"name":"approve","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"}],"name":"payout","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"implementsERC721","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"pure","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"total","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"uint256"}],"name":"codetokenIndexToOwner","outputs":[{"name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_from","type":"address"},{"name":"_to","type":"address"},{"name":"_tokenId","type":"uint256"}],"name":"transferFrom","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_creator","type":"address"}],"name":"setCreator","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_tokenId","type":"uint256"}],"name":"ownerOf","outputs":[{"name":"owner","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"}],"name":"balanceOf","outputs":[{"name":"balance","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"pure","type":"function"},{"constant":true,"inputs":[],"name":"NAME","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_tokenId","type":"uint256"}],"name":"transfer","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_tokenId","type":"uint256"}],"name":"takeOwnership","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_tokenId","type":"uint256"}],"name":"priceOf","outputs":[{"name":"price","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"_tokenId","type":"uint256"}],"name":"getCodeToken","outputs":[{"name":"codetokenName","type":"string"},{"name":"sellingPrice","type":"uint256"},{"name":"owner","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"string"}],"name":"createCodeContract","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_tokenId","type":"uint256"}],"name":"purchase","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":true,"inputs":[],"name":"SYMBOL","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"uint256"}],"name":"codetokenIndexToApproved","outputs":[{"name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"inputs":[],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"name":"tokenId","type":"uint256"},{"indexed":false,"name":"name","type":"string"},{"indexed":false,"name":"owner","type":"address"}],"name":"Birth","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"tokenId","type":"uint256"},{"indexed":false,"name":"oldPrice","type":"uint256"},{"indexed":false,"name":"newPrice","type":"uint256"},{"indexed":false,"name":"prevOwner","type":"address"},{"indexed":false,"name":"winner","type":"address"},{"indexed":false,"name":"name","type":"string"}],"name":"TokenSold","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"from","type":"address"},{"indexed":false,"name":"to","type":"address"},{"indexed":false,"name":"tokenId","type":"uint256"}],"name":"Transfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"owner","type":"address"},{"indexed":true,"name":"approved","type":"address"},{"indexed":false,"name":"tokenId","type":"uint256"}],"name":"Approval","type":"event"}]