Código Fuente del Contrato
Archivo 1 de 1: SkorchToken.sol
pragma solidity ^0.4.18;
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;
}
}
library ExtendedMath {
function limitLessThan(uint a, uint b) internal pure returns (uint c) {
if(a > b) return b;
return a;
}
}
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 ApproveAndCallFallBack {
function receiveApproval(address from, uint256 tokens, address token, bytes data) public;
}
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);
}
}
contract SkorchToken is ERC20Interface, Owned {
using SafeMath for uint;
using ExtendedMath for uint;
string public symbol;
string public name;
uint8 public decimals;
uint public _totalSupply;
uint public latestDifficultyPeriodStarted;
uint public epochCount;
uint public _BLOCKS_PER_READJUSTMENT = 1024;
uint public _MINIMUM_TARGET = 2**16;
uint public _MAXIMUM_TARGET = 2**234;
uint public miningTarget;
uint256 public MinimumPoStokens = 20000 * 10**uint(decimals);
bytes32 public challengeNumber;
uint public rewardEra;
uint public maxSupplyForEra;
address public lastRewardTo;
uint public lastRewardAmount;
uint public lastRewardEthBlockNumber;
mapping(bytes32 => bytes32) solutionForChallenge;
uint public tokensMinted;
mapping(address => uint) balances;
mapping(address => mapping(address => uint)) allowed;
mapping(address => uint256) timer;
uint256 doubleUnit = (31536000) * 1.2;
event Mint(address indexed from, uint reward_amount, uint epochCount, bytes32 newChallengeNumber);
constructor()
public
onlyOwner()
{
symbol = "SKO";
name = "Skorch Token";
decimals = 18;
_totalSupply = 21000000 * 10**uint(decimals);
tokensMinted = 0;
rewardEra = 0;
maxSupplyForEra = _totalSupply.div(2);
miningTarget = _MAXIMUM_TARGET;
latestDifficultyPeriodStarted = block.number;
_startNewMiningEpoch();
}
function setPosTokens(uint256 newTokens)
public
onlyOwner
{
require(newTokens >= 100000);
MinimumPoStokens = newTokens;
}
function mint(uint256 nonce, bytes32 challenge_digest) public returns (bool success) {
bytes32 digest = keccak256(challengeNumber, msg.sender, nonce );
if (digest != challenge_digest) revert();
if(uint256(digest) > miningTarget) revert();
bytes32 solution = solutionForChallenge[challengeNumber];
solutionForChallenge[challengeNumber] = digest;
if(solution != 0x0) revert();
_claimTokens(msg.sender);
uint reward_amount = getMiningReward();
balances[msg.sender] = balances[msg.sender].add(reward_amount);
tokensMinted = tokensMinted.add(reward_amount);
assert(tokensMinted <= maxSupplyForEra);
lastRewardTo = msg.sender;
lastRewardAmount = reward_amount;
lastRewardEthBlockNumber = block.number;
_startNewMiningEpoch();
emit Mint(msg.sender, reward_amount, epochCount, challengeNumber );
return true;
}
function _startNewMiningEpoch() internal {
if( tokensMinted.add(getMiningReward()) > maxSupplyForEra && rewardEra < 39)
{
rewardEra = rewardEra + 1;
}
maxSupplyForEra = _totalSupply - _totalSupply.div( 2**(rewardEra + 1));
epochCount = epochCount.add(1);
if(epochCount % _BLOCKS_PER_READJUSTMENT == 0)
{
_reAdjustDifficulty();
}
challengeNumber = block.blockhash(block.number - 1);
}
function _reAdjustDifficulty() internal {
uint ethBlocksSinceLastDifficultyPeriod = block.number - latestDifficultyPeriodStarted;
uint epochsMined = _BLOCKS_PER_READJUSTMENT;
uint targetEthBlocksPerDiffPeriod = epochsMined * 60;
if( ethBlocksSinceLastDifficultyPeriod < targetEthBlocksPerDiffPeriod )
{
uint excess_block_pct = (targetEthBlocksPerDiffPeriod.mul(100)).div( ethBlocksSinceLastDifficultyPeriod );
uint excess_block_pct_extra = excess_block_pct.sub(100).limitLessThan(1000);
miningTarget = miningTarget.sub(miningTarget.div(2000).mul(excess_block_pct_extra));
}else{
uint shortage_block_pct = (ethBlocksSinceLastDifficultyPeriod.mul(100)).div( targetEthBlocksPerDiffPeriod );
uint shortage_block_pct_extra = shortage_block_pct.sub(100).limitLessThan(1000);
miningTarget = miningTarget.add(miningTarget.div(2000).mul(shortage_block_pct_extra));
}
latestDifficultyPeriodStarted = block.number;
if(miningTarget < _MINIMUM_TARGET)
{
miningTarget = _MINIMUM_TARGET;
}
if(miningTarget > _MAXIMUM_TARGET)
{
miningTarget = _MAXIMUM_TARGET;
}
}
function getChallengeNumber() public constant returns (bytes32) {
return challengeNumber;
}
function getMiningDifficulty() public constant returns (uint) {
return _MAXIMUM_TARGET.div(miningTarget);
}
function getMiningTarget() public constant returns (uint) {
return miningTarget;
}
function getMiningReward() public constant returns (uint) {
return (50 * 10**uint(decimals) ).div( 2**rewardEra ) ;
}
function getMintDigest(uint256 nonce, bytes32 challenge_digest, bytes32 challenge_number) public view returns (bytes32 digesttest) {
bytes32 digest = keccak256(challenge_number,msg.sender,nonce);
return digest;
}
function checkMintSolution(uint256 nonce, bytes32 challenge_digest, bytes32 challenge_number, uint testTarget) public view returns (bool success) {
bytes32 digest = keccak256(challenge_number,msg.sender,nonce);
if(uint256(digest) > testTarget) revert();
return (digest == challenge_digest);
}
function totalSupply() public constant returns (uint) {
return _totalSupply;
}
function balanceOf(address tokenOwner) public constant returns (uint balance) {
return balances[tokenOwner];
}
function transfer(address to, uint tokens) public returns (bool success) {
_claimTokens(msg.sender);
_claimTokens(to);
balances[msg.sender] = balances[msg.sender].sub(tokens);
balances[to] = balances[to].add(tokens);
emit Transfer(msg.sender, to, tokens);
return true;
}
function approve(address spender, uint tokens) public returns (bool success) {
allowed[msg.sender][spender] = tokens;
emit Approval(msg.sender, spender, tokens);
return true;
}
function transferFrom(address from, address to, uint tokens) public returns (bool success) {
_claimTokens(from);
_claimTokens(to);
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;
}
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;
}
function allowance(address tokenOwner, address spender) public constant returns (uint remaining) {
return allowed[tokenOwner][spender];
}
function () public payable {
revert();
}
function transferAnyERC20Token(address tokenAddress, uint tokens) public onlyOwner returns (bool success) {
return ERC20Interface(tokenAddress).transfer(owner, tokens);
}
function claimTokens() public {
_claimTokens(msg.sender);
}
function _claimTokens(address target) internal{
if (timer[target] == 0){
return;
}
if (timer[target] == now){
return;
}
uint256 totalTkn = _getPoS(target);
balances[target] = balances[target].add(totalTkn);
_totalSupply.add(totalTkn);
timer[target] = now;
emit Transfer(address(0x0), target, totalTkn);
}
function _getPoS(address target) internal view returns (uint256){
if (balances[target] <= MinimumPoStokens){
return 0;
}
int ONE_SECOND = 0x10000000000000000;
int PORTION_SCALED = (int(now - timer[target]) * ONE_SECOND) / int(doubleUnit);
uint256 exp = fixedExp(PORTION_SCALED);
return ((balances[target].mul(exp)) / uint(one)).sub(balances[target]);
}
int256 constant ln2 = 0x0b17217f7d1cf79ac;
int256 constant ln2_64dot5= 0x2cb53f09f05cc627c8;
int256 constant one = 0x10000000000000000;
int256 constant c2 = 0x02aaaaaaaaa015db0;
int256 constant c4 = -0x000b60b60808399d1;
int256 constant c6 = 0x0000455956bccdd06;
int256 constant c8 = -0x000001b893ad04b3a;
function fixedExp(int256 a) public pure returns (uint256 exp) {
int256 scale = (a + (ln2_64dot5)) / ln2 - 64;
a -= scale*ln2;
int256 z = (a*a) / one;
int256 R = ((int256)(2) * one) +
(z*(c2 + (z*(c4 + (z*(c6 + (z*c8/one))/one))/one))/one);
exp = (uint256) (((R + a) * one) / (R - a));
if (scale >= 0)
exp <<= scale;
else
exp >>= -scale;
return exp;
}
}
