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pragma solidity ^0.4.16;
/*
* Abstract Token Smart Contract. Copyright © 2017 by ABDK Consulting.
* Author: Mikhail Vladimirov <mikhail.vladimirov@gmail.com>
*/
pragma solidity ^0.4.20;
/*
* EIP-20 Standard Token Smart Contract Interface.
* Copyright © 2016–2018 by ABDK Consulting.
* Author: Mikhail Vladimirov <mikhail.vladimirov@gmail.com>
*/
pragma solidity ^0.4.20;
/**
* ERC-20 standard token interface, as defined
* <a href="https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md">here</a>.
*/
contract Token {
/**
* Get total number of tokens in circulation.
*
* @return total number of tokens in circulation
*/
function totalSupply () public view returns (uint256 supply);
/**
* Get number of tokens currently belonging to given owner.
*
* @param _owner address to get number of tokens currently belonging to the
* owner of
* @return number of tokens currently belonging to the owner of given address
*/
function balanceOf (address _owner) public view returns (uint256 balance);
/**
* Transfer given number of tokens from message sender to given recipient.
*
* @param _to address to transfer tokens to the owner of
* @param _value number of tokens to transfer to the owner of given address
* @return true if tokens were transferred successfully, false otherwise
*/
function transfer (address _to, uint256 _value)
public returns (bool success);
/**
* Transfer given number of tokens from given owner to given recipient.
*
* @param _from address to transfer tokens from the owner of
* @param _to address to transfer tokens to the owner of
* @param _value number of tokens to transfer from given owner to given
* recipient
* @return true if tokens were transferred successfully, false otherwise
*/
function transferFrom (address _from, address _to, uint256 _value)
public returns (bool success);
/**
* Allow given spender to transfer given number of tokens from message sender.
*
* @param _spender address to allow the owner of to transfer tokens from
* message sender
* @param _value number of tokens to allow to transfer
* @return true if token transfer was successfully approved, false otherwise
*/
function approve (address _spender, uint256 _value)
public returns (bool success);
/**
* Tell how many tokens given spender is currently allowed to transfer from
* given owner.
*
* @param _owner address to get number of tokens allowed to be transferred
* from the owner of
* @param _spender address to get number of tokens allowed to be transferred
* by the owner of
* @return number of tokens given spender is currently allowed to transfer
* from given owner
*/
function allowance (address _owner, address _spender)
public view returns (uint256 remaining);
/**
* Logged when tokens were transferred from one owner to another.
*
* @param _from address of the owner, tokens were transferred from
* @param _to address of the owner, tokens were transferred to
* @param _value number of tokens transferred
*/
event Transfer (address indexed _from, address indexed _to, uint256 _value);
/**
* Logged when owner approved his tokens to be transferred by some spender.
*
* @param _owner owner who approved his tokens to be transferred
* @param _spender spender who were allowed to transfer the tokens belonging
* to the owner
* @param _value number of tokens belonging to the owner, approved to be
* transferred by the spender
*/
event Approval (
address indexed _owner, address indexed _spender, uint256 _value);
}
/*
* Safe Math Smart Contract. Copyright © 2016–2017 by ABDK Consulting.
* Author: Mikhail Vladimirov <mikhail.vladimirov@gmail.com>
*/
pragma solidity ^0.4.20;
/**
* Provides methods to safely add, subtract and multiply uint256 numbers.
*/
contract SafeMath {
uint256 constant private MAX_UINT256 =
0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF;
/**
* Add two uint256 values, throw in case of overflow.
*
* @param x first value to add
* @param y second value to add
* @return x + y
*/
function safeAdd (uint256 x, uint256 y)
pure internal
returns (uint256 z) {
assert (x <= MAX_UINT256 - y);
return x + y;
}
/**
* Subtract one uint256 value from another, throw in case of underflow.
*
* @param x value to subtract from
* @param y value to subtract
* @return x - y
*/
function safeSub (uint256 x, uint256 y)
pure internal
returns (uint256 z) {
assert (x >= y);
return x - y;
}
/**
* Multiply two uint256 values, throw in case of overflow.
*
* @param x first value to multiply
* @param y second value to multiply
* @return x * y
*/
function safeMul (uint256 x, uint256 y)
pure internal
returns (uint256 z) {
if (y == 0) return 0; // Prevent division by zero at the next line
assert (x <= MAX_UINT256 / y);
return x * y;
}
}
/**
* Abstract Token Smart Contract that could be used as a base contract for
* ERC-20 token contracts.
*/
contract AbstractToken is Token, SafeMath {
/**
* Create new Abstract Token contract.
*/
function AbstractToken () public {
// Do nothing
}
/**
* Get number of tokens currently belonging to given owner.
*
* @param _owner address to get number of tokens currently belonging to the
* owner of
* @return number of tokens currently belonging to the owner of given address
*/
function balanceOf (address _owner) public view returns (uint256 balance) {
return accounts [_owner];
}
/**
* Transfer given number of tokens from message sender to given recipient.
*
* @param _to address to transfer tokens to the owner of
* @param _value number of tokens to transfer to the owner of given address
* @return true if tokens were transferred successfully, false otherwise
*/
function transfer (address _to, uint256 _value)
public returns (bool success) {
uint256 fromBalance = accounts [msg.sender];
if (fromBalance < _value) return false;
if (_value > 0 && msg.sender != _to) {
accounts [msg.sender] = safeSub (fromBalance, _value);
accounts [_to] = safeAdd (accounts [_to], _value);
}
Transfer (msg.sender, _to, _value);
return true;
}
/**
* Transfer given number of tokens from given owner to given recipient.
*
* @param _from address to transfer tokens from the owner of
* @param _to address to transfer tokens to the owner of
* @param _value number of tokens to transfer from given owner to given
* recipient
* @return true if tokens were transferred successfully, false otherwise
*/
function transferFrom (address _from, address _to, uint256 _value)
public returns (bool success) {
uint256 spenderAllowance = allowances [_from][msg.sender];
if (spenderAllowance < _value) return false;
uint256 fromBalance = accounts [_from];
if (fromBalance < _value) return false;
allowances [_from][msg.sender] =
safeSub (spenderAllowance, _value);
if (_value > 0 && _from != _to) {
accounts [_from] = safeSub (fromBalance, _value);
accounts [_to] = safeAdd (accounts [_to], _value);
}
Transfer (_from, _to, _value);
return true;
}
/**
* Allow given spender to transfer given number of tokens from message sender.
*
* @param _spender address to allow the owner of to transfer tokens from
* message sender
* @param _value number of tokens to allow to transfer
* @return true if token transfer was successfully approved, false otherwise
*/
function approve (address _spender, uint256 _value)
public returns (bool success) {
allowances [msg.sender][_spender] = _value;
Approval (msg.sender, _spender, _value);
return true;
}
/**
* Tell how many tokens given spender is currently allowed to transfer from
* given owner.
*
* @param _owner address to get number of tokens allowed to be transferred
* from the owner of
* @param _spender address to get number of tokens allowed to be transferred
* by the owner of
* @return number of tokens given spender is currently allowed to transfer
* from given owner
*/
function allowance (address _owner, address _spender)
public view returns (uint256 remaining) {
return allowances [_owner][_spender];
}
/**
* Mapping from addresses of token holders to the numbers of tokens belonging
* to these token holders.
*/
mapping (address => uint256) internal accounts;
/**
* Mapping from addresses of token holders to the mapping of addresses of
* spenders to the allowances set by these token holders to these spenders.
*/
mapping (address => mapping (address => uint256)) internal allowances;
}
/**
* Convergence of 4 Dimensions LLC token smart contract.
*/
contract DroidToken is AbstractToken {
/**
* Address of the owner of this smart contract.
*/
address private owner;
/**
* Total number of tokens in circulation.
*/
uint256 tokenCount;
/**
* True if tokens transfers are currently frozen, false otherwise.
*/
bool frozen = false;
/**
* Create new Convergence of 4 Dimensions LLC token smart contract, with given number of tokens issued
* and given to msg.sender, and make msg.sender the owner of this smart
* contract.
*
* @param _tokenCount number of tokens to issue and give to msg.sender
*/
function DroidToken (uint256 _tokenCount) public {
owner = msg.sender;
tokenCount = _tokenCount;
accounts [msg.sender] = _tokenCount;
}
/**
* Get total number of tokens in circulation.
*
* @return total number of tokens in circulation
*/
function totalSupply () public view returns (uint256 supply) {
return tokenCount;
}
/**
* Get name of this token.
*
* @return name of this token
*/
function name () public pure returns (string result) {
return "Droid";
}
/**
* Get symbol of this token.
*
* @return symbol of this token
*/
function symbol () public pure returns (string result) {
return "Droid";
}
/**
* Get number of decimals for this token.
*
* @return number of decimals for this token
*/
function decimals () public pure returns (uint8 result) {
return 8;
}
/**
* Transfer given number of tokens from message sender to given recipient.
*
* @param _to address to transfer tokens to the owner of
* @param _value number of tokens to transfer to the owner of given address
* @return true if tokens were transferred successfully, false otherwise
*/
function transfer (address _to, uint256 _value)
public returns (bool success) {
if (frozen) return false;
else return AbstractToken.transfer (_to, _value);
}
/**
* Transfer given number of tokens from given owner to given recipient.
*
* @param _from address to transfer tokens from the owner of
* @param _to address to transfer tokens to the owner of
* @param _value number of tokens to transfer from given owner to given
* recipient
* @return true if tokens were transferred successfully, false otherwise
*/
function transferFrom (address _from, address _to, uint256 _value)
public returns (bool success) {
if (frozen) return false;
else return AbstractToken.transferFrom (_from, _to, _value);
}
/**
* Change how many tokens given spender is allowed to transfer from message
* spender. In order to prevent double spending of allowance, this method
* receives assumed current allowance value as an argument. If actual
* allowance differs from an assumed one, this method just returns false.
*
* @param _spender address to allow the owner of to transfer tokens from
* message sender
* @param _currentValue assumed number of tokens currently allowed to be
* transferred
* @param _newValue number of tokens to allow to transfer
* @return true if token transfer was successfully approved, false otherwise
*/
function approve (address _spender, uint256 _currentValue, uint256 _newValue)
public returns (bool success) {
if (allowance (msg.sender, _spender) == _currentValue)
return approve (_spender, _newValue);
else return false;
}
/**
* Set new owner for the smart contract.
* May only be called by smart contract owner.
*
* @param _newOwner address of new owner of the smart contract
*/
function setOwner (address _newOwner) public {
require (msg.sender == owner);
owner = _newOwner;
}
/**
* Freeze token transfers.
* May only be called by smart contract owner.
*/
function freezeTransfers () public {
require (msg.sender == owner);
if (!frozen) {
frozen = true;
Freeze ();
}
}
/**
* Unfreeze token transfers.
* May only be called by smart contract owner.
*/
function unfreezeTransfers () public {
require (msg.sender == owner);
if (frozen) {
frozen = false;
Unfreeze ();
}
}
/**
* Logged when token transfers were frozen.
*/
event Freeze ();
/**
* Logged when token transfers were unfrozen.
*/
event Unfreeze ();
}
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