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ERC: Simpler Token Standard #179

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maraoz opened this Issue Nov 18, 2016 · 8 comments

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@maraoz
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maraoz commented Nov 18, 2016

ERC: 179
Title: Simpler Token standard
Status: Draft
Type: Informational
Created: 18-11.2016
Resolution: https://github.com/ethereum/wiki/wiki/Standardized_Contract_APIs

Abstract

The following describes standard functions a token contract can implement.
This ERC describes a simpler version of the ERC20 standard token contract, removing transfer approvals.

Motivation

Some dapps need interfaces simpler than ERC20 as a base for their tokens. We've seen some projects take this approach already (1). The main problems with ERC20 standard token are:

  • Lack of reference implementation and tests
  • Higher complexity due to approve functionality, which not all projects need.
  • Returns boolean values to signal failure instead of throwing.
  • Function totalSupply() could just be implemented as a state variable in most cases.

Specification

totalSupply

uint public totalSupply;

The total token supply

balanceOf

function balanceOf(address who) constant returns (uint);

Get the account balance of another account with address who

transfer

function transfer(address to, uint value);

Send value amount of tokens to address to

Transfer event

event Transfer(address indexed from, address indexed to, uint value);

Triggered when tokens are transferred.

Reference Implementation and tests

https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/token/ERC20Basic.sol
https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/token/BasicToken.sol
https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/test/BasicToken.js

As you can see, the code is simpler and very concise. Comments appreciated.

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sebs commented Nov 18, 2016

Having worked a bit wit the Standard, yeah +1

@Arachnid

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Arachnid commented Nov 22, 2016

Implementing totalSupply as a variable instead of a function still seems like a bad idea to me: it exposes implementation details, and provides very little reduction in complexity.

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nmushegian commented Nov 27, 2016

@Arachnid Note public keyword actually does generate a function, it's just syntactic sugar to generate a getter.

I'm ok with a "reduced ERC20", but the most likely result is some standard wrapped version of your token becomes the more liquid one (I bet it will happen to ETH itself): https://github.com/makerdao/token-wrapper

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Arachnid commented Nov 28, 2016

Note public keyword actually does generate a function, it's just syntactic sugar to generate a getter.

In that case, it should be defined in the spec as the equivalent function.

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frozeman commented Nov 28, 2016

Concerning the totalSupply, @chriseth wrote:
"I think there are currently still some issues with inheritance and virtual functions related to accessor functions. I would advise to not use public variables in an interface because it will allocate a storage slot for that variable with is not the purpose of an interface."

So i would suggest making it a function for now

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maraoz commented Dec 2, 2016

@frozeman @Arachnid Sorry, I still don't understand the problem with using a variable.

You can still use the generated function like so:

import '../token/ERC20Basic.sol';

contract Foo {
  function bar(ERC20Basic token) returns (uint) {
    return token.totalSupply();
  }
}

What are the "issues with inheritance and virtual functions related to accessor functions" that @chriseth mentions?

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Arachnid commented Dec 2, 2016

@maraoz The problem is that the token contract itself can't compute its value on demand; it has to store it.

However, I realised this is academic: The ABI for a variable is the same as that for the getter function it generates. So if you specify a function just like in ERC20, you can implement it with an autogenerated getter if you prefer.

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GriffGreen commented Dec 13, 2016

The Exchanges would flip if we remove approve() from the standard... they all use it to make their system work. If we remove it, it needs to be replaced with something... this is why GNT is not traded outside of the decentralized market BokkyPooBah made

The places that do trade it use a wrapper... so the wrapper part might as well be included in the full spec.

15chrjef referenced this issue in poanetwork/token-wizard Sep 28, 2017

@athlona64 athlona64 referenced this issue Nov 10, 2017

Closed

i got problem #541

mogasns added a commit to mogasns/mileage-of-genesis-A that referenced this issue Oct 17, 2018

Add files via upload
pragma solidity ^0.4.11;


/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see ethereum/EIPs#179
 */
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);
}



/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
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;
  }

}
// Temporarily have SafeMath here until all contracts have been migrated to SafeMathLib version from OpenZeppelin




/**
 * Math operations with safety checks
 */
contract SafeMath {
  function safeMul(uint a, uint b) internal returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function safeDiv(uint a, uint b) internal returns (uint) {
    assert(b > 0);
    uint c = a / b;
    assert(a == b * c + a % b);
    return c;
  }

  function safeSub(uint a, uint b) internal returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function safeAdd(uint a, uint b) internal returns (uint) {
    uint c = a + b;
    assert(c>=a && c>=b);
    return c;
  }

  function max64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a >= b ? a : b;
  }

  function min64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a < b ? a : b;
  }

  function max256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a >= b ? a : b;
  }

  function min256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a < b ? a : b;
  }

}
/**
 * This smart contract code is Copyright 2017 TokenMarket Ltd. For more information see https://tokenmarket.net
 *
 * Licensed under the Apache License, version 2.0: https://github.com/TokenMarketNet/ico/blob/master/LICENSE.txt
 */



/**
 * This smart contract code is Copyright 2017 TokenMarket Ltd. For more information see https://tokenmarket.net
 *
 * Licensed under the Apache License, version 2.0: https://github.com/TokenMarketNet/ico/blob/master/LICENSE.txt
 */










/**
 * @title ERC20 interface
 * @dev see ethereum/EIPs#20
 */
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);
}




/**
 * Standard ERC20 token with Short Hand Attack and approve() race condition mitigation.
 *
 * Based on code by FirstBlood:
 * https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is ERC20, SafeMath {

  /* Token supply got increased and a new owner received these tokens */
  event Minted(address receiver, uint amount);

  /* Actual balances of token holders */
  mapping(address => uint) balances;

  /* approve() allowances */
  mapping (address => mapping (address => uint)) allowed;

  /* Interface declaration */
  function isToken() public constant returns (bool weAre) {
    return true;
  }

  function transfer(address _to, uint _value) returns (bool success) {
    balances[msg.sender] = safeSub(balances[msg.sender], _value);
    balances[_to] = safeAdd(balances[_to], _value);
    Transfer(msg.sender, _to, _value);
    return true;
  }

  function transferFrom(address _from, address _to, uint _value) returns (bool success) {
    uint _allowance = allowed[_from][msg.sender];

    balances[_to] = safeAdd(balances[_to], _value);
    balances[_from] = safeSub(balances[_from], _value);
    allowed[_from][msg.sender] = safeSub(_allowance, _value);
    Transfer(_from, _to, _value);
    return true;
  }

  function balanceOf(address _owner) constant returns (uint balance) {
    return balances[_owner];
  }

  function approve(address _spender, uint _value) returns (bool success) {

    // To change the approve amount you first have to reduce the addresses`
    //  allowance to zero by calling `approve(_spender, 0)` if it is not
    //  already 0 to mitigate the race condition described here:
    //  ethereum/EIPs#20 (comment)
    if ((_value != 0) && (allowed[msg.sender][_spender] != 0)) throw;

    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }

  function allowance(address _owner, address _spender) constant returns (uint remaining) {
    return allowed[_owner][_spender];
  }

}

/**
 * This smart contract code is Copyright 2017 TokenMarket Ltd. For more information see https://tokenmarket.net
 *
 * Licensed under the Apache License, version 2.0: https://github.com/TokenMarketNet/ico/blob/master/LICENSE.txt
 */





/**
 * This smart contract code is Copyright 2017 TokenMarket Ltd. For more information see https://tokenmarket.net
 *
 * Licensed under the Apache License, version 2.0: https://github.com/TokenMarketNet/ico/blob/master/LICENSE.txt
 */



/**
 * Upgrade agent interface inspired by Lunyr.
 *
 * Upgrade agent transfers tokens to a new contract.
 * Upgrade agent itself can be the token contract, or just a middle man contract doing the heavy lifting.
 */
contract UpgradeAgent {

  uint public originalSupply;

  /** Interface marker */
  function isUpgradeAgent() public constant returns (bool) {
    return true;
  }

  function upgradeFrom(address _from, uint256 _value) public;

}


/**
 * A token upgrade mechanism where users can opt-in amount of tokens to the next smart contract revision.
 *
 * First envisioned by Golem and Lunyr projects.
 */
contract UpgradeableToken is StandardToken {

  /** Contract / person who can set the upgrade path. This can be the same as team multisig wallet, as what it is with its default value. */
  address public upgradeMaster;

  /** The next contract where the tokens will be migrated. */
  UpgradeAgent public upgradeAgent;

  /** How many tokens we have upgraded by now. */
  uint256 public totalUpgraded;

  /**
   * Upgrade states.
   *
   * - NotAllowed: The child contract has not reached a condition where the upgrade can bgun
   * - WaitingForAgent: Token allows upgrade, but we don't have a new agent yet
   * - ReadyToUpgrade: The agent is set, but not a single token has been upgraded yet
   * - Upgrading: Upgrade agent is set and the balance holders can upgrade their tokens
   *
   */
  enum UpgradeState {Unknown, NotAllowed, WaitingForAgent, ReadyToUpgrade, Upgrading}

  /**
   * Somebody has upgraded some of his tokens.
   */
  event Upgrade(address indexed _from, address indexed _to, uint256 _value);

  /**
   * New upgrade agent available.
   */
  event UpgradeAgentSet(address agent);

  /**
   * Do not allow construction without upgrade master set.
   */
  function UpgradeableToken(address _upgradeMaster) {
    upgradeMaster = _upgradeMaster;
  }

  /**
   * Allow the token holder to upgrade some of their tokens to a new contract.
   */
  function upgrade(uint256 value) public {

      UpgradeState state = getUpgradeState();
      if(!(state == UpgradeState.ReadyToUpgrade || state == UpgradeState.Upgrading)) {
        // Called in a bad state
        throw;
      }

      // Validate input value.
      if (value == 0) throw;

      balances[msg.sender] = safeSub(balances[msg.sender], value);

      // Take tokens out from circulation
      totalSupply = safeSub(totalSupply, value);
      totalUpgraded = safeAdd(totalUpgraded, value);

      // Upgrade agent reissues the tokens
      upgradeAgent.upgradeFrom(msg.sender, value);
      Upgrade(msg.sender, upgradeAgent, value);
  }

  /**
   * Set an upgrade agent that handles
   */
  function setUpgradeAgent(address agent) external {

      if(!canUpgrade()) {
        // The token is not yet in a state that we could think upgrading
        throw;
      }

      if (agent == 0x0) throw;
      // Only a master can designate the next agent
      if (msg.sender != upgradeMaster) throw;
      // Upgrade has already begun for an agent
      if (getUpgradeState() == UpgradeState.Upgrading) throw;

      upgradeAgent = UpgradeAgent(agent);

      // Bad interface
      if(!upgradeAgent.isUpgradeAgent()) throw;
      // Make sure that token supplies match in source and target
      if (upgradeAgent.originalSupply() != totalSupply) throw;

      UpgradeAgentSet(upgradeAgent);
  }

  /**
   * Get the state of the token upgrade.
   */
  function getUpgradeState() public constant returns(UpgradeState) {
    if(!canUpgrade()) return UpgradeState.NotAllowed;
    else if(address(upgradeAgent) == 0x00) return UpgradeState.WaitingForAgent;
    else if(totalUpgraded == 0) return UpgradeState.ReadyToUpgrade;
    else return UpgradeState.Upgrading;
  }

  /**
   * Change the upgrade master.
   *
   * This allows us to set a new owner for the upgrade mechanism.
   */
  function setUpgradeMaster(address master) public {
      if (master == 0x0) throw;
      if (msg.sender != upgradeMaster) throw;
      upgradeMaster = master;
  }

  /**
   * Child contract can enable to provide the condition when the upgrade can begun.
   */
  function canUpgrade() public constant returns(bool) {
     return true;
  }

}

/**
 * This smart contract code is Copyright 2017 TokenMarket Ltd. For more information see https://tokenmarket.net
 *
 * Licensed under the Apache License, version 2.0: https://github.com/TokenMarketNet/ico/blob/master/LICENSE.txt
 */







/**
 * Define interface for releasing the token transfer after a successful crowdsale.
 */
contract ReleasableToken is ERC20, Ownable {

  /* The finalizer contract that allows unlift the transfer limits on this token */
  address public releaseAgent;

  /** A crowdsale contract can release us to the wild if ICO success. If false we are are in transfer lock up period.*/
  bool public released = false;

  /** Map of agents that are allowed to transfer tokens regardless of the lock down period. These are crowdsale contracts and possible the team multisig itself. */
  mapping (address => bool) public transferAgents;

  /**
   * Limit token transfer until the crowdsale is over.
   *
   */
  modifier canTransfer(address _sender) {

    if(!released) {
        if(!transferAgents[_sender]) {
            throw;
        }
    }

    _;
  }

  /**
   * Set the contract that can call release and make the token transferable.
   *
   * Design choice. Allow reset the release agent to fix fat finger mistakes.
   */
  function setReleaseAgent(address addr) onlyOwner inReleaseState(false) public {

    // We don't do interface check here as we might want to a normal wallet address to act as a release agent
    releaseAgent = addr;
  }

  /**
   * Owner can allow a particular address (a crowdsale contract) to transfer tokens despite the lock up period.
   */
  function setTransferAgent(address addr, bool state) onlyOwner inReleaseState(false) public {
    transferAgents[addr] = state;
  }

  /**
   * One way function to release the tokens to the wild.
   *
   * Can be called only from the release agent that is the final ICO contract. It is only called if the crowdsale has been success (first milestone reached).
   */
  function releaseTokenTransfer() public onlyReleaseAgent {
    released = true;
  }

  /** The function can be called only before or after the tokens have been releasesd */
  modifier inReleaseState(bool releaseState) {
    if(releaseState != released) {
        throw;
    }
    _;
  }

  /** The function can be called only by a whitelisted release agent. */
  modifier onlyReleaseAgent() {
    if(msg.sender != releaseAgent) {
        throw;
    }
    _;
  }

  function transfer(address _to, uint _value) canTransfer(msg.sender) returns (bool success) {
    // Call StandardToken.transfer()
   return super.transfer(_to, _value);
  }

  function transferFrom(address _from, address _to, uint _value) canTransfer(_from) returns (bool success) {
    // Call StandardToken.transferForm()
    return super.transferFrom(_from, _to, _value);
  }

}

/**
 * This smart contract code is Copyright 2017 TokenMarket Ltd. For more information see https://tokenmarket.net
 *
 * Licensed under the Apache License, version 2.0: https://github.com/TokenMarketNet/ico/blob/master/LICENSE.txt
 */




/**
 * This smart contract code is Copyright 2017 TokenMarket Ltd. For more information see https://tokenmarket.net
 *
 * Licensed under the Apache License, version 2.0: https://github.com/TokenMarketNet/ico/blob/master/LICENSE.txt
 */



/**
 * Safe unsigned safe math.
 *
 * https://blog.aragon.one/library-driven-development-in-solidity-2bebcaf88736#.750gwtwli
 *
 * Originally from https://raw.githubusercontent.com/AragonOne/zeppelin-solidity/master/contracts/SafeMathLib.sol
 *
 * Maintained here until merged to mainline zeppelin-solidity.
 *
 */
library SafeMathLibExt {

  function times(uint a, uint b) returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function divides(uint a, uint b) returns (uint) {
    assert(b > 0);
    uint c = a / b;
    assert(a == b * c + a % b);
    return c;
  }

  function minus(uint a, uint b) returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function plus(uint a, uint b) returns (uint) {
    uint c = a + b;
    assert(c>=a);
    return c;
  }

}




/**
 * A token that can increase its supply by another contract.
 *
 * This allows uncapped crowdsale by dynamically increasing the supply when money pours in.
 * Only mint agents, contracts whitelisted by owner, can mint new tokens.
 *
 */
contract MintableTokenExt is StandardToken, Ownable {

  using SafeMathLibExt for uint;

  bool public mintingFinished = false;

  /** List of agents that are allowed to create new tokens */
  mapping (address => bool) public mintAgents;

  event MintingAgentChanged(address addr, bool state  );

  /** inPercentageUnit is percents of tokens multiplied to 10 up to percents decimals.
  * For example, for reserved tokens in percents 2.54%
  * inPercentageUnit = 254
  * inPercentageDecimals = 2
  */
  struct ReservedTokensData {
    uint inTokens;
    uint inPercentageUnit;
    uint inPercentageDecimals;
    bool isReserved;
    bool isDistributed;
  }

  mapping (address => ReservedTokensData) public reservedTokensList;
  address[] public reservedTokensDestinations;
  uint public reservedTokensDestinationsLen = 0;
  bool reservedTokensDestinationsAreSet = false;

  modifier onlyMintAgent() {
    // Only crowdsale contracts are allowed to mint new tokens
    if(!mintAgents[msg.sender]) {
        throw;
    }
    _;
  }

  /** Make sure we are not done yet. */
  modifier canMint() {
    if(mintingFinished) throw;
    _;
  }

  function finalizeReservedAddress(address addr) public onlyMintAgent canMint {
    ReservedTokensData storage reservedTokensData = reservedTokensList[addr];
    reservedTokensData.isDistributed = true;
  }

  function isAddressReserved(address addr) public constant returns (bool isReserved) {
    return reservedTokensList[addr].isReserved;
  }

  function areTokensDistributedForAddress(address addr) public constant returns (bool isDistributed) {
    return reservedTokensList[addr].isDistributed;
  }

  function getReservedTokens(address addr) public constant returns (uint inTokens) {
    return reservedTokensList[addr].inTokens;
  }

  function getReservedPercentageUnit(address addr) public constant returns (uint inPercentageUnit) {
    return reservedTokensList[addr].inPercentageUnit;
  }

  function getReservedPercentageDecimals(address addr) public constant returns (uint inPercentageDecimals) {
    return reservedTokensList[addr].inPercentageDecimals;
  }

  function setReservedTokensListMultiple(
    address[] addrs, 
    uint[] inTokens, 
    uint[] inPercentageUnit, 
    uint[] inPercentageDecimals
  ) public canMint onlyOwner {
    assert(!reservedTokensDestinationsAreSet);
    assert(addrs.length == inTokens.length);
    assert(inTokens.length == inPercentageUnit.length);
    assert(inPercentageUnit.length == inPercentageDecimals.length);
    for (uint iterator = 0; iterator < addrs.length; iterator++) {
      if (addrs[iterator] != address(0)) {
        setReservedTokensList(addrs[iterator], inTokens[iterator], inPercentageUnit[iterator], inPercentageDecimals[iterator]);
      }
    }
    reservedTokensDestinationsAreSet = true;
  }

  /**
   * Create new tokens and allocate them to an address..
   *
   * Only callably by a crowdsale contract (mint agent).
   */
  function mint(address receiver, uint amount) onlyMintAgent canMint public {
    totalSupply = totalSupply.plus(amount);
    balances[receiver] = balances[receiver].plus(amount);

    // This will make the mint transaction apper in EtherScan.io
    // We can remove this after there is a standardized minting event
    Transfer(0, receiver, amount);
  }

  /**
   * Owner can allow a crowdsale contract to mint new tokens.
   */
  function setMintAgent(address addr, bool state) onlyOwner canMint public {
    mintAgents[addr] = state;
    MintingAgentChanged(addr, state);
  }

  function setReservedTokensList(address addr, uint inTokens, uint inPercentageUnit, uint inPercentageDecimals) private canMint onlyOwner {
    assert(addr != address(0));
    if (!isAddressReserved(addr)) {
      reservedTokensDestinations.push(addr);
      reservedTokensDestinationsLen++;
    }

    reservedTokensList[addr] = ReservedTokensData({
      inTokens: inTokens, 
      inPercentageUnit: inPercentageUnit, 
      inPercentageDecimals: inPercentageDecimals,
      isReserved: true,
      isDistributed: false
    });
  }
}


/**
 * A crowdsaled token.
 *
 * An ERC-20 token designed specifically for crowdsales with investor protection and further development path.
 *
 * - The token transfer() is disabled until the crowdsale is over
 * - The token contract gives an opt-in upgrade path to a new contract
 * - The same token can be part of several crowdsales through approve() mechanism
 * - The token can be capped (supply set in the constructor) or uncapped (crowdsale contract can mint new tokens)
 *
 */
contract CrowdsaleTokenExt is ReleasableToken, MintableTokenExt, UpgradeableToken {

  /** Name and symbol were updated. */
  event UpdatedTokenInformation(string newName, string newSymbol);

  event ClaimedTokens(address indexed _token, address indexed _controller, uint _amount);

  string public name;

  string public symbol;

  uint public decimals;

  /* Minimum ammount of tokens every buyer can buy. */
  uint public minCap;

  /**
   * Construct the token.
   *
   * This token must be created through a team multisig wallet, so that it is owned by that wallet.
   *
   * @param _name Token name
   * @param _symbol Token symbol - should be all caps
   * @param _initialSupply How many tokens we start with
   * @param _decimals Number of decimal places
   * @param _mintable Are new tokens created over the crowdsale or do we distribute only the initial supply? Note that when the token becomes transferable the minting always ends.
   */
  function CrowdsaleTokenExt(string _name, string _symbol, uint _initialSupply, uint _decimals, bool _mintable, uint _globalMinCap)
    UpgradeableToken(msg.sender) {

    // Create any address, can be transferred
    // to team multisig via changeOwner(),
    // also remember to call setUpgradeMaster()
    owner = msg.sender;

    name = _name;
    symbol = _symbol;

    totalSupply = _initialSupply;

    decimals = _decimals;

    minCap = _globalMinCap;

    // Create initially all balance on the team multisig
    balances[owner] = totalSupply;

    if(totalSupply > 0) {
      Minted(owner, totalSupply);
    }

    // No more new supply allowed after the token creation
    if(!_mintable) {
      mintingFinished = true;
      if(totalSupply == 0) {
        throw; // Cannot create a token without supply and no minting
      }
    }
  }

  /**
   * When token is released to be transferable, enforce no new tokens can be created.
   */
  function releaseTokenTransfer() public onlyReleaseAgent {
    mintingFinished = true;
    super.releaseTokenTransfer();
  }

  /**
   * Allow upgrade agent functionality kick in only if the crowdsale was success.
   */
  function canUpgrade() public constant returns(bool) {
    return released && super.canUpgrade();
  }

  /**
   * Owner can update token information here.
   *
   * It is often useful to conceal the actual token association, until
   * the token operations, like central issuance or reissuance have been completed.
   *
   * This function allows the token owner to rename the token after the operations
   * have been completed and then point the audience to use the token contract.
   */
  function setTokenInformation(string _name, string _symbol) onlyOwner {
    name = _name;
    symbol = _symbol;

    UpdatedTokenInformation(name, symbol);
  }

  /**
   * Claim tokens that were accidentally sent to this contract.
   *
   * @param _token The address of the token contract that you want to recover.
   */
  function claimTokens(address _token) public onlyOwner {
    require(_token != address(0));

    ERC20 token = ERC20(_token);
    uint balance = token.balanceOf(this);
    token.transfer(owner, balance);

    ClaimedTokens(_token, owner, balance);
  }

}

@liuzerui liuzerui referenced this issue Oct 26, 2018

Open

BFAI #1

@Hitbtc-PT Hitbtc-PT referenced this issue Jan 10, 2019

Open

IMCS Token #1

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