// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;import"../math/SafeMath.sol";
/**
* @title Counters
* @author Matt Condon (@shrugs)
* @dev Provides counters that can only be incremented or decremented by one. This can be used e.g. to track the number
* of elements in a mapping, issuing ERC721 ids, or counting request ids.
*
* Include with `using Counters for Counters.Counter;`
* Since it is not possible to overflow a 256 bit integer with increments of one, `increment` can skip the {SafeMath}
* overflow check, thereby saving gas. This does assume however correct usage, in that the underlying `_value` is never
* directly accessed.
*/libraryCounters{
usingSafeMathforuint256;
structCounter {
// This variable should never be directly accessed by users of the library: interactions must be restricted to// the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add// this feature: see https://github.com/ethereum/solidity/issues/4637uint256 _value; // default: 0
}
functioncurrent(Counter storage counter) internalviewreturns (uint256) {
return counter._value;
}
functionincrement(Counter storage counter) internal{
// The {SafeMath} overflow check can be skipped here, see the comment at the top
counter._value +=1;
}
functiondecrement(Counter storage counter) internal{
counter._value = counter._value.sub(1);
}
}
Contract Source Code
File 5 of 12: ERC20.sol
Contract Source Code
File 6 of 12: ERC20Burnable.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;import"../../utils/Context.sol";
import"./ERC20.sol";
/**
* @dev Extension of {ERC20} that allows token holders to destroy both their own
* tokens and those that they have an allowance for, in a way that can be
* recognized off-chain (via event analysis).
*/abstractcontractERC20BurnableisContext, ERC20{
usingSafeMathforuint256;
/**
* @dev Destroys `amount` tokens from the caller.
*
* See {ERC20-_burn}.
*/functionburn(uint256 amount) publicvirtual{
_burn(_msgSender(), amount);
}
/**
* @dev Destroys `amount` tokens from `account`, deducting from the caller's
* allowance.
*
* See {ERC20-_burn} and {ERC20-allowance}.
*
* Requirements:
*
* - the caller must have allowance for ``accounts``'s tokens of at least
* `amount`.
*/functionburnFrom(address account, uint256 amount) publicvirtual{
uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, "ERC20: burn amount exceeds allowance");
_approve(account, _msgSender(), decreasedAllowance);
_burn(account, amount);
}
}
Contract Source Code
File 7 of 12: ERC20MinterBurnerPauser.sol
pragmasolidity ^0.6.0;// This is adapted from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.0.0/contracts/presets/ERC20PresetMinterPauserAutoId.solimport"@openzeppelin/contracts/access/AccessControl.sol";
import"@openzeppelin/contracts/GSN/Context.sol";
import"@openzeppelin/contracts/utils/Counters.sol";
import"@openzeppelin/contracts/token/ERC20/ERC20.sol";
import"@openzeppelin/contracts/token/ERC20/ERC20Burnable.sol";
import"@openzeppelin/contracts/token/ERC20/ERC20Pausable.sol";
contractERC20MinterBurnerPauserisContext, AccessControl, ERC20Burnable, ERC20Pausable{
bytes32publicconstant MINTER_ROLE =keccak256("MINTER_ROLE");
bytes32publicconstant PAUSER_ROLE =keccak256("PAUSER_ROLE");
/**
* @dev Grants `DEFAULT_ADMIN_ROLE` and `MINTER_ROLE`to the account that
* deploys the contract.
*/constructor(stringmemory name, stringmemory symbol) publicERC20(name, symbol) {
_setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
_setupRole(MINTER_ROLE, _msgSender());
_setupRole(PAUSER_ROLE, _msgSender());
}
/**
* @dev Creates a new token for `to`. Its token ID will be automatically
* assigned (and available on the emitted {Transfer} event), and the token
* URI autogenerated based on the base URI passed at construction.
*
* See {ERC20-_mint}.
*
* Requirements:
*
* - the caller must have the `MINTER_ROLE`.
*/functionmint(address to, uint256 amount) public{
require(hasRole(MINTER_ROLE, _msgSender()), "ERC20MinterBurnerPauser: must have minter role to mint");
_mint(to, amount);
}
/**
* @dev Pauses all token transfers.
*
* See {ERC20Pausable} and {Pausable-_pause}.
*
* Requirements:
*
* - the caller must have the `PAUSER_ROLE`.
*/functionpause() public{
require(hasRole(PAUSER_ROLE, _msgSender()), "ERC20MinterBurnerPauser: must have pauser role to pause");
_pause();
}
/**
* @dev Unpauses all token transfers.
*
* See {ERC20Pausable} and {Pausable-_unpause}.
*
* Requirements:
*
* - the caller must have the `PAUSER_ROLE`.
*/functionunpause() public{
require(hasRole(PAUSER_ROLE, _msgSender()), "ERC20MinterBurnerPauser: must have pauser role to unpause");
_unpause();
}
function_beforeTokenTransfer(addressfrom, address to, uint256 amount) internaloverride(ERC20, ERC20Pausable) {
super._beforeTokenTransfer(from, to, amount);
}
}
Contract Source Code
File 8 of 12: ERC20Pausable.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;import"./ERC20.sol";
import"../../utils/Pausable.sol";
/**
* @dev ERC20 token with pausable token transfers, minting and burning.
*
* Useful for scenarios such as preventing trades until the end of an evaluation
* period, or having an emergency switch for freezing all token transfers in the
* event of a large bug.
*/abstractcontractERC20PausableisERC20, Pausable{
/**
* @dev See {ERC20-_beforeTokenTransfer}.
*
* Requirements:
*
* - the contract must not be paused.
*/function_beforeTokenTransfer(addressfrom, address to, uint256 amount) internalvirtualoverride{
super._beforeTokenTransfer(from, to, amount);
require(!paused(), "ERC20Pausable: token transfer while paused");
}
}
Contract Source Code
File 9 of 12: EnumerableSet.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;/**
* @dev Library for managing
* https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
* types.
*
* Sets have the following properties:
*
* - Elements are added, removed, and checked for existence in constant time
* (O(1)).
* - Elements are enumerated in O(n). No guarantees are made on the ordering.
*
* ```
* contract Example {
* // Add the library methods
* using EnumerableSet for EnumerableSet.AddressSet;
*
* // Declare a set state variable
* EnumerableSet.AddressSet private mySet;
* }
* ```
*
* As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
* and `uint256` (`UintSet`) are supported.
*/libraryEnumerableSet{
// To implement this library for multiple types with as little code// repetition as possible, we write it in terms of a generic Set type with// bytes32 values.// The Set implementation uses private functions, and user-facing// implementations (such as AddressSet) are just wrappers around the// underlying Set.// This means that we can only create new EnumerableSets for types that fit// in bytes32.structSet {
// Storage of set valuesbytes32[] _values;
// Position of the value in the `values` array, plus 1 because index 0// means a value is not in the set.mapping (bytes32=>uint256) _indexes;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/function_add(Set storage set, bytes32 value) privatereturns (bool) {
if (!_contains(set, value)) {
set._values.push(value);
// The value is stored at length-1, but we add 1 to all indexes// and use 0 as a sentinel value
set._indexes[value] = set._values.length;
returntrue;
} else {
returnfalse;
}
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/function_remove(Set storage set, bytes32 value) privatereturns (bool) {
// We read and store the value's index to prevent multiple reads from the same storage slotuint256 valueIndex = set._indexes[value];
if (valueIndex !=0) { // Equivalent to contains(set, value)// To delete an element from the _values array in O(1), we swap the element to delete with the last one in// the array, and then remove the last element (sometimes called as 'swap and pop').// This modifies the order of the array, as noted in {at}.uint256 toDeleteIndex = valueIndex -1;
uint256 lastIndex = set._values.length-1;
// When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs// so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.bytes32 lastvalue = set._values[lastIndex];
// Move the last value to the index where the value to delete is
set._values[toDeleteIndex] = lastvalue;
// Update the index for the moved value
set._indexes[lastvalue] = toDeleteIndex +1; // All indexes are 1-based// Delete the slot where the moved value was stored
set._values.pop();
// Delete the index for the deleted slotdelete set._indexes[value];
returntrue;
} else {
returnfalse;
}
}
/**
* @dev Returns true if the value is in the set. O(1).
*/function_contains(Set storage set, bytes32 value) privateviewreturns (bool) {
return set._indexes[value] !=0;
}
/**
* @dev Returns the number of values on the set. O(1).
*/function_length(Set storage set) privateviewreturns (uint256) {
return set._values.length;
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/function_at(Set storage set, uint256 index) privateviewreturns (bytes32) {
require(set._values.length> index, "EnumerableSet: index out of bounds");
return set._values[index];
}
// Bytes32SetstructBytes32Set {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/functionadd(Bytes32Set storage set, bytes32 value) internalreturns (bool) {
return _add(set._inner, value);
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/functionremove(Bytes32Set storage set, bytes32 value) internalreturns (bool) {
return _remove(set._inner, value);
}
/**
* @dev Returns true if the value is in the set. O(1).
*/functioncontains(Bytes32Set storage set, bytes32 value) internalviewreturns (bool) {
return _contains(set._inner, value);
}
/**
* @dev Returns the number of values in the set. O(1).
*/functionlength(Bytes32Set storage set) internalviewreturns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/functionat(Bytes32Set storage set, uint256 index) internalviewreturns (bytes32) {
return _at(set._inner, index);
}
// AddressSetstructAddressSet {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/functionadd(AddressSet storage set, address value) internalreturns (bool) {
return _add(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/functionremove(AddressSet storage set, address value) internalreturns (bool) {
return _remove(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Returns true if the value is in the set. O(1).
*/functioncontains(AddressSet storage set, address value) internalviewreturns (bool) {
return _contains(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Returns the number of values in the set. O(1).
*/functionlength(AddressSet storage set) internalviewreturns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/functionat(AddressSet storage set, uint256 index) internalviewreturns (address) {
returnaddress(uint160(uint256(_at(set._inner, index))));
}
// UintSetstructUintSet {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/functionadd(UintSet storage set, uint256 value) internalreturns (bool) {
return _add(set._inner, bytes32(value));
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/functionremove(UintSet storage set, uint256 value) internalreturns (bool) {
return _remove(set._inner, bytes32(value));
}
/**
* @dev Returns true if the value is in the set. O(1).
*/functioncontains(UintSet storage set, uint256 value) internalviewreturns (bool) {
return _contains(set._inner, bytes32(value));
}
/**
* @dev Returns the number of values on the set. O(1).
*/functionlength(UintSet storage set) internalviewreturns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/functionat(UintSet storage set, uint256 index) internalviewreturns (uint256) {
returnuint256(_at(set._inner, index));
}
}
Contract Source Code
File 10 of 12: IERC20.sol
Contract Source Code
File 11 of 12: Pausable.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;import"./Context.sol";
/**
* @dev Contract module which allows children to implement an emergency stop
* mechanism that can be triggered by an authorized account.
*
* This module is used through inheritance. It will make available the
* modifiers `whenNotPaused` and `whenPaused`, which can be applied to
* the functions of your contract. Note that they will not be pausable by
* simply including this module, only once the modifiers are put in place.
*/abstractcontractPausableisContext{
/**
* @dev Emitted when the pause is triggered by `account`.
*/eventPaused(address account);
/**
* @dev Emitted when the pause is lifted by `account`.
*/eventUnpaused(address account);
boolprivate _paused;
/**
* @dev Initializes the contract in unpaused state.
*/constructor () internal{
_paused =false;
}
/**
* @dev Returns true if the contract is paused, and false otherwise.
*/functionpaused() publicviewvirtualreturns (bool) {
return _paused;
}
/**
* @dev Modifier to make a function callable only when the contract is not paused.
*
* Requirements:
*
* - The contract must not be paused.
*/modifierwhenNotPaused() {
require(!paused(), "Pausable: paused");
_;
}
/**
* @dev Modifier to make a function callable only when the contract is paused.
*
* Requirements:
*
* - The contract must be paused.
*/modifierwhenPaused() {
require(paused(), "Pausable: not paused");
_;
}
/**
* @dev Triggers stopped state.
*
* Requirements:
*
* - The contract must not be paused.
*/function_pause() internalvirtualwhenNotPaused{
_paused =true;
emit Paused(_msgSender());
}
/**
* @dev Returns to normal state.
*
* Requirements:
*
* - The contract must be paused.
*/function_unpause() internalvirtualwhenPaused{
_paused =false;
emit Unpaused(_msgSender());
}
}
Contract Source Code
File 12 of 12: SafeMath.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/librarySafeMath{
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontryAdd(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
/**
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontrySub(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
if (b > a) return (false, 0);
return (true, a - b);
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontryMul(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the// benefit is lost if 'b' is also tested.// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522if (a ==0) return (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/functiontryDiv(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
if (b ==0) return (false, 0);
return (true, a / b);
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/functiontryMod(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
if (b ==0) return (false, 0);
return (true, a % b);
}
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/functionadd(uint256 a, uint256 b) internalpurereturns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/functionsub(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b <= a, "SafeMath: subtraction overflow");
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/functionmul(uint256 a, uint256 b) internalpurereturns (uint256) {
if (a ==0) return0;
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functiondiv(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b >0, "SafeMath: division by zero");
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functionmod(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b >0, "SafeMath: modulo by zero");
return a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/functionsub(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (uint256) {
require(b <= a, errorMessage);
return a - b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
* division by zero. The result is rounded towards zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryDiv}.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functiondiv(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (uint256) {
require(b >0, errorMessage);
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functionmod(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (uint256) {
require(b >0, errorMessage);
return a % b;
}
}