Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
contract IPhoenix {
function getTotalLevels(address _user) external view returns(uint256){}
}
/**
______ __ ______ ______ ______
/\ == \ /\ \ /\ __ \ /\___ \ /\ ___\
\ \ __< \ \ \____ \ \ __ \ \/_/ /__ \ \ __\
\ \_____\ \ \_____\ \ \_\ \_\ /\_____\ \ \_____\
\/_____/ \/_____/ \/_/\/_/ \/_____/ \/_____/
*/
contract Blaze is ERC20, Ownable {
using SafeMath for uint256;
mapping(address => uint) lastUpdate;
mapping(address => bool) burnAddresses;
mapping(address => uint) tokensOwed;
IPhoenix[] public phoenixContracts;
uint[] ratePerLevel;
constructor() ERC20("Blaze", "BLAZE") {
}
/**
__ __ __ ______ ______ ______ ______ ______ ______ __ ______ __ __
/\ \ /\ "-.\ \ /\__ _\ /\ ___\ /\ == \ /\ __ \ /\ ___\ /\__ _\ /\ \ /\ __ \ /\ "-.\ \
\ \ \ \ \ \-. \ \/_/\ \/ \ \ __\ \ \ __< \ \ __ \ \ \ \____ \/_/\ \/ \ \ \ \ \ \/\ \ \ \ \-. \
\ \_\ \ \_\\"\_\ \ \_\ \ \_____\ \ \_\ \_\ \ \_\ \_\ \ \_____\ \ \_\ \ \_\ \ \_____\ \ \_\\"\_\
\/_/ \/_/ \/_/ \/_/ \/_____/ \/_/ /_/ \/_/\/_/ \/_____/ \/_/ \/_/ \/_____/ \/_/ \/_/
*/
/*
* @dev updates the tokens owed and the last time the user updated, called when leveling up a phoenix or minting
* @dev _userAddress is the address of the user to update
*/
function updateTokens(address _userAddress) external {
if (_userAddress != address(0)) {
uint lastTime = lastUpdate[_userAddress];
uint currentTime = block.timestamp;
lastUpdate[_userAddress] = currentTime;
IPhoenix[] memory phoenix_contracts = phoenixContracts;
uint[] memory ratePerLev = ratePerLevel;
if(lastTime > 0) {
uint claimable;
for(uint i = 0; i < phoenix_contracts.length; i++) {
claimable += phoenix_contracts[i].getTotalLevels(_userAddress).mul(ratePerLev[i]);
}
tokensOwed[_userAddress] += claimable.mul(currentTime - lastTime).div(86400);
}
}
}
/**
* @dev called on token transfer, and updates the tokens owed and last update for each user involved in the transaction
* @param _fromAddress is the address the token is being sent from
* @param _toAddress is the address the token is being sent to
*/
function updateTransfer(address _fromAddress, address _toAddress) external {
uint currentTime = block.timestamp;
uint claimable;
uint timeDifference;
uint lastTime;
IPhoenix[] memory phoenix_contracts = phoenixContracts;
uint[] memory ratePerLev = ratePerLevel;
if(_fromAddress != address(0)) {
lastTime = lastUpdate[_fromAddress];
lastUpdate[_fromAddress] = currentTime;
if(lastTime > 0) {
claimable = 0;
timeDifference = currentTime - lastTime;
for(uint i = 0; i < phoenix_contracts.length; i++) {
claimable += phoenix_contracts[i].getTotalLevels(_fromAddress).mul(ratePerLev[i]);
}
tokensOwed[_fromAddress] += claimable.mul(timeDifference).div(86400);
}
}
if(_toAddress != address(0)) {
lastTime = lastUpdate[_toAddress];
lastUpdate[_toAddress] = currentTime;
if(lastTime > 0) {
claimable = 0;
timeDifference = currentTime - lastTime;
for(uint i = 0; i < phoenix_contracts.length; i++) {
claimable += phoenix_contracts[i].getTotalLevels(_toAddress).mul(ratePerLev[i]);
}
tokensOwed[_toAddress] += claimable.mul(timeDifference).div(86400);
}
}
}
/**
* @dev claims tokens generated and mints into the senders wallet
*/
function claim() external {
address sender = _msgSender();
uint lastUpdated = lastUpdate[sender];
uint time = block.timestamp;
require(lastUpdated > 0, "No tokens to claim");
lastUpdate[sender] = time;
uint unclaimed = getPendingTokens(sender, time - lastUpdated);
if(tokensOwed[sender] > 0) {
unclaimed += tokensOwed[sender];
tokensOwed[sender] = 0;
}
require(unclaimed > 0, "No tokens to claim");
_mint(sender, unclaimed);
}
/**
* @dev burns the desired amount of tokens from the wallet, this can only be called by accepted addresses, prefers burning owed tokens over minted
* @param _from is the address to burn the tokens from
* @param _amount is the number of tokens attempting to be burned
*/
function burn(address _from, uint256 _amount) external {
require(burnAddresses[_msgSender()] == true, "Don't have permission to call this function");
uint owed = tokensOwed[_from];
if(owed >= _amount) {
tokensOwed[_from] -= _amount;
return;
}
uint balance = balanceOf(_from);
if(balance >= _amount) {
_burn(_from, _amount);
return;
}
if(balance + owed >= _amount) {
tokensOwed[_from] = 0;
_burn(_from, _amount - owed);
return;
}
uint lastUpdated = lastUpdate[_from];
require(lastUpdated > 0, "User doesn't have enough blaze to complete this action");
uint time = block.timestamp;
uint claimable = getPendingTokens(_from, time - lastUpdated);
lastUpdate[_from] = time;
if(claimable >= _amount) {
tokensOwed[_from] += claimable - _amount;
return;
}
if(claimable + owed >= _amount) {
tokensOwed[_from] -= _amount - claimable;
return;
}
if(balance + owed + claimable >= _amount) {
tokensOwed[_from] = 0;
_burn(_from, _amount - (owed + claimable));
return;
}
revert("User doesn't have enough blaze available to complete this action");
}
/**
______ ______ ______ _____
/\ == \ /\ ___\ /\ __ \ /\ __-.
\ \ __< \ \ __\ \ \ __ \ \ \ \/\ \
\ \_\ \_\ \ \_____\ \ \_\ \_\ \ \____-
\/_/ /_/ \/_____/ \/_/\/_/ \/____/
*/
/**
* @dev returns the last time an address has updated with the contract
* @param _userAddress is the user address that wants the know the time
*/
function lastUpdateTime(address _userAddress) public view returns(uint) {
return lastUpdate[_userAddress];
}
/**
* @dev Gets the total tokens that are available to be claimed and minted for a given address
* @param _userAddress is the address that the claimable tokens are calculated for
*/
function getClaimableTokens(address _userAddress) public view returns(uint) {
return tokensOwed[_userAddress] + getPendingTokens(_userAddress);
}
/**
* @dev returns the tokens accounted for but not minted for a given address
* @param _userAddress is the address that wants to know whats owed
*/
function getTokensOwed(address _userAddress) public view returns(uint) {
return tokensOwed[_userAddress];
}
/**
* @dev recieves the pending tokens yet to be accounted for
* @param _userAddress is the address which the pending tokens are being calculated for
* @param _timeDifference is the current time minus the last time the _userAddress was updated
*/
function getPendingTokens(address _userAddress, uint _timeDifference) public view returns(uint) {
uint claimable;
for(uint i = 0; i < phoenixContracts.length; i++) {
claimable += phoenixContracts[i].getTotalLevels(_userAddress).mul(ratePerLevel[i]);
}
//multiply by the time in seconds, then divide by the number seconds in the day;
return claimable.mul(_timeDifference).div(86400);
}
/**
* @dev recieves the pending tokens yet to be accounted for, this function is called if the time difference since last update is unknown for the address
* @param _userAddress is the address which the pending tokens are being calculated for
*/
function getPendingTokens(address _userAddress) public view returns(uint) {
uint lastUpdated = lastUpdate[_userAddress];
if(lastUpdated == 0) {
return 0;
}
return getPendingTokens(_userAddress, block.timestamp - lastUpdated);
}
/**
______ __ __ __ __ ______ ______
/\ __ \ /\ \ _ \ \ /\ "-.\ \ /\ ___\ /\ == \
\ \ \/\ \ \ \ \/ ".\ \ \ \ \-. \ \ \ __\ \ \ __<
\ \_____\ \ \__/".~\_\ \ \_\\"\_\ \ \_____\ \ \_\ \_\
\/_____/ \/_/ \/_/ \/_/ \/_/ \/_____/ \/_/ /_/
*/
/**
* @dev Sets a phoenix contract where the phoenixs are capable of burning and generating tokens
* @param _phoenixAddress is the address of the phoenix contract
* @param _index is the index of where to set this information, either to add a new collection, or update an existing one
* @param _ratePerLevel is the rate of token generation per phoenix level for this contract
*/
function setPhoenixContract(address _phoenixAddress, uint _index, uint _ratePerLevel) external onlyOwner {
require(_index <= phoenixContracts.length, "index outside range");
if(phoenixContracts.length == _index) {
phoenixContracts.push(IPhoenix(_phoenixAddress));
ratePerLevel.push(_ratePerLevel);
}
else {
if(burnAddresses[address(phoenixContracts[_index])] == true) {
burnAddresses[address(phoenixContracts[_index])] = false;
}
phoenixContracts[_index] = IPhoenix(_phoenixAddress);
ratePerLevel[_index] = _ratePerLevel;
}
burnAddresses[_phoenixAddress] = true;
}
/**
* @dev sets the addresss that are allowed to call the burn function
* @param _burnAddress is the address being set
* @param _value is to allow or remove burning permission
*/
function setBurnAddress(address _burnAddress, bool _value) external onlyOwner {
burnAddresses[_burnAddress] = _value;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.
/**
* @dev Wrappers over Solidity's arithmetic operations.
*
* NOTE: `SafeMath` is no longer needed starting with Solidity 0.8. The compiler
* now has built in overflow checking.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
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._
*/
function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
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._
*/
function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
// 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/522
if (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._
*/
function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
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._
*/
function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
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.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
return a + b;
}
/**
* @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.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
return a * b;
}
/**
* @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.
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
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.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
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.
*/
function sub(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
unchecked {
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.
*
* 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.
*/
function div(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
unchecked {
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.
*/
function mod(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
unchecked {
require(b > 0, errorMessage);
return a % b;
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/
interface IERC20Metadata is IERC20 {
/**
* @dev Returns the name of the token.
*/
function name() external view returns (string memory);
/**
* @dev Returns the symbol of the token.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the decimals places of the token.
*/
function decimals() external view returns (uint8);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address sender,
address recipient,
uint256 amount
) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin Contracts guidelines: functions revert
* instead returning `false` on failure. This behavior is nonetheless
* conventional and does not conflict with the expectations of ERC20
* applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
/**
* @dev Sets the values for {name} and {symbol}.
*
* The default value of {decimals} is 18. To select a different value for
* {decimals} you should overload it.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5.05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless this function is
* overridden;
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view virtual override returns (uint8) {
return 18;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* Requirements:
*
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for ``sender``'s tokens of at least
* `amount`.
*/
function transferFrom(
address sender,
address recipient,
uint256 amount
) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
uint256 currentAllowance = _allowances[sender][_msgSender()];
require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
unchecked {
_approve(sender, _msgSender(), currentAllowance - amount);
}
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
uint256 currentAllowance = _allowances[_msgSender()][spender];
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(_msgSender(), spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `sender` to `recipient`.
*
* This internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(
address sender,
address recipient,
uint256 amount
) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
uint256 senderBalance = _balances[sender];
require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[sender] = senderBalance - amount;
}
_balances[recipient] += amount;
emit Transfer(sender, recipient, amount);
_afterTokenTransfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply += amount;
_balances[account] += amount;
emit Transfer(address(0), account, amount);
_afterTokenTransfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
}
_totalSupply -= amount;
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(
address owner,
address spender,
uint256 amount
) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _afterTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
abstract contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() {
_setOwner(_msgSender());
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
_setOwner(address(0));
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
_setOwner(newOwner);
}
function _setOwner(address newOwner) private {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}