Contract Source Code:
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)
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() {
_transferOwnership(_msgSender());
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
_checkOwner();
_;
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if the sender is not the owner.
*/
function _checkOwner() internal view virtual {
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 {
_transferOwnership(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");
_transferOwnership(newOwner);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Internal function without access restriction.
*/
function _transferOwnership(address newOwner) internal virtual {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @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);
/**
* @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 `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, 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 `from` to `to` 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 from,
address to,
uint256 amount
) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
* https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
*
* Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
* presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
* need to send a transaction, and thus is not required to hold Ether at all.
*/
interface IERC20Permit {
/**
* @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
* given ``owner``'s signed approval.
*
* IMPORTANT: The same issues {IERC20-approve} has related to transaction
* ordering also apply here.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `deadline` must be a timestamp in the future.
* - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
* over the EIP712-formatted function arguments.
* - the signature must use ``owner``'s current nonce (see {nonces}).
*
* For more information on the signature format, see the
* https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
* section].
*/
function permit(
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) external;
/**
* @dev Returns the current nonce for `owner`. This value must be
* included whenever a signature is generated for {permit}.
*
* Every successful call to {permit} increases ``owner``'s nonce by one. This
* prevents a signature from being used multiple times.
*/
function nonces(address owner) external view returns (uint256);
/**
* @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
*/
// solhint-disable-next-line func-name-mixedcase
function DOMAIN_SEPARATOR() external view returns (bytes32);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.sol";
import "../../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using Address for address;
function safeTransfer(
IERC20 token,
address to,
uint256 value
) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(
IERC20 token,
address from,
address to,
uint256 value
) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(
IERC20 token,
address spender,
uint256 value
) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
require(
(value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
uint256 newAllowance = token.allowance(address(this), spender) + value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
uint256 newAllowance = oldAllowance - value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
}
function safePermit(
IERC20Permit token,
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) internal {
uint256 nonceBefore = token.nonces(owner);
token.permit(owner, spender, value, deadline, v, r, s);
uint256 nonceAfter = token.nonces(owner);
require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) {
// Return data is optional
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)
pragma solidity ^0.8.1;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*
* [IMPORTANT]
* ====
* You shouldn't rely on `isContract` to protect against flash loan attacks!
*
* Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
* like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
* constructor.
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize/address.code.length, which returns 0
// for contracts in construction, since the code is only stored at the end
// of the constructor execution.
return account.code.length > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{value: amount}("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain `call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value
) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value,
string memory errorMessage
) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
(bool success, bytes memory returndata) = target.call{value: value}(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason using the provided one.
*
* _Available since v4.3._
*/
function verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) internal pure returns (bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
/// @solidity memory-safe-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
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
// OpenZeppelin Contracts (last updated v4.7.0) (utils/math/Math.sol)
pragma solidity ^0.8.0;
/**
* @dev Standard math utilities missing in the Solidity language.
*/
library Math {
enum Rounding {
Down, // Toward negative infinity
Up, // Toward infinity
Zero // Toward zero
}
/**
* @dev Returns the largest of two numbers.
*/
function max(uint256 a, uint256 b) internal pure returns (uint256) {
return a >= b ? a : b;
}
/**
* @dev Returns the smallest of two numbers.
*/
function min(uint256 a, uint256 b) internal pure returns (uint256) {
return a < b ? a : b;
}
/**
* @dev Returns the average of two numbers. The result is rounded towards
* zero.
*/
function average(uint256 a, uint256 b) internal pure returns (uint256) {
// (a + b) / 2 can overflow.
return (a & b) + (a ^ b) / 2;
}
/**
* @dev Returns the ceiling of the division of two numbers.
*
* This differs from standard division with `/` in that it rounds up instead
* of rounding down.
*/
function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
// (a + b - 1) / b can overflow on addition, so we distribute.
return a == 0 ? 0 : (a - 1) / b + 1;
}
/**
* @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
* @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
* with further edits by Uniswap Labs also under MIT license.
*/
function mulDiv(
uint256 x,
uint256 y,
uint256 denominator
) internal pure returns (uint256 result) {
unchecked {
// 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
// use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
// variables such that product = prod1 * 2^256 + prod0.
uint256 prod0; // Least significant 256 bits of the product
uint256 prod1; // Most significant 256 bits of the product
assembly {
let mm := mulmod(x, y, not(0))
prod0 := mul(x, y)
prod1 := sub(sub(mm, prod0), lt(mm, prod0))
}
// Handle non-overflow cases, 256 by 256 division.
if (prod1 == 0) {
return prod0 / denominator;
}
// Make sure the result is less than 2^256. Also prevents denominator == 0.
require(denominator > prod1);
///////////////////////////////////////////////
// 512 by 256 division.
///////////////////////////////////////////////
// Make division exact by subtracting the remainder from [prod1 prod0].
uint256 remainder;
assembly {
// Compute remainder using mulmod.
remainder := mulmod(x, y, denominator)
// Subtract 256 bit number from 512 bit number.
prod1 := sub(prod1, gt(remainder, prod0))
prod0 := sub(prod0, remainder)
}
// Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
// See https://cs.stackexchange.com/q/138556/92363.
// Does not overflow because the denominator cannot be zero at this stage in the function.
uint256 twos = denominator & (~denominator + 1);
assembly {
// Divide denominator by twos.
denominator := div(denominator, twos)
// Divide [prod1 prod0] by twos.
prod0 := div(prod0, twos)
// Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
twos := add(div(sub(0, twos), twos), 1)
}
// Shift in bits from prod1 into prod0.
prod0 |= prod1 * twos;
// Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
// that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
// four bits. That is, denominator * inv = 1 mod 2^4.
uint256 inverse = (3 * denominator) ^ 2;
// Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
// in modular arithmetic, doubling the correct bits in each step.
inverse *= 2 - denominator * inverse; // inverse mod 2^8
inverse *= 2 - denominator * inverse; // inverse mod 2^16
inverse *= 2 - denominator * inverse; // inverse mod 2^32
inverse *= 2 - denominator * inverse; // inverse mod 2^64
inverse *= 2 - denominator * inverse; // inverse mod 2^128
inverse *= 2 - denominator * inverse; // inverse mod 2^256
// Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
// This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
// less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
// is no longer required.
result = prod0 * inverse;
return result;
}
}
/**
* @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
*/
function mulDiv(
uint256 x,
uint256 y,
uint256 denominator,
Rounding rounding
) internal pure returns (uint256) {
uint256 result = mulDiv(x, y, denominator);
if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
result += 1;
}
return result;
}
/**
* @dev Returns the square root of a number. It the number is not a perfect square, the value is rounded down.
*
* Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
*/
function sqrt(uint256 a) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
// For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
// We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
// `msb(a) <= a < 2*msb(a)`.
// We also know that `k`, the position of the most significant bit, is such that `msb(a) = 2**k`.
// This gives `2**k < a <= 2**(k+1)` → `2**(k/2) <= sqrt(a) < 2 ** (k/2+1)`.
// Using an algorithm similar to the msb conmputation, we are able to compute `result = 2**(k/2)` which is a
// good first aproximation of `sqrt(a)` with at least 1 correct bit.
uint256 result = 1;
uint256 x = a;
if (x >> 128 > 0) {
x >>= 128;
result <<= 64;
}
if (x >> 64 > 0) {
x >>= 64;
result <<= 32;
}
if (x >> 32 > 0) {
x >>= 32;
result <<= 16;
}
if (x >> 16 > 0) {
x >>= 16;
result <<= 8;
}
if (x >> 8 > 0) {
x >>= 8;
result <<= 4;
}
if (x >> 4 > 0) {
x >>= 4;
result <<= 2;
}
if (x >> 2 > 0) {
result <<= 1;
}
// At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
// since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
// every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
// into the expected uint128 result.
unchecked {
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
return min(result, a / result);
}
}
/**
* @notice Calculates sqrt(a), following the selected rounding direction.
*/
function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
uint256 result = sqrt(a);
if (rounding == Rounding.Up && result * result < a) {
result += 1;
}
return result;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/math/SafeCast.sol)
pragma solidity ^0.8.0;
/**
* @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
* checks.
*
* Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
* easily result in undesired exploitation or bugs, since developers usually
* assume that overflows raise errors. `SafeCast` restores this intuition by
* reverting the transaction when such 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.
*
* Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
* all math on `uint256` and `int256` and then downcasting.
*/
library SafeCast {
/**
* @dev Returns the downcasted uint248 from uint256, reverting on
* overflow (when the input is greater than largest uint248).
*
* Counterpart to Solidity's `uint248` operator.
*
* Requirements:
*
* - input must fit into 248 bits
*
* _Available since v4.7._
*/
function toUint248(uint256 value) internal pure returns (uint248) {
require(value <= type(uint248).max, "SafeCast: value doesn't fit in 248 bits");
return uint248(value);
}
/**
* @dev Returns the downcasted uint240 from uint256, reverting on
* overflow (when the input is greater than largest uint240).
*
* Counterpart to Solidity's `uint240` operator.
*
* Requirements:
*
* - input must fit into 240 bits
*
* _Available since v4.7._
*/
function toUint240(uint256 value) internal pure returns (uint240) {
require(value <= type(uint240).max, "SafeCast: value doesn't fit in 240 bits");
return uint240(value);
}
/**
* @dev Returns the downcasted uint232 from uint256, reverting on
* overflow (when the input is greater than largest uint232).
*
* Counterpart to Solidity's `uint232` operator.
*
* Requirements:
*
* - input must fit into 232 bits
*
* _Available since v4.7._
*/
function toUint232(uint256 value) internal pure returns (uint232) {
require(value <= type(uint232).max, "SafeCast: value doesn't fit in 232 bits");
return uint232(value);
}
/**
* @dev Returns the downcasted uint224 from uint256, reverting on
* overflow (when the input is greater than largest uint224).
*
* Counterpart to Solidity's `uint224` operator.
*
* Requirements:
*
* - input must fit into 224 bits
*
* _Available since v4.2._
*/
function toUint224(uint256 value) internal pure returns (uint224) {
require(value <= type(uint224).max, "SafeCast: value doesn't fit in 224 bits");
return uint224(value);
}
/**
* @dev Returns the downcasted uint216 from uint256, reverting on
* overflow (when the input is greater than largest uint216).
*
* Counterpart to Solidity's `uint216` operator.
*
* Requirements:
*
* - input must fit into 216 bits
*
* _Available since v4.7._
*/
function toUint216(uint256 value) internal pure returns (uint216) {
require(value <= type(uint216).max, "SafeCast: value doesn't fit in 216 bits");
return uint216(value);
}
/**
* @dev Returns the downcasted uint208 from uint256, reverting on
* overflow (when the input is greater than largest uint208).
*
* Counterpart to Solidity's `uint208` operator.
*
* Requirements:
*
* - input must fit into 208 bits
*
* _Available since v4.7._
*/
function toUint208(uint256 value) internal pure returns (uint208) {
require(value <= type(uint208).max, "SafeCast: value doesn't fit in 208 bits");
return uint208(value);
}
/**
* @dev Returns the downcasted uint200 from uint256, reverting on
* overflow (when the input is greater than largest uint200).
*
* Counterpart to Solidity's `uint200` operator.
*
* Requirements:
*
* - input must fit into 200 bits
*
* _Available since v4.7._
*/
function toUint200(uint256 value) internal pure returns (uint200) {
require(value <= type(uint200).max, "SafeCast: value doesn't fit in 200 bits");
return uint200(value);
}
/**
* @dev Returns the downcasted uint192 from uint256, reverting on
* overflow (when the input is greater than largest uint192).
*
* Counterpart to Solidity's `uint192` operator.
*
* Requirements:
*
* - input must fit into 192 bits
*
* _Available since v4.7._
*/
function toUint192(uint256 value) internal pure returns (uint192) {
require(value <= type(uint192).max, "SafeCast: value doesn't fit in 192 bits");
return uint192(value);
}
/**
* @dev Returns the downcasted uint184 from uint256, reverting on
* overflow (when the input is greater than largest uint184).
*
* Counterpart to Solidity's `uint184` operator.
*
* Requirements:
*
* - input must fit into 184 bits
*
* _Available since v4.7._
*/
function toUint184(uint256 value) internal pure returns (uint184) {
require(value <= type(uint184).max, "SafeCast: value doesn't fit in 184 bits");
return uint184(value);
}
/**
* @dev Returns the downcasted uint176 from uint256, reverting on
* overflow (when the input is greater than largest uint176).
*
* Counterpart to Solidity's `uint176` operator.
*
* Requirements:
*
* - input must fit into 176 bits
*
* _Available since v4.7._
*/
function toUint176(uint256 value) internal pure returns (uint176) {
require(value <= type(uint176).max, "SafeCast: value doesn't fit in 176 bits");
return uint176(value);
}
/**
* @dev Returns the downcasted uint168 from uint256, reverting on
* overflow (when the input is greater than largest uint168).
*
* Counterpart to Solidity's `uint168` operator.
*
* Requirements:
*
* - input must fit into 168 bits
*
* _Available since v4.7._
*/
function toUint168(uint256 value) internal pure returns (uint168) {
require(value <= type(uint168).max, "SafeCast: value doesn't fit in 168 bits");
return uint168(value);
}
/**
* @dev Returns the downcasted uint160 from uint256, reverting on
* overflow (when the input is greater than largest uint160).
*
* Counterpart to Solidity's `uint160` operator.
*
* Requirements:
*
* - input must fit into 160 bits
*
* _Available since v4.7._
*/
function toUint160(uint256 value) internal pure returns (uint160) {
require(value <= type(uint160).max, "SafeCast: value doesn't fit in 160 bits");
return uint160(value);
}
/**
* @dev Returns the downcasted uint152 from uint256, reverting on
* overflow (when the input is greater than largest uint152).
*
* Counterpart to Solidity's `uint152` operator.
*
* Requirements:
*
* - input must fit into 152 bits
*
* _Available since v4.7._
*/
function toUint152(uint256 value) internal pure returns (uint152) {
require(value <= type(uint152).max, "SafeCast: value doesn't fit in 152 bits");
return uint152(value);
}
/**
* @dev Returns the downcasted uint144 from uint256, reverting on
* overflow (when the input is greater than largest uint144).
*
* Counterpart to Solidity's `uint144` operator.
*
* Requirements:
*
* - input must fit into 144 bits
*
* _Available since v4.7._
*/
function toUint144(uint256 value) internal pure returns (uint144) {
require(value <= type(uint144).max, "SafeCast: value doesn't fit in 144 bits");
return uint144(value);
}
/**
* @dev Returns the downcasted uint136 from uint256, reverting on
* overflow (when the input is greater than largest uint136).
*
* Counterpart to Solidity's `uint136` operator.
*
* Requirements:
*
* - input must fit into 136 bits
*
* _Available since v4.7._
*/
function toUint136(uint256 value) internal pure returns (uint136) {
require(value <= type(uint136).max, "SafeCast: value doesn't fit in 136 bits");
return uint136(value);
}
/**
* @dev Returns the downcasted uint128 from uint256, reverting on
* overflow (when the input is greater than largest uint128).
*
* Counterpart to Solidity's `uint128` operator.
*
* Requirements:
*
* - input must fit into 128 bits
*
* _Available since v2.5._
*/
function toUint128(uint256 value) internal pure returns (uint128) {
require(value <= type(uint128).max, "SafeCast: value doesn't fit in 128 bits");
return uint128(value);
}
/**
* @dev Returns the downcasted uint120 from uint256, reverting on
* overflow (when the input is greater than largest uint120).
*
* Counterpart to Solidity's `uint120` operator.
*
* Requirements:
*
* - input must fit into 120 bits
*
* _Available since v4.7._
*/
function toUint120(uint256 value) internal pure returns (uint120) {
require(value <= type(uint120).max, "SafeCast: value doesn't fit in 120 bits");
return uint120(value);
}
/**
* @dev Returns the downcasted uint112 from uint256, reverting on
* overflow (when the input is greater than largest uint112).
*
* Counterpart to Solidity's `uint112` operator.
*
* Requirements:
*
* - input must fit into 112 bits
*
* _Available since v4.7._
*/
function toUint112(uint256 value) internal pure returns (uint112) {
require(value <= type(uint112).max, "SafeCast: value doesn't fit in 112 bits");
return uint112(value);
}
/**
* @dev Returns the downcasted uint104 from uint256, reverting on
* overflow (when the input is greater than largest uint104).
*
* Counterpart to Solidity's `uint104` operator.
*
* Requirements:
*
* - input must fit into 104 bits
*
* _Available since v4.7._
*/
function toUint104(uint256 value) internal pure returns (uint104) {
require(value <= type(uint104).max, "SafeCast: value doesn't fit in 104 bits");
return uint104(value);
}
/**
* @dev Returns the downcasted uint96 from uint256, reverting on
* overflow (when the input is greater than largest uint96).
*
* Counterpart to Solidity's `uint96` operator.
*
* Requirements:
*
* - input must fit into 96 bits
*
* _Available since v4.2._
*/
function toUint96(uint256 value) internal pure returns (uint96) {
require(value <= type(uint96).max, "SafeCast: value doesn't fit in 96 bits");
return uint96(value);
}
/**
* @dev Returns the downcasted uint88 from uint256, reverting on
* overflow (when the input is greater than largest uint88).
*
* Counterpart to Solidity's `uint88` operator.
*
* Requirements:
*
* - input must fit into 88 bits
*
* _Available since v4.7._
*/
function toUint88(uint256 value) internal pure returns (uint88) {
require(value <= type(uint88).max, "SafeCast: value doesn't fit in 88 bits");
return uint88(value);
}
/**
* @dev Returns the downcasted uint80 from uint256, reverting on
* overflow (when the input is greater than largest uint80).
*
* Counterpart to Solidity's `uint80` operator.
*
* Requirements:
*
* - input must fit into 80 bits
*
* _Available since v4.7._
*/
function toUint80(uint256 value) internal pure returns (uint80) {
require(value <= type(uint80).max, "SafeCast: value doesn't fit in 80 bits");
return uint80(value);
}
/**
* @dev Returns the downcasted uint72 from uint256, reverting on
* overflow (when the input is greater than largest uint72).
*
* Counterpart to Solidity's `uint72` operator.
*
* Requirements:
*
* - input must fit into 72 bits
*
* _Available since v4.7._
*/
function toUint72(uint256 value) internal pure returns (uint72) {
require(value <= type(uint72).max, "SafeCast: value doesn't fit in 72 bits");
return uint72(value);
}
/**
* @dev Returns the downcasted uint64 from uint256, reverting on
* overflow (when the input is greater than largest uint64).
*
* Counterpart to Solidity's `uint64` operator.
*
* Requirements:
*
* - input must fit into 64 bits
*
* _Available since v2.5._
*/
function toUint64(uint256 value) internal pure returns (uint64) {
require(value <= type(uint64).max, "SafeCast: value doesn't fit in 64 bits");
return uint64(value);
}
/**
* @dev Returns the downcasted uint56 from uint256, reverting on
* overflow (when the input is greater than largest uint56).
*
* Counterpart to Solidity's `uint56` operator.
*
* Requirements:
*
* - input must fit into 56 bits
*
* _Available since v4.7._
*/
function toUint56(uint256 value) internal pure returns (uint56) {
require(value <= type(uint56).max, "SafeCast: value doesn't fit in 56 bits");
return uint56(value);
}
/**
* @dev Returns the downcasted uint48 from uint256, reverting on
* overflow (when the input is greater than largest uint48).
*
* Counterpart to Solidity's `uint48` operator.
*
* Requirements:
*
* - input must fit into 48 bits
*
* _Available since v4.7._
*/
function toUint48(uint256 value) internal pure returns (uint48) {
require(value <= type(uint48).max, "SafeCast: value doesn't fit in 48 bits");
return uint48(value);
}
/**
* @dev Returns the downcasted uint40 from uint256, reverting on
* overflow (when the input is greater than largest uint40).
*
* Counterpart to Solidity's `uint40` operator.
*
* Requirements:
*
* - input must fit into 40 bits
*
* _Available since v4.7._
*/
function toUint40(uint256 value) internal pure returns (uint40) {
require(value <= type(uint40).max, "SafeCast: value doesn't fit in 40 bits");
return uint40(value);
}
/**
* @dev Returns the downcasted uint32 from uint256, reverting on
* overflow (when the input is greater than largest uint32).
*
* Counterpart to Solidity's `uint32` operator.
*
* Requirements:
*
* - input must fit into 32 bits
*
* _Available since v2.5._
*/
function toUint32(uint256 value) internal pure returns (uint32) {
require(value <= type(uint32).max, "SafeCast: value doesn't fit in 32 bits");
return uint32(value);
}
/**
* @dev Returns the downcasted uint24 from uint256, reverting on
* overflow (when the input is greater than largest uint24).
*
* Counterpart to Solidity's `uint24` operator.
*
* Requirements:
*
* - input must fit into 24 bits
*
* _Available since v4.7._
*/
function toUint24(uint256 value) internal pure returns (uint24) {
require(value <= type(uint24).max, "SafeCast: value doesn't fit in 24 bits");
return uint24(value);
}
/**
* @dev Returns the downcasted uint16 from uint256, reverting on
* overflow (when the input is greater than largest uint16).
*
* Counterpart to Solidity's `uint16` operator.
*
* Requirements:
*
* - input must fit into 16 bits
*
* _Available since v2.5._
*/
function toUint16(uint256 value) internal pure returns (uint16) {
require(value <= type(uint16).max, "SafeCast: value doesn't fit in 16 bits");
return uint16(value);
}
/**
* @dev Returns the downcasted uint8 from uint256, reverting on
* overflow (when the input is greater than largest uint8).
*
* Counterpart to Solidity's `uint8` operator.
*
* Requirements:
*
* - input must fit into 8 bits
*
* _Available since v2.5._
*/
function toUint8(uint256 value) internal pure returns (uint8) {
require(value <= type(uint8).max, "SafeCast: value doesn't fit in 8 bits");
return uint8(value);
}
/**
* @dev Converts a signed int256 into an unsigned uint256.
*
* Requirements:
*
* - input must be greater than or equal to 0.
*
* _Available since v3.0._
*/
function toUint256(int256 value) internal pure returns (uint256) {
require(value >= 0, "SafeCast: value must be positive");
return uint256(value);
}
/**
* @dev Returns the downcasted int248 from int256, reverting on
* overflow (when the input is less than smallest int248 or
* greater than largest int248).
*
* Counterpart to Solidity's `int248` operator.
*
* Requirements:
*
* - input must fit into 248 bits
*
* _Available since v4.7._
*/
function toInt248(int256 value) internal pure returns (int248) {
require(value >= type(int248).min && value <= type(int248).max, "SafeCast: value doesn't fit in 248 bits");
return int248(value);
}
/**
* @dev Returns the downcasted int240 from int256, reverting on
* overflow (when the input is less than smallest int240 or
* greater than largest int240).
*
* Counterpart to Solidity's `int240` operator.
*
* Requirements:
*
* - input must fit into 240 bits
*
* _Available since v4.7._
*/
function toInt240(int256 value) internal pure returns (int240) {
require(value >= type(int240).min && value <= type(int240).max, "SafeCast: value doesn't fit in 240 bits");
return int240(value);
}
/**
* @dev Returns the downcasted int232 from int256, reverting on
* overflow (when the input is less than smallest int232 or
* greater than largest int232).
*
* Counterpart to Solidity's `int232` operator.
*
* Requirements:
*
* - input must fit into 232 bits
*
* _Available since v4.7._
*/
function toInt232(int256 value) internal pure returns (int232) {
require(value >= type(int232).min && value <= type(int232).max, "SafeCast: value doesn't fit in 232 bits");
return int232(value);
}
/**
* @dev Returns the downcasted int224 from int256, reverting on
* overflow (when the input is less than smallest int224 or
* greater than largest int224).
*
* Counterpart to Solidity's `int224` operator.
*
* Requirements:
*
* - input must fit into 224 bits
*
* _Available since v4.7._
*/
function toInt224(int256 value) internal pure returns (int224) {
require(value >= type(int224).min && value <= type(int224).max, "SafeCast: value doesn't fit in 224 bits");
return int224(value);
}
/**
* @dev Returns the downcasted int216 from int256, reverting on
* overflow (when the input is less than smallest int216 or
* greater than largest int216).
*
* Counterpart to Solidity's `int216` operator.
*
* Requirements:
*
* - input must fit into 216 bits
*
* _Available since v4.7._
*/
function toInt216(int256 value) internal pure returns (int216) {
require(value >= type(int216).min && value <= type(int216).max, "SafeCast: value doesn't fit in 216 bits");
return int216(value);
}
/**
* @dev Returns the downcasted int208 from int256, reverting on
* overflow (when the input is less than smallest int208 or
* greater than largest int208).
*
* Counterpart to Solidity's `int208` operator.
*
* Requirements:
*
* - input must fit into 208 bits
*
* _Available since v4.7._
*/
function toInt208(int256 value) internal pure returns (int208) {
require(value >= type(int208).min && value <= type(int208).max, "SafeCast: value doesn't fit in 208 bits");
return int208(value);
}
/**
* @dev Returns the downcasted int200 from int256, reverting on
* overflow (when the input is less than smallest int200 or
* greater than largest int200).
*
* Counterpart to Solidity's `int200` operator.
*
* Requirements:
*
* - input must fit into 200 bits
*
* _Available since v4.7._
*/
function toInt200(int256 value) internal pure returns (int200) {
require(value >= type(int200).min && value <= type(int200).max, "SafeCast: value doesn't fit in 200 bits");
return int200(value);
}
/**
* @dev Returns the downcasted int192 from int256, reverting on
* overflow (when the input is less than smallest int192 or
* greater than largest int192).
*
* Counterpart to Solidity's `int192` operator.
*
* Requirements:
*
* - input must fit into 192 bits
*
* _Available since v4.7._
*/
function toInt192(int256 value) internal pure returns (int192) {
require(value >= type(int192).min && value <= type(int192).max, "SafeCast: value doesn't fit in 192 bits");
return int192(value);
}
/**
* @dev Returns the downcasted int184 from int256, reverting on
* overflow (when the input is less than smallest int184 or
* greater than largest int184).
*
* Counterpart to Solidity's `int184` operator.
*
* Requirements:
*
* - input must fit into 184 bits
*
* _Available since v4.7._
*/
function toInt184(int256 value) internal pure returns (int184) {
require(value >= type(int184).min && value <= type(int184).max, "SafeCast: value doesn't fit in 184 bits");
return int184(value);
}
/**
* @dev Returns the downcasted int176 from int256, reverting on
* overflow (when the input is less than smallest int176 or
* greater than largest int176).
*
* Counterpart to Solidity's `int176` operator.
*
* Requirements:
*
* - input must fit into 176 bits
*
* _Available since v4.7._
*/
function toInt176(int256 value) internal pure returns (int176) {
require(value >= type(int176).min && value <= type(int176).max, "SafeCast: value doesn't fit in 176 bits");
return int176(value);
}
/**
* @dev Returns the downcasted int168 from int256, reverting on
* overflow (when the input is less than smallest int168 or
* greater than largest int168).
*
* Counterpart to Solidity's `int168` operator.
*
* Requirements:
*
* - input must fit into 168 bits
*
* _Available since v4.7._
*/
function toInt168(int256 value) internal pure returns (int168) {
require(value >= type(int168).min && value <= type(int168).max, "SafeCast: value doesn't fit in 168 bits");
return int168(value);
}
/**
* @dev Returns the downcasted int160 from int256, reverting on
* overflow (when the input is less than smallest int160 or
* greater than largest int160).
*
* Counterpart to Solidity's `int160` operator.
*
* Requirements:
*
* - input must fit into 160 bits
*
* _Available since v4.7._
*/
function toInt160(int256 value) internal pure returns (int160) {
require(value >= type(int160).min && value <= type(int160).max, "SafeCast: value doesn't fit in 160 bits");
return int160(value);
}
/**
* @dev Returns the downcasted int152 from int256, reverting on
* overflow (when the input is less than smallest int152 or
* greater than largest int152).
*
* Counterpart to Solidity's `int152` operator.
*
* Requirements:
*
* - input must fit into 152 bits
*
* _Available since v4.7._
*/
function toInt152(int256 value) internal pure returns (int152) {
require(value >= type(int152).min && value <= type(int152).max, "SafeCast: value doesn't fit in 152 bits");
return int152(value);
}
/**
* @dev Returns the downcasted int144 from int256, reverting on
* overflow (when the input is less than smallest int144 or
* greater than largest int144).
*
* Counterpart to Solidity's `int144` operator.
*
* Requirements:
*
* - input must fit into 144 bits
*
* _Available since v4.7._
*/
function toInt144(int256 value) internal pure returns (int144) {
require(value >= type(int144).min && value <= type(int144).max, "SafeCast: value doesn't fit in 144 bits");
return int144(value);
}
/**
* @dev Returns the downcasted int136 from int256, reverting on
* overflow (when the input is less than smallest int136 or
* greater than largest int136).
*
* Counterpart to Solidity's `int136` operator.
*
* Requirements:
*
* - input must fit into 136 bits
*
* _Available since v4.7._
*/
function toInt136(int256 value) internal pure returns (int136) {
require(value >= type(int136).min && value <= type(int136).max, "SafeCast: value doesn't fit in 136 bits");
return int136(value);
}
/**
* @dev Returns the downcasted int128 from int256, reverting on
* overflow (when the input is less than smallest int128 or
* greater than largest int128).
*
* Counterpart to Solidity's `int128` operator.
*
* Requirements:
*
* - input must fit into 128 bits
*
* _Available since v3.1._
*/
function toInt128(int256 value) internal pure returns (int128) {
require(value >= type(int128).min && value <= type(int128).max, "SafeCast: value doesn't fit in 128 bits");
return int128(value);
}
/**
* @dev Returns the downcasted int120 from int256, reverting on
* overflow (when the input is less than smallest int120 or
* greater than largest int120).
*
* Counterpart to Solidity's `int120` operator.
*
* Requirements:
*
* - input must fit into 120 bits
*
* _Available since v4.7._
*/
function toInt120(int256 value) internal pure returns (int120) {
require(value >= type(int120).min && value <= type(int120).max, "SafeCast: value doesn't fit in 120 bits");
return int120(value);
}
/**
* @dev Returns the downcasted int112 from int256, reverting on
* overflow (when the input is less than smallest int112 or
* greater than largest int112).
*
* Counterpart to Solidity's `int112` operator.
*
* Requirements:
*
* - input must fit into 112 bits
*
* _Available since v4.7._
*/
function toInt112(int256 value) internal pure returns (int112) {
require(value >= type(int112).min && value <= type(int112).max, "SafeCast: value doesn't fit in 112 bits");
return int112(value);
}
/**
* @dev Returns the downcasted int104 from int256, reverting on
* overflow (when the input is less than smallest int104 or
* greater than largest int104).
*
* Counterpart to Solidity's `int104` operator.
*
* Requirements:
*
* - input must fit into 104 bits
*
* _Available since v4.7._
*/
function toInt104(int256 value) internal pure returns (int104) {
require(value >= type(int104).min && value <= type(int104).max, "SafeCast: value doesn't fit in 104 bits");
return int104(value);
}
/**
* @dev Returns the downcasted int96 from int256, reverting on
* overflow (when the input is less than smallest int96 or
* greater than largest int96).
*
* Counterpart to Solidity's `int96` operator.
*
* Requirements:
*
* - input must fit into 96 bits
*
* _Available since v4.7._
*/
function toInt96(int256 value) internal pure returns (int96) {
require(value >= type(int96).min && value <= type(int96).max, "SafeCast: value doesn't fit in 96 bits");
return int96(value);
}
/**
* @dev Returns the downcasted int88 from int256, reverting on
* overflow (when the input is less than smallest int88 or
* greater than largest int88).
*
* Counterpart to Solidity's `int88` operator.
*
* Requirements:
*
* - input must fit into 88 bits
*
* _Available since v4.7._
*/
function toInt88(int256 value) internal pure returns (int88) {
require(value >= type(int88).min && value <= type(int88).max, "SafeCast: value doesn't fit in 88 bits");
return int88(value);
}
/**
* @dev Returns the downcasted int80 from int256, reverting on
* overflow (when the input is less than smallest int80 or
* greater than largest int80).
*
* Counterpart to Solidity's `int80` operator.
*
* Requirements:
*
* - input must fit into 80 bits
*
* _Available since v4.7._
*/
function toInt80(int256 value) internal pure returns (int80) {
require(value >= type(int80).min && value <= type(int80).max, "SafeCast: value doesn't fit in 80 bits");
return int80(value);
}
/**
* @dev Returns the downcasted int72 from int256, reverting on
* overflow (when the input is less than smallest int72 or
* greater than largest int72).
*
* Counterpart to Solidity's `int72` operator.
*
* Requirements:
*
* - input must fit into 72 bits
*
* _Available since v4.7._
*/
function toInt72(int256 value) internal pure returns (int72) {
require(value >= type(int72).min && value <= type(int72).max, "SafeCast: value doesn't fit in 72 bits");
return int72(value);
}
/**
* @dev Returns the downcasted int64 from int256, reverting on
* overflow (when the input is less than smallest int64 or
* greater than largest int64).
*
* Counterpart to Solidity's `int64` operator.
*
* Requirements:
*
* - input must fit into 64 bits
*
* _Available since v3.1._
*/
function toInt64(int256 value) internal pure returns (int64) {
require(value >= type(int64).min && value <= type(int64).max, "SafeCast: value doesn't fit in 64 bits");
return int64(value);
}
/**
* @dev Returns the downcasted int56 from int256, reverting on
* overflow (when the input is less than smallest int56 or
* greater than largest int56).
*
* Counterpart to Solidity's `int56` operator.
*
* Requirements:
*
* - input must fit into 56 bits
*
* _Available since v4.7._
*/
function toInt56(int256 value) internal pure returns (int56) {
require(value >= type(int56).min && value <= type(int56).max, "SafeCast: value doesn't fit in 56 bits");
return int56(value);
}
/**
* @dev Returns the downcasted int48 from int256, reverting on
* overflow (when the input is less than smallest int48 or
* greater than largest int48).
*
* Counterpart to Solidity's `int48` operator.
*
* Requirements:
*
* - input must fit into 48 bits
*
* _Available since v4.7._
*/
function toInt48(int256 value) internal pure returns (int48) {
require(value >= type(int48).min && value <= type(int48).max, "SafeCast: value doesn't fit in 48 bits");
return int48(value);
}
/**
* @dev Returns the downcasted int40 from int256, reverting on
* overflow (when the input is less than smallest int40 or
* greater than largest int40).
*
* Counterpart to Solidity's `int40` operator.
*
* Requirements:
*
* - input must fit into 40 bits
*
* _Available since v4.7._
*/
function toInt40(int256 value) internal pure returns (int40) {
require(value >= type(int40).min && value <= type(int40).max, "SafeCast: value doesn't fit in 40 bits");
return int40(value);
}
/**
* @dev Returns the downcasted int32 from int256, reverting on
* overflow (when the input is less than smallest int32 or
* greater than largest int32).
*
* Counterpart to Solidity's `int32` operator.
*
* Requirements:
*
* - input must fit into 32 bits
*
* _Available since v3.1._
*/
function toInt32(int256 value) internal pure returns (int32) {
require(value >= type(int32).min && value <= type(int32).max, "SafeCast: value doesn't fit in 32 bits");
return int32(value);
}
/**
* @dev Returns the downcasted int24 from int256, reverting on
* overflow (when the input is less than smallest int24 or
* greater than largest int24).
*
* Counterpart to Solidity's `int24` operator.
*
* Requirements:
*
* - input must fit into 24 bits
*
* _Available since v4.7._
*/
function toInt24(int256 value) internal pure returns (int24) {
require(value >= type(int24).min && value <= type(int24).max, "SafeCast: value doesn't fit in 24 bits");
return int24(value);
}
/**
* @dev Returns the downcasted int16 from int256, reverting on
* overflow (when the input is less than smallest int16 or
* greater than largest int16).
*
* Counterpart to Solidity's `int16` operator.
*
* Requirements:
*
* - input must fit into 16 bits
*
* _Available since v3.1._
*/
function toInt16(int256 value) internal pure returns (int16) {
require(value >= type(int16).min && value <= type(int16).max, "SafeCast: value doesn't fit in 16 bits");
return int16(value);
}
/**
* @dev Returns the downcasted int8 from int256, reverting on
* overflow (when the input is less than smallest int8 or
* greater than largest int8).
*
* Counterpart to Solidity's `int8` operator.
*
* Requirements:
*
* - input must fit into 8 bits
*
* _Available since v3.1._
*/
function toInt8(int256 value) internal pure returns (int8) {
require(value >= type(int8).min && value <= type(int8).max, "SafeCast: value doesn't fit in 8 bits");
return int8(value);
}
/**
* @dev Converts an unsigned uint256 into a signed int256.
*
* Requirements:
*
* - input must be less than or equal to maxInt256.
*
* _Available since v3.0._
*/
function toInt256(uint256 value) internal pure returns (int256) {
// Note: Unsafe cast below is okay because `type(int256).max` is guaranteed to be positive
require(value <= uint256(type(int256).max), "SafeCast: value doesn't fit in an int256");
return int256(value);
}
}
// SPDX-License-Identifier: GPL-3.0
/// @title PriceFeed Interface
/*********************************
* ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
* ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
* ░░░░░░█████████░░█████████░░░ *
* ░░░░░░██░░░████░░██░░░████░░░ *
* ░░██████░░░████████░░░████░░░ *
* ░░██░░██░░░████░░██░░░████░░░ *
* ░░██░░██░░░████░░██░░░████░░░ *
* ░░░░░░█████████░░█████████░░░ *
* ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
* ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
*********************************/
pragma solidity ^0.8.17;
import { IERC20 } from 'openzeppelin-contracts/contracts/token/ERC20/IERC20.sol';
interface IPayer {
function payBackDebt(uint256 amount) external;
function totalDebt() external view returns (uint256);
function paymentToken() external view returns (IERC20);
}
// SPDX-License-Identifier: GPL-3.0
/*********************************
* ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
* ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
* ░░░░░░█████████░░█████████░░░ *
* ░░░░░░██░░░████░░██░░░████░░░ *
* ░░██████░░░████████░░░████░░░ *
* ░░██░░██░░░████░░██░░░████░░░ *
* ░░██░░██░░░████░░██░░░████░░░ *
* ░░░░░░█████████░░█████████░░░ *
* ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
* ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
*********************************/
pragma solidity ^0.8.17;
import { Ownable } from 'openzeppelin-contracts/contracts/access/Ownable.sol';
import { IERC20 } from 'openzeppelin-contracts/contracts/token/ERC20/IERC20.sol';
import { SafeERC20 } from 'openzeppelin-contracts/contracts/token/ERC20/utils/SafeERC20.sol';
import { Math } from 'openzeppelin-contracts/contracts/utils/math/Math.sol';
import { DebtQueue } from './libs/DebtQueue.sol';
import { IPayer } from './IPayer.sol';
/// @title Payer
/// @notice This is used to pay users from a balance of ERC20 tokens.
/// If there's not enough balance, a debt entry is saved and the debt will be paid when there's balance available
contract Payer is IPayer, Ownable {
using SafeERC20 for IERC20;
using DebtQueue for DebtQueue.DebtDeque;
/**
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
IMMUTABLES
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*/
/// @notice The ERC20 token used to pay users
IERC20 public immutable paymentToken;
/**
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
STORAGE VARIABLES
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
*/
/// @notice The total debt owed to users in `paymentToken` tokens
uint256 public totalDebt;
/// @notice A queue of debt entries waiting to be paid
/// @dev The queue is FIFO
DebtQueue.DebtDeque public queue;
/**
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
EVENTS
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
*/
/// @notice Emitted when debt is paid back to the user
event PaidBackDebt(address indexed account, uint256 amount, uint256 remainingDebt);
/// @notice Emitted when a new debt entry is added
event RegisteredDebt(address indexed account, uint256 amount);
/// @notice Emitted when the contract owner withdraws the `paymentToken` balance
event TokensWithdrawn(address indexed account, uint256 amount);
/**
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
ERRORS
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
*/
error CastError();
/**
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
CONSTRUCTOR
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
*/
/// @param _owner The address of the contract owner, allowed to performed certain operations
/// @param _paymentToken The address of the ERC20 token used for payments
constructor(address _owner, address _paymentToken) {
paymentToken = IERC20(_paymentToken);
_transferOwnership(_owner);
}
/**
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
EXTERNAL FUNCTIONS (ONLY OWNER)
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*/
/// @notice Pays a user a certain amount of tokens. Adds a debt entry if there's not enough tokens.
/// @dev Only the owner is allowed to call this function
/// @param account The address of the user to be paid
/// @param amount The maximum amount of tokens to be paid
function sendOrRegisterDebt(address account, uint256 amount) external onlyOwner {
uint256 availableBalance = paymentToken.balanceOf(address(this));
if (amount <= availableBalance) {
// If there's enough balance to pay in full: send the entire amount
paymentToken.safeTransfer(account, amount);
} else if (availableBalance > 0) {
// If there's some balance, but not enough to pay in full
// 1. Pay what we can
paymentToken.safeTransfer(account, availableBalance);
// 2. Add a debt entry for the remaining amount
registerDebt(account, amount - availableBalance);
} else {
// Zero balance, add a debt entry for the entire amount
registerDebt(account, amount);
}
}
/// @notice Withdraws the entire balance of `paymentToken` to the owner
/// @dev Only the owner is allowed to call this function
function withdrawPaymentToken() external onlyOwner {
address to = msg.sender; // This is owner() because using `onlyOwner`
uint256 amount = paymentToken.balanceOf(address(this));
paymentToken.safeTransfer(to, amount);
emit TokensWithdrawn(to, amount);
}
/**
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
EXTERNAL FUNCTIONS (ANYONE CAN CALL)
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*/
/// @notice Pays back debt up to `amount` of `paymentToken`. Debt is paid in FIFO order.
/// @param amount The maximum amount of tokens to send. This is expected to be the token balance of this contract
/// @dev Assumes new entries are add to the 'back' of the queue, meaning oldest entries are at the 'front' of the queue
function payBackDebt(uint256 amount) external {
uint256 debtPaidBack = 0;
// While there are tokens left, and debt entries exist
while (amount > 0 && !queue.empty()) {
// Get the oldest entry
DebtQueue.DebtEntry storage debt = queue.front();
// Cache storage values
uint96 _debtAmount = debt.amount;
address _debtAccount = debt.account;
if (amount < _debtAmount) {
// Not enough to cover entire debt, pay what you can and leave
// cast is safe because `amount` < `_debtAmount` (uint96)
uint96 remainingDebt = _debtAmount - uint96(amount);
// Update remaining debt in queue
debt.amount = remainingDebt;
// Update debt paid back
debtPaidBack += amount;
// Pay user what we can
paymentToken.safeTransfer(_debtAccount, amount);
emit PaidBackDebt(_debtAccount, amount, remainingDebt);
// No more tokens, leave
break;
} else {
// Enough to cover entire debt entry, pay in full and remove from queue
// Update amount of tokens left to pay back debt
amount -= _debtAmount;
// Update debt paid back
debtPaidBack += _debtAmount;
// Remove entry from queue
queue.popFront();
// Pay user the entire amount
paymentToken.safeTransfer(_debtAccount, _debtAmount);
emit PaidBackDebt(_debtAccount, _debtAmount, 0);
}
}
// Update totalDebt
if (debtPaidBack > 0) {
totalDebt -= debtPaidBack;
}
}
/**
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
VIEW FUNCTIONS
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
*/
/// @notice Returns the amount of debt owed to `account`
/// @dev It takes into account there may be more that one debt entry for an account
/// @param account The address of the account to check
/// @return amount The amount of tokens the contract owes `account`
function debtOf(address account) external view returns (uint256 amount) {
uint256 queueLength = queue.length();
for (uint256 i; i < queueLength; ++i) {
DebtQueue.DebtEntry storage debtEntry = queue.at(i);
if (debtEntry.account == account) {
amount += debtEntry.amount;
}
}
}
/// @notice Returns the details of debt entry at index `index` in the queue
/// @dev Index 0 is front of the queue
/// @param index The index of the debt entry in the queue
/// @return account The address of the account owed debt
/// @return amount The amount of debt owed in `paymentToken` tokens
function queueAt(uint256 index) external view returns (address account, uint256 amount) {
DebtQueue.DebtEntry storage debtEntry = queue.at(index);
return (debtEntry.account, debtEntry.amount);
}
/**
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
INTERNAL FUNCTIONS
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
*/
/// @notice Adds a new debt entry to the queue
/// @dev Pushes to the back of the queue, to maintain FIFO order
/// @param account The address of the account owed debt
/// @param amount The amount of debt owed in `paymentToken` tokens
function registerDebt(address account, uint256 amount) internal {
queue.pushBack(DebtQueue.DebtEntry({ account: account, amount: toUint96(amount) }));
totalDebt += amount;
emit RegisteredDebt(account, amount);
}
/// @notice Safe casting to from uint256 to uint96
function toUint96(uint256 value) internal pure returns (uint96) {
if (value > type(uint96).max) revert CastError();
return uint96(value);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (utils/structs/DoubleEndedQueue.sol)
pragma solidity ^0.8.4;
import 'openzeppelin-contracts/contracts/utils/math/SafeCast.sol';
/**
* @notice Modified version of Open Zeppelin's DoubleEndedQueue, but using `DebtEntry` instead of `bytes32` for the values in the queue
* DoubleEndedQueue: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.7.3/contracts/utils/structs/DoubleEndedQueue.sol
* The purpose of the queue is to keep track of accounts holding debt and their order
* @dev The queue is intended to be used only as FIFO, so the functions `popBack`, `pushFront`, `back`, `clear` were removed
*/
library DebtQueue {
/**
* @dev An operation (e.g. {front}) couldn't be completed due to the queue being empty.
*/
error Empty();
/**
* @dev An operation (e.g. {at}) couldn't be completed due to an index being out of bounds.
*/
error OutOfBounds();
struct DebtEntry {
address account;
uint96 amount;
}
/**
* @dev Indices are signed integers because the queue can grow in any direction. They are 128 bits so begin and end
* are packed in a single storage slot for efficient access. Since the items are added one at a time we can safely
* assume that these 128-bit indices will not overflow, and use unchecked arithmetic.
*
* Struct members have an underscore prefix indicating that they are "private" and should not be read or written to
* directly. Use the functions provided below instead. Modifying the struct manually may violate assumptions and
* lead to unexpected behavior.
*
* Indices are in the range [begin, end) which means the first item is at data[begin] and the last item is at
* data[end - 1].
*/
struct DebtDeque {
int128 _begin;
int128 _end;
mapping(int128 => DebtEntry) _data;
}
/**
* @dev Inserts an item at the end of the queue.
*/
function pushBack(DebtDeque storage deque, DebtEntry memory debtEntry) internal {
int128 backIndex = deque._end;
deque._data[backIndex] = debtEntry;
unchecked {
deque._end = backIndex + 1;
}
}
/**
* @dev Removes the item at the beginning of the queue and returns it.
*
* Reverts with `Empty` if the queue is empty.
*/
function popFront(DebtDeque storage deque) internal returns (DebtEntry memory value) {
if (empty(deque)) revert Empty();
int128 frontIndex = deque._begin;
value = deque._data[frontIndex];
delete deque._data[frontIndex];
unchecked {
deque._begin = frontIndex + 1;
}
}
/**
* @dev Returns the item at the beginning of the queue.
*
* Reverts with `Empty` if the queue is empty.
*/
function front(DebtDeque storage deque) internal view returns (DebtEntry storage value) {
if (empty(deque)) revert Empty();
int128 frontIndex = deque._begin;
return deque._data[frontIndex];
}
/**
* @dev Return the item at a position in the queue given by `index`, with the first item at 0 and last item at
* `length(deque) - 1`.
*
* Reverts with `OutOfBounds` if the index is out of bounds.
*/
function at(DebtDeque storage deque, uint256 index) internal view returns (DebtEntry storage value) {
// int256(deque._begin) is a safe upcast
int128 idx = SafeCast.toInt128(int256(deque._begin) + SafeCast.toInt256(index));
if (idx >= deque._end) revert OutOfBounds();
return deque._data[idx];
}
/**
* @dev Returns the number of items in the queue.
*/
function length(DebtDeque storage deque) internal view returns (uint256) {
// The interface preserves the invariant that begin <= end so we assume this will not overflow.
// We also assume there are at most int256.max items in the queue.
unchecked {
return uint256(int256(deque._end) - int256(deque._begin));
}
}
/**
* @dev Returns true if the queue is empty.
*/
function empty(DebtDeque storage deque) internal view returns (bool) {
return deque._end <= deque._begin;
}
}