// SPDX-License-Identifier: MIT 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 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 */ 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 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 */ 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 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 */ 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 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 */ 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 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 */ 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 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 */ 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. */ 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. */ function toUint256(int256 value) internal pure returns (uint256) { require(value >= 0, "SafeCast: value must be positive"); return uint256(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 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 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 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. */ 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); } }