30 lines
1.2 KiB
Solidity
30 lines
1.2 KiB
Solidity
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// SPDX-License-Identifier: MIT
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pragma solidity =0.7.6;
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library HexStrings {
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bytes16 internal constant ALPHABET = '0123456789abcdef';
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/// @notice Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
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/// @dev Credit to Open Zeppelin under MIT license https://github.com/OpenZeppelin/openzeppelin-contracts/blob/243adff49ce1700e0ecb99fe522fb16cff1d1ddc/contracts/utils/Strings.sol#L55
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function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
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bytes memory buffer = new bytes(2 * length + 2);
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buffer[0] = '0';
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buffer[1] = 'x';
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for (uint256 i = 2 * length + 1; i > 1; --i) {
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buffer[i] = ALPHABET[value & 0xf];
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value >>= 4;
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}
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require(value == 0, 'Strings: hex length insufficient');
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return string(buffer);
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}
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function toHexStringNoPrefix(uint256 value, uint256 length) internal pure returns (string memory) {
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bytes memory buffer = new bytes(2 * length);
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for (uint256 i = buffer.length; i > 0; i--) {
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buffer[i - 1] = ALPHABET[value & 0xf];
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value >>= 4;
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}
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return string(buffer);
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}
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}
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