laconicd/tests-solidity/suites/proxy/contracts/IsContract.sol

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pragma solidity ^0.4.24;
contract IsContract {
/*
* NOTE: this should NEVER be used for authentication
* (see pitfalls: https://github.com/fergarrui/ethereum-security/tree/master/contracts/extcodesize).
*
* This is only intended to be used as a sanity check that an address is actually a contract,
* RATHER THAN an address not being a contract.
*/
function isContract(address _target) internal view returns (bool) {
if (_target == address(0)) {
return false;
}
uint256 size;
assembly { size := extcodesize(_target) }
return size > 0;
}
}