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Diffstat (limited to 'packages/contracts/src/1.0.0/UnlimitedAllowanceToken')
-rw-r--r-- | packages/contracts/src/1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/packages/contracts/src/1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol b/packages/contracts/src/1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol new file mode 100644 index 000000000..46379c43d --- /dev/null +++ b/packages/contracts/src/1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol @@ -0,0 +1,52 @@ +/* + + Copyright 2018 ZeroEx Intl. + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. + +*/ + +pragma solidity ^0.4.11; + +import { ERC20Token_v1 as ERC20Token } from "../ERC20Token/ERC20Token_v1.sol"; + +contract UnlimitedAllowanceToken_v1 is ERC20Token { + + uint constant MAX_UINT = 2**256 - 1; + + /// @dev ERC20 transferFrom, modified such that an allowance of MAX_UINT represents an unlimited allowance. + /// @param _from Address to transfer from. + /// @param _to Address to transfer to. + /// @param _value Amount to transfer. + /// @return Success of transfer. + function transferFrom(address _from, address _to, uint _value) + public + returns (bool) + { + uint allowance = allowed[_from][msg.sender]; + if (balances[_from] >= _value + && allowance >= _value + && balances[_to] + _value >= balances[_to] + ) { + balances[_to] += _value; + balances[_from] -= _value; + if (allowance < MAX_UINT) { + allowed[_from][msg.sender] -= _value; + } + Transfer(_from, _to, _value); + return true; + } else { + return false; + } + } +} |