aboutsummaryrefslogtreecommitdiffstats
path: root/packages/contracts/src/1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol
diff options
context:
space:
mode:
Diffstat (limited to 'packages/contracts/src/1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol')
-rw-r--r--packages/contracts/src/1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol52
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;
+ }
+ }
+}