1 files changed, 56 insertions, 0 deletions
diff --git a/contracts/exchange/contracts/examples/Validator.sol b/contracts/exchange/contracts/examples/Validator.sol
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+++ b/contracts/exchange/contracts/examples/Validator.sol
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+/*
+
+  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 0.4.24;
+
+import "../src/interfaces/IValidator.sol";
+
+
+contract Validator is 
+    IValidator
+{
+
+    // The single valid signer for this wallet.
+    // solhint-disable-next-line var-name-mixedcase
+    address internal VALID_SIGNER;
+
+    /// @dev constructs a new `Validator` with a single valid signer.
+    /// @param validSigner The sole, valid signer.
+    constructor (address validSigner) public {
+        VALID_SIGNER = validSigner;
+    }
+
+    /// @dev Verifies that a signature is valid. `signer` must match `VALID_SIGNER`.
+    /// @param hash Message hash that is signed.
+    /// @param signerAddress Address that should have signed the given hash.
+    /// @param signature Proof of signing.
+    /// @return Validity of signature.
+    // solhint-disable no-unused-vars
+    function isValidSignature(
+        bytes32 hash,
+        address signerAddress,
+        bytes signature
+    )
+        external
+        view
+        returns (bool isValid)
+    {
+        return (signerAddress == VALID_SIGNER);
+    }
+    // solhint-enable no-unused-vars
+}