Split contract by Mikhail Vladimirov

BranchSender.sol

// Simple smart contract that allows anyone to send ether from one address to
// another in certain branch of the blockchain only.  This contract is supposed
// to be used after hard forks to clearly separate "classic" ether from "new"
// ether.
contract BranchSender {
        // Is set to true if and only if we are currently in the "right" branch of
        // the blockchain, i.e. the branch this contract allows sending money in.
        bool public isRightBranch;

        // Instantiate the contract.
        //
        // @param blockNumber number of block in the "right" blockchain whose hash is
        //        known
        // @param blockHash known hash of the given block in the "right" blockchain
        function BranchSender(uint blockNumber, bytes32 blockHash) {
                if (msg.value > 0) throw; // We do not accept any money here
                isRightBranch = (block.number < 256 || blockNumber > block.number - 256) &&
                        (blockNumber < block.number) &&
                        (block.blockhash(blockNumber) == blockHash);
        }
        // Default function just throws.
        function() {
                throw;
        }        // If we are currently in the "right" branch of the blockchain, send money to
        // the given recipient.  Otherwise, throw.
        //
        // @param recipient address to send money to if we are currently in the
        //                  "right" branch of the blockchain
        function send(address recipient) {
                if (!isRightBranch) throw;
                if (!recipient.send(msg.value)) throw;
        }
}