contract usingProvable {

    using CBOR for Buffer.buffer;

    ProvableI provable;
    OracleAddrResolverI OAR;

    uint constant day = 60 * 60 * 24;
    uint constant week = 60 * 60 * 24 * 7;
    uint constant month = 60 * 60 * 24 * 30;

    byte constant proofType_NONE = 0x00;
    byte constant proofType_Ledger = 0x30;
    byte constant proofType_Native = 0xF0;
    byte constant proofStorage_IPFS = 0x01;
    byte constant proofType_Android = 0x40;
    byte constant proofType_TLSNotary = 0x10;

    string provable_network_name;
    uint8 constant networkID_auto = 0;
    uint8 constant networkID_morden = 2;
    uint8 constant networkID_mainnet = 1;
    uint8 constant networkID_testnet = 2;
    uint8 constant networkID_consensys = 161;

    mapping(bytes32 => bytes32) provable_randomDS_args;
    mapping(bytes32 => bool) provable_randomDS_sessionKeysHashVerified;

    modifier provableAPI {
        if ((address(OAR) == address(0)) || (getCodeSize(address(OAR)) == 0)) {
            provable_setNetwork(networkID_auto);
        }
        if (address(provable) != OAR.getAddress()) {
            provable = ProvableI(OAR.getAddress());
        }
        _;
    }

    modifier provable_randomDS_proofVerify(bytes32 _queryId, string memory _result, bytes memory _proof) {
        // RandomDS Proof Step 1: The prefix has to match 'LP\x01' (Ledger Proof version 1)
        require((_proof[0] == "L") && (_proof[1] == "P") && (uint8(_proof[2]) == uint8(1)));
        bool proofVerified = provable_randomDS_proofVerify__main(_proof, _queryId, bytes(_result), provable_getNetworkName());
        require(proofVerified);
        _;
    }

    function provable_setNetwork(uint8 _networkID) internal returns (bool _networkSet) {
      _networkID; // NOTE: Silence the warning and remain backwards compatible
      return provable_setNetwork();
    }

    function provable_setNetworkName(string memory _network_name) internal {
        provable_network_name = _network_name;
    }

    function provable_getNetworkName() internal view returns (string memory _networkName) {
        return provable_network_name;
    }

    function provable_setNetwork() internal returns (bool _networkSet) {
        if (getCodeSize(0x1d3B2638a7cC9f2CB3D298A3DA7a90B67E5506ed) > 0) { //mainnet
            OAR = OracleAddrResolverI(0x1d3B2638a7cC9f2CB3D298A3DA7a90B67E5506ed);
            provable_setNetworkName("eth_mainnet");
            return true;
        }
        if (getCodeSize(0xc03A2615D5efaf5F49F60B7BB6583eaec212fdf1) > 0) { //ropsten testnet
            OAR = OracleAddrResolverI(0xc03A2615D5efaf5F49F60B7BB6583eaec212fdf1);
            provable_setNetworkName("eth_ropsten3");
            return true;
        }
        if (getCodeSize(0xB7A07BcF2Ba2f2703b24C0691b5278999C59AC7e) > 0) { //kovan testnet
            OAR = OracleAddrResolverI(0xB7A07BcF2Ba2f2703b24C0691b5278999C59AC7e);
            provable_setNetworkName("eth_kovan");
            return true;
        }
        if (getCodeSize(0x146500cfd35B22E4A392Fe0aDc06De1a1368Ed48) > 0) { //rinkeby testnet
            OAR = OracleAddrResolverI(0x146500cfd35B22E4A392Fe0aDc06De1a1368Ed48);
            provable_setNetworkName("eth_rinkeby");
            return true;
        }
        if (getCodeSize(0xa2998EFD205FB9D4B4963aFb70778D6354ad3A41) > 0) { //goerli testnet
            OAR = OracleAddrResolverI(0xa2998EFD205FB9D4B4963aFb70778D6354ad3A41);
            provable_setNetworkName("eth_goerli");
            return true;
        }
        if (getCodeSize(0x6f485C8BF6fc43eA212E93BBF8ce046C7f1cb475) > 0) { //ethereum-bridge
            OAR = OracleAddrResolverI(0x6f485C8BF6fc43eA212E93BBF8ce046C7f1cb475);
            return true;
        }
        if (getCodeSize(0x20e12A1F859B3FeaE5Fb2A0A32C18F5a65555bBF) > 0) { //ether.camp ide
            OAR = OracleAddrResolverI(0x20e12A1F859B3FeaE5Fb2A0A32C18F5a65555bBF);
            return true;
        }
        if (getCodeSize(0x51efaF4c8B3C9AfBD5aB9F4bbC82784Ab6ef8fAA) > 0) { //browser-solidity
            OAR = OracleAddrResolverI(0x51efaF4c8B3C9AfBD5aB9F4bbC82784Ab6ef8fAA);
            return true;
        }
        return false;
    }
    /**
     * @dev The following `__callback` functions are just placeholders ideally
     *      meant to be defined in child contract when proofs are used.
     *      The function bodies simply silence compiler warnings.
     */
    function __callback(bytes32 _myid, string memory _result) public {
        __callback(_myid, _result, new bytes(0));
    }

    function __callback(bytes32 _myid, string memory _result, bytes memory _proof) public {
      _myid; _result; _proof;
      provable_randomDS_args[bytes32(0)] = bytes32(0);
    }

    function provable_getPrice(string memory _datasource) provableAPI internal returns (uint _queryPrice) {
        return provable.getPrice(_datasource);
    }

    function provable_getPrice(string memory _datasource, uint _gasLimit) provableAPI internal returns (uint _queryPrice) {
        return provable.getPrice(_datasource, _gasLimit);
    }

    function provable_query(string memory _datasource, string memory _arg) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource);
        if (price > 1 ether + tx.gasprice * 200000) {
            return 0; // Unexpectedly high price
        }
        return provable.query.value(price)(0, _datasource, _arg);
    }

    function provable_query(uint _timestamp, string memory _datasource, string memory _arg) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource);
        if (price > 1 ether + tx.gasprice * 200000) {
            return 0; // Unexpectedly high price
        }
        return provable.query.value(price)(_timestamp, _datasource, _arg);
    }

    function provable_query(uint _timestamp, string memory _datasource, string memory _arg, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource,_gasLimit);
        if (price > 1 ether + tx.gasprice * _gasLimit) {
            return 0; // Unexpectedly high price
        }
        return provable.query_withGasLimit.value(price)(_timestamp, _datasource, _arg, _gasLimit);
    }

    function provable_query(string memory _datasource, string memory _arg, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource, _gasLimit);
        if (price > 1 ether + tx.gasprice * _gasLimit) {
           return 0; // Unexpectedly high price
        }
        return provable.query_withGasLimit.value(price)(0, _datasource, _arg, _gasLimit);
    }

    function provable_query(string memory _datasource, string memory _arg1, string memory _arg2) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource);
        if (price > 1 ether + tx.gasprice * 200000) {
            return 0; // Unexpectedly high price
        }
        return provable.query2.value(price)(0, _datasource, _arg1, _arg2);
    }

    function provable_query(uint _timestamp, string memory _datasource, string memory _arg1, string memory _arg2) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource);
        if (price > 1 ether + tx.gasprice * 200000) {
            return 0; // Unexpectedly high price
        }
        return provable.query2.value(price)(_timestamp, _datasource, _arg1, _arg2);
    }

    function provable_query(uint _timestamp, string memory _datasource, string memory _arg1, string memory _arg2, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource, _gasLimit);
        if (price > 1 ether + tx.gasprice * _gasLimit) {
            return 0; // Unexpectedly high price
        }
        return provable.query2_withGasLimit.value(price)(_timestamp, _datasource, _arg1, _arg2, _gasLimit);
    }

    function provable_query(string memory _datasource, string memory _arg1, string memory _arg2, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource, _gasLimit);
        if (price > 1 ether + tx.gasprice * _gasLimit) {
            return 0; // Unexpectedly high price
        }
        return provable.query2_withGasLimit.value(price)(0, _datasource, _arg1, _arg2, _gasLimit);
    }

    function provable_query(string memory _datasource, string[] memory _argN) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource);
        if (price > 1 ether + tx.gasprice * 200000) {
            return 0; // Unexpectedly high price
        }
        bytes memory args = stra2cbor(_argN);
        return provable.queryN.value(price)(0, _datasource, args);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[] memory _argN) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource);
        if (price > 1 ether + tx.gasprice * 200000) {
            return 0; // Unexpectedly high price
        }
        bytes memory args = stra2cbor(_argN);
        return provable.queryN.value(price)(_timestamp, _datasource, args);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[] memory _argN, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource, _gasLimit);
        if (price > 1 ether + tx.gasprice * _gasLimit) {
            return 0; // Unexpectedly high price
        }
        bytes memory args = stra2cbor(_argN);
        return provable.queryN_withGasLimit.value(price)(_timestamp, _datasource, args, _gasLimit);
    }

    function provable_query(string memory _datasource, string[] memory _argN, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource, _gasLimit);
        if (price > 1 ether + tx.gasprice * _gasLimit) {
            return 0; // Unexpectedly high price
        }
        bytes memory args = stra2cbor(_argN);
        return provable.queryN_withGasLimit.value(price)(0, _datasource, args, _gasLimit);
    }

    function provable_query(string memory _datasource, string[1] memory _args) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](1);
        dynargs[0] = _args[0];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[1] memory _args) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](1);
        dynargs[0] = _args[0];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[1] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](1);
        dynargs[0] = _args[0];
        return provable_query(_timestamp, _datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, string[1] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](1);
        dynargs[0] = _args[0];
        return provable_query(_datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, string[2] memory _args) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](2);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[2] memory _args) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](2);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[2] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](2);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        return provable_query(_timestamp, _datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, string[2] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](2);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        return provable_query(_datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, string[3] memory _args) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](3);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[3] memory _args) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](3);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[3] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](3);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        return provable_query(_timestamp, _datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, string[3] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](3);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        return provable_query(_datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, string[4] memory _args) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](4);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[4] memory _args) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](4);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[4] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](4);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        return provable_query(_timestamp, _datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, string[4] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](4);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        return provable_query(_datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, string[5] memory _args) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](5);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        dynargs[4] = _args[4];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[5] memory _args) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](5);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        dynargs[4] = _args[4];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, string[5] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](5);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        dynargs[4] = _args[4];
        return provable_query(_timestamp, _datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, string[5] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        string[] memory dynargs = new string[](5);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        dynargs[4] = _args[4];
        return provable_query(_datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[] memory _argN) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource);
        if (price > 1 ether + tx.gasprice * 200000) {
            return 0; // Unexpectedly high price
        }
        bytes memory args = ba2cbor(_argN);
        return provable.queryN.value(price)(0, _datasource, args);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[] memory _argN) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource);
        if (price > 1 ether + tx.gasprice * 200000) {
            return 0; // Unexpectedly high price
        }
        bytes memory args = ba2cbor(_argN);
        return provable.queryN.value(price)(_timestamp, _datasource, args);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[] memory _argN, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource, _gasLimit);
        if (price > 1 ether + tx.gasprice * _gasLimit) {
            return 0; // Unexpectedly high price
        }
        bytes memory args = ba2cbor(_argN);
        return provable.queryN_withGasLimit.value(price)(_timestamp, _datasource, args, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[] memory _argN, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        uint price = provable.getPrice(_datasource, _gasLimit);
        if (price > 1 ether + tx.gasprice * _gasLimit) {
            return 0; // Unexpectedly high price
        }
        bytes memory args = ba2cbor(_argN);
        return provable.queryN_withGasLimit.value(price)(0, _datasource, args, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[1] memory _args) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](1);
        dynargs[0] = _args[0];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[1] memory _args) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](1);
        dynargs[0] = _args[0];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[1] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](1);
        dynargs[0] = _args[0];
        return provable_query(_timestamp, _datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[1] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](1);
        dynargs[0] = _args[0];
        return provable_query(_datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[2] memory _args) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](2);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[2] memory _args) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](2);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[2] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](2);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        return provable_query(_timestamp, _datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[2] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](2);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        return provable_query(_datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[3] memory _args) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](3);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[3] memory _args) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](3);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[3] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](3);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        return provable_query(_timestamp, _datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[3] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](3);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        return provable_query(_datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[4] memory _args) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](4);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[4] memory _args) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](4);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[4] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](4);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        return provable_query(_timestamp, _datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[4] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](4);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        return provable_query(_datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[5] memory _args) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](5);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        dynargs[4] = _args[4];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[5] memory _args) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](5);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        dynargs[4] = _args[4];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(uint _timestamp, string memory _datasource, bytes[5] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](5);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        dynargs[4] = _args[4];
        return provable_query(_timestamp, _datasource, dynargs, _gasLimit);
    }

    function provable_query(string memory _datasource, bytes[5] memory _args, uint _gasLimit) provableAPI internal returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](5);
        dynargs[0] = _args[0];
        dynargs[1] = _args[1];
        dynargs[2] = _args[2];
        dynargs[3] = _args[3];
        dynargs[4] = _args[4];
        return provable_query(_datasource, dynargs, _gasLimit);
    }

    function provable_setProof(byte _proofP) provableAPI internal {
        return provable.setProofType(_proofP);
    }


    function provable_cbAddress() provableAPI internal returns (address _callbackAddress) {
        return provable.cbAddress();
    }

    function getCodeSize(address _addr) view internal returns (uint _size) {
        assembly {
            _size := extcodesize(_addr)
        }
    }

    function provable_setCustomGasPrice(uint _gasPrice) provableAPI internal {
        return provable.setCustomGasPrice(_gasPrice);
    }

    function provable_randomDS_getSessionPubKeyHash() provableAPI internal returns (bytes32 _sessionKeyHash) {
        return provable.randomDS_getSessionPubKeyHash();
    }

    function parseAddr(string memory _a) internal pure returns (address _parsedAddress) {
        bytes memory tmp = bytes(_a);
        uint160 iaddr = 0;
        uint160 b1;
        uint160 b2;
        for (uint i = 2; i < 2 + 2 * 20; i += 2) {
            iaddr *= 256;
            b1 = uint160(uint8(tmp[i]));
            b2 = uint160(uint8(tmp[i + 1]));
            if ((b1 >= 97) && (b1 <= 102)) {
                b1 -= 87;
            } else if ((b1 >= 65) && (b1 <= 70)) {
                b1 -= 55;
            } else if ((b1 >= 48) && (b1 <= 57)) {
                b1 -= 48;
            }
            if ((b2 >= 97) && (b2 <= 102)) {
                b2 -= 87;
            } else if ((b2 >= 65) && (b2 <= 70)) {
                b2 -= 55;
            } else if ((b2 >= 48) && (b2 <= 57)) {
                b2 -= 48;
            }
            iaddr += (b1 * 16 + b2);
        }
        return address(iaddr);
    }

    function strCompare(string memory _a, string memory _b) internal pure returns (int _returnCode) {
        bytes memory a = bytes(_a);
        bytes memory b = bytes(_b);
        uint minLength = a.length;
        if (b.length < minLength) {
            minLength = b.length;
        }
        for (uint i = 0; i < minLength; i ++) {
            if (a[i] < b[i]) {
                return -1;
            } else if (a[i] > b[i]) {
                return 1;
            }
        }
        if (a.length < b.length) {
            return -1;
        } else if (a.length > b.length) {
            return 1;
        } else {
            return 0;
        }
    }

    function indexOf(string memory _haystack, string memory _needle) internal pure returns (int _returnCode) {
        bytes memory h = bytes(_haystack);
        bytes memory n = bytes(_needle);
        if (h.length < 1 || n.length < 1 || (n.length > h.length)) {
            return -1;
        } else if (h.length > (2 ** 128 - 1)) {
            return -1;
        } else {
            uint subindex = 0;
            for (uint i = 0; i < h.length; i++) {
                if (h[i] == n[0]) {
                    subindex = 1;
                    while(subindex < n.length && (i + subindex) < h.length && h[i + subindex] == n[subindex]) {
                        subindex++;
                    }
                    if (subindex == n.length) {
                        return int(i);
                    }
                }
            }
            return -1;
        }
    }

    function strConcat(string memory _a, string memory _b) internal pure returns (string memory _concatenatedString) {
        return strConcat(_a, _b, "", "", "");
    }

    function strConcat(string memory _a, string memory _b, string memory _c) internal pure returns (string memory _concatenatedString) {
        return strConcat(_a, _b, _c, "", "");
    }

    function strConcat(string memory _a, string memory _b, string memory _c, string memory _d) internal pure returns (string memory _concatenatedString) {
        return strConcat(_a, _b, _c, _d, "");
    }

    function strConcat(string memory _a, string memory _b, string memory _c, string memory _d, string memory _e) internal pure returns (string memory _concatenatedString) {
        bytes memory _ba = bytes(_a);
        bytes memory _bb = bytes(_b);
        bytes memory _bc = bytes(_c);
        bytes memory _bd = bytes(_d);
        bytes memory _be = bytes(_e);
        string memory abcde = new string(_ba.length + _bb.length + _bc.length + _bd.length + _be.length);
        bytes memory babcde = bytes(abcde);
        uint k = 0;
        uint i = 0;
        for (i = 0; i < _ba.length; i++) {
            babcde[k++] = _ba[i];
        }
        for (i = 0; i < _bb.length; i++) {
            babcde[k++] = _bb[i];
        }
        for (i = 0; i < _bc.length; i++) {
            babcde[k++] = _bc[i];
        }
        for (i = 0; i < _bd.length; i++) {
            babcde[k++] = _bd[i];
        }
        for (i = 0; i < _be.length; i++) {
            babcde[k++] = _be[i];
        }
        return string(babcde);
    }

    function safeParseInt(string memory _a) internal pure returns (uint _parsedInt) {
        return safeParseInt(_a, 0);
    }

    function safeParseInt(string memory _a, uint _b) internal pure returns (uint _parsedInt) {
        bytes memory bresult = bytes(_a);
        uint mint = 0;
        bool decimals = false;
        for (uint i = 0; i < bresult.length; i++) {
            if ((uint(uint8(bresult[i])) >= 48) && (uint(uint8(bresult[i])) <= 57)) {
                if (decimals) {
                   if (_b == 0) break;
                    else _b--;
                }
                mint *= 10;
                mint += uint(uint8(bresult[i])) - 48;
            } else if (uint(uint8(bresult[i])) == 46) {
                require(!decimals, 'More than one decimal encountered in string!');
                decimals = true;
            } else {
                revert("Non-numeral character encountered in string!");
            }
        }
        if (_b > 0) {
            mint *= 10 ** _b;
        }
        return mint;
    }

    function parseInt(string memory _a) internal pure returns (uint _parsedInt) {
        return parseInt(_a, 0);
    }

    function parseInt(string memory _a, uint _b) internal pure returns (uint _parsedInt) {
        bytes memory bresult = bytes(_a);
        uint mint = 0;
        bool decimals = false;
        for (uint i = 0; i < bresult.length; i++) {
            if ((uint(uint8(bresult[i])) >= 48) && (uint(uint8(bresult[i])) <= 57)) {
                if (decimals) {
                   if (_b == 0) {
                       break;
                   } else {
                       _b--;
                   }
                }
                mint *= 10;
                mint += uint(uint8(bresult[i])) - 48;
            } else if (uint(uint8(bresult[i])) == 46) {
                decimals = true;
            }
        }
        if (_b > 0) {
            mint *= 10 ** _b;
        }
        return mint;
    }

    function uint2str(uint _i) internal pure returns (string memory _uintAsString) {
        if (_i == 0) {
            return "0";
        }
        uint j = _i;
        uint len;
        while (j != 0) {
            len++;
            j /= 10;
        }
        bytes memory bstr = new bytes(len);
        uint k = len - 1;
        while (_i != 0) {
            bstr[k--] = byte(uint8(48 + _i % 10));
            _i /= 10;
        }
        return string(bstr);
    }

    function stra2cbor(string[] memory _arr) internal pure returns (bytes memory _cborEncoding) {
        safeMemoryCleaner();
        Buffer.buffer memory buf;
        Buffer.init(buf, 1024);
        buf.startArray();
        for (uint i = 0; i < _arr.length; i++) {
            buf.encodeString(_arr[i]);
        }
        buf.endSequence();
        return buf.buf;
    }

    function ba2cbor(bytes[] memory _arr) internal pure returns (bytes memory _cborEncoding) {
        safeMemoryCleaner();
        Buffer.buffer memory buf;
        Buffer.init(buf, 1024);
        buf.startArray();
        for (uint i = 0; i < _arr.length; i++) {
            buf.encodeBytes(_arr[i]);
        }
        buf.endSequence();
        return buf.buf;
    }

    function provable_newRandomDSQuery(uint _delay, uint _nbytes, uint _customGasLimit) internal returns (bytes32 _queryId) {
        require((_nbytes > 0) && (_nbytes <= 32));
        _delay *= 10; // Convert from seconds to ledger timer ticks
        bytes memory nbytes = new bytes(1);
        nbytes[0] = byte(uint8(_nbytes));
        bytes memory unonce = new bytes(32);
        bytes memory sessionKeyHash = new bytes(32);
        bytes32 sessionKeyHash_bytes32 = provable_randomDS_getSessionPubKeyHash();
        assembly {
            mstore(unonce, 0x20)
            /*
             The following variables can be relaxed.
             Check the relaxed random contract at https://github.com/oraclize/ethereum-examples
             for an idea on how to override and replace commit hash variables.
            */
            mstore(add(unonce, 0x20), xor(blockhash(sub(number, 1)), xor(coinbase, timestamp)))
            mstore(sessionKeyHash, 0x20)
            mstore(add(sessionKeyHash, 0x20), sessionKeyHash_bytes32)
        }
        bytes memory delay = new bytes(32);
        assembly {
            mstore(add(delay, 0x20), _delay)
        }
        bytes memory delay_bytes8 = new bytes(8);
        copyBytes(delay, 24, 8, delay_bytes8, 0);
        bytes[4] memory args = [unonce, nbytes, sessionKeyHash, delay];
        bytes32 queryId = provable_query("random", args, _customGasLimit);
        bytes memory delay_bytes8_left = new bytes(8);
        assembly {
            let x := mload(add(delay_bytes8, 0x20))
            mstore8(add(delay_bytes8_left, 0x27), div(x, 0x100000000000000000000000000000000000000000000000000000000000000))
            mstore8(add(delay_bytes8_left, 0x26), div(x, 0x1000000000000000000000000000000000000000000000000000000000000))
            mstore8(add(delay_bytes8_left, 0x25), div(x, 0x10000000000000000000000000000000000000000000000000000000000))
            mstore8(add(delay_bytes8_left, 0x24), div(x, 0x100000000000000000000000000000000000000000000000000000000))
            mstore8(add(delay_bytes8_left, 0x23), div(x, 0x1000000000000000000000000000000000000000000000000000000))
            mstore8(add(delay_bytes8_left, 0x22), div(x, 0x10000000000000000000000000000000000000000000000000000))
            mstore8(add(delay_bytes8_left, 0x21), div(x, 0x100000000000000000000000000000000000000000000000000))
            mstore8(add(delay_bytes8_left, 0x20), div(x, 0x1000000000000000000000000000000000000000000000000))
        }
        provable_randomDS_setCommitment(queryId, keccak256(abi.encodePacked(delay_bytes8_left, args[1], sha256(args[0]), args[2])));
        return queryId;
    }

    function provable_randomDS_setCommitment(bytes32 _queryId, bytes32 _commitment) internal {
        provable_randomDS_args[_queryId] = _commitment;
    }

    function verifySig(bytes32 _tosignh, bytes memory _dersig, bytes memory _pubkey) internal returns (bool _sigVerified) {
        bool sigok;
        address signer;
        bytes32 sigr;
        bytes32 sigs;
        bytes memory sigr_ = new bytes(32);
        uint offset = 4 + (uint(uint8(_dersig[3])) - 0x20);
        sigr_ = copyBytes(_dersig, offset, 32, sigr_, 0);
        bytes memory sigs_ = new bytes(32);
        offset += 32 + 2;
        sigs_ = copyBytes(_dersig, offset + (uint(uint8(_dersig[offset - 1])) - 0x20), 32, sigs_, 0);
        assembly {
            sigr := mload(add(sigr_, 32))
            sigs := mload(add(sigs_, 32))
        }
        (sigok, signer) = safer_ecrecover(_tosignh, 27, sigr, sigs);
        if (address(uint160(uint256(keccak256(_pubkey)))) == signer) {
            return true;
        } else {
            (sigok, signer) = safer_ecrecover(_tosignh, 28, sigr, sigs);
            return (address(uint160(uint256(keccak256(_pubkey)))) == signer);
        }
    }

    function provable_randomDS_proofVerify__sessionKeyValidity(bytes memory _proof, uint _sig2offset) internal returns (bool _proofVerified) {
        bool sigok;
        // Random DS Proof Step 6: Verify the attestation signature, APPKEY1 must sign the sessionKey from the correct ledger app (CODEHASH)
        bytes memory sig2 = new bytes(uint(uint8(_proof[_sig2offset + 1])) + 2);
        copyBytes(_proof, _sig2offset, sig2.length, sig2, 0);
        bytes memory appkey1_pubkey = new bytes(64);
        copyBytes(_proof, 3 + 1, 64, appkey1_pubkey, 0);
        bytes memory tosign2 = new bytes(1 + 65 + 32);
        tosign2[0] = byte(uint8(1)); //role
        copyBytes(_proof, _sig2offset - 65, 65, tosign2, 1);
        bytes memory CODEHASH = hex"fd94fa71bc0ba10d39d464d0d8f465efeef0a2764e3887fcc9df41ded20f505c";
        copyBytes(CODEHASH, 0, 32, tosign2, 1 + 65);
        sigok = verifySig(sha256(tosign2), sig2, appkey1_pubkey);
        if (!sigok) {
            return false;
        }
        // Random DS Proof Step 7: Verify the APPKEY1 provenance (must be signed by Ledger)
        bytes memory LEDGERKEY = hex"7fb956469c5c9b89840d55b43537e66a98dd4811ea0a27224272c2e5622911e8537a2f8e86a46baec82864e98dd01e9ccc2f8bc5dfc9cbe5a91a290498dd96e4";
        bytes memory tosign3 = new bytes(1 + 65);
        tosign3[0] = 0xFE;
        copyBytes(_proof, 3, 65, tosign3, 1);
        bytes memory sig3 = new bytes(uint(uint8(_proof[3 + 65 + 1])) + 2);
        copyBytes(_proof, 3 + 65, sig3.length, sig3, 0);
        sigok = verifySig(sha256(tosign3), sig3, LEDGERKEY);
        return sigok;
    }

    function provable_randomDS_proofVerify__returnCode(bytes32 _queryId, string memory _result, bytes memory _proof) internal returns (uint8 _returnCode) {
        // Random DS Proof Step 1: The prefix has to match 'LP\x01' (Ledger Proof version 1)
        if ((_proof[0] != "L") || (_proof[1] != "P") || (uint8(_proof[2]) != uint8(1))) {
            return 1;
        }
        bool proofVerified = provable_randomDS_proofVerify__main(_proof, _queryId, bytes(_result), provable_getNetworkName());
        if (!proofVerified) {
            return 2;
        }
        return 0;
    }

    function matchBytes32Prefix(bytes32 _content, bytes memory _prefix, uint _nRandomBytes) internal pure returns (bool _matchesPrefix) {
        bool match_ = true;
        require(_prefix.length == _nRandomBytes);
        for (uint256 i = 0; i< _nRandomBytes; i++) {
            if (_content[i] != _prefix[i]) {
                match_ = false;
            }
        }
        return match_;
    }

    function provable_randomDS_proofVerify__main(bytes memory _proof, bytes32 _queryId, bytes memory _result, string memory _contextName) internal returns (bool _proofVerified) {
        // Random DS Proof Step 2: The unique keyhash has to match with the sha256 of (context name + _queryId)
        uint ledgerProofLength = 3 + 65 + (uint(uint8(_proof[3 + 65 + 1])) + 2) + 32;
        bytes memory keyhash = new bytes(32);
        copyBytes(_proof, ledgerProofLength, 32, keyhash, 0);
        if (!(keccak256(keyhash) == keccak256(abi.encodePacked(sha256(abi.encodePacked(_contextName, _queryId)))))) {
            return false;
        }
        bytes memory sig1 = new bytes(uint(uint8(_proof[ledgerProofLength + (32 + 8 + 1 + 32) + 1])) + 2);
        copyBytes(_proof, ledgerProofLength + (32 + 8 + 1 + 32), sig1.length, sig1, 0);
        // Random DS Proof Step 3: We assume sig1 is valid (it will be verified during step 5) and we verify if '_result' is the _prefix of sha256(sig1)
        if (!matchBytes32Prefix(sha256(sig1), _result, uint(uint8(_proof[ledgerProofLength + 32 + 8])))) {
            return false;
        }
        // Random DS Proof Step 4: Commitment match verification, keccak256(delay, nbytes, unonce, sessionKeyHash) == commitment in storage.
        // This is to verify that the computed args match with the ones specified in the query.
        bytes memory commitmentSlice1 = new bytes(8 + 1 + 32);
        copyBytes(_proof, ledgerProofLength + 32, 8 + 1 + 32, commitmentSlice1, 0);
        bytes memory sessionPubkey = new bytes(64);
        uint sig2offset = ledgerProofLength + 32 + (8 + 1 + 32) + sig1.length + 65;
        copyBytes(_proof, sig2offset - 64, 64, sessionPubkey, 0);
        bytes32 sessionPubkeyHash = sha256(sessionPubkey);
        if (provable_randomDS_args[_queryId] == keccak256(abi.encodePacked(commitmentSlice1, sessionPubkeyHash))) { //unonce, nbytes and sessionKeyHash match
            delete provable_randomDS_args[_queryId];
        } else return false;
        // Random DS Proof Step 5: Validity verification for sig1 (keyhash and args signed with the sessionKey)
        bytes memory tosign1 = new bytes(32 + 8 + 1 + 32);
        copyBytes(_proof, ledgerProofLength, 32 + 8 + 1 + 32, tosign1, 0);
        if (!verifySig(sha256(tosign1), sig1, sessionPubkey)) {
            return false;
        }
        // Verify if sessionPubkeyHash was verified already, if not.. let's do it!
        if (!provable_randomDS_sessionKeysHashVerified[sessionPubkeyHash]) {
            provable_randomDS_sessionKeysHashVerified[sessionPubkeyHash] = provable_randomDS_proofVerify__sessionKeyValidity(_proof, sig2offset);
        }
        return provable_randomDS_sessionKeysHashVerified[sessionPubkeyHash];
    }
    /*
     The following function has been written by Alex Beregszaszi (@axic), use it under the terms of the MIT license
    */
    function copyBytes(bytes memory _from, uint _fromOffset, uint _length, bytes memory _to, uint _toOffset) internal pure returns (bytes memory _copiedBytes) {
        uint minLength = _length + _toOffset;
        require(_to.length >= minLength); // Buffer too small. Should be a better way?
        uint i = 32 + _fromOffset; // NOTE: the offset 32 is added to skip the `size` field of both bytes variables
        uint j = 32 + _toOffset;
        while (i < (32 + _fromOffset + _length)) {
            assembly {
                let tmp := mload(add(_from, i))
                mstore(add(_to, j), tmp)
            }
            i += 32;
            j += 32;
        }
        return _to;
    }
    /*
     The following function has been written by Alex Beregszaszi (@axic), use it under the terms of the MIT license
     Duplicate Solidity's ecrecover, but catching the CALL return value
    */
    function safer_ecrecover(bytes32 _hash, uint8 _v, bytes32 _r, bytes32 _s) internal returns (bool _success, address _recoveredAddress) {
        /*
         We do our own memory management here. Solidity uses memory offset
         0x40 to store the current end of memory. We write past it (as
         writes are memory extensions), but don't update the offset so
         Solidity will reuse it. The memory used here is only needed for
         this context.
         FIXME: inline assembly can't access return values
        */
        bool ret;
        address addr;
        assembly {
            let size := mload(0x40)
            mstore(size, _hash)
            mstore(add(size, 32), _v)
            mstore(add(size, 64), _r)
            mstore(add(size, 96), _s)
            ret := call(3000, 1, 0, size, 128, size, 32) // NOTE: we can reuse the request memory because we deal with the return code.
            addr := mload(size)
        }
        return (ret, addr);
    }
    /*
     The following function has been written by Alex Beregszaszi (@axic), use it under the terms of the MIT license
    */
    function ecrecovery(bytes32 _hash, bytes memory _sig) internal returns (bool _success, address _recoveredAddress) {
        bytes32 r;
        bytes32 s;
        uint8 v;
        if (_sig.length != 65) {
            return (false, address(0));
        }
        /*
         The signature format is a compact form of:
           {bytes32 r}{bytes32 s}{uint8 v}
         Compact means, uint8 is not padded to 32 bytes.
        */
        assembly {
            r := mload(add(_sig, 32))
            s := mload(add(_sig, 64))
            /*
             Here we are loading the last 32 bytes. We exploit the fact that
             'mload' will pad with zeroes if we overread.
             There is no 'mload8' to do this, but that would be nicer.
            */
            v := byte(0, mload(add(_sig, 96)))
            /*
              Alternative solution:
              'byte' is not working due to the Solidity parser, so lets
              use the second best option, 'and'
              v := and(mload(add(_sig, 65)), 255)
            */
        }
        /*
         albeit non-transactional signatures are not specified by the YP, one would expect it
         to match the YP range of [27, 28]
         geth uses [0, 1] and some clients have followed. This might change, see:
         https://github.com/ethereum/go-ethereum/issues/2053
        */
        if (v < 27) {
            v += 27;
        }
        if (v != 27 && v != 28) {
            return (false, address(0));
        }
        return safer_ecrecover(_hash, v, r, s);
    }

    function safeMemoryCleaner() internal pure {
        assembly {
            let fmem := mload(0x40)
            codecopy(fmem, codesize, sub(msize, fmem))
        }
    }
}
function ecrecovery(bytes32 _hash, bytes memory _sig) internal returns (bool _success, address _recoveredAddress) {
    bytes32 r;
    bytes32 s;
    uint8 v;
    if (_sig.length != 65) {
        return (false, address(0));
    }
    /*
     The signature format is a compact form of:
       {bytes32 r}{bytes32 s}{uint8 v}
     Compact means, uint8 is not padded to 32 bytes.
    */
    assembly {
        r := mload(add(_sig, 32))
        s := mload(add(_sig, 64))
        /*
         Here we are loading the last 32 bytes. We exploit the fact that
         'mload' will pad with zeroes if we overread.
         There is no 'mload8' to do this, but that would be nicer.
        */
        v := byte(0, mload(add(_sig, 96)))
        /*
          Alternative solution:
          'byte' is not working due to the Solidity parser, so lets
          use the second best option, 'and'
          v := and(mload(add(_sig, 65)), 255)
        */
    }
    /*
     albeit non-transactional signatures are not specified by the YP, one would expect it
     to match the YP range of [27, 28]
     geth uses [0, 1] and some clients have followed. This might change, see:
     https://github.com/ethereum/go-ethereum/issues/2053
    */
    if (v < 27) {
        v += 27;
    }
    if (v != 27 && v != 28) {
        return (false, address(0));
    }
    return safer_ecrecover(_hash, v, r, s);
}

/*
 The following function has been written by Alex Beregszaszi (@axic), use it under the terms of the MIT license
 */