/**
 *Submitted for verification at Etherscan.io on 2020-11-02
 */

// SPDX-License-Identifier: MIT

/*
MIT License

Copyright (c) 2018 requestnetwork
Copyright (c) 2018 Fragments, Inc.
Copyright (c) 2020 VAMP

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

*/

pragma solidity 0.5.17;

/**
 * @title SafeMath
 * @dev Math operations with safety checks that revert on error
 */
library SafeMath {
    /**
     * @dev Multiplies two numbers, reverts on overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
     * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0); // Solidity only automatically asserts when dividing by 0
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Adds two numbers, reverts on overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
     * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
     * reverts when dividing by zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}

library SafeMathInt {
    int256 private constant MIN_INT256 = int256(1) << 255;
    int256 private constant MAX_INT256 = ~(int256(1) << 255);

    /**
     * @dev Multiplies two int256 variables and fails on overflow.
     */
    function mul(int256 a, int256 b) internal pure returns (int256) {
        int256 c = a * b;

        // Detect overflow when multiplying MIN_INT256 with -1
        require(c != MIN_INT256 || (a & MIN_INT256) != (b & MIN_INT256));
        require((b == 0) || (c / b == a));
        return c;
    }

    /**
     * @dev Division of two int256 variables and fails on overflow.
     */
    function div(int256 a, int256 b) internal pure returns (int256) {
        // Prevent overflow when dividing MIN_INT256 by -1
        require(b != -1 || a != MIN_INT256);

        // Solidity already throws when dividing by 0.
        return a / b;
    }

    /**
     * @dev Subtracts two int256 variables and fails on overflow.
     */
    function sub(int256 a, int256 b) internal pure returns (int256) {
        int256 c = a - b;
        require((b >= 0 && c <= a) || (b < 0 && c > a));
        return c;
    }

    /**
     * @dev Adds two int256 variables and fails on overflow.
     */
    function add(int256 a, int256 b) internal pure returns (int256) {
        int256 c = a + b;
        require((b >= 0 && c >= a) || (b < 0 && c < a));
        return c;
    }

    /**
     * @dev Converts to absolute value, and fails on overflow.
     */
    function abs(int256 a) internal pure returns (int256) {
        require(a != MIN_INT256);
        return a < 0 ? -a : a;
    }
}

/**
 * @title Various utilities useful for uint256.
 */
library UInt256Lib {
    uint256 private constant MAX_INT256 = ~(uint256(1) << 255);

    /**
     * @dev Safely converts a uint256 to an int256.
     */
    function toInt256Safe(uint256 a) internal pure returns (int256) {
        require(a <= MAX_INT256);
        return int256(a);
    }
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
interface IERC20 {
    function totalSupply() external view returns (uint256);

    function balanceOf(address who) external view returns (uint256);

    function allowance(address owner, address spender)
        external
        view
        returns (uint256);

    function transfer(address to, uint256 value) external returns (bool);

    function approve(address spender, uint256 value) external returns (bool);

    function transferFrom(
        address from,
        address to,
        uint256 value
    ) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}

interface IOracle {
    function getData() external view returns (uint256);

    function update() external;
}

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address private _owner;

    event OwnershipRenounced(address indexed previousOwner);

    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor() public {
        _owner = msg.sender;
    }

    /**
     * @return the address of the owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Allows the current owner to relinquish control of the contract.
     * @notice Renouncing to ownership will leave the contract without an owner.
     * It will not be possible to call the functions with the `onlyOwner`
     * modifier anymore.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipRenounced(_owner);
        _owner = address(0);
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// <provableAPI>
/*

https://github.com/provable-things/ethereum-api/blob/master/provableAPI_0.5.sol

Copyright (c) 2015-2016 Oraclize SRL
Copyright (c) 2016-2019 Oraclize LTD
Copyright (c) 2019 Provable Things Limited

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

*/
pragma solidity >=0.5.0 <0.6.0; // Incompatible compiler version - please select a compiler within the stated pragma range, or use a different version of the provableAPI!

// Dummy contract only used to emit to end-user they are using wrong solc
contract solcChecker {
    /* INCOMPATIBLE SOLC: import the following instead: "github.com/oraclize/ethereum-api/oraclizeAPI_0.4.sol" */
    function f(bytes calldata x) external;
}

contract ProvableI {
    address public cbAddress;

    function setProofType(bytes1 _proofType) external;

    function setCustomGasPrice(uint256 _gasPrice) external;

    function getPrice(string memory _datasource)
        public
        returns (uint256 _dsprice);

    function randomDS_getSessionPubKeyHash()
        external
        view
        returns (bytes32 _sessionKeyHash);

    function getPrice(string memory _datasource, uint256 _gasLimit)
        public
        returns (uint256 _dsprice);

    function queryN(
        uint256 _timestamp,
        string memory _datasource,
        bytes memory _argN
    ) public payable returns (bytes32 _id);

    function query(
        uint256 _timestamp,
        string calldata _datasource,
        string calldata _arg
    ) external payable returns (bytes32 _id);

    function query2(
        uint256 _timestamp,
        string memory _datasource,
        string memory _arg1,
        string memory _arg2
    ) public payable returns (bytes32 _id);

    function query_withGasLimit(
        uint256 _timestamp,
        string calldata _datasource,
        string calldata _arg,
        uint256 _gasLimit
    ) external payable returns (bytes32 _id);

    function queryN_withGasLimit(
        uint256 _timestamp,
        string calldata _datasource,
        bytes calldata _argN,
        uint256 _gasLimit
    ) external payable returns (bytes32 _id);

    function query2_withGasLimit(
        uint256 _timestamp,
        string calldata _datasource,
        string calldata _arg1,
        string calldata _arg2,
        uint256 _gasLimit
    ) external payable returns (bytes32 _id);
}

contract OracleAddrResolverI {
    function getAddress() public returns (address _address);
}

/*

Begin solidity-cborutils

https://github.com/smartcontractkit/solidity-cborutils

MIT License

Copyright (c) 2018 SmartContract ChainLink, Ltd.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

*/
library Buffer {
    struct buffer {
        bytes buf;
        uint256 capacity;
    }

    function init(buffer memory _buf, uint256 _capacity) internal pure {
        uint256 capacity = _capacity;
        if (capacity % 32 != 0) {
            capacity += 32 - (capacity % 32);
        }
        _buf.capacity = capacity; // Allocate space for the buffer data
        assembly {
            let ptr := mload(0x40)
            mstore(_buf, ptr)
            mstore(ptr, 0)
            mstore(0x40, add(ptr, capacity))
        }
    }

    function resize(buffer memory _buf, uint256 _capacity) private pure {
        bytes memory oldbuf = _buf.buf;
        init(_buf, _capacity);
        append(_buf, oldbuf);
    }

    function max(uint256 _a, uint256 _b) private pure returns (uint256 _max) {
        if (_a > _b) {
            return _a;
        }
        return _b;
    }

    /**
     * @dev Appends a byte array to the end of the buffer. Resizes if doing so
     *      would exceed the capacity of the buffer.
     * @param _buf The buffer to append to.
     * @param _data The data to append.
     * @return The original buffer.
     *
     */
    function append(buffer memory _buf, bytes memory _data)
        internal
        pure
        returns (buffer memory _buffer)
    {
        if (_data.length + _buf.buf.length > _buf.capacity) {
            resize(_buf, max(_buf.capacity, _data.length) * 2);
        }
        uint256 dest;
        uint256 src;
        uint256 len = _data.length;
        assembly {
            let bufptr := mload(_buf) // Memory address of the buffer data
            let buflen := mload(bufptr) // Length of existing buffer data
            dest := add(add(bufptr, buflen), 32) // Start address = buffer address + buffer length + sizeof(buffer length)
            mstore(bufptr, add(buflen, mload(_data))) // Update buffer length
            src := add(_data, 32)
        }
        for (; len >= 32; len -= 32) {
            // Copy word-length chunks while possible
            assembly {
                mstore(dest, mload(src))
            }
            dest += 32;
            src += 32;
        }
        uint256 mask = 256**(32 - len) - 1; // Copy remaining bytes
        assembly {
            let srcpart := and(mload(src), not(mask))
            let destpart := and(mload(dest), mask)
            mstore(dest, or(destpart, srcpart))
        }
        return _buf;
    }

    /**
     *
     * @dev Appends a byte to the end of the buffer. Resizes if doing so would
     * exceed the capacity of the buffer.
     * @param _buf The buffer to append to.
     * @param _data The data to append.
     * @return The original buffer.
     *
     */
    function append(buffer memory _buf, uint8 _data) internal pure {
        if (_buf.buf.length + 1 > _buf.capacity) {
            resize(_buf, _buf.capacity * 2);
        }
        assembly {
            let bufptr := mload(_buf) // Memory address of the buffer data
            let buflen := mload(bufptr) // Length of existing buffer data
            let dest := add(add(bufptr, buflen), 32) // Address = buffer address + buffer length + sizeof(buffer length)
            mstore8(dest, _data)
            mstore(bufptr, add(buflen, 1)) // Update buffer length
        }
    }

    /**
     *
     * @dev Appends a byte to the end of the buffer. Resizes if doing so would
     * exceed the capacity of the buffer.
     * @param _buf The buffer to append to.
     * @param _data The data to append.
     * @return The original buffer.
     *
     */
    function appendInt(
        buffer memory _buf,
        uint256 _data,
        uint256 _len
    ) internal pure returns (buffer memory _buffer) {
        if (_len + _buf.buf.length > _buf.capacity) {
            resize(_buf, max(_buf.capacity, _len) * 2);
        }
        uint256 mask = 256**_len - 1;
        assembly {
            let bufptr := mload(_buf) // Memory address of the buffer data
            let buflen := mload(bufptr) // Length of existing buffer data
            let dest := add(add(bufptr, buflen), _len) // Address = buffer address + buffer length + sizeof(buffer length) + len
            mstore(dest, or(and(mload(dest), not(mask)), _data))
            mstore(bufptr, add(buflen, _len)) // Update buffer length
        }
        return _buf;
    }
}

library CBOR {
    using Buffer for Buffer.buffer;

    uint8 private constant MAJOR_TYPE_INT = 0;
    uint8 private constant MAJOR_TYPE_MAP = 5;
    uint8 private constant MAJOR_TYPE_BYTES = 2;
    uint8 private constant MAJOR_TYPE_ARRAY = 4;
    uint8 private constant MAJOR_TYPE_STRING = 3;
    uint8 private constant MAJOR_TYPE_NEGATIVE_INT = 1;
    uint8 private constant MAJOR_TYPE_CONTENT_FREE = 7;

    function encodeType(
        Buffer.buffer memory _buf,
        uint8 _major,
        uint256 _value
    ) private pure {
        if (_value <= 23) {
            _buf.append(uint8((_major << 5) | _value));
        } else if (_value <= 0xFF) {
            _buf.append(uint8((_major << 5) | 24));
            _buf.appendInt(_value, 1);
        } else if (_value <= 0xFFFF) {
            _buf.append(uint8((_major << 5) | 25));
            _buf.appendInt(_value, 2);
        } else if (_value <= 0xFFFFFFFF) {
            _buf.append(uint8((_major << 5) | 26));
            _buf.appendInt(_value, 4);
        } else if (_value <= 0xFFFFFFFFFFFFFFFF) {
            _buf.append(uint8((_major << 5) | 27));
            _buf.appendInt(_value, 8);
        }
    }

    function encodeIndefiniteLengthType(Buffer.buffer memory _buf, uint8 _major)
        private
        pure
    {
        _buf.append(uint8((_major << 5) | 31));
    }

    function encodeUInt(Buffer.buffer memory _buf, uint256 _value)
        internal
        pure
    {
        encodeType(_buf, MAJOR_TYPE_INT, _value);
    }

    function encodeInt(Buffer.buffer memory _buf, int256 _value) internal pure {
        if (_value >= 0) {
            encodeType(_buf, MAJOR_TYPE_INT, uint256(_value));
        } else {
            encodeType(_buf, MAJOR_TYPE_NEGATIVE_INT, uint256(-1 - _value));
        }
    }

    function encodeBytes(Buffer.buffer memory _buf, bytes memory _value)
        internal
        pure
    {
        encodeType(_buf, MAJOR_TYPE_BYTES, _value.length);
        _buf.append(_value);
    }

    function encodeString(Buffer.buffer memory _buf, string memory _value)
        internal
        pure
    {
        encodeType(_buf, MAJOR_TYPE_STRING, bytes(_value).length);
        _buf.append(bytes(_value));
    }

    function startArray(Buffer.buffer memory _buf) internal pure {
        encodeIndefiniteLengthType(_buf, MAJOR_TYPE_ARRAY);
    }

    function startMap(Buffer.buffer memory _buf) internal pure {
        encodeIndefiniteLengthType(_buf, MAJOR_TYPE_MAP);
    }

    function endSequence(Buffer.buffer memory _buf) internal pure {
        encodeIndefiniteLengthType(_buf, MAJOR_TYPE_CONTENT_FREE);
    }
}

/*

End solidity-cborutils

*/
contract usingProvable {
    using CBOR for Buffer.buffer;

    ProvableI provable;
    OracleAddrResolverI OAR;

    uint256 constant day = 60 * 60 * 24;
    uint256 constant week = 60 * 60 * 24 * 7;
    uint256 constant month = 60 * 60 * 24 * 30;

    bytes1 constant proofType_NONE = 0x00;
    bytes1 constant proofType_Ledger = 0x30;
    bytes1 constant proofType_Native = 0xF0;
    bytes1 constant proofStorage_IPFS = 0x01;
    bytes1 constant proofType_Android = 0x40;
    bytes1 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)
        internal
        provableAPI
        returns (uint256 _queryPrice)
    {
        return provable.getPrice(_datasource);
    }

    function provable_getPrice(string memory _datasource, uint256 _gasLimit)
        internal
        provableAPI
        returns (uint256 _queryPrice)
    {
        return provable.getPrice(_datasource, _gasLimit);
    }

    function provable_query(string memory _datasource, string memory _arg)
        internal
        provableAPI
        returns (bytes32 _id)
    {
        uint256 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(
        uint256 _timestamp,
        string memory _datasource,
        string memory _arg
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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(
        uint256 _timestamp,
        string memory _datasource,
        string memory _arg,
        uint256 _gasLimit
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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,
        uint256 _gasLimit
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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(
        uint256 _timestamp,
        string memory _datasource,
        string memory _arg1,
        string memory _arg2
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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(
        uint256 _timestamp,
        string memory _datasource,
        string memory _arg1,
        string memory _arg2,
        uint256 _gasLimit
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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,
        uint256 _gasLimit
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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)
        internal
        provableAPI
        returns (bytes32 _id)
    {
        uint256 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(
        uint256 _timestamp,
        string memory _datasource,
        string[] memory _argN
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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(
        uint256 _timestamp,
        string memory _datasource,
        string[] memory _argN,
        uint256 _gasLimit
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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,
        uint256 _gasLimit
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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)
        internal
        provableAPI
        returns (bytes32 _id)
    {
        string[] memory dynargs = new string[](1);
        dynargs[0] = _args[0];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(
        uint256 _timestamp,
        string memory _datasource,
        string[1] memory _args
    ) internal provableAPI returns (bytes32 _id) {
        string[] memory dynargs = new string[](1);
        dynargs[0] = _args[0];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(
        uint256 _timestamp,
        string memory _datasource,
        string[1] memory _args,
        uint256 _gasLimit
    ) internal provableAPI 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,
        uint256 _gasLimit
    ) internal provableAPI 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)
        internal
        provableAPI
        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(
        uint256 _timestamp,
        string memory _datasource,
        string[2] memory _args
    ) internal provableAPI 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(
        uint256 _timestamp,
        string memory _datasource,
        string[2] memory _args,
        uint256 _gasLimit
    ) internal provableAPI 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,
        uint256 _gasLimit
    ) internal provableAPI 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)
        internal
        provableAPI
        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(
        uint256 _timestamp,
        string memory _datasource,
        string[3] memory _args
    ) internal provableAPI 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(
        uint256 _timestamp,
        string memory _datasource,
        string[3] memory _args,
        uint256 _gasLimit
    ) internal provableAPI 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,
        uint256 _gasLimit
    ) internal provableAPI 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)
        internal
        provableAPI
        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(
        uint256 _timestamp,
        string memory _datasource,
        string[4] memory _args
    ) internal provableAPI 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(
        uint256 _timestamp,
        string memory _datasource,
        string[4] memory _args,
        uint256 _gasLimit
    ) internal provableAPI 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,
        uint256 _gasLimit
    ) internal provableAPI 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)
        internal
        provableAPI
        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(
        uint256 _timestamp,
        string memory _datasource,
        string[5] memory _args
    ) internal provableAPI 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(
        uint256 _timestamp,
        string memory _datasource,
        string[5] memory _args,
        uint256 _gasLimit
    ) internal provableAPI 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,
        uint256 _gasLimit
    ) internal provableAPI 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)
        internal
        provableAPI
        returns (bytes32 _id)
    {
        uint256 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(
        uint256 _timestamp,
        string memory _datasource,
        bytes[] memory _argN
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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(
        uint256 _timestamp,
        string memory _datasource,
        bytes[] memory _argN,
        uint256 _gasLimit
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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,
        uint256 _gasLimit
    ) internal provableAPI returns (bytes32 _id) {
        uint256 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)
        internal
        provableAPI
        returns (bytes32 _id)
    {
        bytes[] memory dynargs = new bytes[](1);
        dynargs[0] = _args[0];
        return provable_query(_datasource, dynargs);
    }

    function provable_query(
        uint256 _timestamp,
        string memory _datasource,
        bytes[1] memory _args
    ) internal provableAPI returns (bytes32 _id) {
        bytes[] memory dynargs = new bytes[](1);
        dynargs[0] = _args[0];
        return provable_query(_timestamp, _datasource, dynargs);
    }

    function provable_query(
        uint256 _timestamp,
        string memory _datasource,
        bytes[1] memory _args,
        uint256 _gasLimit
    ) internal provableAPI 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,
        uint256 _gasLimit
    ) internal provableAPI 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)
        internal
        provableAPI
        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(
        uint256 _timestamp,
        string memory _datasource,
        bytes[2] memory _args
    ) internal provableAPI 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(
        uint256 _timestamp,
        string memory _datasource,
        bytes[2] memory _args,
        uint256 _gasLimit
    ) internal provableAPI 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,
        uint256 _gasLimit
    ) internal provableAPI 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)
        internal
        provableAPI
        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(
        uint256 _timestamp,
        string memory _datasource,
        bytes[3] memory _args
    ) internal provableAPI 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(
        uint256 _timestamp,
        string memory _datasource,
        bytes[3] memory _args,
        uint256 _gasLimit
    ) internal provableAPI 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,
        uint256 _gasLimit
    ) internal provableAPI 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)
        internal
        provableAPI
        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(
        uint256 _timestamp,
        string memory _datasource,
        bytes[4] memory _args
    ) internal provableAPI 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(
        uint256 _timestamp,
        string memory _datasource,
        bytes[4] memory _args,
        uint256 _gasLimit
    ) internal provableAPI 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,
        uint256 _gasLimit
    ) internal provableAPI 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)
        internal
        provableAPI
        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(
        uint256 _timestamp,
        string memory _datasource,
        bytes[5] memory _args
    ) internal provableAPI 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(
        uint256 _timestamp,
        string memory _datasource,
        bytes[5] memory _args,
        uint256 _gasLimit
    ) internal provableAPI 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,
        uint256 _gasLimit
    ) internal provableAPI 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(bytes1 _proofP) internal provableAPI {
        return provable.setProofType(_proofP);
    }

    function provable_cbAddress()
        internal
        provableAPI
        returns (address _callbackAddress)
    {
        return provable.cbAddress();
    }

    function getCodeSize(address _addr) internal view returns (uint256 _size) {
        assembly {
            _size := extcodesize(_addr)
        }
    }

    function provable_setCustomGasPrice(uint256 _gasPrice)
        internal
        provableAPI
    {
        return provable.setCustomGasPrice(_gasPrice);
    }

    function provable_randomDS_getSessionPubKeyHash()
        internal
        provableAPI
        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 (uint256 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 (int256 _returnCode)
    {
        bytes memory a = bytes(_a);
        bytes memory b = bytes(_b);
        uint256 minLength = a.length;
        if (b.length < minLength) {
            minLength = b.length;
        }
        for (uint256 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 (int256 _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 {
            uint256 subindex = 0;
            for (uint256 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 int256(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);
        uint256 k = 0;
        uint256 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 (uint256 _parsedInt)
    {
        return safeParseInt(_a, 0);
    }

    function safeParseInt(string memory _a, uint256 _b)
        internal
        pure
        returns (uint256 _parsedInt)
    {
        bytes memory bresult = bytes(_a);
        uint256 mint = 0;
        bool decimals = false;
        for (uint256 i = 0; i < bresult.length; i++) {
            if (
                (uint256(uint8(bresult[i])) >= 48) &&
                (uint256(uint8(bresult[i])) <= 57)
            ) {
                if (decimals) {
                    if (_b == 0) break;
                    else _b--;
                }
                mint *= 10;
                mint += uint256(uint8(bresult[i])) - 48;
            } else if (uint256(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 (uint256 _parsedInt)
    {
        return parseInt(_a, 0);
    }

    function parseInt(string memory _a, uint256 _b)
        internal
        pure
        returns (uint256 _parsedInt)
    {
        bytes memory bresult = bytes(_a);
        uint256 mint = 0;
        bool decimals = false;
        for (uint256 i = 0; i < bresult.length; i++) {
            if (
                (uint256(uint8(bresult[i])) >= 48) &&
                (uint256(uint8(bresult[i])) <= 57)
            ) {
                if (decimals) {
                    if (_b == 0) {
                        break;
                    } else {
                        _b--;
                    }
                }
                mint *= 10;
                mint += uint256(uint8(bresult[i])) - 48;
            } else if (uint256(uint8(bresult[i])) == 46) {
                decimals = true;
            }
        }
        if (_b > 0) {
            mint *= 10**_b;
        }
        return mint;
    }

    function uint2str(uint256 _i)
        internal
        pure
        returns (string memory _uintAsString)
    {
        if (_i == 0) {
            return "0";
        }
        uint256 j = _i;
        uint256 len;
        while (j != 0) {
            len++;
            j /= 10;
        }
        bytes memory bstr = new bytes(len);
        uint256 k = len - 1;
        while (_i != 0) {
            bstr[k--] = bytes1(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 (uint256 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 (uint256 i = 0; i < _arr.length; i++) {
            buf.encodeBytes(_arr[i]);
        }
        buf.endSequence();
        return buf.buf;
    }

    function provable_newRandomDSQuery(
        uint256 _delay,
        uint256 _nbytes,
        uint256 _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] = bytes1(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);
        uint256 offset = 4 + (uint256(uint8(_dersig[3])) - 0x20);
        sigr_ = copyBytes(_dersig, offset, 32, sigr_, 0);
        bytes memory sigs_ = new bytes(32);
        offset += 32 + 2;
        sigs_ = copyBytes(
            _dersig,
            offset + (uint256(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,
        uint256 _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(
            uint256(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] = bytes1(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(uint256(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,
        uint256 _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)
        uint256 ledgerProofLength = 3 +
            65 +
            (uint256(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(
            uint256(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,
                uint256(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);
        uint256 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,
        uint256 _fromOffset,
        uint256 _length,
        bytes memory _to,
        uint256 _toOffset
    ) internal pure returns (bytes memory _copiedBytes) {
        uint256 minLength = _length + _toOffset;
        require(_to.length >= minLength); // Buffer too small. Should be a better way?
        uint256 i = 32 + _fromOffset; // NOTE: the offset 32 is added to skip the `size` field of both bytes variables
        uint256 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))
        }
    }
}

// </provableAPI>

interface IVAMP {
    function totalSupply() external view returns (uint256);

    function rebase(int256 supplyDelta) external returns (uint256);
}

/**
 * @title vamp Controller
 * @dev Controller for an elastic supply currency based on the uFragments Ideal Money protocol a.k.a. Ampleforth.
 *      uFragments operates symmetrically on expansion and contraction. It will both split and
 *      combine coins to maintain a stable unit price.
 *
 *      This component regulates the token supply of the uFragments ERC20 token in response to
 *      market oracles.
 */
contract VAMPRebaser is usingProvable, Ownable {
    using SafeMath for uint256;
    using SafeMathInt for int256;

    uint256 public constant BASE = 10**18;

    /// @notice More than this much time must pass between rebase operations.
    uint256 public minRebaseTimeIntervalSec;

    /// @notice Block timestamp of last rebase operation
    uint256 public lastRebaseTimestampSec;

    /// @notice The rebase window begins this many seconds into the minRebaseTimeInterval period.
    // For example if minRebaseTimeInterval is 24hrs, it represents the time of day in seconds.
    uint256 public rebaseWindowOffsetSec;

    /// @notice The length of the time window where a rebase operation is allowed to execute, in seconds.
    uint256 public rebaseWindowLengthSec;

    /// @notice The number of rebase cycles since inception
    uint256 public epoch;

    /// @notice delays rebasing activation to facilitate liquidity
    uint256 public constant rebaseDelay = 12 hours;

    /// @notice Time of TWAP initialization
    uint256 public rebaseActivatedTime;

    bool public rebasePrepared = false;

    /// @notice last TWAP cumulative price;
    uint256 public priceCumulativeLast;

    /// @notice Governance address
    address public gov;

    /// @notice Pending Governance address
    address public pendingGov;

    /// @notice VAMP token address
    address public VAMPAddress;

    /// @notice reserve token
    address public reserveToken;

    /// @notice pair for reserveToken <> VAMP
    address public uniswap_pair;

    /// @notice last TWAP update time
    uint32 public blockTimestampLast;

    int256 public rebaserMultiplier = 10;

    /// @notice Whether or not this token is first in uniswap VAMP<>Reserve pair
    bool public isToken0;

    // rebasing is not active initially. It can be activated at T+12 hours from
    // deployment time
    ///@notice boolean showing rebase activation status
    bool public rebasingActive;

    /// @notice Value we want to use as the minimum level when deciding to rebase or not
    uint256 public rebaseFloor;

    /// @notice Value we want to use as the max level when deciding to rebase or not
    uint256 public rebaseCeiling;

    /// @notice these values could pos/neg
    int256 public rebaseUpPriceUpVolRate;
    /// @notice these values could pos/neg
    int256 public rebaseUpPriceDownVolRate;
    /// @notice these values could pos/neg
    int256 public rebaseDownPriceUpVolRate;
    /// @notice these values could pos/neg
    int256 public rebaseDownPriceDownVolRate;
    
    int256 public twapUp;
    int256 public twapDown;

    IVAMP public VAMP;

    IOracle public marketOracle;

    uint256 public currentVolumeUsd;

    /// @notice the last volume on uniswap for a certain time window
    uint256 public lastVolumeUsd;

    /// @notice the last TWAP we stored in rebase
    uint256 public lastTwapPrice;

    /// @notice the TWAP we just received
    uint256 public currentTwapPrice;

    /**
     * @notice Event emitted when pendingGov is changed
     */
    event NewPendingGov(address oldPendingGov, address newPendingGov);

    /**
     * @notice Event emitted when gov is changed
     */
    event NewGov(address oldGov, address newGov);

    event RebaseStatus(
        uint256 timestap,
        bool rebasing,
        uint256 twap,
        uint256 floor,
        uint256 ceiling
    );

    event RebaseCompleted(
        int256 rebaseAmount,
        int256 rebaseRate,
        uint256 lastVolume,
        uint256 lastPrice
    );

    event LogNewUsdVolume(string newVolume);

    event RebasePrepared(string newVolume, uint256 currentTwapPrice);

    modifier onlyGov() {
        require(msg.sender == gov);
        _;
    }

    constructor(address VAMPAddress_) public {
        VAMP = IVAMP(VAMPAddress_);
        // Changed in deployment scripts to facilitate protocol initiation
        gov = msg.sender;

        // $0.96
        rebaseFloor = 96 * 10**16;

        // $1.06
        rebaseCeiling = 106 * 10**16;

        // 0.01 :: 1% ( 1 * 10 ** 16) - slash to 0.5%
        rebaseUpPriceUpVolRate = 5 * 10**15;

        // 0.005 :: 0.5% (5 * 10 ** 15) - slash to 0.25%
        rebaseUpPriceDownVolRate = 25 * 10**14;

        // 0.0025 :: 0.25% (25 * 10 ** 14)- slash to 0.12
        rebaseDownPriceUpVolRate = 12 * 10**14;

        // -0.01 :: -1% ( 1 * 10 ** 16) slash to 0.5%
        rebaseDownPriceDownVolRate = -5 * 10**15;

        //0.25% increase if volume is 0 and price is up
        twapUp = 25 * 10**14;

        //-0.25% decrease if volume is 0 and price is down
        twapDown = - 25 * 10**14;
    }

    /**
     * @notice Sets the reference to the market oracle.
     * @param marketOracle_ The address of the market oracle contract.
     */
    function setMarketOracle(IOracle marketOracle_) external onlyOwner {
        marketOracle = marketOracle_;
    }

    function setRebaserMultiplier(int256 _amount) external onlyOwner {
        rebaserMultiplier = _amount;
    }

    /** @notice Activates rebasing
     *   @dev One way function, cannot be undone, callable by anyone
     */
    function activate_rebasing(uint256 _volume) public onlyOwner {
        rebasingActive = true;
        lastTwapPrice = marketOracle.getData();
        rebaseActivatedTime = now;
        marketOracle.update();
        lastVolumeUsd = _volume;
    }

    function __callback(bytes32 _myid, string memory _result) public {
        require(msg.sender == provable_cbAddress(), "Revert at callback");
        // 4dps resolution
        currentVolumeUsd = parseInt(_result, 4);
        rebasePrepared = true;
        emit RebasePrepared(_result, currentTwapPrice);
    }

    function calcRebaseAmount(
        bool posPriceChange,
        bool posVolChange,
        uint256 totalSupply
    ) public view returns (int256 rebaseAmount, int256 rebaseRate) {
        if (currentVolumeUsd == 0) { //if volume is 0
            if(posPriceChange){
                rebaseRate = twapUp;
            } else {
                rebaseRate = twapDown;
            }
        } else {//if volume is more than 0
            if (posPriceChange && posVolChange) {
                rebaseRate = rebaseUpPriceUpVolRate;
            } else if (posPriceChange && !posVolChange) {
                rebaseRate = rebaseUpPriceDownVolRate;
            } else if (!posPriceChange && posVolChange) {
                rebaseRate = rebaseDownPriceUpVolRate;
            } else if (!posPriceChange && !posVolChange) {
                rebaseRate = rebaseDownPriceDownVolRate;
            } else {
                rebaseRate = 0;
                rebaseAmount = 0;
            }
        }

        // calc rebaseAmount and normalise
        rebaseAmount = rebaseRate.mul(int256(totalSupply)).div(10**18);
    }

    /**
     * Do the actual rebase
     */
    function _doRebase() internal {
        int256 changeInVol = int256(currentVolumeUsd - lastVolumeUsd);
        bool posVolChange = changeInVol > 0;
        int256 changeInPrice = int256(currentTwapPrice - lastTwapPrice);
        bool posPriceChange = changeInPrice > 0;

        // get the correct rebase amounts based on vol and price changes.
        (int256 rebaseAmount, int256 rebaseRate) = calcRebaseAmount(
            posVolChange,
            posPriceChange,
            VAMP.totalSupply()
        );
        // Perform rebase.
        VAMP.rebase(rebaseAmount);

        marketOracle.update();

        // now commit back the prices.
        lastVolumeUsd = currentVolumeUsd;
        lastTwapPrice = currentTwapPrice;
        lastRebaseTimestampSec = block.timestamp;
        currentTwapPrice = 0;
        rebasePrepared = false;

        emit RebaseCompleted(
            rebaseAmount,
            rebaseRate,
            lastVolumeUsd,
            lastTwapPrice
        );
    }

    /**
     * @notice Calls the _dorebase to do the actual rebase
     *
     */
    function rebase() public onlyOwner {
        require(tx.origin == msg.sender);
        require(
            block.timestamp > rebaseActivatedTime.add(rebaseDelay),
            "Must wait one period after activating rebase"
        );
        require(
            block.timestamp > lastRebaseTimestampSec.add(rebaseDelay),
            "Must wait for rebase cooldown"
        );
        require(
            rebasingActive && rebasePrepared,
            "Rebasing is disabled or not prepared"
        );
        epoch = epoch.add(1);

        // figure out if rebase is happening.
        // if $0.96 < twap < $1.06
        if (
            rebaseFloor < currentTwapPrice && currentTwapPrice < rebaseCeiling
        ) {
            emit RebaseStatus(
                now,
                false,
                currentTwapPrice,
                rebaseFloor,
                rebaseCeiling
            );
        } else {
            emit RebaseStatus(
                now,
                true,
                currentTwapPrice,
                rebaseFloor,
                rebaseCeiling
            );
            _doRebase();
        }
    }

    /**
     * @notice Prepares the rebase by calling the volume oracle.
     *
     */
    function prepare_rebase() public payable onlyOwner {
        // get twap from uniswap v2 and save here for later (i.e. the current price)
        currentTwapPrice = marketOracle.getData();
        //calls volume oracle
        provable_query(
            "URL",
            "BKm/7gwT7kf+wtshQJpqYkFV3su8/QNzyNR3HTYxaobe20/SqDQ0EWxw05oMXn9M0Vfb1KauBcqGoZLTkI0+mWvKeH4TwDRquo1OLy2l/1/2ZQjkdraciiUgR0aFq4g6rk24AFxwNhHW08U4WwJVkg=="
        );
    }
}