// proxy.sol - execute actions atomically through the proxy's identity

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.23;

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    constructor() public {
        owner = msg.sender;
        emit LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        emit LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        emit LogSetAuthority(authority);
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }
}

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
        uint              wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        emit LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}

// DSProxy
// Allows code execution using a persistant identity This can be very
// useful to execute a sequence of atomic actions. Since the owner of
// the proxy can be changed, this allows for dynamic ownership models
// i.e. a multisig
contract DSProxy is DSAuth, DSNote {
    DSProxyCache public cache;  // global cache for contracts

    constructor(address _cacheAddr) public {
        require(setCache(_cacheAddr));
    }

    function() public payable {
    }

    // use the proxy to execute calldata _data on contract _code
    function execute(bytes _code, bytes _data)
        public
        payable
        returns (address target, bytes32 response)
    {
        target = cache.read(_code);
        if (target == 0x0) {
            // deploy contract & store its address in cache
            target = cache.write(_code);
        }

        response = execute(target, _data);
    }

    function execute(address _target, bytes _data)
        public
        auth
        note
        payable
        returns (bytes32 response)
    {
        require(_target != 0x0);

        // call contract in current context
        assembly {
            let succeeded := delegatecall(sub(gas, 5000), _target, add(_data, 0x20), mload(_data), 0, 32)
            response := mload(0)      // load delegatecall output
            switch iszero(succeeded)
            case 1 {
                // throw if delegatecall failed
                revert(0, 0)
            }
        }
    }

    //set new cache
    function setCache(address _cacheAddr)
        public
        auth
        note
        returns (bool)
    {
        require(_cacheAddr != 0x0);        // invalid cache address
        cache = DSProxyCache(_cacheAddr);  // overwrite cache
        return true;
    }
}

// DSProxyFactory
// This factory deploys new proxy instances through build()
// Deployed proxy addresses are logged
contract DSProxyFactory {
    event Created(address indexed sender, address indexed owner, address proxy, address cache);
    mapping(address=>bool) public isProxy;
    DSProxyCache public cache = new DSProxyCache();

    // deploys a new proxy instance
    // sets owner of proxy to caller
    function build() public returns (DSProxy proxy) {
        proxy = build(msg.sender);
    }

    // deploys a new proxy instance
    // sets custom owner of proxy
    function build(address owner) public returns (DSProxy proxy) {
        proxy = new DSProxy(cache);
        emit Created(msg.sender, owner, address(proxy), address(cache));
        proxy.setOwner(owner);
        isProxy[proxy] = true;
    }
}

// DSProxyCache
// This global cache stores addresses of contracts previously deployed
// by a proxy. This saves gas from repeat deployment of the same
// contracts and eliminates blockchain bloat.

// By default, all proxies deployed from the same factory store
// contracts in the same cache. The cache a proxy instance uses can be
// changed.  The cache uses the sha3 hash of a contract's bytecode to
// lookup the address
contract DSProxyCache {
    mapping(bytes32 => address) cache;

    function read(bytes _code) public view returns (address) {
        bytes32 hash = keccak256(_code);
        return cache[hash];
    }

    function write(bytes _code) public returns (address target) {
        assembly {
            target := create(0, add(_code, 0x20), mload(_code))
            switch iszero(extcodesize(target))
            case 1 {
                // throw if contract failed to deploy
                revert(0, 0)
            }
        }
        bytes32 hash = keccak256(_code);
        cache[hash] = target;
    }
}

// hevm: flattened sources of src/tub.sol
pragma solidity ^0.4.18;

////// lib/ds-guard/lib/ds-auth/src/auth.sol
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    function DSAuth() public {
        owner = msg.sender;
        LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        LogSetAuthority(authority);
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }
}

////// lib/ds-spell/lib/ds-note/src/note.sol
/// note.sol -- the `note' modifier, for logging calls as events

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
        uint              wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}

////// lib/ds-thing/lib/ds-math/src/math.sol
/// math.sol -- mixin for inline numerical wizardry

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x);
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x);
    }
    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x);
    }

    function min(uint x, uint y) internal pure returns (uint z) {
        return x <= y ? x : y;
    }
    function max(uint x, uint y) internal pure returns (uint z) {
        return x >= y ? x : y;
    }
    function imin(int x, int y) internal pure returns (int z) {
        return x <= y ? x : y;
    }
    function imax(int x, int y) internal pure returns (int z) {
        return x >= y ? x : y;
    }

    uint constant WAD = 10 ** 18;
    uint constant RAY = 10 ** 27;

    function wmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }
    function rmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }
    function wdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, WAD), y / 2) / y;
    }
    function rdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint x, uint n) internal pure returns (uint z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}

////// lib/ds-thing/src/thing.sol
// thing.sol - `auth` with handy mixins. your things should be DSThings

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import 'ds-auth/auth.sol'; */
/* import 'ds-note/note.sol'; */
/* import 'ds-math/math.sol'; */

contract DSThing is DSAuth, DSNote, DSMath {

    function S(string s) internal pure returns (bytes4) {
        return bytes4(keccak256(s));
    }

}

////// lib/ds-token/lib/ds-stop/src/stop.sol
/// stop.sol -- mixin for enable/disable functionality

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-auth/auth.sol"; */
/* import "ds-note/note.sol"; */

contract DSStop is DSNote, DSAuth {

    bool public stopped;

    modifier stoppable {
        require(!stopped);
        _;
    }
    function stop() public auth note {
        stopped = true;
    }
    function start() public auth note {
        stopped = false;
    }

}

////// lib/ds-token/lib/erc20/src/erc20.sol
/// erc20.sol -- API for the ERC20 token standard

// See <https://github.com/ethereum/EIPs/issues/20>.

// This file likely does not meet the threshold of originality
// required for copyright to apply.  As a result, this is free and
// unencumbered software belonging to the public domain.

/* pragma solidity ^0.4.8; */

contract ERC20Events {
    event Approval(address indexed src, address indexed guy, uint wad);
    event Transfer(address indexed src, address indexed dst, uint wad);
}

contract ERC20 is ERC20Events {
    function totalSupply() public view returns (uint);
    function balanceOf(address guy) public view returns (uint);
    function allowance(address src, address guy) public view returns (uint);

    function approve(address guy, uint wad) public returns (bool);
    function transfer(address dst, uint wad) public returns (bool);
    function transferFrom(
        address src, address dst, uint wad
    ) public returns (bool);
}

////// lib/ds-token/src/base.sol
/// base.sol -- basic ERC20 implementation

// Copyright (C) 2015, 2016, 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "erc20/erc20.sol"; */
/* import "ds-math/math.sol"; */

contract DSTokenBase is ERC20, DSMath {
    uint256                                            _supply;
    mapping (address => uint256)                       _balances;
    mapping (address => mapping (address => uint256))  _approvals;

    function DSTokenBase(uint supply) public {
        _balances[msg.sender] = supply;
        _supply = supply;
    }

    function totalSupply() public view returns (uint) {
        return _supply;
    }
    function balanceOf(address src) public view returns (uint) {
        return _balances[src];
    }
    function allowance(address src, address guy) public view returns (uint) {
        return _approvals[src][guy];
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        if (src != msg.sender) {
            _approvals[src][msg.sender] = sub(_approvals[src][msg.sender], wad);
        }

        _balances[src] = sub(_balances[src], wad);
        _balances[dst] = add(_balances[dst], wad);

        Transfer(src, dst, wad);

        return true;
    }

    function approve(address guy, uint wad) public returns (bool) {
        _approvals[msg.sender][guy] = wad;

        Approval(msg.sender, guy, wad);

        return true;
    }
}

////// lib/ds-token/src/token.sol
/// token.sol -- ERC20 implementation with minting and burning

// Copyright (C) 2015, 2016, 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-stop/stop.sol"; */

/* import "./base.sol"; */

contract DSToken is DSTokenBase(0), DSStop {

    bytes32  public  symbol;
    uint256  public  decimals = 18; // standard token precision. override to customize

    function DSToken(bytes32 symbol_) public {
        symbol = symbol_;
    }

    event Mint(address indexed guy, uint wad);
    event Burn(address indexed guy, uint wad);

    function approve(address guy) public stoppable returns (bool) {
        return super.approve(guy, uint(-1));
    }

    function approve(address guy, uint wad) public stoppable returns (bool) {
        return super.approve(guy, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        stoppable
        returns (bool)
    {
        if (src != msg.sender && _approvals[src][msg.sender] != uint(-1)) {
            _approvals[src][msg.sender] = sub(_approvals[src][msg.sender], wad);
        }

        _balances[src] = sub(_balances[src], wad);
        _balances[dst] = add(_balances[dst], wad);

        Transfer(src, dst, wad);

        return true;
    }

    function push(address dst, uint wad) public {
        transferFrom(msg.sender, dst, wad);
    }
    function pull(address src, uint wad) public {
        transferFrom(src, msg.sender, wad);
    }
    function move(address src, address dst, uint wad) public {
        transferFrom(src, dst, wad);
    }

    function mint(uint wad) public {
        mint(msg.sender, wad);
    }
    function burn(uint wad) public {
        burn(msg.sender, wad);
    }
    function mint(address guy, uint wad) public auth stoppable {
        _balances[guy] = add(_balances[guy], wad);
        _supply = add(_supply, wad);
        Mint(guy, wad);
    }
    function burn(address guy, uint wad) public auth stoppable {
        if (guy != msg.sender && _approvals[guy][msg.sender] != uint(-1)) {
            _approvals[guy][msg.sender] = sub(_approvals[guy][msg.sender], wad);
        }

        _balances[guy] = sub(_balances[guy], wad);
        _supply = sub(_supply, wad);
        Burn(guy, wad);
    }

    // Optional token name
    bytes32   public  name = "";

    function setName(bytes32 name_) public auth {
        name = name_;
    }
}

////// lib/ds-value/src/value.sol
/// value.sol - a value is a simple thing, it can be get and set

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import 'ds-thing/thing.sol'; */

contract DSValue is DSThing {
    bool    has;
    bytes32 val;
    function peek() public view returns (bytes32, bool) {
        return (val,has);
    }
    function read() public view returns (bytes32) {
        var (wut, haz) = peek();
        assert(haz);
        return wut;
    }
    function poke(bytes32 wut) public note auth {
        val = wut;
        has = true;
    }
    function void() public note auth {  // unset the value
        has = false;
    }
}

////// src/vox.sol
/// vox.sol -- target price feed

// Copyright (C) 2016, 2017  Nikolai Mushegian <[email protected]>
// Copyright (C) 2016, 2017  Daniel Brockman <[email protected]>
// Copyright (C) 2017        Rain Break <[email protected]>

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.18; */

/* import "ds-thing/thing.sol"; */

contract SaiVox is DSThing {
    uint256  _par;
    uint256  _way;

    uint256  public  fix;
    uint256  public  how;
    uint256  public  tau;

    function SaiVox(uint par_) public {
        _par = fix = par_;
        _way = RAY;
        tau  = era();
    }

    function era() public view returns (uint) {
        return block.timestamp;
    }

    function mold(bytes32 param, uint val) public note auth {
        if (param == 'way') _way = val;
    }

    // Dai Target Price (ref per dai)
    function par() public returns (uint) {
        prod();
        return _par;
    }
    function way() public returns (uint) {
        prod();
        return _way;
    }

    function tell(uint256 ray) public note auth {
        fix = ray;
    }
    function tune(uint256 ray) public note auth {
        how = ray;
    }

    function prod() public note {
        var age = era() - tau;
        if (age == 0) return;  // optimised
        tau = era();

        if (_way != RAY) _par = rmul(_par, rpow(_way, age));  // optimised

        if (how == 0) return;  // optimised
        var wag = int128(how * age);
        _way = inj(prj(_way) + (fix < _par ? wag : -wag));
    }

    function inj(int128 x) internal pure returns (uint256) {
        return x >= 0 ? uint256(x) + RAY
            : rdiv(RAY, RAY + uint256(-x));
    }
    function prj(uint256 x) internal pure returns (int128) {
        return x >= RAY ? int128(x - RAY)
            : int128(RAY) - int128(rdiv(RAY, x));
    }
}

////// src/tub.sol
/// tub.sol -- simplified CDP engine (baby brother of `vat')

// Copyright (C) 2017  Nikolai Mushegian <[email protected]>
// Copyright (C) 2017  Daniel Brockman <[email protected]>
// Copyright (C) 2017  Rain Break <[email protected]>

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.18; */

/* import "ds-thing/thing.sol"; */
/* import "ds-token/token.sol"; */
/* import "ds-value/value.sol"; */

/* import "./vox.sol"; */

contract SaiTubEvents {
    event LogNewCup(address indexed lad, bytes32 cup);
}

contract SaiTub is DSThing, SaiTubEvents {
    DSToken  public  sai;  // Stablecoin
    DSToken  public  sin;  // Debt (negative sai)

    DSToken  public  skr;  // Abstracted collateral
    ERC20    public  gem;  // Underlying collateral

    DSToken  public  gov;  // Governance token

    SaiVox   public  vox;  // Target price feed
    DSValue  public  pip;  // Reference price feed
    DSValue  public  pep;  // Governance price feed

    address  public  tap;  // Liquidator
    address  public  pit;  // Governance Vault

    uint256  public  axe;  // Liquidation penalty
    uint256  public  cap;  // Debt ceiling
    uint256  public  mat;  // Liquidation ratio
    uint256  public  tax;  // Stability fee
    uint256  public  fee;  // Governance fee
    uint256  public  gap;  // Join-Exit Spread

    bool     public  off;  // Cage flag
    bool     public  out;  // Post cage exit

    uint256  public  fit;  // REF per SKR (just before settlement)

    uint256  public  rho;  // Time of last drip
    uint256         _chi;  // Accumulated Tax Rates
    uint256         _rhi;  // Accumulated Tax + Fee Rates
    uint256  public  rum;  // Total normalised debt

    uint256                   public  cupi;
    mapping (bytes32 => Cup)  public  cups;

    struct Cup {
        address  lad;      // CDP owner
        uint256  ink;      // Locked collateral (in SKR)
        uint256  art;      // Outstanding normalised debt (tax only)
        uint256  ire;      // Outstanding normalised debt
    }

    function lad(bytes32 cup) public view returns (address) {
        return cups[cup].lad;
    }
    function ink(bytes32 cup) public view returns (uint) {
        return cups[cup].ink;
    }
    function tab(bytes32 cup) public returns (uint) {
        return rmul(cups[cup].art, chi());
    }
    function rap(bytes32 cup) public returns (uint) {
        return sub(rmul(cups[cup].ire, rhi()), tab(cup));
    }

    // Total CDP Debt
    function din() public returns (uint) {
        return rmul(rum, chi());
    }
    // Backing collateral
    function air() public view returns (uint) {
        return skr.balanceOf(this);
    }
    // Raw collateral
    function pie() public view returns (uint) {
        return gem.balanceOf(this);
    }

    //------------------------------------------------------------------

    function SaiTub(
        DSToken  sai_,
        DSToken  sin_,
        DSToken  skr_,
        ERC20    gem_,
        DSToken  gov_,
        DSValue  pip_,
        DSValue  pep_,
        SaiVox   vox_,
        address  pit_
    ) public {
        gem = gem_;
        skr = skr_;

        sai = sai_;
        sin = sin_;

        gov = gov_;
        pit = pit_;

        pip = pip_;
        pep = pep_;
        vox = vox_;

        axe = RAY;
        mat = RAY;
        tax = RAY;
        fee = RAY;
        gap = WAD;

        _chi = RAY;
        _rhi = RAY;

        rho = era();
    }

    function era() public constant returns (uint) {
        return block.timestamp;
    }

    //--Risk-parameter-config-------------------------------------------

    function mold(bytes32 param, uint val) public note auth {
        if      (param == 'cap') cap = val;
        else if (param == 'mat') { require(val >= RAY); mat = val; }
        else if (param == 'tax') { require(val >= RAY); drip(); tax = val; }
        else if (param == 'fee') { require(val >= RAY); drip(); fee = val; }
        else if (param == 'axe') { require(val >= RAY); axe = val; }
        else if (param == 'gap') { require(val >= WAD); gap = val; }
        else return;
    }

    //--Price-feed-setters----------------------------------------------

    function setPip(DSValue pip_) public note auth {
        pip = pip_;
    }
    function setPep(DSValue pep_) public note auth {
        pep = pep_;
    }
    function setVox(SaiVox vox_) public note auth {
        vox = vox_;
    }

    //--Tap-setter------------------------------------------------------
    function turn(address tap_) public note {
        require(tap  == 0);
        require(tap_ != 0);
        tap = tap_;
    }

    //--Collateral-wrapper----------------------------------------------

    // Wrapper ratio (gem per skr)
    function per() public view returns (uint ray) {
        return skr.totalSupply() == 0 ? RAY : rdiv(pie(), skr.totalSupply());
    }
    // Join price (gem per skr)
    function ask(uint wad) public view returns (uint) {
        return rmul(wad, wmul(per(), gap));
    }
    // Exit price (gem per skr)
    function bid(uint wad) public view returns (uint) {
        return rmul(wad, wmul(per(), sub(2 * WAD, gap)));
    }
    function join(uint wad) public note {
        require(!off);
        require(ask(wad) > 0);
        require(gem.transferFrom(msg.sender, this, ask(wad)));
        skr.mint(msg.sender, wad);
    }
    function exit(uint wad) public note {
        require(!off || out);
        require(gem.transfer(msg.sender, bid(wad)));
        skr.burn(msg.sender, wad);
    }

    //--Stability-fee-accumulation--------------------------------------

    // Accumulated Rates
    function chi() public returns (uint) {
        drip();
        return _chi;
    }
    function rhi() public returns (uint) {
        drip();
        return _rhi;
    }
    function drip() public note {
        if (off) return;

        var rho_ = era();
        var age = rho_ - rho;
        if (age == 0) return;    // optimised
        rho = rho_;

        var inc = RAY;

        if (tax != RAY) {  // optimised
            var _chi_ = _chi;
            inc = rpow(tax, age);
            _chi = rmul(_chi, inc);
            sai.mint(tap, rmul(sub(_chi, _chi_), rum));
        }

        // optimised
        if (fee != RAY) inc = rmul(inc, rpow(fee, age));
        if (inc != RAY) _rhi = rmul(_rhi, inc);
    }


    //--CDP-risk-indicator----------------------------------------------

    // Abstracted collateral price (ref per skr)
    function tag() public view returns (uint wad) {
        return off ? fit : wmul(per(), uint(pip.read()));
    }
    // Returns true if cup is well-collateralized
    function safe(bytes32 cup) public returns (bool) {
        var pro = rmul(tag(), ink(cup));
        var con = rmul(vox.par(), tab(cup));
        var min = rmul(con, mat);
        return pro >= min;
    }


    //--CDP-operations--------------------------------------------------

    function open() public note returns (bytes32 cup) {
        require(!off);
        cupi = add(cupi, 1);
        cup = bytes32(cupi);
        cups[cup].lad = msg.sender;
        LogNewCup(msg.sender, cup);
    }
    function give(bytes32 cup, address guy) public note {
        require(msg.sender == cups[cup].lad);
        require(guy != 0);
        cups[cup].lad = guy;
    }

    function lock(bytes32 cup, uint wad) public note {
        require(!off);
        cups[cup].ink = add(cups[cup].ink, wad);
        skr.pull(msg.sender, wad);
        require(cups[cup].ink == 0 || cups[cup].ink > 0.005 ether);
    }
    function free(bytes32 cup, uint wad) public note {
        require(msg.sender == cups[cup].lad);
        cups[cup].ink = sub(cups[cup].ink, wad);
        skr.push(msg.sender, wad);
        require(safe(cup));
        require(cups[cup].ink == 0 || cups[cup].ink > 0.005 ether);
    }

    function draw(bytes32 cup, uint wad) public note {
        require(!off);
        require(msg.sender == cups[cup].lad);
        require(rdiv(wad, chi()) > 0);

        cups[cup].art = add(cups[cup].art, rdiv(wad, chi()));
        rum = add(rum, rdiv(wad, chi()));

        cups[cup].ire = add(cups[cup].ire, rdiv(wad, rhi()));
        sai.mint(cups[cup].lad, wad);

        require(safe(cup));
        require(sai.totalSupply() <= cap);
    }
    function wipe(bytes32 cup, uint wad) public note {
        require(!off);

        var owe = rmul(wad, rdiv(rap(cup), tab(cup)));

        cups[cup].art = sub(cups[cup].art, rdiv(wad, chi()));
        rum = sub(rum, rdiv(wad, chi()));

        cups[cup].ire = sub(cups[cup].ire, rdiv(add(wad, owe), rhi()));
        sai.burn(msg.sender, wad);

        var (val, ok) = pep.peek();
        if (ok && val != 0) gov.move(msg.sender, pit, wdiv(owe, uint(val)));
    }

    function shut(bytes32 cup) public note {
        require(!off);
        require(msg.sender == cups[cup].lad);
        if (tab(cup) != 0) wipe(cup, tab(cup));
        if (ink(cup) != 0) free(cup, ink(cup));
        delete cups[cup];
    }

    function bite(bytes32 cup) public note {
        require(!safe(cup) || off);

        // Take on all of the debt, except unpaid fees
        var rue = tab(cup);
        sin.mint(tap, rue);
        rum = sub(rum, cups[cup].art);
        cups[cup].art = 0;
        cups[cup].ire = 0;

        // Amount owed in SKR, including liquidation penalty
        var owe = rdiv(rmul(rmul(rue, axe), vox.par()), tag());

        if (owe > cups[cup].ink) {
            owe = cups[cup].ink;
        }

        skr.push(tap, owe);
        cups[cup].ink = sub(cups[cup].ink, owe);
    }

    //------------------------------------------------------------------

    function cage(uint fit_, uint jam) public note auth {
        require(!off && fit_ != 0);
        off = true;
        axe = RAY;
        gap = WAD;
        fit = fit_;         // ref per skr
        require(gem.transfer(tap, jam));
    }
    function flow() public note auth {
        require(off);
        out = true;
    }
}

pragma solidity ^0.4.13;

////// lib/ds-math/src/math.sol
/// math.sol -- mixin for inline numerical wizardry

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x);
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x);
    }
    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x);
    }

    function min(uint x, uint y) internal pure returns (uint z) {
        return x <= y ? x : y;
    }
    function max(uint x, uint y) internal pure returns (uint z) {
        return x >= y ? x : y;
    }
    function imin(int x, int y) internal pure returns (int z) {
        return x <= y ? x : y;
    }
    function imax(int x, int y) internal pure returns (int z) {
        return x >= y ? x : y;
    }

    uint constant WAD = 10 ** 18;
    uint constant RAY = 10 ** 27;

    function wmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }
    function rmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }
    function wdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, WAD), y / 2) / y;
    }
    function rdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint x, uint n) internal pure returns (uint z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}

////// lib/ds-stop/lib/ds-auth/src/auth.sol
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    function DSAuth() public {
        owner = msg.sender;
        LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        LogSetAuthority(authority);
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }
}

////// lib/ds-stop/lib/ds-note/src/note.sol
/// note.sol -- the `note' modifier, for logging calls as events

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
        uint              wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}

////// lib/ds-stop/src/stop.sol
/// stop.sol -- mixin for enable/disable functionality

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-auth/auth.sol"; */
/* import "ds-note/note.sol"; */

contract DSStop is DSNote, DSAuth {

    bool public stopped;

    modifier stoppable {
        require(!stopped);
        _;
    }
    function stop() public auth note {
        stopped = true;
    }
    function start() public auth note {
        stopped = false;
    }

}

////// lib/erc20/src/erc20.sol
/// erc20.sol -- API for the ERC20 token standard

// See <https://github.com/ethereum/EIPs/issues/20>.

// This file likely does not meet the threshold of originality
// required for copyright to apply.  As a result, this is free and
// unencumbered software belonging to the public domain.

/* pragma solidity ^0.4.8; */

contract ERC20Events {
    event Approval(address indexed src, address indexed guy, uint wad);
    event Transfer(address indexed src, address indexed dst, uint wad);
}

contract ERC20 is ERC20Events {
    function totalSupply() public view returns (uint);
    function balanceOf(address guy) public view returns (uint);
    function allowance(address src, address guy) public view returns (uint);

    function approve(address guy, uint wad) public returns (bool);
    function transfer(address dst, uint wad) public returns (bool);
    function transferFrom(
        address src, address dst, uint wad
    ) public returns (bool);
}

////// src/base.sol
/// base.sol -- basic ERC20 implementation

// Copyright (C) 2015, 2016, 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "erc20/erc20.sol"; */
/* import "ds-math/math.sol"; */

contract DSTokenBase is ERC20, DSMath {
    uint256                                            _supply;
    mapping (address => uint256)                       _balances;
    mapping (address => mapping (address => uint256))  _approvals;

    function DSTokenBase(uint supply) public {
        _balances[msg.sender] = supply;
        _supply = supply;
    }

    function totalSupply() public view returns (uint) {
        return _supply;
    }
    function balanceOf(address src) public view returns (uint) {
        return _balances[src];
    }
    function allowance(address src, address guy) public view returns (uint) {
        return _approvals[src][guy];
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        if (src != msg.sender) {
            _approvals[src][msg.sender] = sub(_approvals[src][msg.sender], wad);
        }

        _balances[src] = sub(_balances[src], wad);
        _balances[dst] = add(_balances[dst], wad);

        Transfer(src, dst, wad);

        return true;
    }

    function approve(address guy, uint wad) public returns (bool) {
        _approvals[msg.sender][guy] = wad;

        Approval(msg.sender, guy, wad);

        return true;
    }
}

////// src/token.sol
/// token.sol -- ERC20 implementation with minting and burning

// Copyright (C) 2015, 2016, 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-stop/stop.sol"; */

/* import "./base.sol"; */

contract DSToken is DSTokenBase(0), DSStop {

    bytes32  public  symbol;
    uint256  public  decimals = 18; // standard token precision. override to customize

    function DSToken(bytes32 symbol_) public {
        symbol = symbol_;
    }

    event Mint(address indexed guy, uint wad);
    event Burn(address indexed guy, uint wad);

    function approve(address guy) public stoppable returns (bool) {
        return super.approve(guy, uint(-1));
    }

    function approve(address guy, uint wad) public stoppable returns (bool) {
        return super.approve(guy, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        stoppable
        returns (bool)
    {
        if (src != msg.sender && _approvals[src][msg.sender] != uint(-1)) {
            _approvals[src][msg.sender] = sub(_approvals[src][msg.sender], wad);
        }

        _balances[src] = sub(_balances[src], wad);
        _balances[dst] = add(_balances[dst], wad);

        Transfer(src, dst, wad);

        return true;
    }

    function push(address dst, uint wad) public {
        transferFrom(msg.sender, dst, wad);
    }
    function pull(address src, uint wad) public {
        transferFrom(src, msg.sender, wad);
    }
    function move(address src, address dst, uint wad) public {
        transferFrom(src, dst, wad);
    }

    function mint(uint wad) public {
        mint(msg.sender, wad);
    }
    function burn(uint wad) public {
        burn(msg.sender, wad);
    }
    function mint(address guy, uint wad) public auth stoppable {
        _balances[guy] = add(_balances[guy], wad);
        _supply = add(_supply, wad);
        Mint(guy, wad);
    }
    function burn(address guy, uint wad) public auth stoppable {
        if (guy != msg.sender && _approvals[guy][msg.sender] != uint(-1)) {
            _approvals[guy][msg.sender] = sub(_approvals[guy][msg.sender], wad);
        }

        _balances[guy] = sub(_balances[guy], wad);
        _supply = sub(_supply, wad);
        Burn(guy, wad);
    }

    // Optional token name
    bytes32   public  name = "";

    function setName(bytes32 name_) public auth {
        name = name_;
    }
}

/// matching_market.sol

//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

pragma solidity ^0.4.18;

/// expiring_market.sol

//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

pragma solidity ^0.4.18;

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.13;

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    function DSAuth() public {
        owner = msg.sender;
        LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        LogSetAuthority(authority);
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }
}

/// simple_market.sol

//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

pragma solidity ^0.4.18;

/// math.sol -- mixin for inline numerical wizardry

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.13;

contract DSMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x);
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x);
    }
    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x);
    }

    function min(uint x, uint y) internal pure returns (uint z) {
        return x <= y ? x : y;
    }
    function max(uint x, uint y) internal pure returns (uint z) {
        return x >= y ? x : y;
    }
    function imin(int x, int y) internal pure returns (int z) {
        return x <= y ? x : y;
    }
    function imax(int x, int y) internal pure returns (int z) {
        return x >= y ? x : y;
    }

    uint constant WAD = 10 ** 18;
    uint constant RAY = 10 ** 27;

    function wmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }
    function rmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }
    function wdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, WAD), y / 2) / y;
    }
    function rdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint x, uint n) internal pure returns (uint z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}

/// erc20.sol -- API for the ERC20 token standard

// See <https://github.com/ethereum/EIPs/issues/20>.

// This file likely does not meet the threshold of originality
// required for copyright to apply.  As a result, this is free and
// unencumbered software belonging to the public domain.

pragma solidity ^0.4.8;

contract ERC20Events {
    event Approval(address indexed src, address indexed guy, uint wad);
    event Transfer(address indexed src, address indexed dst, uint wad);
}

contract ERC20 is ERC20Events {
    function totalSupply() public view returns (uint);
    function balanceOf(address guy) public view returns (uint);
    function allowance(address src, address guy) public view returns (uint);

    function approve(address guy, uint wad) public returns (bool);
    function transfer(address dst, uint wad) public returns (bool);
    function transferFrom(
        address src, address dst, uint wad
    ) public returns (bool);
}

contract EventfulMarket {
    event LogItemUpdate(uint id);
    event LogTrade(uint pay_amt, address indexed pay_gem,
                   uint buy_amt, address indexed buy_gem);

    event LogMake(
        bytes32  indexed  id,
        bytes32  indexed  pair,
        address  indexed  maker,
        ERC20             pay_gem,
        ERC20             buy_gem,
        uint128           pay_amt,
        uint128           buy_amt,
        uint64            timestamp
    );

    event LogBump(
        bytes32  indexed  id,
        bytes32  indexed  pair,
        address  indexed  maker,
        ERC20             pay_gem,
        ERC20             buy_gem,
        uint128           pay_amt,
        uint128           buy_amt,
        uint64            timestamp
    );

    event LogTake(
        bytes32           id,
        bytes32  indexed  pair,
        address  indexed  maker,
        ERC20             pay_gem,
        ERC20             buy_gem,
        address  indexed  taker,
        uint128           take_amt,
        uint128           give_amt,
        uint64            timestamp
    );

    event LogKill(
        bytes32  indexed  id,
        bytes32  indexed  pair,
        address  indexed  maker,
        ERC20             pay_gem,
        ERC20             buy_gem,
        uint128           pay_amt,
        uint128           buy_amt,
        uint64            timestamp
    );
}

contract SimpleMarket is EventfulMarket, DSMath {

    uint public last_offer_id;

    mapping (uint => OfferInfo) public offers;

    bool locked;

    struct OfferInfo {
        uint     pay_amt;
        ERC20    pay_gem;
        uint     buy_amt;
        ERC20    buy_gem;
        address  owner;
        uint64   timestamp;
    }

    modifier can_buy(uint id) {
        require(isActive(id));
        _;
    }

    modifier can_cancel(uint id) {
        require(isActive(id));
        require(getOwner(id) == msg.sender);
        _;
    }

    modifier can_offer {
        _;
    }

    modifier synchronized {
        require(!locked);
        locked = true;
        _;
        locked = false;
    }

    function isActive(uint id) public constant returns (bool active) {
        return offers[id].timestamp > 0;
    }

    function getOwner(uint id) public constant returns (address owner) {
        return offers[id].owner;
    }

    function getOffer(uint id) public constant returns (uint, ERC20, uint, ERC20) {
      var offer = offers[id];
      return (offer.pay_amt, offer.pay_gem,
              offer.buy_amt, offer.buy_gem);
    }

    // ---- Public entrypoints ---- //

    function bump(bytes32 id_)
        public
        can_buy(uint256(id_))
    {
        var id = uint256(id_);
        LogBump(
            id_,
            keccak256(offers[id].pay_gem, offers[id].buy_gem),
            offers[id].owner,
            offers[id].pay_gem,
            offers[id].buy_gem,
            uint128(offers[id].pay_amt),
            uint128(offers[id].buy_amt),
            offers[id].timestamp
        );
    }

    // Accept given `quantity` of an offer. Transfers funds from caller to
    // offer maker, and from market to caller.
    function buy(uint id, uint quantity)
        public
        can_buy(id)
        synchronized
        returns (bool)
    {
        OfferInfo memory offer = offers[id];
        uint spend = mul(quantity, offer.buy_amt) / offer.pay_amt;

        require(uint128(spend) == spend);
        require(uint128(quantity) == quantity);

        // For backwards semantic compatibility.
        if (quantity == 0 || spend == 0 ||
            quantity > offer.pay_amt || spend > offer.buy_amt)
        {
            return false;
        }

        offers[id].pay_amt = sub(offer.pay_amt, quantity);
        offers[id].buy_amt = sub(offer.buy_amt, spend);
        require( offer.buy_gem.transferFrom(msg.sender, offer.owner, spend) );
        require( offer.pay_gem.transfer(msg.sender, quantity) );

        LogItemUpdate(id);
        LogTake(
            bytes32(id),
            keccak256(offer.pay_gem, offer.buy_gem),
            offer.owner,
            offer.pay_gem,
            offer.buy_gem,
            msg.sender,
            uint128(quantity),
            uint128(spend),
            uint64(now)
        );
        LogTrade(quantity, offer.pay_gem, spend, offer.buy_gem);

        if (offers[id].pay_amt == 0) {
          delete offers[id];
        }

        return true;
    }

    // Cancel an offer. Refunds offer maker.
    function cancel(uint id)
        public
        can_cancel(id)
        synchronized
        returns (bool success)
    {
        // read-only offer. Modify an offer by directly accessing offers[id]
        OfferInfo memory offer = offers[id];
        delete offers[id];

        require( offer.pay_gem.transfer(offer.owner, offer.pay_amt) );

        LogItemUpdate(id);
        LogKill(
            bytes32(id),
            keccak256(offer.pay_gem, offer.buy_gem),
            offer.owner,
            offer.pay_gem,
            offer.buy_gem,
            uint128(offer.pay_amt),
            uint128(offer.buy_amt),
            uint64(now)
        );

        success = true;
    }

    function kill(bytes32 id)
        public
    {
        require(cancel(uint256(id)));
    }

    function make(
        ERC20    pay_gem,
        ERC20    buy_gem,
        uint128  pay_amt,
        uint128  buy_amt
    )
        public
        returns (bytes32 id)
    {
        return bytes32(offer(pay_amt, pay_gem, buy_amt, buy_gem));
    }

    // Make a new offer. Takes funds from the caller into market escrow.
    function offer(uint pay_amt, ERC20 pay_gem, uint buy_amt, ERC20 buy_gem)
        public
        can_offer
        synchronized
        returns (uint id)
    {
        require(uint128(pay_amt) == pay_amt);
        require(uint128(buy_amt) == buy_amt);
        require(pay_amt > 0);
        require(pay_gem != ERC20(0x0));
        require(buy_amt > 0);
        require(buy_gem != ERC20(0x0));
        require(pay_gem != buy_gem);

        OfferInfo memory info;
        info.pay_amt = pay_amt;
        info.pay_gem = pay_gem;
        info.buy_amt = buy_amt;
        info.buy_gem = buy_gem;
        info.owner = msg.sender;
        info.timestamp = uint64(now);
        id = _next_id();
        offers[id] = info;

        require( pay_gem.transferFrom(msg.sender, this, pay_amt) );

        LogItemUpdate(id);
        LogMake(
            bytes32(id),
            keccak256(pay_gem, buy_gem),
            msg.sender,
            pay_gem,
            buy_gem,
            uint128(pay_amt),
            uint128(buy_amt),
            uint64(now)
        );
    }

    function take(bytes32 id, uint128 maxTakeAmount)
        public
    {
        require(buy(uint256(id), maxTakeAmount));
    }

    function _next_id()
        internal
        returns (uint)
    {
        last_offer_id++; return last_offer_id;
    }
}

// Simple Market with a market lifetime. When the close_time has been reached,
// offers can only be cancelled (offer and buy will throw).

contract ExpiringMarket is DSAuth, SimpleMarket {
    uint64 public close_time;
    bool public stopped;

    // after close_time has been reached, no new offers are allowed
    modifier can_offer {
        require(!isClosed());
        _;
    }

    // after close, no new buys are allowed
    modifier can_buy(uint id) {
        require(isActive(id));
        require(!isClosed());
        _;
    }

    // after close, anyone can cancel an offer
    modifier can_cancel(uint id) {
        require(isActive(id));
        require((msg.sender == getOwner(id)) || isClosed());
        _;
    }

    function ExpiringMarket(uint64 _close_time)
        public
    {
        close_time = _close_time;
    }

    function isClosed() public constant returns (bool closed) {
        return stopped || getTime() > close_time;
    }

    function getTime() public constant returns (uint64) {
        return uint64(now);
    }

    function stop() public auth {
        stopped = true;
    }
}

/// note.sol -- the `note' modifier, for logging calls as events

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.13;

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
        uint              wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}

contract MatchingEvents {
    event LogBuyEnabled(bool isEnabled);
    event LogMinSell(address pay_gem, uint min_amount);
    event LogMatchingEnabled(bool isEnabled);
    event LogUnsortedOffer(uint id);
    event LogSortedOffer(uint id);
    event LogInsert(address keeper, uint id);
    event LogDelete(address keeper, uint id);
}

contract MatchingMarket is MatchingEvents, ExpiringMarket, DSNote {
    bool public buyEnabled = true;      //buy enabled
    bool public matchingEnabled = true; //true: enable matching,
                                         //false: revert to expiring market
    struct sortInfo {
        uint next;  //points to id of next higher offer
        uint prev;  //points to id of previous lower offer
        uint delb;  //the blocknumber where this entry was marked for delete
    }
    mapping(uint => sortInfo) public _rank;                     //doubly linked lists of sorted offer ids
    mapping(address => mapping(address => uint)) public _best;  //id of the highest offer for a token pair
    mapping(address => mapping(address => uint)) public _span;  //number of offers stored for token pair in sorted orderbook
    mapping(address => uint) public _dust;                      //minimum sell amount for a token to avoid dust offers
    mapping(uint => uint) public _near;         //next unsorted offer id
    uint _head;                                 //first unsorted offer id
    uint public dustId;                         // id of the latest offer marked as dust


    function MatchingMarket(uint64 close_time) ExpiringMarket(close_time) public {
    }

    // After close, anyone can cancel an offer
    modifier can_cancel(uint id) {
        require(isActive(id), "Offer was deleted or taken, or never existed.");
        require(
            isClosed() || msg.sender == getOwner(id) || id == dustId,
            "Offer can not be cancelled because user is not owner, and market is open, and offer sells required amount of tokens."
        );
        _;
    }

    // ---- Public entrypoints ---- //

    function make(
        ERC20    pay_gem,
        ERC20    buy_gem,
        uint128  pay_amt,
        uint128  buy_amt
    )
        public
        returns (bytes32)
    {
        return bytes32(offer(pay_amt, pay_gem, buy_amt, buy_gem));
    }

    function take(bytes32 id, uint128 maxTakeAmount) public {
        require(buy(uint256(id), maxTakeAmount));
    }

    function kill(bytes32 id) public {
        require(cancel(uint256(id)));
    }

    // Make a new offer. Takes funds from the caller into market escrow.
    //
    // If matching is enabled:
    //     * creates new offer without putting it in
    //       the sorted list.
    //     * available to authorized contracts only!
    //     * keepers should call insert(id,pos)
    //       to put offer in the sorted list.
    //
    // If matching is disabled:
    //     * calls expiring market's offer().
    //     * available to everyone without authorization.
    //     * no sorting is done.
    //
    function offer(
        uint pay_amt,    //maker (ask) sell how much
        ERC20 pay_gem,   //maker (ask) sell which token
        uint buy_amt,    //taker (ask) buy how much
        ERC20 buy_gem    //taker (ask) buy which token
    )
        public
        returns (uint)
    {
        require(!locked, "Reentrancy attempt");
        var fn = matchingEnabled ? _offeru : super.offer;
        return fn(pay_amt, pay_gem, buy_amt, buy_gem);
    }

    // Make a new offer. Takes funds from the caller into market escrow.
    function offer(
        uint pay_amt,    //maker (ask) sell how much
        ERC20 pay_gem,   //maker (ask) sell which token
        uint buy_amt,    //maker (ask) buy how much
        ERC20 buy_gem,   //maker (ask) buy which token
        uint pos         //position to insert offer, 0 should be used if unknown
    )
        public
        can_offer
        returns (uint)
    {
        return offer(pay_amt, pay_gem, buy_amt, buy_gem, pos, true);
    }

    function offer(
        uint pay_amt,    //maker (ask) sell how much
        ERC20 pay_gem,   //maker (ask) sell which token
        uint buy_amt,    //maker (ask) buy how much
        ERC20 buy_gem,   //maker (ask) buy which token
        uint pos,        //position to insert offer, 0 should be used if unknown
        bool rounding    //match "close enough" orders?
    )
        public
        can_offer
        returns (uint)
    {
        require(!locked, "Reentrancy attempt");
        require(_dust[pay_gem] <= pay_amt);

        if (matchingEnabled) {
          return _matcho(pay_amt, pay_gem, buy_amt, buy_gem, pos, rounding);
        }
        return super.offer(pay_amt, pay_gem, buy_amt, buy_gem);
    }

    //Transfers funds from caller to offer maker, and from market to caller.
    function buy(uint id, uint amount)
        public
        can_buy(id)
        returns (bool)
    {
        require(!locked, "Reentrancy attempt");
        var fn = matchingEnabled ? _buys : super.buy;
        return fn(id, amount);
    }

    // Cancel an offer. Refunds offer maker.
    function cancel(uint id)
        public
        can_cancel(id)
        returns (bool success)
    {
        require(!locked, "Reentrancy attempt");
        if (matchingEnabled) {
            if (isOfferSorted(id)) {
                require(_unsort(id));
            } else {
                require(_hide(id));
            }
        }
        return super.cancel(id);    //delete the offer.
    }

    //insert offer into the sorted list
    //keepers need to use this function
    function insert(
        uint id,   //maker (ask) id
        uint pos   //position to insert into
    )
        public
        returns (bool)
    {
        require(!locked, "Reentrancy attempt");
        require(!isOfferSorted(id));    //make sure offers[id] is not yet sorted
        require(isActive(id));          //make sure offers[id] is active

        _hide(id);                      //remove offer from unsorted offers list
        _sort(id, pos);                 //put offer into the sorted offers list
        LogInsert(msg.sender, id);
        return true;
    }

    //deletes _rank [id]
    //  Function should be called by keepers.
    function del_rank(uint id)
        public
        returns (bool)
    {
        require(!locked, "Reentrancy attempt");
        require(!isActive(id) && _rank[id].delb != 0 && _rank[id].delb < block.number - 10);
        delete _rank[id];
        LogDelete(msg.sender, id);
        return true;
    }

    //set the minimum sell amount for a token
    //    Function is used to avoid "dust offers" that have
    //    very small amount of tokens to sell, and it would
    //    cost more gas to accept the offer, than the value
    //    of tokens received.
    function setMinSell(
        ERC20 pay_gem,     //token to assign minimum sell amount to
        uint dust          //maker (ask) minimum sell amount
    )
        public
        auth
        note
        returns (bool)
    {
        _dust[pay_gem] = dust;
        LogMinSell(pay_gem, dust);
        return true;
    }

    //returns the minimum sell amount for an offer
    function getMinSell(
        ERC20 pay_gem      //token for which minimum sell amount is queried
    )
        public
        constant
        returns (uint)
    {
        return _dust[pay_gem];
    }

    //set buy functionality enabled/disabled
    function setBuyEnabled(bool buyEnabled_) public auth returns (bool) {
        buyEnabled = buyEnabled_;
        LogBuyEnabled(buyEnabled);
        return true;
    }

    //set matching enabled/disabled
    //    If matchingEnabled true(default), then inserted offers are matched.
    //    Except the ones inserted by contracts, because those end up
    //    in the unsorted list of offers, that must be later sorted by
    //    keepers using insert().
    //    If matchingEnabled is false then MatchingMarket is reverted to ExpiringMarket,
    //    and matching is not done, and sorted lists are disabled.
    function setMatchingEnabled(bool matchingEnabled_) public auth returns (bool) {
        matchingEnabled = matchingEnabled_;
        LogMatchingEnabled(matchingEnabled);
        return true;
    }

    //return the best offer for a token pair
    //      the best offer is the lowest one if it's an ask,
    //      and highest one if it's a bid offer
    function getBestOffer(ERC20 sell_gem, ERC20 buy_gem) public constant returns(uint) {
        return _best[sell_gem][buy_gem];
    }

    //return the next worse offer in the sorted list
    //      the worse offer is the higher one if its an ask,
    //      a lower one if its a bid offer,
    //      and in both cases the newer one if they're equal.
    function getWorseOffer(uint id) public constant returns(uint) {
        return _rank[id].prev;
    }

    //return the next better offer in the sorted list
    //      the better offer is in the lower priced one if its an ask,
    //      the next higher priced one if its a bid offer
    //      and in both cases the older one if they're equal.
    function getBetterOffer(uint id) public constant returns(uint) {

        return _rank[id].next;
    }

    //return the amount of better offers for a token pair
    function getOfferCount(ERC20 sell_gem, ERC20 buy_gem) public constant returns(uint) {
        return _span[sell_gem][buy_gem];
    }

    //get the first unsorted offer that was inserted by a contract
    //      Contracts can't calculate the insertion position of their offer because it is not an O(1) operation.
    //      Their offers get put in the unsorted list of offers.
    //      Keepers can calculate the insertion position offchain and pass it to the insert() function to insert
    //      the unsorted offer into the sorted list. Unsorted offers will not be matched, but can be bought with buy().
    function getFirstUnsortedOffer() public constant returns(uint) {
        return _head;
    }

    //get the next unsorted offer
    //      Can be used to cycle through all the unsorted offers.
    function getNextUnsortedOffer(uint id) public constant returns(uint) {
        return _near[id];
    }

    function isOfferSorted(uint id) public constant returns(bool) {
        return _rank[id].next != 0
               || _rank[id].prev != 0
               || _best[offers[id].pay_gem][offers[id].buy_gem] == id;
    }

    function sellAllAmount(ERC20 pay_gem, uint pay_amt, ERC20 buy_gem, uint min_fill_amount)
        public
        returns (uint fill_amt)
    {
        require(!locked, "Reentrancy attempt");
        uint offerId;
        while (pay_amt > 0) {                           //while there is amount to sell
            offerId = getBestOffer(buy_gem, pay_gem);   //Get the best offer for the token pair
            require(offerId != 0);                      //Fails if there are not more offers

            // There is a chance that pay_amt is smaller than 1 wei of the other token
            if (pay_amt * 1 ether < wdiv(offers[offerId].buy_amt, offers[offerId].pay_amt)) {
                break;                                  //We consider that all amount is sold
            }
            if (pay_amt >= offers[offerId].buy_amt) {                       //If amount to sell is higher or equal than current offer amount to buy
                fill_amt = add(fill_amt, offers[offerId].pay_amt);          //Add amount bought to acumulator
                pay_amt = sub(pay_amt, offers[offerId].buy_amt);            //Decrease amount to sell
                take(bytes32(offerId), uint128(offers[offerId].pay_amt));   //We take the whole offer
            } else { // if lower
                var baux = rmul(pay_amt * 10 ** 9, rdiv(offers[offerId].pay_amt, offers[offerId].buy_amt)) / 10 ** 9;
                fill_amt = add(fill_amt, baux);         //Add amount bought to acumulator
                take(bytes32(offerId), uint128(baux));  //We take the portion of the offer that we need
                pay_amt = 0;                            //All amount is sold
            }
        }
        require(fill_amt >= min_fill_amount);
    }

    function buyAllAmount(ERC20 buy_gem, uint buy_amt, ERC20 pay_gem, uint max_fill_amount)
        public
        returns (uint fill_amt)
    {
        require(!locked, "Reentrancy attempt");
        uint offerId;
        while (buy_amt > 0) {                           //Meanwhile there is amount to buy
            offerId = getBestOffer(buy_gem, pay_gem);   //Get the best offer for the token pair
            require(offerId != 0);

            // There is a chance that buy_amt is smaller than 1 wei of the other token
            if (buy_amt * 1 ether < wdiv(offers[offerId].pay_amt, offers[offerId].buy_amt)) {
                break;                                  //We consider that all amount is sold
            }
            if (buy_amt >= offers[offerId].pay_amt) {                       //If amount to buy is higher or equal than current offer amount to sell
                fill_amt = add(fill_amt, offers[offerId].buy_amt);          //Add amount sold to acumulator
                buy_amt = sub(buy_amt, offers[offerId].pay_amt);            //Decrease amount to buy
                take(bytes32(offerId), uint128(offers[offerId].pay_amt));   //We take the whole offer
            } else {                                                        //if lower
                fill_amt = add(fill_amt, rmul(buy_amt * 10 ** 9, rdiv(offers[offerId].buy_amt, offers[offerId].pay_amt)) / 10 ** 9); //Add amount sold to acumulator
                take(bytes32(offerId), uint128(buy_amt));                   //We take the portion of the offer that we need
                buy_amt = 0;                                                //All amount is bought
            }
        }
        require(fill_amt <= max_fill_amount);
    }

    function getBuyAmount(ERC20 buy_gem, ERC20 pay_gem, uint pay_amt) public constant returns (uint fill_amt) {
        var offerId = getBestOffer(buy_gem, pay_gem);           //Get best offer for the token pair
        while (pay_amt > offers[offerId].buy_amt) {
            fill_amt = add(fill_amt, offers[offerId].pay_amt);  //Add amount to buy accumulator
            pay_amt = sub(pay_amt, offers[offerId].buy_amt);    //Decrease amount to pay
            if (pay_amt > 0) {                                  //If we still need more offers
                offerId = getWorseOffer(offerId);               //We look for the next best offer
                require(offerId != 0);                          //Fails if there are not enough offers to complete
            }
        }
        fill_amt = add(fill_amt, rmul(pay_amt * 10 ** 9, rdiv(offers[offerId].pay_amt, offers[offerId].buy_amt)) / 10 ** 9); //Add proportional amount of last offer to buy accumulator
    }

    function getPayAmount(ERC20 pay_gem, ERC20 buy_gem, uint buy_amt) public constant returns (uint fill_amt) {
        var offerId = getBestOffer(buy_gem, pay_gem);           //Get best offer for the token pair
        while (buy_amt > offers[offerId].pay_amt) {
            fill_amt = add(fill_amt, offers[offerId].buy_amt);  //Add amount to pay accumulator
            buy_amt = sub(buy_amt, offers[offerId].pay_amt);    //Decrease amount to buy
            if (buy_amt > 0) {                                  //If we still need more offers
                offerId = getWorseOffer(offerId);               //We look for the next best offer
                require(offerId != 0);                          //Fails if there are not enough offers to complete
            }
        }
        fill_amt = add(fill_amt, rmul(buy_amt * 10 ** 9, rdiv(offers[offerId].buy_amt, offers[offerId].pay_amt)) / 10 ** 9); //Add proportional amount of last offer to pay accumulator
    }

    // ---- Internal Functions ---- //

    function _buys(uint id, uint amount)
        internal
        returns (bool)
    {
        require(buyEnabled);
        if (amount == offers[id].pay_amt) {
            if (isOfferSorted(id)) {
                //offers[id] must be removed from sorted list because all of it is bought
                _unsort(id);
            }else{
                _hide(id);
            }
        }
        require(super.buy(id, amount));
        // If offer has become dust during buy, we cancel it
        if (isActive(id) && offers[id].pay_amt < _dust[offers[id].pay_gem]) {
            dustId = id; //enable current msg.sender to call cancel(id)
            cancel(id);
        }
        return true;
    }

    //find the id of the next higher offer after offers[id]
    function _find(uint id)
        internal
        view
        returns (uint)
    {
        require( id > 0 );

        address buy_gem = address(offers[id].buy_gem);
        address pay_gem = address(offers[id].pay_gem);
        uint top = _best[pay_gem][buy_gem];
        uint old_top = 0;

        // Find the larger-than-id order whose successor is less-than-id.
        while (top != 0 && _isPricedLtOrEq(id, top)) {
            old_top = top;
            top = _rank[top].prev;
        }
        return old_top;
    }

    //find the id of the next higher offer after offers[id]
    function _findpos(uint id, uint pos)
        internal
        view
        returns (uint)
    {
        require(id > 0);

        // Look for an active order.
        while (pos != 0 && !isActive(pos)) {
            pos = _rank[pos].prev;
        }

        if (pos == 0) {
            //if we got to the end of list without a single active offer
            return _find(id);

        } else {
            // if we did find a nearby active offer
            // Walk the order book down from there...
            if(_isPricedLtOrEq(id, pos)) {
                uint old_pos;

                // Guaranteed to run at least once because of
                // the prior if statements.
                while (pos != 0 && _isPricedLtOrEq(id, pos)) {
                    old_pos = pos;
                    pos = _rank[pos].prev;
                }
                return old_pos;

            // ...or walk it up.
            } else {
                while (pos != 0 && !_isPricedLtOrEq(id, pos)) {
                    pos = _rank[pos].next;
                }
                return pos;
            }
        }
    }

    //return true if offers[low] priced less than or equal to offers[high]
    function _isPricedLtOrEq(
        uint low,   //lower priced offer's id
        uint high   //higher priced offer's id
    )
        internal
        view
        returns (bool)
    {
        return mul(offers[low].buy_amt, offers[high].pay_amt)
          >= mul(offers[high].buy_amt, offers[low].pay_amt);
    }

    //these variables are global only because of solidity local variable limit

    //match offers with taker offer, and execute token transactions
    function _matcho(
        uint t_pay_amt,    //taker sell how much
        ERC20 t_pay_gem,   //taker sell which token
        uint t_buy_amt,    //taker buy how much
        ERC20 t_buy_gem,   //taker buy which token
        uint pos,          //position id
        bool rounding      //match "close enough" orders?
    )
        internal
        returns (uint id)
    {
        uint best_maker_id;    //highest maker id
        uint t_buy_amt_old;    //taker buy how much saved
        uint m_buy_amt;        //maker offer wants to buy this much token
        uint m_pay_amt;        //maker offer wants to sell this much token

        // there is at least one offer stored for token pair
        while (_best[t_buy_gem][t_pay_gem] > 0) {
            best_maker_id = _best[t_buy_gem][t_pay_gem];
            m_buy_amt = offers[best_maker_id].buy_amt;
            m_pay_amt = offers[best_maker_id].pay_amt;

            // Ugly hack to work around rounding errors. Based on the idea that
            // the furthest the amounts can stray from their "true" values is 1.
            // Ergo the worst case has t_pay_amt and m_pay_amt at +1 away from
            // their "correct" values and m_buy_amt and t_buy_amt at -1.
            // Since (c - 1) * (d - 1) > (a + 1) * (b + 1) is equivalent to
            // c * d > a * b + a + b + c + d, we write...
            if (mul(m_buy_amt, t_buy_amt) > mul(t_pay_amt, m_pay_amt) +
                (rounding ? m_buy_amt + t_buy_amt + t_pay_amt + m_pay_amt : 0))
            {
                break;
            }
            // ^ The `rounding` parameter is a compromise borne of a couple days
            // of discussion.
            buy(best_maker_id, min(m_pay_amt, t_buy_amt));
            t_buy_amt_old = t_buy_amt;
            t_buy_amt = sub(t_buy_amt, min(m_pay_amt, t_buy_amt));
            t_pay_amt = mul(t_buy_amt, t_pay_amt) / t_buy_amt_old;

            if (t_pay_amt == 0 || t_buy_amt == 0) {
                break;
            }
        }

        if (t_buy_amt > 0 && t_pay_amt > 0 && t_pay_amt >= _dust[t_pay_gem]) {
            //new offer should be created
            id = super.offer(t_pay_amt, t_pay_gem, t_buy_amt, t_buy_gem);
            //insert offer into the sorted list
            _sort(id, pos);
        }
    }

    // Make a new offer without putting it in the sorted list.
    // Takes funds from the caller into market escrow.
    // ****Available to authorized contracts only!**********
    // Keepers should call insert(id,pos) to put offer in the sorted list.
    function _offeru(
        uint pay_amt,      //maker (ask) sell how much
        ERC20 pay_gem,     //maker (ask) sell which token
        uint buy_amt,      //maker (ask) buy how much
        ERC20 buy_gem      //maker (ask) buy which token
    )
        internal
        returns (uint id)
    {
        require(_dust[pay_gem] <= pay_amt);
        id = super.offer(pay_amt, pay_gem, buy_amt, buy_gem);
        _near[id] = _head;
        _head = id;
        LogUnsortedOffer(id);
    }

    //put offer into the sorted list
    function _sort(
        uint id,    //maker (ask) id
        uint pos    //position to insert into
    )
        internal
    {
        require(isActive(id));

        address buy_gem = address(offers[id].buy_gem);
        address pay_gem = address(offers[id].pay_gem);
        uint prev_id;                                      //maker (ask) id

        pos = pos == 0 || offers[pos].pay_gem != pay_gem || offers[pos].buy_gem != buy_gem || !isOfferSorted(pos)
        ?
            _find(id)
        :
            _findpos(id, pos);

        if (pos != 0) {                                    //offers[id] is not the highest offer
            //requirement below is satisfied by statements above
            //require(_isPricedLtOrEq(id, pos));
            prev_id = _rank[pos].prev;
            _rank[pos].prev = id;
            _rank[id].next = pos;
        } else {                                           //offers[id] is the highest offer
            prev_id = _best[pay_gem][buy_gem];
            _best[pay_gem][buy_gem] = id;
        }

        if (prev_id != 0) {                               //if lower offer does exist
            //requirement below is satisfied by statements above
            //require(!_isPricedLtOrEq(id, prev_id));
            _rank[prev_id].next = id;
            _rank[id].prev = prev_id;
        }

        _span[pay_gem][buy_gem]++;
        LogSortedOffer(id);
    }

    // Remove offer from the sorted list (does not cancel offer)
    function _unsort(
        uint id    //id of maker (ask) offer to remove from sorted list
    )
        internal
        returns (bool)
    {
        address buy_gem = address(offers[id].buy_gem);
        address pay_gem = address(offers[id].pay_gem);
        require(_span[pay_gem][buy_gem] > 0);

        require(_rank[id].delb == 0 &&                    //assert id is in the sorted list
                 isOfferSorted(id));

        if (id != _best[pay_gem][buy_gem]) {              // offers[id] is not the highest offer
            require(_rank[_rank[id].next].prev == id);
            _rank[_rank[id].next].prev = _rank[id].prev;
        } else {                                          //offers[id] is the highest offer
            _best[pay_gem][buy_gem] = _rank[id].prev;
        }

        if (_rank[id].prev != 0) {                        //offers[id] is not the lowest offer
            require(_rank[_rank[id].prev].next == id);
            _rank[_rank[id].prev].next = _rank[id].next;
        }

        _span[pay_gem][buy_gem]--;
        _rank[id].delb = block.number;                    //mark _rank[id] for deletion
        return true;
    }

    //Hide offer from the unsorted order book (does not cancel offer)
    function _hide(
        uint id     //id of maker offer to remove from unsorted list
    )
        internal
        returns (bool)
    {
        uint uid = _head;               //id of an offer in unsorted offers list
        uint pre = uid;                 //id of previous offer in unsorted offers list

        require(!isOfferSorted(id));    //make sure offer id is not in sorted offers list

        if (_head == id) {              //check if offer is first offer in unsorted offers list
            _head = _near[id];          //set head to new first unsorted offer
            _near[id] = 0;              //delete order from unsorted order list
            return true;
        }
        while (uid > 0 && uid != id) {  //find offer in unsorted order list
            pre = uid;
            uid = _near[uid];
        }
        if (uid != id) {                //did not find offer id in unsorted offers list
            return false;
        }
        _near[pre] = _near[id];         //set previous unsorted offer to point to offer after offer id
        _near[id] = 0;                  //delete order from unsorted order list
        return true;
    }
}

// MKR Token

// hevm: flattened sources of src/mkr-499.sol
pragma solidity ^0.4.15;

////// lib/ds-roles/lib/ds-auth/src/auth.sol
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    function DSAuth() public {
        owner = msg.sender;
        LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        LogSetAuthority(authority);
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }
}

////// lib/ds-thing/lib/ds-math/src/math.sol
/// math.sol -- mixin for inline numerical wizardry

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x);
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x);
    }
    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x);
    }

    function min(uint x, uint y) internal pure returns (uint z) {
        return x <= y ? x : y;
    }
    function max(uint x, uint y) internal pure returns (uint z) {
        return x >= y ? x : y;
    }
    function imin(int x, int y) internal pure returns (int z) {
        return x <= y ? x : y;
    }
    function imax(int x, int y) internal pure returns (int z) {
        return x >= y ? x : y;
    }

    uint constant WAD = 10 ** 18;
    uint constant RAY = 10 ** 27;

    function wmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }
    function rmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }
    function wdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, WAD), y / 2) / y;
    }
    function rdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint x, uint n) internal pure returns (uint z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}

////// lib/ds-thing/lib/ds-note/src/note.sol
/// note.sol -- the `note' modifier, for logging calls as events

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
        uint              wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}

////// lib/ds-thing/src/thing.sol
// thing.sol - `auth` with handy mixins. your things should be DSThings

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import 'ds-auth/auth.sol'; */
/* import 'ds-note/note.sol'; */
/* import 'ds-math/math.sol'; */

contract DSThing is DSAuth, DSNote, DSMath {
}

////// lib/ds-token/lib/ds-stop/src/stop.sol
/// stop.sol -- mixin for enable/disable functionality

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-auth/auth.sol"; */
/* import "ds-note/note.sol"; */

contract DSStop is DSNote, DSAuth {

    bool public stopped;

    modifier stoppable {
        require(!stopped);
        _;
    }
    function stop() public auth note {
        stopped = true;
    }
    function start() public auth note {
        stopped = false;
    }

}

////// lib/ds-token/lib/erc20/src/erc20.sol
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.8; */

// Token standard API
// https://github.com/ethereum/EIPs/issues/20

contract ERC20 {
    function totalSupply() public view returns (uint supply);
    function balanceOf( address who ) public view returns (uint value);
    function allowance( address owner, address spender ) public view returns (uint _allowance);

    function transfer( address to, uint value) public returns (bool ok);
    function transferFrom( address from, address to, uint value) public returns (bool ok);
    function approve( address spender, uint value ) public returns (bool ok);

    event Transfer( address indexed from, address indexed to, uint value);
    event Approval( address indexed owner, address indexed spender, uint value);
}

////// lib/ds-token/src/base.sol
/// base.sol -- basic ERC20 implementation

// Copyright (C) 2015, 2016, 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "erc20/erc20.sol"; */
/* import "ds-math/math.sol"; */

contract DSTokenBase is ERC20, DSMath {
    uint256                                            _supply;
    mapping (address => uint256)                       _balances;
    mapping (address => mapping (address => uint256))  _approvals;

    function DSTokenBase(uint supply) public {
        _balances[msg.sender] = supply;
        _supply = supply;
    }

    function totalSupply() public view returns (uint) {
        return _supply;
    }
    function balanceOf(address src) public view returns (uint) {
        return _balances[src];
    }
    function allowance(address src, address guy) public view returns (uint) {
        return _approvals[src][guy];
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        if (src != msg.sender) {
            _approvals[src][msg.sender] = sub(_approvals[src][msg.sender], wad);
        }

        _balances[src] = sub(_balances[src], wad);
        _balances[dst] = add(_balances[dst], wad);

        Transfer(src, dst, wad);

        return true;
    }

    function approve(address guy, uint wad) public returns (bool) {
        _approvals[msg.sender][guy] = wad;

        Approval(msg.sender, guy, wad);

        return true;
    }
}

////// lib/ds-token/src/token.sol
/// token.sol -- ERC20 implementation with minting and burning

// Copyright (C) 2015, 2016, 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-stop/stop.sol"; */

/* import "./base.sol"; */

contract DSToken is DSTokenBase(0), DSStop {

    bytes32  public  symbol;
    uint256  public  decimals = 18; // standard token precision. override to customize

    function DSToken(bytes32 symbol_) public {
        symbol = symbol_;
    }

    event Mint(address indexed guy, uint wad);
    event Burn(address indexed guy, uint wad);

    function approve(address guy) public stoppable returns (bool) {
        return super.approve(guy, uint(-1));
    }

    function approve(address guy, uint wad) public stoppable returns (bool) {
        return super.approve(guy, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        stoppable
        returns (bool)
    {
        if (src != msg.sender && _approvals[src][msg.sender] != uint(-1)) {
            _approvals[src][msg.sender] = sub(_approvals[src][msg.sender], wad);
        }

        _balances[src] = sub(_balances[src], wad);
        _balances[dst] = add(_balances[dst], wad);

        Transfer(src, dst, wad);

        return true;
    }

    function push(address dst, uint wad) public {
        transferFrom(msg.sender, dst, wad);
    }
    function pull(address src, uint wad) public {
        transferFrom(src, msg.sender, wad);
    }
    function move(address src, address dst, uint wad) public {
        transferFrom(src, dst, wad);
    }

    function mint(uint wad) public {
        mint(msg.sender, wad);
    }
    function burn(uint wad) public {
        burn(msg.sender, wad);
    }
    function mint(address guy, uint wad) public auth stoppable {
        _balances[guy] = add(_balances[guy], wad);
        _supply = add(_supply, wad);
        Mint(guy, wad);
    }
    function burn(address guy, uint wad) public auth stoppable {
        if (guy != msg.sender && _approvals[guy][msg.sender] != uint(-1)) {
            _approvals[guy][msg.sender] = sub(_approvals[guy][msg.sender], wad);
        }

        _balances[guy] = sub(_balances[guy], wad);
        _supply = sub(_supply, wad);
        Burn(guy, wad);
    }

    // Optional token name
    bytes32   public  name = "";

    function setName(bytes32 name_) public auth {
        name = name_;
    }
}

pragma solidity ^0.4.13;

////// lib/ds-math/src/math.sol
/// math.sol -- mixin for inline numerical wizardry

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x);
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x);
    }
    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x);
    }

    function min(uint x, uint y) internal pure returns (uint z) {
        return x <= y ? x : y;
    }
    function max(uint x, uint y) internal pure returns (uint z) {
        return x >= y ? x : y;
    }
    function imin(int x, int y) internal pure returns (int z) {
        return x <= y ? x : y;
    }
    function imax(int x, int y) internal pure returns (int z) {
        return x >= y ? x : y;
    }

    uint constant WAD = 10 ** 18;
    uint constant RAY = 10 ** 27;

    function wmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }
    function rmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }
    function wdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, WAD), y / 2) / y;
    }
    function rdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint x, uint n) internal pure returns (uint z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}

////// lib/ds-stop/lib/ds-auth/src/auth.sol
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    function DSAuth() public {
        owner = msg.sender;
        LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        LogSetAuthority(authority);
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }
}

////// lib/ds-stop/lib/ds-note/src/note.sol
/// note.sol -- the `note' modifier, for logging calls as events

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
        uint              wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}

////// lib/ds-stop/src/stop.sol
/// stop.sol -- mixin for enable/disable functionality

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-auth/auth.sol"; */
/* import "ds-note/note.sol"; */

contract DSStop is DSNote, DSAuth {

    bool public stopped;

    modifier stoppable {
        require(!stopped);
        _;
    }
    function stop() public auth note {
        stopped = true;
    }
    function start() public auth note {
        stopped = false;
    }

}

////// lib/erc20/src/erc20.sol
/// erc20.sol -- API for the ERC20 token standard

// See <https://github.com/ethereum/EIPs/issues/20>.

// This file likely does not meet the threshold of originality
// required for copyright to apply.  As a result, this is free and
// unencumbered software belonging to the public domain.

/* pragma solidity ^0.4.8; */

contract ERC20Events {
    event Approval(address indexed src, address indexed guy, uint wad);
    event Transfer(address indexed src, address indexed dst, uint wad);
}

contract ERC20 is ERC20Events {
    function totalSupply() public view returns (uint);
    function balanceOf(address guy) public view returns (uint);
    function allowance(address src, address guy) public view returns (uint);

    function approve(address guy, uint wad) public returns (bool);
    function transfer(address dst, uint wad) public returns (bool);
    function transferFrom(
        address src, address dst, uint wad
    ) public returns (bool);
}

////// src/base.sol
/// base.sol -- basic ERC20 implementation

// Copyright (C) 2015, 2016, 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "erc20/erc20.sol"; */
/* import "ds-math/math.sol"; */

contract DSTokenBase is ERC20, DSMath {
    uint256                                            _supply;
    mapping (address => uint256)                       _balances;
    mapping (address => mapping (address => uint256))  _approvals;

    function DSTokenBase(uint supply) public {
        _balances[msg.sender] = supply;
        _supply = supply;
    }

    function totalSupply() public view returns (uint) {
        return _supply;
    }
    function balanceOf(address src) public view returns (uint) {
        return _balances[src];
    }
    function allowance(address src, address guy) public view returns (uint) {
        return _approvals[src][guy];
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        if (src != msg.sender) {
            _approvals[src][msg.sender] = sub(_approvals[src][msg.sender], wad);
        }

        _balances[src] = sub(_balances[src], wad);
        _balances[dst] = add(_balances[dst], wad);

        Transfer(src, dst, wad);

        return true;
    }

    function approve(address guy, uint wad) public returns (bool) {
        _approvals[msg.sender][guy] = wad;

        Approval(msg.sender, guy, wad);

        return true;
    }
}

////// src/token.sol
/// token.sol -- ERC20 implementation with minting and burning

// Copyright (C) 2015, 2016, 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-stop/stop.sol"; */

/* import "./base.sol"; */

contract DSToken is DSTokenBase(0), DSStop {

    bytes32  public  symbol;
    uint256  public  decimals = 18; // standard token precision. override to customize

    function DSToken(bytes32 symbol_) public {
        symbol = symbol_;
    }

    event Mint(address indexed guy, uint wad);
    event Burn(address indexed guy, uint wad);

    function approve(address guy) public stoppable returns (bool) {
        return super.approve(guy, uint(-1));
    }

    function approve(address guy, uint wad) public stoppable returns (bool) {
        return super.approve(guy, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        stoppable
        returns (bool)
    {
        if (src != msg.sender && _approvals[src][msg.sender] != uint(-1)) {
            _approvals[src][msg.sender] = sub(_approvals[src][msg.sender], wad);
        }

        _balances[src] = sub(_balances[src], wad);
        _balances[dst] = add(_balances[dst], wad);

        Transfer(src, dst, wad);

        return true;
    }

    function push(address dst, uint wad) public {
        transferFrom(msg.sender, dst, wad);
    }
    function pull(address src, uint wad) public {
        transferFrom(src, msg.sender, wad);
    }
    function move(address src, address dst, uint wad) public {
        transferFrom(src, dst, wad);
    }

    function mint(uint wad) public {
        mint(msg.sender, wad);
    }
    function burn(uint wad) public {
        burn(msg.sender, wad);
    }
    function mint(address guy, uint wad) public auth stoppable {
        _balances[guy] = add(_balances[guy], wad);
        _supply = add(_supply, wad);
        Mint(guy, wad);
    }
    function burn(address guy, uint wad) public auth stoppable {
        if (guy != msg.sender && _approvals[guy][msg.sender] != uint(-1)) {
            _approvals[guy][msg.sender] = sub(_approvals[guy][msg.sender], wad);
        }

        _balances[guy] = sub(_balances[guy], wad);
        _supply = sub(_supply, wad);
        Burn(guy, wad);
    }

    // Optional token name
    bytes32   public  name = "";

    function setName(bytes32 name_) public auth {
        name = name_;
    }
}

contract GemPit {
    function burn(DSToken gem) public {
        gem.burn(gem.balanceOf(this));
    }
}

pragma solidity ^0.4.13;

////// lib/ds-math/src/math.sol
/// math.sol -- mixin for inline numerical wizardry

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x);
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x);
    }
    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x);
    }

    function min(uint x, uint y) internal pure returns (uint z) {
        return x <= y ? x : y;
    }
    function max(uint x, uint y) internal pure returns (uint z) {
        return x >= y ? x : y;
    }
    function imin(int x, int y) internal pure returns (int z) {
        return x <= y ? x : y;
    }
    function imax(int x, int y) internal pure returns (int z) {
        return x >= y ? x : y;
    }

    uint constant WAD = 10 ** 18;
    uint constant RAY = 10 ** 27;

    function wmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }
    function rmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }
    function wdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, WAD), y / 2) / y;
    }
    function rdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint x, uint n) internal pure returns (uint z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}

////// lib/ds-stop/lib/ds-auth/src/auth.sol
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    function DSAuth() public {
        owner = msg.sender;
        LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        LogSetAuthority(authority);
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }
}

////// lib/ds-stop/lib/ds-note/src/note.sol
/// note.sol -- the `note' modifier, for logging calls as events

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
        uint              wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}

////// lib/ds-stop/src/stop.sol
/// stop.sol -- mixin for enable/disable functionality

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-auth/auth.sol"; */
/* import "ds-note/note.sol"; */

contract DSStop is DSNote, DSAuth {

    bool public stopped;

    modifier stoppable {
        require(!stopped);
        _;
    }
    function stop() public auth note {
        stopped = true;
    }
    function start() public auth note {
        stopped = false;
    }

}

////// lib/erc20/src/erc20.sol
/// erc20.sol -- API for the ERC20 token standard

// See <https://github.com/ethereum/EIPs/issues/20>.

// This file likely does not meet the threshold of originality
// required for copyright to apply.  As a result, this is free and
// unencumbered software belonging to the public domain.

/* pragma solidity ^0.4.8; */

contract ERC20Events {
    event Approval(address indexed src, address indexed guy, uint wad);
    event Transfer(address indexed src, address indexed dst, uint wad);
}

contract ERC20 is ERC20Events {
    function totalSupply() public view returns (uint);
    function balanceOf(address guy) public view returns (uint);
    function allowance(address src, address guy) public view returns (uint);

    function approve(address guy, uint wad) public returns (bool);
    function transfer(address dst, uint wad) public returns (bool);
    function transferFrom(
        address src, address dst, uint wad
    ) public returns (bool);
}

////// src/base.sol
/// base.sol -- basic ERC20 implementation

// Copyright (C) 2015, 2016, 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "erc20/erc20.sol"; */
/* import "ds-math/math.sol"; */

contract DSTokenBase is ERC20, DSMath {
    uint256                                            _supply;
    mapping (address => uint256)                       _balances;
    mapping (address => mapping (address => uint256))  _approvals;

    function DSTokenBase(uint supply) public {
        _balances[msg.sender] = supply;
        _supply = supply;
    }

    function totalSupply() public view returns (uint) {
        return _supply;
    }
    function balanceOf(address src) public view returns (uint) {
        return _balances[src];
    }
    function allowance(address src, address guy) public view returns (uint) {
        return _approvals[src][guy];
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        if (src != msg.sender) {
            _approvals[src][msg.sender] = sub(_approvals[src][msg.sender], wad);
        }

        _balances[src] = sub(_balances[src], wad);
        _balances[dst] = add(_balances[dst], wad);

        Transfer(src, dst, wad);

        return true;
    }

    function approve(address guy, uint wad) public returns (bool) {
        _approvals[msg.sender][guy] = wad;

        Approval(msg.sender, guy, wad);

        return true;
    }
}

////// src/token.sol
/// token.sol -- ERC20 implementation with minting and burning

// Copyright (C) 2015, 2016, 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-stop/stop.sol"; */

/* import "./base.sol"; */

contract DSToken is DSTokenBase(0), DSStop {

    bytes32  public  symbol;
    uint256  public  decimals = 18; // standard token precision. override to customize

    function DSToken(bytes32 symbol_) public {
        symbol = symbol_;
    }

    event Mint(address indexed guy, uint wad);
    event Burn(address indexed guy, uint wad);

    function approve(address guy) public stoppable returns (bool) {
        return super.approve(guy, uint(-1));
    }

    function approve(address guy, uint wad) public stoppable returns (bool) {
        return super.approve(guy, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        stoppable
        returns (bool)
    {
        if (src != msg.sender && _approvals[src][msg.sender] != uint(-1)) {
            _approvals[src][msg.sender] = sub(_approvals[src][msg.sender], wad);
        }

        _balances[src] = sub(_balances[src], wad);
        _balances[dst] = add(_balances[dst], wad);

        Transfer(src, dst, wad);

        return true;
    }

    function push(address dst, uint wad) public {
        transferFrom(msg.sender, dst, wad);
    }
    function pull(address src, uint wad) public {
        transferFrom(src, msg.sender, wad);
    }
    function move(address src, address dst, uint wad) public {
        transferFrom(src, dst, wad);
    }

    function mint(uint wad) public {
        mint(msg.sender, wad);
    }
    function burn(uint wad) public {
        burn(msg.sender, wad);
    }
    function mint(address guy, uint wad) public auth stoppable {
        _balances[guy] = add(_balances[guy], wad);
        _supply = add(_supply, wad);
        Mint(guy, wad);
    }
    function burn(address guy, uint wad) public auth stoppable {
        if (guy != msg.sender && _approvals[guy][msg.sender] != uint(-1)) {
            _approvals[guy][msg.sender] = sub(_approvals[guy][msg.sender], wad);
        }

        _balances[guy] = sub(_balances[guy], wad);
        _supply = sub(_supply, wad);
        Burn(guy, wad);
    }

    // Optional token name
    bytes32   public  name = "";

    function setName(bytes32 name_) public auth {
        name = name_;
    }
}

// hevm: flattened sources of src/vox.sol
pragma solidity ^0.4.18;

////// lib/ds-guard/lib/ds-auth/src/auth.sol
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    function DSAuth() public {
        owner = msg.sender;
        LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        LogSetAuthority(authority);
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }
}

////// lib/ds-spell/lib/ds-note/src/note.sol
/// note.sol -- the `note' modifier, for logging calls as events

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
        uint              wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}

////// lib/ds-thing/lib/ds-math/src/math.sol
/// math.sol -- mixin for inline numerical wizardry

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x);
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x);
    }
    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x);
    }

    function min(uint x, uint y) internal pure returns (uint z) {
        return x <= y ? x : y;
    }
    function max(uint x, uint y) internal pure returns (uint z) {
        return x >= y ? x : y;
    }
    function imin(int x, int y) internal pure returns (int z) {
        return x <= y ? x : y;
    }
    function imax(int x, int y) internal pure returns (int z) {
        return x >= y ? x : y;
    }

    uint constant WAD = 10 ** 18;
    uint constant RAY = 10 ** 27;

    function wmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }
    function rmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }
    function wdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, WAD), y / 2) / y;
    }
    function rdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint x, uint n) internal pure returns (uint z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}

////// lib/ds-thing/src/thing.sol
// thing.sol - `auth` with handy mixins. your things should be DSThings

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import 'ds-auth/auth.sol'; */
/* import 'ds-note/note.sol'; */
/* import 'ds-math/math.sol'; */

contract DSThing is DSAuth, DSNote, DSMath {

    function S(string s) internal pure returns (bytes4) {
        return bytes4(keccak256(s));
    }

}

////// src/vox.sol
/// vox.sol -- target price feed

// Copyright (C) 2016, 2017  Nikolai Mushegian <[email protected]>
// Copyright (C) 2016, 2017  Daniel Brockman <[email protected]>
// Copyright (C) 2017        Rain Break <[email protected]>

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.18; */

/* import "ds-thing/thing.sol"; */

contract SaiVox is DSThing {
    uint256  _par;
    uint256  _way;

    uint256  public  fix;
    uint256  public  how;
    uint256  public  tau;

    function SaiVox(uint par_) public {
        _par = fix = par_;
        _way = RAY;
        tau  = era();
    }

    function era() public view returns (uint) {
        return block.timestamp;
    }

    function mold(bytes32 param, uint val) public note auth {
        if (param == 'way') _way = val;
    }

    // Dai Target Price (ref per dai)
    function par() public returns (uint) {
        prod();
        return _par;
    }
    function way() public returns (uint) {
        prod();
        return _way;
    }

    function tell(uint256 ray) public note auth {
        fix = ray;
    }
    function tune(uint256 ray) public note auth {
        how = ray;
    }

    function prod() public note {
        var age = era() - tau;
        if (age == 0) return;  // optimised
        tau = era();

        if (_way != RAY) _par = rmul(_par, rpow(_way, age));  // optimised

        if (how == 0) return;  // optimised
        var wag = int128(how * age);
        _way = inj(prj(_way) + (fix < _par ? wag : -wag));
    }

    function inj(int128 x) internal pure returns (uint256) {
        return x >= 0 ? uint256(x) + RAY
            : rdiv(RAY, RAY + uint256(-x));
    }
    function prj(uint256 x) internal pure returns (int128) {
        return x >= RAY ? int128(x - RAY)
            : int128(RAY) - int128(rdiv(RAY, x));
    }
}

// Copyright (C) 2015, 2016, 2017 Dapphub

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.18;

contract WETH9 {
    string public name     = "Wrapped Ether";
    string public symbol   = "WETH";
    uint8  public decimals = 18;

    event  Approval(address indexed src, address indexed guy, uint wad);
    event  Transfer(address indexed src, address indexed dst, uint wad);
    event  Deposit(address indexed dst, uint wad);
    event  Withdrawal(address indexed src, uint wad);

    mapping (address => uint)                       public  balanceOf;
    mapping (address => mapping (address => uint))  public  allowance;

    function() public payable {
        deposit();
    }
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
        Deposit(msg.sender, msg.value);
    }
    function withdraw(uint wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
        Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint) {
        return this.balance;
    }

    function approve(address guy, uint wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
        Approval(msg.sender, guy, wad);
        return true;
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        require(balanceOf[src] >= wad);

        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }

        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

        Transfer(src, dst, wad);

        return true;
    }
}


/*
                    GNU GENERAL PUBLIC LICENSE
                       Version 3, 29 June 2007

 Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

                            Preamble

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software and other kinds of works.

  The licenses for most software and other practical works are designed
to take away your freedom to share and change the works.  By contrast,
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share and change all versions of a program--to make sure it remains free
software for all its users.  We, the Free Software Foundation, use the
GNU General Public License for most of our software; it applies also to
any other work released this way by its authors.  You can apply it to
your programs, too.

  When we speak of free software, we are referring to freedom, not
price.  Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
them if you wish), that you receive source code or can get it if you
want it, that you can change the software or use pieces of it in new
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            How to Apply These Terms to Your New Programs

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possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
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    <one line to give the program's name and a brief idea of what it does.>
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Also add information on how to contact you by electronic and paper mail.

  If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:

    <program>  Copyright (C) <year>  <name of author>
    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
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    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License.  Of course, your program's commands
might be different; for a GUI interface, you would use an "about box".

  You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<http://www.gnu.org/licenses/>.

  The GNU General Public License does not permit incorporating your program
into proprietary programs.  If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library.  If this is what you want to do, use the GNU Lesser General
Public License instead of this License.  But first, please read
<http://www.gnu.org/philosophy/why-not-lgpl.html>.

*/

pragma solidity ^0.4.23;

/// math.sol -- mixin for inline numerical wizardry

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.13;

contract DSMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x);
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x);
    }
    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x);
    }

    function min(uint x, uint y) internal pure returns (uint z) {
        return x <= y ? x : y;
    }
    function max(uint x, uint y) internal pure returns (uint z) {
        return x >= y ? x : y;
    }
    function imin(int x, int y) internal pure returns (int z) {
        return x <= y ? x : y;
    }
    function imax(int x, int y) internal pure returns (int z) {
        return x >= y ? x : y;
    }

    uint constant WAD = 10 ** 18;
    uint constant RAY = 10 ** 27;

    function wmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }
    function rmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }
    function wdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, WAD), y / 2) / y;
    }
    function rdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint x, uint n) internal pure returns (uint z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}

contract TubInterface {
    function open() public returns (bytes32);
    function join(uint) public;
    function exit(uint) public;
    function lock(bytes32, uint) public;
    function free(bytes32, uint) public;
    function draw(bytes32, uint) public;
    function wipe(bytes32, uint) public;
    function give(bytes32, address) public;
    function shut(bytes32) public;
    function cups(bytes32) public view returns (address, uint, uint, uint);
    function gem() public view returns (TokenInterface);
    function gov() public view returns (TokenInterface);
    function skr() public view returns (TokenInterface);
    function sai() public view returns (TokenInterface);
    function mat() public view returns (uint);
    function ink(bytes32) public view returns (uint);
    function tab(bytes32) public view returns (uint);
    function rap(bytes32) public view returns (uint);
    function per() public view returns (uint);
    function pep() public view returns (PepInterface);
}

contract TokenInterface {
    function allowance(address, address) public view returns (uint);
    function balanceOf(address) public view returns (uint);
    function approve(address, uint) public;
    function transfer(address, uint) public returns (bool);
    function transferFrom(address, address, uint) public returns (bool);
    function deposit() public payable;
    function withdraw(uint) public;
}

contract PepInterface {
    function peek() public returns (bytes32, bool);
}

contract OtcInterface {
    function getPayAmount(address, address, uint) public view returns (uint);
    function buyAllAmount(address, uint, address pay_gem, uint) public returns (uint);
}

contract SaiProxy is DSMath {
    function open(address tub_) public returns (bytes32) {
        return TubInterface(tub_).open();
    }

    function give(address tub_, bytes32 cup, address lad) public {
        TubInterface(tub_).give(cup, lad);
    }

    function lock(address tub_, bytes32 cup) public payable {
        if (msg.value > 0) {
            TubInterface tub = TubInterface(tub_);

            (address lad,,,) = tub.cups(cup);
            require(lad == address(this), "cup-not-owned");

            tub.gem().deposit.value(msg.value)();

            uint ink = rdiv(msg.value, tub.per());
            ink = rmul(ink, tub.per()) <= msg.value ? ink : ink - 1;

            if (tub.gem().allowance(this, tub) != uint(-1)) {
                tub.gem().approve(tub, uint(-1));
            }
            tub.join(ink);

            if (tub.skr().allowance(this, tub) != uint(-1)) {
                tub.skr().approve(tub, uint(-1));
            }
            tub.lock(cup, ink);
        }
    }

    function draw(address tub_, bytes32 cup, uint wad) public {
        if (wad > 0) {
            TubInterface tub = TubInterface(tub_);
            tub.draw(cup, wad);
            tub.sai().transfer(msg.sender, wad);
        }
    }

    function handleGovFee(TubInterface tub, uint saiDebtFee, address otc_) internal {
        bytes32 val;
        bool ok;
        (val, ok) = tub.pep().peek();
        if (ok && val != 0) {
            uint govAmt = wdiv(saiDebtFee, uint(val));
            if (otc_ != address(0)) {
                uint saiGovAmt = OtcInterface(otc_).getPayAmount(tub.sai(), tub.gov(), govAmt);
                if (tub.sai().allowance(this, otc_) != uint(-1)) {
                    tub.sai().approve(otc_, uint(-1));
                }
                tub.sai().transferFrom(msg.sender, this, saiGovAmt);
                OtcInterface(otc_).buyAllAmount(tub.gov(), govAmt, tub.sai(), saiGovAmt);
            } else {
                tub.gov().transferFrom(msg.sender, this, govAmt);
            }
        }
    }

    function wipe(address tub_, bytes32 cup, uint wad, address otc_) public {
        if (wad > 0) {
            TubInterface tub = TubInterface(tub_);

            tub.sai().transferFrom(msg.sender, this, wad);
            handleGovFee(tub, rmul(wad, rdiv(tub.rap(cup), tub.tab(cup))), otc_);

            if (tub.sai().allowance(this, tub) != uint(-1)) {
                tub.sai().approve(tub, uint(-1));
            }
            if (tub.gov().allowance(this, tub) != uint(-1)) {
                tub.gov().approve(tub, uint(-1));
            }
            tub.wipe(cup, wad);
        }
    }

    function wipe(address tub_, bytes32 cup, uint wad) public {
        wipe(tub_, cup, wad, address(0));
    }

    function free(address tub_, bytes32 cup, uint jam) public {
        if (jam > 0) {
            TubInterface tub = TubInterface(tub_);
            uint ink = rdiv(jam, tub.per());
            ink = rmul(ink, tub.per()) <= jam ? ink : ink - 1;
            tub.free(cup, ink);
            if (tub.skr().allowance(this, tub) != uint(-1)) {
                tub.skr().approve(tub, uint(-1));
            }
            tub.exit(ink);
            uint freeJam = tub.gem().balanceOf(this); // Withdraw possible previous stuck WETH as well
            tub.gem().withdraw(freeJam);
            address(msg.sender).transfer(freeJam);
        }
    }

    function lockAndDraw(address tub_, bytes32 cup, uint wad) public payable {
        lock(tub_, cup);
        draw(tub_, cup, wad);
    }

    function lockAndDraw(address tub_, uint wad) public payable returns (bytes32 cup) {
        cup = open(tub_);
        lockAndDraw(tub_, cup, wad);
    }

    function wipeAndFree(address tub_, bytes32 cup, uint jam, uint wad) public payable {
        wipe(tub_, cup, wad);
        free(tub_, cup, jam);
    }

    function wipeAndFree(address tub_, bytes32 cup, uint jam, uint wad, address otc_) public payable {
        wipe(tub_, cup, wad, otc_);
        free(tub_, cup, jam);
    }

    function shut(address tub_, bytes32 cup) public {
        TubInterface tub = TubInterface(tub_);
        wipeAndFree(tub_, cup, rmul(tub.ink(cup), tub.per()), tub.tab(cup));
        tub.shut(cup);
    }

    function shut(address tub_, bytes32 cup, address otc_) public {
        TubInterface tub = TubInterface(tub_);
        wipeAndFree(tub_, cup, rmul(tub.ink(cup), tub.per()), tub.tab(cup), otc_);
        tub.shut(cup);
    }
}

contract ProxyRegistryInterface {
    function build(address) public returns (address);
}

contract SaiProxyCreateAndExecute is SaiProxy {

    // Create a DSProxy instance and open a cup
    function createAndOpen(address registry_, address tub_) public returns (address proxy, bytes32 cup) {
        proxy = ProxyRegistryInterface(registry_).build(msg.sender);
        cup = open(tub_);
        TubInterface(tub_).give(cup, proxy);
    }

    // Create a DSProxy instance, open a cup, and lock collateral
    function createOpenAndLock(address registry_, address tub_) public payable returns (address proxy, bytes32 cup) {
        proxy = ProxyRegistryInterface(registry_).build(msg.sender);
        cup = open(tub_);
        lock(tub_, cup);
        TubInterface(tub_).give(cup, proxy);
    }

    // Create a DSProxy instance, open a cup, lock collateral, and draw DAI
    function createOpenLockAndDraw(address registry_, address tub_, uint wad) public payable returns (address proxy, bytes32 cup) {
        proxy = ProxyRegistryInterface(registry_).build(msg.sender);
        cup = open(tub_);
        lockAndDraw(tub_, cup, wad);
        TubInterface(tub_).give(cup, proxy);
    }
}

// hevm: flattened sources of src/osm.sol
pragma solidity ^0.4.24;

////// lib/ds-stop/lib/ds-auth/src/auth.sol
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.23; */

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    constructor() public {
        owner = msg.sender;
        emit LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        emit LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        emit LogSetAuthority(authority);
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }
}

////// lib/ds-stop/lib/ds-note/src/note.sol
/// note.sol -- the `note' modifier, for logging calls as events

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.23; */

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
        uint              wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        emit LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}

////// lib/ds-stop/src/stop.sol
/// stop.sol -- mixin for enable/disable functionality

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.23; */

/* import "ds-auth/auth.sol"; */
/* import "ds-note/note.sol"; */

contract DSStop is DSNote, DSAuth {

    bool public stopped;

    modifier stoppable {
        require(!stopped);
        _;
    }
    function stop() public auth note {
        stopped = true;
    }
    function start() public auth note {
        stopped = false;
    }

}

////// src/osm.sol
/// osm.sol - oracle security module

// Copyright (C) 2018  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.24; */

/* import "ds-auth/auth.sol"; */
/* import "ds-stop/stop.sol"; */
// import "ds-value/value.sol";

interface DSValue {
    function peek() external returns (bytes32,bool);
    function read() external returns (bytes32);
}

contract OSM is DSAuth, DSStop {
    DSValue public src;
    
    uint16 constant ONE_HOUR = uint16(3600);

    uint16 public hop = ONE_HOUR;
    uint64 public zzz;

    struct Feed {
        uint128 val;
        bool    has;
    }

    Feed cur;
    Feed nxt;

    event LogValue(bytes32 val);
    
    constructor (DSValue src_) public {
        src = src_;
        (bytes32 wut, bool ok) = src_.peek();
        if (ok) {
            cur = nxt = Feed(uint128(wut), ok);
            zzz = prev(era());
        }
    }

    function era() internal view returns (uint) {
        return block.timestamp;
    }

    function prev(uint ts) internal view returns (uint64) {
        return uint64(ts - (ts % hop));
    }

    function step(uint16 ts) external auth {
        require(ts > 0);
        hop = ts;
    }

    function void() external auth {
        cur = nxt = Feed(0, false);
        stopped = true;
    }

    function pass() public view returns (bool ok) {
        return era() >= zzz + hop;
    }

    function poke() external stoppable {
        require(pass());
        (bytes32 wut, bool ok) = src.peek();
        cur = nxt;
        nxt = Feed(uint128(wut), ok);
        zzz = prev(era());
        emit LogValue(bytes32(cur.val));
    }

    function peek() external view returns (bytes32,bool) {
        return (bytes32(cur.val), cur.has);
    }

    function peep() external view returns (bytes32,bool) {
        return (bytes32(nxt.val), nxt.has);
    }

    function read() external view returns (bytes32) {
        require(cur.has);
        return (bytes32(cur.val));
    }
}

// hevm: flattened sources of src/guard.sol
pragma solidity ^0.4.13;

////// lib/ds-auth/src/auth.sol
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    function DSAuth() public {
        owner = msg.sender;
        LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        LogSetAuthority(authority);
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }
}

////// src/guard.sol
// guard.sol -- simple whitelist implementation of DSAuthority

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity ^0.4.13; */

/* import "ds-auth/auth.sol"; */

contract DSGuardEvents {
    event LogPermit(
        bytes32 indexed src,
        bytes32 indexed dst,
        bytes32 indexed sig
    );

    event LogForbid(
        bytes32 indexed src,
        bytes32 indexed dst,
        bytes32 indexed sig
    );
}

contract DSGuard is DSAuth, DSAuthority, DSGuardEvents {
    bytes32 constant public ANY = bytes32(uint(-1));

    mapping (bytes32 => mapping (bytes32 => mapping (bytes32 => bool))) acl;

    function canCall(
        address src_, address dst_, bytes4 sig
    ) public view returns (bool) {
        var src = bytes32(src_);
        var dst = bytes32(dst_);

        return acl[src][dst][sig]
            || acl[src][dst][ANY]
            || acl[src][ANY][sig]
            || acl[src][ANY][ANY]
            || acl[ANY][dst][sig]
            || acl[ANY][dst][ANY]
            || acl[ANY][ANY][sig]
            || acl[ANY][ANY][ANY];
    }

    function permit(bytes32 src, bytes32 dst, bytes32 sig) public auth {
        acl[src][dst][sig] = true;
        LogPermit(src, dst, sig);
    }

    function forbid(bytes32 src, bytes32 dst, bytes32 sig) public auth {
        acl[src][dst][sig] = false;
        LogForbid(src, dst, sig);
    }

    function permit(address src, address dst, bytes32 sig) public {
        permit(bytes32(src), bytes32(dst), sig);
    }
    function forbid(address src, address dst, bytes32 sig) public {
        forbid(bytes32(src), bytes32(dst), sig);
    }

}

contract DSGuardFactory {
    mapping (address => bool)  public  isGuard;

    function newGuard() public returns (DSGuard guard) {
        guard = new DSGuard();
        guard.setOwner(msg.sender);
        isGuard[guard] = true;
    }
}

/// return median value of feeds

// Copyright (C) 2017  DappHub, LLC

// Licensed under the Apache License, Version 2.0 (the "License").
// You may not use this file except in compliance with the License.

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND (express or implied).

pragma solidity ^0.4.8;

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) constant returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    function DSAuth() {
        owner = msg.sender;
        LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        auth
    {
        owner = owner_;
        LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        auth
    {
        authority = authority_;
        LogSetAuthority(authority);
    }

    modifier auth {
        assert(isAuthorized(msg.sender, msg.sig));
        _;
    }

    modifier authorized(bytes4 sig) {
        assert(isAuthorized(msg.sender, sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, this, sig);
        }
    }

    function assert(bool x) internal {
        if (!x) throw;
    }
}

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
	uint	 	  wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}

contract DSMath {
    
    /*
    standard uint256 functions
     */

    function add(uint256 x, uint256 y) constant internal returns (uint256 z) {
        assert((z = x + y) >= x);
    }

    function sub(uint256 x, uint256 y) constant internal returns (uint256 z) {
        assert((z = x - y) <= x);
    }

    function mul(uint256 x, uint256 y) constant internal returns (uint256 z) {
        assert((z = x * y) >= x);
    }

    function div(uint256 x, uint256 y) constant internal returns (uint256 z) {
        z = x / y;
    }

    function min(uint256 x, uint256 y) constant internal returns (uint256 z) {
        return x <= y ? x : y;
    }
    function max(uint256 x, uint256 y) constant internal returns (uint256 z) {
        return x >= y ? x : y;
    }

    /*
    uint128 functions (h is for half)
     */


    function hadd(uint128 x, uint128 y) constant internal returns (uint128 z) {
        assert((z = x + y) >= x);
    }

    function hsub(uint128 x, uint128 y) constant internal returns (uint128 z) {
        assert((z = x - y) <= x);
    }

    function hmul(uint128 x, uint128 y) constant internal returns (uint128 z) {
        assert((z = x * y) >= x);
    }

    function hdiv(uint128 x, uint128 y) constant internal returns (uint128 z) {
        z = x / y;
    }

    function hmin(uint128 x, uint128 y) constant internal returns (uint128 z) {
        return x <= y ? x : y;
    }
    function hmax(uint128 x, uint128 y) constant internal returns (uint128 z) {
        return x >= y ? x : y;
    }


    /*
    int256 functions
     */

    function imin(int256 x, int256 y) constant internal returns (int256 z) {
        return x <= y ? x : y;
    }
    function imax(int256 x, int256 y) constant internal returns (int256 z) {
        return x >= y ? x : y;
    }

    /*
    WAD math
     */

    uint128 constant WAD = 10 ** 18;

    function wadd(uint128 x, uint128 y) constant internal returns (uint128) {
        return hadd(x, y);
    }

    function wsub(uint128 x, uint128 y) constant internal returns (uint128) {
        return hsub(x, y);
    }

    function wmul(uint128 x, uint128 y) constant internal returns (uint128 z) {
        z = cast((uint256(x) * y + WAD / 2) / WAD);
    }

    function wdiv(uint128 x, uint128 y) constant internal returns (uint128 z) {
        z = cast((uint256(x) * WAD + y / 2) / y);
    }

    function wmin(uint128 x, uint128 y) constant internal returns (uint128) {
        return hmin(x, y);
    }
    function wmax(uint128 x, uint128 y) constant internal returns (uint128) {
        return hmax(x, y);
    }

    /*
    RAY math
     */

    uint128 constant RAY = 10 ** 27;

    function radd(uint128 x, uint128 y) constant internal returns (uint128) {
        return hadd(x, y);
    }

    function rsub(uint128 x, uint128 y) constant internal returns (uint128) {
        return hsub(x, y);
    }

    function rmul(uint128 x, uint128 y) constant internal returns (uint128 z) {
        z = cast((uint256(x) * y + RAY / 2) / RAY);
    }

    function rdiv(uint128 x, uint128 y) constant internal returns (uint128 z) {
        z = cast((uint256(x) * RAY + y / 2) / y);
    }

    function rpow(uint128 x, uint64 n) constant internal returns (uint128 z) {
        // This famous algorithm is called "exponentiation by squaring"
        // and calculates x^n with x as fixed-point and n as regular unsigned.
        //
        // It's O(log n), instead of O(n) for naive repeated multiplication.
        //
        // These facts are why it works:
        //
        //  If n is even, then x^n = (x^2)^(n/2).
        //  If n is odd,  then x^n = x * x^(n-1),
        //   and applying the equation for even x gives
        //    x^n = x * (x^2)^((n-1) / 2).
        //
        //  Also, EVM division is flooring and
        //    floor[(n-1) / 2] = floor[n / 2].

        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }

    function rmin(uint128 x, uint128 y) constant internal returns (uint128) {
        return hmin(x, y);
    }
    function rmax(uint128 x, uint128 y) constant internal returns (uint128) {
        return hmax(x, y);
    }

    function cast(uint256 x) constant internal returns (uint128 z) {
        assert((z = uint128(x)) == x);
    }

}

contract DSThing is DSAuth, DSNote, DSMath {
}

contract DSValue is DSThing {
    bool    has;
    bytes32 val;
    function peek() constant returns (bytes32, bool) {
        return (val,has);
    }
    function read() constant returns (bytes32) {
        var (wut, has) = peek();
        assert(has);
        return wut;
    }
    function poke(bytes32 wut) note auth {
        val = wut;
        has = true;
    }
    function void() note auth { // unset the value
        has = false;
    }
}

contract Medianizer is DSValue {
    mapping (bytes12 => address) public values;
    mapping (address => bytes12) public indexes;
    bytes12 public next = 0x1;

    uint96 public min = 0x1;

    function set(address wat) auth {
        bytes12 nextId = bytes12(uint96(next) + 1);
        assert(nextId != 0x0);
        set(next, wat);
        next = nextId;
    }

    function set(bytes12 pos, address wat) note auth {
        if (pos == 0x0) throw;

        if (wat != 0 && indexes[wat] != 0) throw;

        indexes[values[pos]] = 0; // Making sure to remove a possible existing address in that position

        if (wat != 0) {
            indexes[wat] = pos;
        }

        values[pos] = wat;
    }

    function setMin(uint96 min_) note auth {
        if (min_ == 0x0) throw;
        min = min_;
    }

    function setNext(bytes12 next_) note auth {
        if (next_ == 0x0) throw;
        next = next_;
    }

    function unset(bytes12 pos) {
        set(pos, 0);
    }

    function unset(address wat) {
        set(indexes[wat], 0);
    }

    function poke() {
        poke(0);
    }

    function poke(bytes32) note {
        (val, has) = compute();
    }

    function compute() constant returns (bytes32, bool) {
        bytes32[] memory wuts = new bytes32[](uint96(next) - 1);
        uint96 ctr = 0;
        for (uint96 i = 1; i < uint96(next); i++) {
            if (values[bytes12(i)] != 0) {
                var (wut, wuz) = DSValue(values[bytes12(i)]).peek();
                if (wuz) {
                    if (ctr == 0 || wut >= wuts[ctr - 1]) {
                        wuts[ctr] = wut;
                    } else {
                        uint96 j = 0;
                        while (wut >= wuts[j]) {
                            j++;
                        }
                        for (uint96 k = ctr; k > j; k--) {
                            wuts[k] = wuts[k - 1];
                        }
                        wuts[j] = wut;
                    }
                    ctr++;
                }
            }
        }

        if (ctr < min) return (val, false);

        bytes32 value;
        if (ctr % 2 == 0) {
            uint128 val1 = uint128(wuts[(ctr / 2) - 1]);
            uint128 val2 = uint128(wuts[ctr / 2]);
            value = bytes32(wdiv(hadd(val1, val2), 2 ether));
        } else {
            value = wuts[(ctr - 1) / 2];
        }

        return (value, true);
    }

}