Contract Address Details

// SPDX-License-Identifier: MIT
pragma solidity 0.7.6;

import "../interface/IISupply.sol";
import "../../tokenPools/interface/IITokenPool.sol";
import "../../token/lib/CheckPointHistory.sol";
import "../../token/lib/CheckPointHistoryCache.sol";
import "../../governance/implementation/Governed.sol";
import "../../addressUpdater/implementation/AddressUpdatable.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";


/**
 * @title Supply contract
 * @notice This contract maintains and computes various native token supply totals.
 **/

contract Supply is IISupply, Governed, AddressUpdatable {
    using CheckPointHistory for CheckPointHistory.CheckPointHistoryState;
    using CheckPointHistoryCache for CheckPointHistoryCache.CacheState;
    using SafeMath for uint256;

    address payable private constant BURN_ADDRESS = 0x000000000000000000000000000000000000dEaD;
    
    struct SupplyData {
        IITokenPool tokenPool;
        uint256 totalLockedWei;
        uint256 totalInflationAuthorizedWei;
        uint256 totalClaimedWei;
    }

    string internal constant ERR_INFLATION_ONLY = "inflation only";
    string internal constant ERR_TOKEN_POOL_ALREADY_ADDED = "token pool already added";
    string internal constant ERR_INITIAL_GENESIS_AMOUNT_ZERO = "initial genesis amount zero";

    CheckPointHistory.CheckPointHistoryState private circulatingSupplyWei;
    CheckPointHistoryCache.CacheState private circulatingSupplyWeiCache;

    uint256 immutable public initialGenesisAmountWei;
    uint256 immutable public totalExcludedSupplyWei; // Foundation supply, distribution treasury, team escrow
    uint256 public distributedExcludedSupplyWei;
    uint256 public totalLockedWei; // Amounts temporary locked and not considered in the inflatable supply
    uint256 public totalInflationAuthorizedWei;
    uint256 public totalClaimedWei;

    SupplyData[] public tokenPools;

    address public inflation;

    // balance of burn address at last check - needed for updating circulating supply
    uint256 private burnAddressBalance;

    // events
    event AuthorizedInflationUpdateError(uint256 actual, uint256 expected);

    modifier onlyInflation {
        require(msg.sender == inflation, ERR_INFLATION_ONLY);
        _;
    }

    constructor(
        address _governance,
        address _addressUpdater,
        uint256 _initialGenesisAmountWei,
        uint256 _totalExcludedSupplyWei,
        IITokenPool[] memory _tokenPools
    )
        Governed(_governance) AddressUpdatable(_addressUpdater)
    {
        require(_initialGenesisAmountWei > 0, ERR_INITIAL_GENESIS_AMOUNT_ZERO);
        initialGenesisAmountWei = _initialGenesisAmountWei;
        totalExcludedSupplyWei = _totalExcludedSupplyWei;

        _increaseCirculatingSupply(_initialGenesisAmountWei.sub(_totalExcludedSupplyWei));

        for (uint256 i = 0; i < _tokenPools.length; i++) {
            _addTokenPool(_tokenPools[i]);
        }

        _updateCirculatingSupply(BURN_ADDRESS);
    }

    /**
     * @notice Updates circulating supply
     * @dev Also updates the burn address amount
    */
    function updateCirculatingSupply() external override onlyInflation {
        _updateCirculatingSupply(BURN_ADDRESS);
    }

    /**
     * @notice Updates authorized inflation and circulating supply - emits event if error
     * @param _inflationAuthorizedWei               Authorized inflation
     * @dev Also updates the burn address amount
    */
    function updateAuthorizedInflationAndCirculatingSupply(
            uint256 _inflationAuthorizedWei
    )
        external override
        onlyInflation 
    {
        // Save old total inflation authorized value to compare with after update.
        uint256 oldTotalInflationAuthorizedWei = totalInflationAuthorizedWei;
        
        _updateCirculatingSupply(BURN_ADDRESS);
        
        // Check if new authorized inflation was distributed and updated correctly.
        if (totalInflationAuthorizedWei != oldTotalInflationAuthorizedWei.add(_inflationAuthorizedWei)) {
            emit AuthorizedInflationUpdateError(totalInflationAuthorizedWei - oldTotalInflationAuthorizedWei,
                _inflationAuthorizedWei);
        }
    }

    /**
     * @notice Adds token pool so it can call updateTokenPoolDistributedAmount method when 
        some tokens are distributed
     * @param _tokenPool                            Token pool address
     * @param _increaseDistributedSupplyByAmountWei If token pool was given initial supply from excluded supply, 
        increase distributed value by this amount
     */
    function addTokenPool(
        IITokenPool _tokenPool,
        uint256 _increaseDistributedSupplyByAmountWei
    )
        external
        onlyGovernance
    {
        _increaseDistributedSupply(_increaseDistributedSupplyByAmountWei);
        _addTokenPool(_tokenPool);
        _updateCirculatingSupply(BURN_ADDRESS);
    }

    /**
     * @notice Increase distributed supply when excluded funds are released to a token pool or team members
     * @param _amountWei                            Amount to increase by
     */
    function increaseDistributedSupply(uint256 _amountWei) external onlyGovernance {
        _increaseDistributedSupply(_amountWei);
        _updateCirculatingSupply(BURN_ADDRESS);
    }

    /**
     * @notice Descrease distributed supply if excluded funds are no longer locked to a token pool
     * @param _amountWei                            Amount to decrease by
     */
    function decreaseDistributedSupply(uint256 _amountWei) external onlyGovernance {
        distributedExcludedSupplyWei = distributedExcludedSupplyWei.sub(_amountWei);
        _decreaseCirculatingSupply(_amountWei);
        _updateCirculatingSupply(BURN_ADDRESS);
    }
    
    /**
     * @notice Get approximate circulating supply for given block number from cache - only past block
     * @param _blockNumber                          Block number
     * @return _circulatingSupplyWei Return approximate circulating supply for last known block <= _blockNumber
    */
    function getCirculatingSupplyAtCached(
        uint256 _blockNumber
    )
        external override 
        returns(uint256 _circulatingSupplyWei)
    {
        // use cache only for the past (the value will never change)
        require(_blockNumber < block.number, "Can only be used for past blocks");
        (_circulatingSupplyWei,) = circulatingSupplyWeiCache.valueAt(circulatingSupplyWei, _blockNumber);
    }
    
    /**
     * @notice Get approximate circulating supply for given block number
     * @param _blockNumber                          Block number
     * @return _circulatingSupplyWei Return approximate circulating supply for last known block <= _blockNumber
    */
    function getCirculatingSupplyAt(
        uint256 _blockNumber
    )
        external view override 
        returns(uint256 _circulatingSupplyWei)
    {
        return circulatingSupplyWei.valueAt(_blockNumber);
    }

    /**
     * @notice Get total inflatable balance (initial genesis amount + total claimed - total excluded/locked amount)
     * @return _inflatableBalanceWei Return inflatable balance
    */
    function getInflatableBalance() external view override returns(uint256 _inflatableBalanceWei) {
        return initialGenesisAmountWei
            .add(totalClaimedWei)
            .sub(totalExcludedSupplyWei.sub(distributedExcludedSupplyWei))
            .sub(totalLockedWei);
    }

    /**
     * Return the burn address (a constant).
     */
    function burnAddress() external pure returns (address payable) {
        return BURN_ADDRESS;
    }

    /**
     * @notice Implementation of the AddressUpdatable abstract method.
     */
    function _updateContractAddresses(
        bytes32[] memory _contractNameHashes,
        address[] memory _contractAddresses
    )
        internal override
    {
        inflation = _getContractAddress(_contractNameHashes, _contractAddresses, "Inflation");
    }

    function _increaseCirculatingSupply(uint256 _increaseBy) internal {
        circulatingSupplyWei.writeValue(circulatingSupplyWei.valueAtNow().add(_increaseBy));
    }

    function _decreaseCirculatingSupply(uint256 _descreaseBy) internal {
        circulatingSupplyWei.writeValue(circulatingSupplyWei.valueAtNow().sub(_descreaseBy));
    }

    function _updateCirculatingSupply(address _burnAddress) internal {
        uint256 len = tokenPools.length;
        for (uint256 i = 0; i < len; i++) {
            SupplyData storage data = tokenPools[i];

            uint256 newTotalLockedWei;
            uint256 newTotalInflationAuthorizedWei;
            uint256 newTotalClaimedWei;
            
            (newTotalLockedWei, newTotalInflationAuthorizedWei, newTotalClaimedWei) = 
                data.tokenPool.getTokenPoolSupplyData();
            assert(newTotalLockedWei.add(newTotalInflationAuthorizedWei) >= newTotalClaimedWei);
            
            // updates total inflation authorized with daily authorized inflation
            uint256 dailyInflationAuthorizedWei = newTotalInflationAuthorizedWei.sub(data.totalInflationAuthorizedWei);
            totalInflationAuthorizedWei = totalInflationAuthorizedWei.add(dailyInflationAuthorizedWei);

            // updates circulating supply
            uint256 claimChange = newTotalClaimedWei.sub(data.totalClaimedWei);
            _increaseCirculatingSupply(claimChange);
            totalClaimedWei = totalClaimedWei.add(claimChange);
            if (newTotalLockedWei >= data.totalLockedWei) {
                uint256 lockChange = newTotalLockedWei - data.totalLockedWei;
                _decreaseCirculatingSupply(lockChange);
                totalLockedWei = totalLockedWei.add(lockChange);
            } else {
                // if founds are unlocked, they are returned to excluded amount
                uint256 lockChange = data.totalLockedWei - newTotalLockedWei;
                distributedExcludedSupplyWei = distributedExcludedSupplyWei.sub(lockChange);
                totalLockedWei = totalLockedWei.sub(lockChange);
            }

            // update data
            data.totalLockedWei = newTotalLockedWei;
            data.totalInflationAuthorizedWei = newTotalInflationAuthorizedWei;
            data.totalClaimedWei = newTotalClaimedWei;
        }

        _updateBurnAddressAmount(_burnAddress);
    }

    function _updateBurnAddressAmount(address _burnAddress) internal {
        uint256 newBalance = _burnAddress.balance;
        _decreaseCirculatingSupply(newBalance.sub(burnAddressBalance));
        burnAddressBalance = newBalance;
    }

    function _addTokenPool(IITokenPool _tokenPool) internal {
        uint256 len = tokenPools.length;
        for (uint256 i = 0; i < len; i++) {
            if (_tokenPool == tokenPools[i].tokenPool) {
                revert(ERR_TOKEN_POOL_ALREADY_ADDED);
            }
        }
        tokenPools.push();
        tokenPools[len].tokenPool = _tokenPool;
    }
    
    function _increaseDistributedSupply(uint256 _amountWei) internal {
        assert(totalExcludedSupplyWei.sub(distributedExcludedSupplyWei) >= _amountWei);
        _increaseCirculatingSupply(_amountWei);
        distributedExcludedSupplyWei = distributedExcludedSupplyWei.add(_amountWei);
    }
}
        

// SPDX-License-Identifier: MIT
pragma solidity 0.7.6;

import "../interface/IIAddressUpdatable.sol";


abstract contract AddressUpdatable is IIAddressUpdatable {

    // https://docs.soliditylang.org/en/v0.8.7/contracts.html#constant-and-immutable-state-variables
    // No storage slot is allocated
    bytes32 internal constant ADDRESS_STORAGE_POSITION = 
        keccak256("flare.diamond.AddressUpdatable.ADDRESS_STORAGE_POSITION");

    modifier onlyAddressUpdater() {
        require (msg.sender == getAddressUpdater(), "only address updater");
        _;
    }

    constructor(address _addressUpdater) {
        setAddressUpdaterValue(_addressUpdater);
    }

    function getAddressUpdater() public view returns (address _addressUpdater) {
        // Only direct constants are allowed in inline assembly, so we assign it here
        bytes32 position = ADDRESS_STORAGE_POSITION;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            _addressUpdater := sload(position)
        }
    }

    /**
     * @notice external method called from AddressUpdater only
     */
    function updateContractAddresses(
        bytes32[] memory _contractNameHashes,
        address[] memory _contractAddresses
    )
        external override
        onlyAddressUpdater
    {
        // update addressUpdater address
        setAddressUpdaterValue(_getContractAddress(_contractNameHashes, _contractAddresses, "AddressUpdater"));
        // update all other addresses
        _updateContractAddresses(_contractNameHashes, _contractAddresses);
    }

    /**
     * @notice virtual method that a contract extending AddressUpdatable must implement
     */
    function _updateContractAddresses(
        bytes32[] memory _contractNameHashes,
        address[] memory _contractAddresses
    ) internal virtual;

    /**
     * @notice helper method to get contract address
     * @dev it reverts if contract name does not exist
     */
    function _getContractAddress(
        bytes32[] memory _nameHashes,
        address[] memory _addresses,
        string memory _nameToFind
    )
        internal pure
        returns(address)
    {
        bytes32 nameHash = keccak256(abi.encode(_nameToFind));
        address a = address(0);
        for (uint256 i = 0; i < _nameHashes.length; i++) {
            if (nameHash == _nameHashes[i]) {
                a = _addresses[i];
                break;
            }
        }
        require(a != address(0), "address zero");
        return a;
    }

    function setAddressUpdaterValue(address _addressUpdater) internal {
        // Only direct constants are allowed in inline assembly, so we assign it here
        bytes32 position = ADDRESS_STORAGE_POSITION;
        // solhint-disable-next-line no-inline-assembly  
        assembly {
            sstore(position, _addressUpdater)
        }
    }
}
          

// SPDX-License-Identifier: MIT
pragma solidity >=0.7.6 <0.9;


interface IIAddressUpdatable {
    /**
     * @notice Updates contract addresses - should be called only from AddressUpdater contract
     * @param _contractNameHashes       list of keccak256(abi.encode(...)) contract names
     * @param _contractAddresses        list of contract addresses corresponding to the contract names
     */
    function updateContractAddresses(
        bytes32[] memory _contractNameHashes,
        address[] memory _contractAddresses
        ) external;
}
          

// SPDX-License-Identifier: MIT
pragma solidity 0.7.6;

import { GovernedBase } from "./GovernedBase.sol";


/**
 * @title Governed
 * @dev For deployed, governed contracts, enforce a non-zero address at create time.
 **/
contract Governed is GovernedBase {
    constructor(address _governance) GovernedBase(_governance) {
        require(_governance != address(0), "_governance zero");
    }
}
          

// SPDX-License-Identifier: MIT
pragma solidity 0.7.6;

import "../../userInterfaces/IGovernanceSettings.sol";


/**
 * @title Governed Base
 * @notice This abstract base class defines behaviors for a governed contract.
 * @dev This class is abstract so that specific behaviors can be defined for the constructor.
 *   Contracts should not be left ungoverned, but not all contract will have a constructor
 *   (for example those pre-defined in genesis).
 **/
abstract contract GovernedBase {
    struct TimelockedCall {
        uint256 allowedAfterTimestamp;
        bytes encodedCall;
    }
    
    // solhint-disable-next-line const-name-snakecase
    IGovernanceSettings public constant governanceSettings = 
        IGovernanceSettings(0x1000000000000000000000000000000000000007);

    address private initialGovernance;

    bool private initialised;
    
    bool public productionMode;
    
    bool private executing;
    
    mapping(bytes4 => TimelockedCall) public timelockedCalls;
    
    event GovernanceCallTimelocked(bytes4 selector, uint256 allowedAfterTimestamp, bytes encodedCall);
    event TimelockedGovernanceCallExecuted(bytes4 selector, uint256 timestamp);
    event TimelockedGovernanceCallCanceled(bytes4 selector, uint256 timestamp);
    
    event GovernanceInitialised(address initialGovernance);
    event GovernedProductionModeEntered(address governanceSettings);
    
    modifier onlyGovernance {
        if (executing || !productionMode) {
            _beforeExecute();
            _;
        } else {
            _recordTimelockedCall(msg.data);
        }
    }
    
    modifier onlyImmediateGovernance () {
        _checkOnlyGovernance();
        _;
    }

    constructor(address _initialGovernance) {
        if (_initialGovernance != address(0)) {
            initialise(_initialGovernance);
        }
    }

    /**
     * @notice Execute the timelocked governance calls once the timelock period expires.
     * @dev Only executor can call this method.
     * @param _selector The method selector (only one timelocked call per method is stored).
     */
    function executeGovernanceCall(bytes4 _selector) external {
        require(governanceSettings.isExecutor(msg.sender), "only executor");
        TimelockedCall storage call = timelockedCalls[_selector];
        require(call.allowedAfterTimestamp != 0, "timelock: invalid selector");
        require(block.timestamp >= call.allowedAfterTimestamp, "timelock: not allowed yet");
        bytes memory encodedCall = call.encodedCall;
        delete timelockedCalls[_selector];
        executing = true;
        //solhint-disable-next-line avoid-low-level-calls
        (bool success,) = address(this).call(encodedCall);
        executing = false;
        emit TimelockedGovernanceCallExecuted(_selector, block.timestamp);
        _passReturnOrRevert(success);
    }
    
    /**
     * Cancel a timelocked governance call before it has been executed.
     * @dev Only governance can call this method.
     * @param _selector The method selector.
     */
    function cancelGovernanceCall(bytes4 _selector) external onlyImmediateGovernance {
        require(timelockedCalls[_selector].allowedAfterTimestamp != 0, "timelock: invalid selector");
        emit TimelockedGovernanceCallCanceled(_selector, block.timestamp);
        delete timelockedCalls[_selector];
    }
    
    /**
     * Enter the production mode after all the initial governance settings have been set.
     * This enables timelocks and the governance is afterwards obtained by calling 
     * governanceSettings.getGovernanceAddress(). 
     */
    function switchToProductionMode() external {
        _checkOnlyGovernance();
        require(!productionMode, "already in production mode");
        initialGovernance = address(0);
        productionMode = true;
        emit GovernedProductionModeEntered(address(governanceSettings));
    }

    /**
     * @notice Initialize the governance address if not first initialized.
     */
    function initialise(address _initialGovernance) public virtual {
        require(initialised == false, "initialised != false");
        initialised = true;
        initialGovernance = _initialGovernance;
        emit GovernanceInitialised(_initialGovernance);
    }
    
    /**
     * Returns the current effective governance address.
     */
    function governance() public view returns (address) {
        return productionMode ? governanceSettings.getGovernanceAddress() : initialGovernance;
    }

    function _beforeExecute() private {
        if (executing) {
            // can only be run from executeGovernanceCall(), where we check that only executor can call
            // make sure nothing else gets executed, even in case of reentrancy
            assert(msg.sender == address(this));
            executing = false;
        } else {
            // must be called with: productionMode=false
            // must check governance in this case
            _checkOnlyGovernance();
        }
    }

    function _recordTimelockedCall(bytes calldata _data) private {
        _checkOnlyGovernance();
        bytes4 selector;
        //solhint-disable-next-line no-inline-assembly
        assembly {
            selector := calldataload(_data.offset)
        }
        uint256 timelock = governanceSettings.getTimelock();
        uint256 allowedAt = block.timestamp + timelock;
        timelockedCalls[selector] = TimelockedCall({
            allowedAfterTimestamp: allowedAt,
            encodedCall: _data
        });
        emit GovernanceCallTimelocked(selector, allowedAt, _data);
    }
    
    function _checkOnlyGovernance() private view {
        require(msg.sender == governance(), "only governance");
    }
    
    function _passReturnOrRevert(bool _success) private pure {
        // pass exact return or revert data - needs to be done in assembly
        //solhint-disable-next-line no-inline-assembly
        assembly {
            let size := returndatasize()
            let ptr := mload(0x40)
            mstore(0x40, add(ptr, size))
            returndatacopy(ptr, 0, size)
            if _success {
                return(ptr, size)
            }
            revert(ptr, size)
        }
    }
}
          

// SPDX-License-Identifier: MIT
pragma solidity >=0.7.6 <0.9;


interface IISupply {

    /**
     * @notice Updates circulating supply
     * @dev Also updates the burn address amount
    */
    function updateCirculatingSupply() external;

    /**
     * @notice Updates authorized inflation and circulating supply - emits event if error
     * @param _inflationAuthorizedWei               Authorized inflation
     * @dev Also updates the burn address amount
    */
    function updateAuthorizedInflationAndCirculatingSupply(uint256 _inflationAuthorizedWei) external;

    /**
     * @notice Get approximate circulating supply for given block number from cache - only past block
     * @param _blockNumber                          Block number
     * @return _circulatingSupplyWei Return approximate circulating supply for last known block <= _blockNumber
    */
    function getCirculatingSupplyAtCached(uint256 _blockNumber) external returns(uint256 _circulatingSupplyWei);

    /**
     * @notice Get approximate circulating supply for given block number
     * @param _blockNumber                          Block number
     * @return _circulatingSupplyWei Return approximate circulating supply for last known block <= _blockNumber
    */
    function getCirculatingSupplyAt(uint256 _blockNumber) external view returns(uint256 _circulatingSupplyWei);

    /**
     * @notice Get total inflatable balance (initial genesis amount + total authorized inflation)
     * @return _inflatableBalanceWei Return inflatable balance
    */
    function getInflatableBalance() external view returns(uint256 _inflatableBalanceWei);
}
          

// SPDX-License-Identifier: MIT
pragma solidity 0.7.6;

import "@openzeppelin/contracts/math/Math.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/utils/SafeCast.sol";


/**
 * @title Check Point History library
 * @notice A contract to manage checkpoints as of a given block.
 * @dev Store value history by block number with detachable state.
 **/
library CheckPointHistory {
    using SafeMath for uint256;
    using SafeCast for uint256;

    /**
     * @dev `CheckPoint` is the structure that attaches a block number to a
     *  given value; the block number attached is the one that last changed the
     *  value
     **/
    struct CheckPoint {
        // `value` is the amount of tokens at a specific block number
        uint192 value;
        // `fromBlock` is the block number that the value was generated from
        uint64 fromBlock;
    }

    struct CheckPointHistoryState {
        // `checkpoints` is an array that tracks values at non-contiguous block numbers
        mapping(uint256 => CheckPoint) checkpoints;
        // `checkpoints` before `startIndex` have been deleted
        // INVARIANT: checkpoints.endIndex == 0 || startIndex < checkpoints.endIndex      (strict!)
        // startIndex and endIndex are both less then fromBlock, so 64 bits is enough
        uint64 startIndex;
        // the index AFTER last
        uint64 endIndex;
    }

    /**
     * @notice Binary search of _checkpoints array.
     * @param _checkpoints An array of CheckPoint to search.
     * @param _startIndex Smallest possible index to be returned.
     * @param _blockNumber The block number to search for.
     */
    function _indexOfGreatestBlockLessThan(
        mapping(uint256 => CheckPoint) storage _checkpoints, 
        uint256 _startIndex,
        uint256 _endIndex,
        uint256 _blockNumber
    )
        private view 
        returns (uint256 index)
    {
        // Binary search of the value by given block number in the array
        uint256 min = _startIndex;
        uint256 max = _endIndex.sub(1);
        while (max > min) {
            uint256 mid = (max.add(min).add(1)).div(2);
            if (_checkpoints[mid].fromBlock <= _blockNumber) {
                min = mid;
            } else {
                max = mid.sub(1);
            }
        }
        return min;
    }

    /**
     * @notice Queries the value at a specific `_blockNumber`
     * @param _self A CheckPointHistoryState instance to manage.
     * @param _blockNumber The block number of the value active at that time
     * @return _value The value at `_blockNumber`     
     **/
    function valueAt(
        CheckPointHistoryState storage _self, 
        uint256 _blockNumber
    )
        internal view 
        returns (uint256 _value)
    {
        uint256 historyCount = _self.endIndex;

        // No _checkpoints, return 0
        if (historyCount == 0) return 0;

        // Shortcut for the actual value (extra optimized for current block, to save one storage read)
        // historyCount - 1 is safe, since historyCount != 0
        if (_blockNumber >= block.number || _blockNumber >= _self.checkpoints[historyCount - 1].fromBlock) {
            return _self.checkpoints[historyCount - 1].value;
        }
        
        // guard values at start    
        uint256 startIndex = _self.startIndex;
        if (_blockNumber < _self.checkpoints[startIndex].fromBlock) {
            // reading data before `startIndex` is only safe before first cleanup
            require(startIndex == 0, "CheckPointHistory: reading from cleaned-up block");
            return 0;
        }

        // Find the block with number less than or equal to block given
        uint256 index = _indexOfGreatestBlockLessThan(_self.checkpoints, startIndex, _self.endIndex, _blockNumber);

        return _self.checkpoints[index].value;
    }

    /**
     * @notice Queries the value at `block.number`
     * @param _self A CheckPointHistoryState instance to manage.
     * @return _value The value at `block.number`
     **/
    function valueAtNow(CheckPointHistoryState storage _self) internal view returns (uint256 _value) {
        uint256 historyCount = _self.endIndex;
        // No _checkpoints, return 0
        if (historyCount == 0) return 0;
        // Return last value
        return _self.checkpoints[historyCount - 1].value;
    }

    /**
     * @notice Writes the value at the current block.
     * @param _self A CheckPointHistoryState instance to manage.
     * @param _value Value to write.
     **/
    function writeValue(
        CheckPointHistoryState storage _self, 
        uint256 _value
    )
        internal
    {
        uint256 historyCount = _self.endIndex;
        if (historyCount == 0) {
            // checkpoints array empty, push new CheckPoint
            _self.checkpoints[0] = 
                CheckPoint({ fromBlock: block.number.toUint64(), value: _toUint192(_value) });
            _self.endIndex = 1;
        } else {
            // historyCount - 1 is safe, since historyCount != 0
            CheckPoint storage lastCheckpoint = _self.checkpoints[historyCount - 1];
            uint256 lastBlock = lastCheckpoint.fromBlock;
            // slither-disable-next-line incorrect-equality
            if (block.number == lastBlock) {
                // If last check point is the current block, just update
                lastCheckpoint.value = _toUint192(_value);
            } else {
                // we should never have future blocks in history
                assert (block.number > lastBlock);
                // push new CheckPoint
                _self.checkpoints[historyCount] = 
                    CheckPoint({ fromBlock: block.number.toUint64(), value: _toUint192(_value) });
                _self.endIndex = uint64(historyCount + 1);  // 64 bit safe, because historyCount <= block.number
            }
        }
    }
    
    /**
     * Delete at most `_count` of the oldest checkpoints.
     * At least one checkpoint at or before `_cleanupBlockNumber` will remain 
     * (unless the history was empty to start with).
     */    
    function cleanupOldCheckpoints(
        CheckPointHistoryState storage _self, 
        uint256 _count,
        uint256 _cleanupBlockNumber
    )
        internal
        returns (uint256)
    {
        if (_cleanupBlockNumber == 0) return 0;   // optimization for when cleaning is not enabled
        uint256 length = _self.endIndex;
        if (length == 0) return 0;
        uint256 startIndex = _self.startIndex;
        // length - 1 is safe, since length != 0 (check above)
        uint256 endIndex = Math.min(startIndex.add(_count), length - 1);    // last element can never be deleted
        uint256 index = startIndex;
        // we can delete `checkpoint[index]` while the next checkpoint is at `_cleanupBlockNumber` or before
        while (index < endIndex && _self.checkpoints[index + 1].fromBlock <= _cleanupBlockNumber) {
            delete _self.checkpoints[index];
            index++;
        }
        if (index > startIndex) {   // index is the first not deleted index
            _self.startIndex = index.toUint64();
        }
        return index - startIndex;  // safe: index >= startIndex at start and then increases
    }

    // SafeCast lib is missing cast to uint192    
    function _toUint192(uint256 _value) internal pure returns (uint192) {
        require(_value < 2**192, "value doesn't fit in 192 bits");
        return uint192(_value);
    }
}
          

// SPDX-License-Identifier: MIT
pragma solidity 0.7.6;

import "@openzeppelin/contracts/math/SafeMath.sol";
import "./CheckPointHistory.sol";


library CheckPointHistoryCache {
    using SafeMath for uint256;
    using CheckPointHistory for CheckPointHistory.CheckPointHistoryState;
    
    struct CacheState {
        // mapping blockNumber => (value + 1)
        mapping(uint256 => uint256) cache;
    }
    
    function valueAt(
        CacheState storage _self,
        CheckPointHistory.CheckPointHistoryState storage _checkPointHistory,
        uint256 _blockNumber
    )
        internal returns (uint256 _value, bool _cacheCreated)
    {
        // is it in cache?
        uint256 cachedValue = _self.cache[_blockNumber];
        if (cachedValue != 0) {
            return (cachedValue - 1, false);    // safe, cachedValue != 0
        }
        // read from _checkPointHistory
        uint256 historyValue = _checkPointHistory.valueAt(_blockNumber);
        _self.cache[_blockNumber] = historyValue.add(1);  // store to cache (add 1 to differentiate from empty)
        return (historyValue, true);
    }
    
    function deleteAt(
        CacheState storage _self,
        uint256 _blockNumber
    )
        internal returns (uint256 _deleted)
    {
        if (_self.cache[_blockNumber] != 0) {
            _self.cache[_blockNumber] = 0;
            return 1;
        }
        return 0;
    }
}
          

// SPDX-License-Identifier: MIT
pragma solidity >=0.7.6 <0.9;

interface IITokenPool {

    /**
     * @notice Return token pool supply data
     * @return _lockedFundsWei                  Funds that are intentionally locked in the token pool 
     * and not part of circulating supply
     * @return _totalInflationAuthorizedWei     Total inflation authorized amount (wei)
     * @return _totalClaimedWei                 Total claimed amount (wei)
     */
    function getTokenPoolSupplyData() external returns (
        uint256 _lockedFundsWei,
        uint256 _totalInflationAuthorizedWei,
        uint256 _totalClaimedWei
    );
}
          

// SPDX-License-Identifier: MIT
pragma solidity 0.7.6;


/**
 * A special contract that holds Flare governance address.
 * This contract enables updating governance address and timelock only by hard forking the network,
 * meaning only by updating validator code.
 */
interface IGovernanceSettings {
    /**
     * Get the governance account address.
     * The governance address can only be changed by a hardfork.
     */
    function getGovernanceAddress() external view returns (address);
    
    /**
     * Get the time in seconds that must pass between a governance call and execution.
     * The timelock value can only be changed by a hardfork.
     */
    function getTimelock() external view returns (uint256);
    
    /**
     * Get the addresses of the accounts that are allowed to execute the timelocked governance calls
     * once the timelock period expires.
     * Executors can be changed without a hardfork, via a normal governance call.
     */
    function getExecutors() external view returns (address[] memory);
    
    /**
     * Check whether an address is one of the executors.
     */
    function isExecutor(address _address) external view returns (bool);
}
          

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow, so we distribute
        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
    }
}
          

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        uint256 c = a + b;
        if (c < a) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b > a) return (false, 0);
        return (true, a - b);
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) return (true, 0);
        uint256 c = a * b;
        if (c / a != b) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a / b);
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a % b);
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) return 0;
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: division by zero");
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: modulo by zero");
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        return a - b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryDiv}.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a % b;
    }
}
          

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;


/**
 * @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
 * checks.
 *
 * Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
 * easily result in undesired exploitation or bugs, since developers usually
 * assume that overflows raise errors. `SafeCast` restores this intuition by
 * reverting the transaction when such an operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 *
 * Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
 * all math on `uint256` and `int256` and then downcasting.
 */
library SafeCast {

    /**
     * @dev Returns the downcasted uint128 from uint256, reverting on
     * overflow (when the input is greater than largest uint128).
     *
     * Counterpart to Solidity's `uint128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     */
    function toUint128(uint256 value) internal pure returns (uint128) {
        require(value < 2**128, "SafeCast: value doesn\'t fit in 128 bits");
        return uint128(value);
    }

    /**
     * @dev Returns the downcasted uint64 from uint256, reverting on
     * overflow (when the input is greater than largest uint64).
     *
     * Counterpart to Solidity's `uint64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     */
    function toUint64(uint256 value) internal pure returns (uint64) {
        require(value < 2**64, "SafeCast: value doesn\'t fit in 64 bits");
        return uint64(value);
    }

    /**
     * @dev Returns the downcasted uint32 from uint256, reverting on
     * overflow (when the input is greater than largest uint32).
     *
     * Counterpart to Solidity's `uint32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     */
    function toUint32(uint256 value) internal pure returns (uint32) {
        require(value < 2**32, "SafeCast: value doesn\'t fit in 32 bits");
        return uint32(value);
    }

    /**
     * @dev Returns the downcasted uint16 from uint256, reverting on
     * overflow (when the input is greater than largest uint16).
     *
     * Counterpart to Solidity's `uint16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     */
    function toUint16(uint256 value) internal pure returns (uint16) {
        require(value < 2**16, "SafeCast: value doesn\'t fit in 16 bits");
        return uint16(value);
    }

    /**
     * @dev Returns the downcasted uint8 from uint256, reverting on
     * overflow (when the input is greater than largest uint8).
     *
     * Counterpart to Solidity's `uint8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits.
     */
    function toUint8(uint256 value) internal pure returns (uint8) {
        require(value < 2**8, "SafeCast: value doesn\'t fit in 8 bits");
        return uint8(value);
    }

    /**
     * @dev Converts a signed int256 into an unsigned uint256.
     *
     * Requirements:
     *
     * - input must be greater than or equal to 0.
     */
    function toUint256(int256 value) internal pure returns (uint256) {
        require(value >= 0, "SafeCast: value must be positive");
        return uint256(value);
    }

    /**
     * @dev Returns the downcasted int128 from int256, reverting on
     * overflow (when the input is less than smallest int128 or
     * greater than largest int128).
     *
     * Counterpart to Solidity's `int128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     *
     * _Available since v3.1._
     */
    function toInt128(int256 value) internal pure returns (int128) {
        require(value >= -2**127 && value < 2**127, "SafeCast: value doesn\'t fit in 128 bits");
        return int128(value);
    }

    /**
     * @dev Returns the downcasted int64 from int256, reverting on
     * overflow (when the input is less than smallest int64 or
     * greater than largest int64).
     *
     * Counterpart to Solidity's `int64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     *
     * _Available since v3.1._
     */
    function toInt64(int256 value) internal pure returns (int64) {
        require(value >= -2**63 && value < 2**63, "SafeCast: value doesn\'t fit in 64 bits");
        return int64(value);
    }

    /**
     * @dev Returns the downcasted int32 from int256, reverting on
     * overflow (when the input is less than smallest int32 or
     * greater than largest int32).
     *
     * Counterpart to Solidity's `int32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     *
     * _Available since v3.1._
     */
    function toInt32(int256 value) internal pure returns (int32) {
        require(value >= -2**31 && value < 2**31, "SafeCast: value doesn\'t fit in 32 bits");
        return int32(value);
    }

    /**
     * @dev Returns the downcasted int16 from int256, reverting on
     * overflow (when the input is less than smallest int16 or
     * greater than largest int16).
     *
     * Counterpart to Solidity's `int16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     *
     * _Available since v3.1._
     */
    function toInt16(int256 value) internal pure returns (int16) {
        require(value >= -2**15 && value < 2**15, "SafeCast: value doesn\'t fit in 16 bits");
        return int16(value);
    }

    /**
     * @dev Returns the downcasted int8 from int256, reverting on
     * overflow (when the input is less than smallest int8 or
     * greater than largest int8).
     *
     * Counterpart to Solidity's `int8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits.
     *
     * _Available since v3.1._
     */
    function toInt8(int256 value) internal pure returns (int8) {
        require(value >= -2**7 && value < 2**7, "SafeCast: value doesn\'t fit in 8 bits");
        return int8(value);
    }

    /**
     * @dev Converts an unsigned uint256 into a signed int256.
     *
     * Requirements:
     *
     * - input must be less than or equal to maxInt256.
     */
    function toInt256(uint256 value) internal pure returns (int256) {
        require(value < 2**255, "SafeCast: value doesn't fit in an int256");
        return int256(value);
    }
}