Contract Source Code:
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/ERC20.sol)
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* The default value of {decimals} is 18. To change this, you should override
* this function so it returns a different value.
*
* We have followed general OpenZeppelin Contracts guidelines: functions revert
* instead returning `false` on failure. This behavior is nonetheless
* conventional and does not conflict with the expectations of ERC20
* applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
/**
* @dev Sets the values for {name} and {symbol}.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5.05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the default value returned by this function, unless
* it's overridden.
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view virtual override returns (uint8) {
return 18;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address to, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_transfer(owner, to, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
* `transferFrom`. This is semantically equivalent to an infinite approval.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_approve(owner, spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* NOTE: Does not update the allowance if the current allowance
* is the maximum `uint256`.
*
* Requirements:
*
* - `from` and `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
* - the caller must have allowance for ``from``'s tokens of at least
* `amount`.
*/
function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
address spender = _msgSender();
_spendAllowance(from, spender, amount);
_transfer(from, to, amount);
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
address owner = _msgSender();
_approve(owner, spender, allowance(owner, spender) + addedValue);
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
address owner = _msgSender();
uint256 currentAllowance = allowance(owner, spender);
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `from` to `to`.
*
* This internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
*/
function _transfer(address from, address to, uint256 amount) internal virtual {
require(from != address(0), "ERC20: transfer from the zero address");
require(to != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(from, to, amount);
uint256 fromBalance = _balances[from];
require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[from] = fromBalance - amount;
// Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
// decrementing then incrementing.
_balances[to] += amount;
}
emit Transfer(from, to, amount);
_afterTokenTransfer(from, to, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply += amount;
unchecked {
// Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
_balances[account] += amount;
}
emit Transfer(address(0), account, amount);
_afterTokenTransfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
// Overflow not possible: amount <= accountBalance <= totalSupply.
_totalSupply -= amount;
}
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(address owner, address spender, uint256 amount) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Updates `owner` s allowance for `spender` based on spent `amount`.
*
* Does not update the allowance amount in case of infinite allowance.
* Revert if not enough allowance is available.
*
* Might emit an {Approval} event.
*/
function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
uint256 currentAllowance = allowance(owner, spender);
if (currentAllowance != type(uint256).max) {
require(currentAllowance >= amount, "ERC20: insufficient allowance");
unchecked {
_approve(owner, spender, currentAllowance - amount);
}
}
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/
interface IERC20Metadata is IERC20 {
/**
* @dev Returns the name of the token.
*/
function name() external view returns (string memory);
/**
* @dev Returns the symbol of the token.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the decimals places of the token.
*/
function decimals() external view returns (uint8);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `from` to `to` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(address from, address to, uint256 amount) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^0.8.0;
/**
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}
// SPDX-License-Identifier: AGPL-3.0
pragma solidity 0.8.19;
interface IStaking {
function stake(address _to, uint256 _amount) external;
function unstake(address _to, uint256 _amount) external;
function rebase() external;
function index() external view returns (uint256);
}
// SPDX-License-Identifier: AGPL-3.0
pragma solidity 0.8.19;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
interface IsVEC is IERC20 {
function rebase(uint256 amount_, uint epoch_) external returns (uint256);
function circulatingSupply() external view returns (uint256);
function gonsForBalance(uint amount) external view returns (uint);
function balanceForGons(uint gons) external view returns (uint);
function index() external view returns (uint);
}
// SPDX-License-Identifier: AGPL-3.0
pragma solidity 0.8.19;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "../interface/IsVEC.sol";
import "../interface/IStaking.sol";
/// @title sVEC
/// @notice Staked Vector
contract sVEC is IsVEC, ERC20 {
/// EVENTS ///
event LogSupply(uint256 indexed epoch, uint256 totalSupply);
event LogRebase(uint256 indexed epoch, uint256 rebase, uint256 index);
event LogStakingContractUpdated(address stakingContract);
/// MODIFIERS ///
modifier onlyStakingContract() {
require(
msg.sender == stakingContract,
"StakingContract: call is not staking contract"
);
_;
}
/// DATA STRUCTURES ///
struct Rebase {
uint256 epoch;
uint256 rebase; // 18 decimals
uint256 totalStakedBefore;
uint256 totalStakedAfter;
uint256 amountRebased;
uint256 index;
uint256 blockNumberOccured;
}
/// STATE VARIABLES ///
address internal initializer;
address public stakingContract; // balance used to calc rebase
uint256 internal _totalSupply;
uint256 internal INDEX; // Index Gons - tracks rebase growth
uint256 private constant MAX_UINT256 = type(uint256).max;
uint256 private constant INITIAL_FRAGMENTS_SUPPLY = 25_000_000 * 10 ** 9;
// TOTAL_GONS is a multiple of INITIAL_FRAGMENTS_SUPPLY so that _gonsPerFragment is an integer.
// Use the highest value that fits in a uint256 for max granularity.
uint256 private constant TOTAL_GONS =
MAX_UINT256 - (MAX_UINT256 % INITIAL_FRAGMENTS_SUPPLY);
// MAX_SUPPLY = maximum integer < (sqrt(4*TOTAL_GONS + 1) - 1) / 2
uint256 private constant MAX_SUPPLY = ~uint128(0); // (2^128) - 1
uint256 private _gonsPerFragment;
Rebase[] public rebases; // past rebase data
mapping(address => uint256) private _gonBalances;
mapping(address => mapping(address => uint256)) private _allowedValue;
/// CONSTRUCTOR ///
constructor() ERC20("Staked Vector", "sVEC") {
initializer = msg.sender;
_totalSupply = INITIAL_FRAGMENTS_SUPPLY;
_gonsPerFragment = TOTAL_GONS / _totalSupply;
}
function decimals() public view virtual override returns (uint8) {
return 9;
}
/// INITIALIZATION ///
/// @notice Sets initial index
/// @param _index Initial index
function setIndex(uint256 _index) external {
require(
msg.sender == initializer,
"Initializer: caller is not initializer"
);
require(INDEX == 0, "Cannot set INDEX again");
INDEX = gonsForBalance(_index);
}
/// @notice Initialize contract
/// @param _stakingContract Address of staking contract
function initialize(address _stakingContract) external {
require(
msg.sender == initializer,
"Initializer: caller is not initializer"
);
require(_stakingContract != address(0), "Zero address: Staking");
stakingContract = _stakingContract;
_gonBalances[stakingContract] = TOTAL_GONS;
emit Transfer(address(0x0), stakingContract, _totalSupply);
emit LogStakingContractUpdated(stakingContract);
initializer = address(0);
}
/// REBASE ///
/// @notice Increases sVEC supply
/// @param amount_ Amount to rebase for
/// @param epoch_ Epoch number
/// @return _newSupply New total supply
function rebase(
uint256 amount_,
uint256 epoch_
) public override onlyStakingContract returns (uint256 _newSupply) {
uint256 rebaseAmount;
uint256 circulatingSupply_ = circulatingSupply();
if (amount_ == 0) {
emit LogSupply(epoch_, _totalSupply);
emit LogRebase(epoch_, 0, index());
return _totalSupply;
} else if (circulatingSupply_ > 0) {
rebaseAmount = (amount_ * _totalSupply) / circulatingSupply_;
} else {
rebaseAmount = amount_;
}
_totalSupply = _totalSupply + rebaseAmount;
if (_totalSupply > MAX_SUPPLY) {
_totalSupply = MAX_SUPPLY;
}
_gonsPerFragment = TOTAL_GONS / _totalSupply;
_storeRebase(circulatingSupply_, amount_, epoch_);
return _totalSupply;
}
/// @notice Stores rebase
/// @param previousCirculating_ Previous circ supply
/// @param profit_ Amount of profic for epoch
/// @param epoch_ Epoch number
function _storeRebase(
uint256 previousCirculating_,
uint256 profit_,
uint256 epoch_
) internal {
uint256 rebasePercent;
if (previousCirculating_ > 0)
rebasePercent = (profit_ * 1e18) / previousCirculating_;
rebases.push(
Rebase({
epoch: epoch_,
rebase: rebasePercent, // 18 decimals
totalStakedBefore: previousCirculating_,
totalStakedAfter: circulatingSupply(),
amountRebased: profit_,
index: index(),
blockNumberOccured: block.number
})
);
emit LogSupply(epoch_, _totalSupply);
emit LogRebase(epoch_, rebasePercent, index());
}
/// MUTATIVE FUNCTIONS ///
/// @notice Transfer sVEC from msg.sender
/// @param to Address sending sVEC to
/// @param value Amount of sVEC to send
function transfer(
address to,
uint256 value
) public override(IERC20, ERC20) returns (bool) {
uint256 gonValue = value * _gonsPerFragment;
_gonBalances[msg.sender] = _gonBalances[msg.sender] - gonValue;
_gonBalances[to] = _gonBalances[to] + gonValue;
emit Transfer(msg.sender, to, value);
return true;
}
/// @notice Transfer sVEC
/// @param from Address sending sVEC from
/// @param to Address sending sVEC to
/// @param value Amount of sVEC to send
function transferFrom(
address from,
address to,
uint256 value
) public override(IERC20, ERC20) returns (bool) {
_allowedValue[from][msg.sender] =
_allowedValue[from][msg.sender] -
value;
emit Approval(from, msg.sender, _allowedValue[from][msg.sender]);
uint256 gonValue = gonsForBalance(value);
_gonBalances[from] = _gonBalances[from] - gonValue;
_gonBalances[to] = _gonBalances[to] + gonValue;
emit Transfer(from, to, value);
return true;
}
function approve(
address spender,
uint256 value
) public override(IERC20, ERC20) returns (bool) {
_approve(msg.sender, spender, value);
return true;
}
function increaseAllowance(
address spender,
uint256 addedValue
) public override returns (bool) {
_approve(
msg.sender,
spender,
_allowedValue[msg.sender][spender] + addedValue
);
return true;
}
function decreaseAllowance(
address spender,
uint256 subtractedValue
) public override returns (bool) {
uint256 oldValue = _allowedValue[msg.sender][spender];
if (subtractedValue >= oldValue) {
_approve(msg.sender, spender, 0);
} else {
_approve(msg.sender, spender, oldValue - subtractedValue);
}
return true;
}
/// INTERNAL FUNCTIONS ///
function _approve(
address owner,
address spender,
uint256 value
) internal virtual override {
_allowedValue[owner][spender] = value;
emit Approval(owner, spender, value);
}
/// VIEW FUNCTIONS ///
/// @notice Returns balance of an address
/// @param who Address of who to get balance from
function balanceOf(
address who
) public view override(IERC20, ERC20) returns (uint256) {
return _gonBalances[who] / _gonsPerFragment;
}
/// @notice Returns calculation of gons for amount of sVEC
/// @param amount Amount of sVEC to calculate gons for
function gonsForBalance(
uint256 amount
) public view override returns (uint256) {
return amount * _gonsPerFragment;
}
/// @notice Returns calculation of balance for gons amount
/// @param gons Amount of gons to calculate sVEC for
function balanceForGons(
uint256 gons
) public view override returns (uint256) {
return gons / _gonsPerFragment;
}
/// @notice Returns sVEC circulating supply (Total Supply - Staking Contract Balance)
function circulatingSupply() public view override returns (uint256) {
return _totalSupply - balanceOf(stakingContract);
}
/// @notice Returns current sVEC index
function index() public view override returns (uint256) {
return balanceForGons(INDEX);
}
function allowance(
address owner_,
address spender
) public view override(IERC20, ERC20) returns (uint256) {
return _allowedValue[owner_][spender];
}
}