Contract Source Code:
File 1 of 1 : Converter
// File: @openzeppelin/contracts/introspection/ERC165Checker.sol
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.2 <0.8.0;
/**
* @dev Library used to query support of an interface declared via {IERC165}.
*
* Note that these functions return the actual result of the query: they do not
* `revert` if an interface is not supported. It is up to the caller to decide
* what to do in these cases.
*/
library ERC165Checker {
// As per the EIP-165 spec, no interface should ever match 0xffffffff
bytes4 private constant _INTERFACE_ID_INVALID = 0xffffffff;
/*
* bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
*/
bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
/**
* @dev Returns true if `account` supports the {IERC165} interface,
*/
function supportsERC165(address account) internal view returns (bool) {
// Any contract that implements ERC165 must explicitly indicate support of
// InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid
return _supportsERC165Interface(account, _INTERFACE_ID_ERC165) &&
!_supportsERC165Interface(account, _INTERFACE_ID_INVALID);
}
/**
* @dev Returns true if `account` supports the interface defined by
* `interfaceId`. Support for {IERC165} itself is queried automatically.
*
* See {IERC165-supportsInterface}.
*/
function supportsInterface(address account, bytes4 interfaceId) internal view returns (bool) {
// query support of both ERC165 as per the spec and support of _interfaceId
return supportsERC165(account) &&
_supportsERC165Interface(account, interfaceId);
}
/**
* @dev Returns true if `account` supports all the interfaces defined in
* `interfaceIds`. Support for {IERC165} itself is queried automatically.
*
* Batch-querying can lead to gas savings by skipping repeated checks for
* {IERC165} support.
*
* See {IERC165-supportsInterface}.
*/
function supportsAllInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool) {
// query support of ERC165 itself
if (!supportsERC165(account)) {
return false;
}
// query support of each interface in _interfaceIds
for (uint256 i = 0; i < interfaceIds.length; i++) {
if (!_supportsERC165Interface(account, interfaceIds[i])) {
return false;
}
}
// all interfaces supported
return true;
}
/**
* @notice Query if a contract implements an interface, does not check ERC165 support
* @param account The address of the contract to query for support of an interface
* @param interfaceId The interface identifier, as specified in ERC-165
* @return true if the contract at account indicates support of the interface with
* identifier interfaceId, false otherwise
* @dev Assumes that account contains a contract that supports ERC165, otherwise
* the behavior of this method is undefined. This precondition can be checked
* with {supportsERC165}.
* Interface identification is specified in ERC-165.
*/
function _supportsERC165Interface(address account, bytes4 interfaceId) private view returns (bool) {
// success determines whether the staticcall succeeded and result determines
// whether the contract at account indicates support of _interfaceId
(bool success, bool result) = _callERC165SupportsInterface(account, interfaceId);
return (success && result);
}
/**
* @notice Calls the function with selector 0x01ffc9a7 (ERC165) and suppresses throw
* @param account The address of the contract to query for support of an interface
* @param interfaceId The interface identifier, as specified in ERC-165
* @return success true if the STATICCALL succeeded, false otherwise
* @return result true if the STATICCALL succeeded and the contract at account
* indicates support of the interface with identifier interfaceId, false otherwise
*/
function _callERC165SupportsInterface(address account, bytes4 interfaceId)
private
view
returns (bool, bool)
{
bytes memory encodedParams = abi.encodeWithSelector(_INTERFACE_ID_ERC165, interfaceId);
(bool success, bytes memory result) = account.staticcall{ gas: 30000 }(encodedParams);
if (result.length < 32) return (false, false);
return (success, abi.decode(result, (bool)));
}
}
// File: @openzeppelin/contracts/GSN/Context.sol
pragma solidity >=0.6.0 <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 GSN 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 payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// File: @openzeppelin/contracts/token/ERC20/IERC20.sol
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @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 `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, 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 `sender` to `recipient` 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 sender, address recipient, uint256 amount) external returns (bool);
/**
* @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);
}
// File: @openzeppelin/contracts/math/SafeMath.sol
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, 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) {
return sub(a, b, "SafeMath: subtraction overflow");
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* 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);
uint256 c = a - b;
return c;
}
/**
* @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) {
// 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 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts 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) {
return div(a, b, "SafeMath: division by zero");
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts 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) {
return mod(a, b, "SafeMath: modulo by zero");
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
// File: @openzeppelin/contracts/token/ERC20/ERC20.sol
pragma solidity >=0.6.0 <0.8.0;
/**
* @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.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin guidelines: functions revert instead
* of 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 {
using SafeMath for uint256;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
/**
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with
* a default value of 18.
*
* To select a different value for {decimals}, use {_setupDecimals}.
*
* All three of these values are immutable: they can only be set once during
* construction.
*/
constructor (string memory name_, string memory symbol_) public {
_name = name_;
_symbol = symbol_;
_decimals = 18;
}
/**
* @dev Returns the name of the token.
*/
function name() public view returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view 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 value {ERC20} uses, unless {_setupDecimals} is
* called.
*
* 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 returns (uint8) {
return _decimals;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, 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}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), 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}.
*
* Requirements:
*
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for ``sender``'s tokens of at least
* `amount`.
*/
function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
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) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(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) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
return true;
}
/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is 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:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(address sender, address recipient, uint256 amount) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, 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:
*
* - `to` 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 = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(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);
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(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 Sets {decimals} to a value other than the default one of 18.
*
* WARNING: This function should only be called from the constructor. Most
* applications that interact with token contracts will not expect
* {decimals} to ever change, and may work incorrectly if it does.
*/
function _setupDecimals(uint8 decimals_) internal {
_decimals = decimals_;
}
/**
* @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 to 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 { }
}
// File: @openzeppelin/contracts/introspection/IERC165.sol
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Interface of the ERC165 standard, as defined in the
* https://eips.ethereum.org/EIPS/eip-165[EIP].
*
* Implementers can declare support of contract interfaces, which can then be
* queried by others ({ERC165Checker}).
*
* For an implementation, see {ERC165}.
*/
interface IERC165 {
/**
* @dev Returns true if this contract implements the interface defined by
* `interfaceId`. See the corresponding
* https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
* to learn more about how these ids are created.
*
* This function call must use less than 30 000 gas.
*/
function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
// File: @openzeppelin/contracts/token/ERC721/IERC721.sol
pragma solidity >=0.6.2 <0.8.0;
/**
* @dev Required interface of an ERC721 compliant contract.
*/
interface IERC721 is IERC165 {
/**
* @dev Emitted when `tokenId` token is transferred from `from` to `to`.
*/
event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
/**
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
*/
event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
/**
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
*/
event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
/**
* @dev Returns the number of tokens in ``owner``'s account.
*/
function balanceOf(address owner) external view returns (uint256 balance);
/**
* @dev Returns the owner of the `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function ownerOf(uint256 tokenId) external view returns (address owner);
/**
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
* are aware of the ERC721 protocol to prevent tokens from being forever locked.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(address from, address to, uint256 tokenId) external;
/**
* @dev Transfers `tokenId` token from `from` to `to`.
*
* WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
*
* Emits a {Transfer} event.
*/
function transferFrom(address from, address to, uint256 tokenId) external;
/**
* @dev Gives permission to `to` to transfer `tokenId` token to another account.
* The approval is cleared when the token is transferred.
*
* Only a single account can be approved at a time, so approving the zero address clears previous approvals.
*
* Requirements:
*
* - The caller must own the token or be an approved operator.
* - `tokenId` must exist.
*
* Emits an {Approval} event.
*/
function approve(address to, uint256 tokenId) external;
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function getApproved(uint256 tokenId) external view returns (address operator);
/**
* @dev Approve or remove `operator` as an operator for the caller.
* Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
*
* Requirements:
*
* - The `operator` cannot be the caller.
*
* Emits an {ApprovalForAll} event.
*/
function setApprovalForAll(address operator, bool _approved) external;
/**
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}
*/
function isApprovedForAll(address owner, address operator) external view returns (bool);
/**
* @dev Safely transfers `tokenId` token from `from` to `to`.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;
}
// File: @openzeppelin/contracts/token/ERC1155/IERC1155.sol
pragma solidity >=0.6.2 <0.8.0;
/**
* @dev Required interface of an ERC1155 compliant contract, as defined in the
* https://eips.ethereum.org/EIPS/eip-1155[EIP].
*
* _Available since v3.1._
*/
interface IERC1155 is IERC165 {
/**
* @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
*/
event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);
/**
* @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
* transfers.
*/
event TransferBatch(address indexed operator, address indexed from, address indexed to, uint256[] ids, uint256[] values);
/**
* @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
* `approved`.
*/
event ApprovalForAll(address indexed account, address indexed operator, bool approved);
/**
* @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
*
* If an {URI} event was emitted for `id`, the standard
* https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
* returned by {IERC1155MetadataURI-uri}.
*/
event URI(string value, uint256 indexed id);
/**
* @dev Returns the amount of tokens of token type `id` owned by `account`.
*
* Requirements:
*
* - `account` cannot be the zero address.
*/
function balanceOf(address account, uint256 id) external view returns (uint256);
/**
* @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
*
* Requirements:
*
* - `accounts` and `ids` must have the same length.
*/
function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids) external view returns (uint256[] memory);
/**
* @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
*
* Emits an {ApprovalForAll} event.
*
* Requirements:
*
* - `operator` cannot be the caller.
*/
function setApprovalForAll(address operator, bool approved) external;
/**
* @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
*
* See {setApprovalForAll}.
*/
function isApprovedForAll(address account, address operator) external view returns (bool);
/**
* @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
*
* Emits a {TransferSingle} event.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
* - `from` must have a balance of tokens of type `id` of at least `amount`.
* - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
* acceptance magic value.
*/
function safeTransferFrom(address from, address to, uint256 id, uint256 amount, bytes calldata data) external;
/**
* @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
*
* Emits a {TransferBatch} event.
*
* Requirements:
*
* - `ids` and `amounts` must have the same length.
* - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
* acceptance magic value.
*/
function safeBatchTransferFrom(address from, address to, uint256[] calldata ids, uint256[] calldata amounts, bytes calldata data) external;
}
// File: @openzeppelin/contracts/token/ERC1155/IERC1155Receiver.sol
pragma solidity >=0.6.0 <0.8.0;
/**
* _Available since v3.1._
*/
interface IERC1155Receiver is IERC165 {
/**
@dev Handles the receipt of a single ERC1155 token type. This function is
called at the end of a `safeTransferFrom` after the balance has been updated.
To accept the transfer, this must return
`bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
(i.e. 0xf23a6e61, or its own function selector).
@param operator The address which initiated the transfer (i.e. msg.sender)
@param from The address which previously owned the token
@param id The ID of the token being transferred
@param value The amount of tokens being transferred
@param data Additional data with no specified format
@return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` if transfer is allowed
*/
function onERC1155Received(
address operator,
address from,
uint256 id,
uint256 value,
bytes calldata data
)
external
returns(bytes4);
/**
@dev Handles the receipt of a multiple ERC1155 token types. This function
is called at the end of a `safeBatchTransferFrom` after the balances have
been updated. To accept the transfer(s), this must return
`bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
(i.e. 0xbc197c81, or its own function selector).
@param operator The address which initiated the batch transfer (i.e. msg.sender)
@param from The address which previously owned the token
@param ids An array containing ids of each token being transferred (order and length must match values array)
@param values An array containing amounts of each token being transferred (order and length must match ids array)
@param data Additional data with no specified format
@return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` if transfer is allowed
*/
function onERC1155BatchReceived(
address operator,
address from,
uint256[] calldata ids,
uint256[] calldata values,
bytes calldata data
)
external
returns(bytes4);
}
// File: @openzeppelin/contracts/introspection/ERC165.sol
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Implementation of the {IERC165} interface.
*
* Contracts may inherit from this and call {_registerInterface} to declare
* their support of an interface.
*/
abstract contract ERC165 is IERC165 {
/*
* bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
*/
bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
/**
* @dev Mapping of interface ids to whether or not it's supported.
*/
mapping(bytes4 => bool) private _supportedInterfaces;
constructor () internal {
// Derived contracts need only register support for their own interfaces,
// we register support for ERC165 itself here
_registerInterface(_INTERFACE_ID_ERC165);
}
/**
* @dev See {IERC165-supportsInterface}.
*
* Time complexity O(1), guaranteed to always use less than 30 000 gas.
*/
function supportsInterface(bytes4 interfaceId) public view override returns (bool) {
return _supportedInterfaces[interfaceId];
}
/**
* @dev Registers the contract as an implementer of the interface defined by
* `interfaceId`. Support of the actual ERC165 interface is automatic and
* registering its interface id is not required.
*
* See {IERC165-supportsInterface}.
*
* Requirements:
*
* - `interfaceId` cannot be the ERC165 invalid interface (`0xffffffff`).
*/
function _registerInterface(bytes4 interfaceId) internal virtual {
require(interfaceId != 0xffffffff, "ERC165: invalid interface id");
_supportedInterfaces[interfaceId] = true;
}
}
// File: @openzeppelin/contracts/token/ERC1155/ERC1155Receiver.sol
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev _Available since v3.1._
*/
abstract contract ERC1155Receiver is ERC165, IERC1155Receiver {
constructor() internal {
_registerInterface(
ERC1155Receiver(0).onERC1155Received.selector ^
ERC1155Receiver(0).onERC1155BatchReceived.selector
);
}
}
// File: contracts/interfaces/IUnicFactory.sol
pragma solidity >=0.5.0;
interface IUnicFactory {
event TokenCreated(address indexed caller, address indexed uToken);
function feeTo() external view returns (address);
function feeToSetter() external view returns (address);
function getUToken(address uToken) external view returns (uint);
function uTokens(uint) external view returns (address);
function uTokensLength() external view returns (uint);
function createUToken(uint256 totalSupply, uint8 decimals, string calldata name, string calldata symbol, uint256 threshold, string calldata description) external returns (address);
function setFeeTo(address) external;
function setFeeToSetter(address) external;
}
// File: contracts/Converter.sol
pragma solidity 0.6.12;
contract Converter is ERC20, ERC1155Receiver {
using SafeMath for uint;
// List of NFTs that have been deposited
struct NFT {
address contractAddr;
uint256 tokenId;
uint256 amount;
bool claimed;
}
struct Bid {
address bidder;
uint256 amount;
uint time;
}
mapping(uint256 => NFT) public nfts;
// Current index and length of nfts
uint256 public currentNFTIndex = 0;
// If active, NFTs can’t be withdrawn
bool public active = false;
uint256 public totalBidAmount = 0;
uint256 public unlockVotes = 0;
uint256 public _threshold;
address public issuer;
string public _description;
uint256 public cap;
// Amount of uTokens each user has voted to unlock collection
mapping(address => uint256) public unlockApproved;
IUnicFactory public factory;
// NFT index to Bid
mapping(uint256 => Bid) public bids;
// NFT index to address to amount
mapping(uint256 => mapping(address => uint256)) public bidRefunds;
uint public constant TOP_BID_LOCK_TIME = 3 days;
event Deposited(uint256[] tokenIDs, uint256[] amounts, address contractAddr);
event Refunded();
event Issued();
event BidCreated(address sender, uint256 nftIndex, uint256 bidAmount);
event BidRemoved(address sender, uint256 nftIndex);
event ClaimedNFT(address winner, uint256 nftIndex, uint256 tokenId);
bytes private constant VALIDATOR = bytes('JCMY');
constructor (uint256 totalSupply, uint8 decimals, string memory name, string memory symbol, uint256 threshold, string memory description, address _issuer, IUnicFactory _factory)
public
ERC20(name, symbol)
{
_setupDecimals(decimals);
issuer = _issuer;
_description = description;
_threshold = threshold;
factory = _factory;
cap = totalSupply;
}
// deposits an nft using the transferFrom action of the NFT contractAddr
function deposit(uint256[] calldata tokenIDs, uint256[] calldata amounts, address contractAddr) external {
require(msg.sender == issuer, "Converter: Only issuer can deposit");
require(tokenIDs.length <= 50, "Converter: A maximum of 50 tokens can be deposited in one go");
require(tokenIDs.length > 0, "Converter: You must specify at least one token ID");
if (ERC165Checker.supportsInterface(contractAddr, 0xd9b67a26)){
IERC1155(contractAddr).safeBatchTransferFrom(msg.sender, address(this), tokenIDs, amounts, VALIDATOR);
for (uint8 i = 0; i < 50; i++){
if (tokenIDs.length == i){
break;
}
nfts[currentNFTIndex++] = NFT(contractAddr, tokenIDs[i], amounts[i], false);
}
}
else if (ERC165Checker.supportsInterface(contractAddr, 0x80ac58cd)){
for (uint8 i = 0; i < 50; i++){
if (tokenIDs.length == i){
break;
}
IERC721(contractAddr).transferFrom(msg.sender, address(this), tokenIDs[i]);
nfts[currentNFTIndex++] = NFT(contractAddr, tokenIDs[i], 1, false);
}
}
emit Deposited(tokenIDs, amounts, contractAddr);
}
// Function that locks NFT collateral and issues the uTokens to the issuer
function issue() external {
require(msg.sender == issuer, "Converter: Only issuer can issue the tokens");
require(active == false, "Converter: Token is already active");
active = true;
address feeTo = factory.feeTo();
uint256 feeAmount = 0;
if (feeTo != address(0)) {
// 0.5% of uToken supply is sent to feeToAddress if fee is on
feeAmount = cap.div(200);
_mint(feeTo, feeAmount);
}
_mint(issuer, cap - feeAmount);
emit Issued();
}
// Function that allows NFTs to be refunded (prior to issue being called)
function refund(address _to) external {
require(!active, "Converter: Contract is already active - cannot refund");
require(msg.sender == issuer, "Converter: Only issuer can refund");
// Only transfer maximum of 50 at a time to limit gas per call
uint8 _i = 0;
uint256 _index = currentNFTIndex;
bytes memory data;
while (_index > 0 && _i < 50){
NFT memory nft = nfts[_index - 1];
if (ERC165Checker.supportsInterface(nft.contractAddr, 0xd9b67a26)){
IERC1155(nft.contractAddr).safeTransferFrom(address(this), _to, nft.tokenId, nft.amount, data);
}
else if (ERC165Checker.supportsInterface(nft.contractAddr, 0x80ac58cd)){
IERC721(nft.contractAddr).safeTransferFrom(address(this), _to, nft.tokenId);
}
delete nfts[_index - 1];
_index--;
_i++;
}
currentNFTIndex = _index;
emit Refunded();
}
function bid(uint256 nftIndex) external payable {
require(unlockVotes < _threshold, "Converter: Release threshold has been met, no more bids allowed");
Bid memory topBid = bids[nftIndex];
require(topBid.bidder != msg.sender, "Converter: You have an active bid");
require(topBid.amount < msg.value, "Converter: Bid too low");
require(bidRefunds[nftIndex][msg.sender] == 0, "Converter: Collect bid refund");
bids[nftIndex] = Bid(msg.sender, msg.value, getBlockTimestamp());
bidRefunds[nftIndex][topBid.bidder] = topBid.amount;
totalBidAmount += msg.value - topBid.amount;
emit BidCreated(msg.sender, nftIndex, msg.value);
}
function unbid(uint256 nftIndex) external {
Bid memory topBid = bids[nftIndex];
bool isTopBidder = topBid.bidder == msg.sender;
if (unlockVotes >= _threshold) {
require(!isTopBidder, "Converter: Release threshold has been met, winner can't unbid");
}
if (isTopBidder) {
require(topBid.time + TOP_BID_LOCK_TIME < getBlockTimestamp(), "Converter: Top bid locked");
totalBidAmount -= topBid.amount;
bids[nftIndex] = Bid(address(0), 0, getBlockTimestamp());
(bool sent, bytes memory data) = msg.sender.call{value: topBid.amount}("");
require(sent, "Converter: Failed to send Ether");
emit BidRemoved(msg.sender, nftIndex);
}
else {
uint256 refundAmount = bidRefunds[nftIndex][msg.sender];
require(refundAmount > 0, "Converter: no bid found");
bidRefunds[nftIndex][msg.sender] = 0;
(bool sent, bytes memory data) = msg.sender.call{value: refundAmount}("");
require(sent, "Converter: Failed to send Ether");
}
}
// Claim NFT if address is winning bidder
function claim(uint256 nftIndex) external {
require(unlockVotes >= _threshold, "Converter: Threshold not met");
require(!nfts[nftIndex].claimed, "Converter: Already claimed");
Bid memory topBid = bids[nftIndex];
require(msg.sender == topBid.bidder, "Converter: Only winner can claim");
nfts[nftIndex].claimed = true;
NFT memory winningNFT = nfts[nftIndex];
if (ERC165Checker.supportsInterface(winningNFT.contractAddr, 0xd9b67a26)){
bytes memory data;
IERC1155(winningNFT.contractAddr).safeTransferFrom(address(this), topBid.bidder, winningNFT.tokenId, winningNFT.amount, data);
}
else if (ERC165Checker.supportsInterface(winningNFT.contractAddr, 0x80ac58cd)){
IERC721(winningNFT.contractAddr).safeTransferFrom(address(this), topBid.bidder, winningNFT.tokenId);
}
emit ClaimedNFT(topBid.bidder, nftIndex, winningNFT.tokenId);
}
// Approve collection unlock
function approveUnlock(uint256 amount) external {
require(unlockVotes < _threshold, "Converter: Threshold reached");
_transfer(msg.sender, address(this), amount);
unlockApproved[msg.sender] += amount;
unlockVotes += amount;
}
// Unapprove collection unlock
function unapproveUnlock(uint256 amount) external {
require(unlockVotes < _threshold, "Converter: Threshold reached");
require(unlockApproved[msg.sender] >= amount, "Converter: Not enough uTokens locked by user");
unlockVotes -= amount;
unlockApproved[msg.sender] -= amount;
_transfer(address(this), msg.sender, amount);
}
// Claim ETH function
function redeemETH(uint256 amount) external {
require(unlockVotes >= _threshold, "Converter: Threshold not met");
// Deposit uTokens
if (amount > 0) {
_transfer(msg.sender, address(this), amount);
}
// Combine approved balance + newly deposited balance
uint256 finalBalance = amount + unlockApproved[msg.sender];
// Remove locked uTokens tracked for user
unlockApproved[msg.sender] = 0;
// Redeem ETH corresponding to uToken amount
(bool sent, bytes memory data) = msg.sender.call{value: totalBidAmount.mul(finalBalance).div(this.totalSupply())}("");
require(sent, "Converter: Failed to send Ether");
}
function getBlockTimestamp() internal view returns (uint) {
// solium-disable-next-line security/no-block-members
return block.timestamp;
}
/**
* ERC1155 Token ERC1155Receiver
*/
function onERC1155Received(address _operator, address _from, uint256 _id, uint256 _value, bytes calldata _data) override external returns(bytes4) {
if(keccak256(_data) == keccak256(VALIDATOR)){
return 0xf23a6e61;
}
}
function onERC1155BatchReceived(address _operator, address _from, uint256[] calldata _ids, uint256[] calldata _values, bytes calldata _data) override external returns(bytes4) {
if(keccak256(_data) == keccak256(VALIDATOR)){
return 0xbc197c81;
}
}
}