> For the complete documentation index, see [llms.txt](https://docs.xft.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.xft.finance/technical-implementation/contract-overview.md).

# Contract Overview

All XFT tokenized products implement the following ERC-20 token logic.

#### Features

* Access Control
* Rebasing token mechanism
* Minting and burning functionality
* Block/Unblock accounts
* Pausing emergency stop mechanism
* Reward multiplier system
* EIP-2612 permit support
* OpenZeppelin UUPS upgrade pattern

**Public and External Functions**

* `initialize(string memory name_, string memory symbol_, address owner)`: Initializes the contract.
* `name()`: Returns the name of the token.
* `symbol()`: Returns the symbol of the token.
* `decimals()`: Returns the number of decimals the token uses.
* `convertToShares(uint256 amount)`: Converts an amount of tokens to shares.
* `convertToTokens(uint256 shares)`: Converts an amount of shares to tokens.
* `totalShares()`: Returns the total amount of shares.
* `totalSupply()`: Returns the total supply.
* `balanceOf(address account)`: Returns the account blanace.
* `sharesOf(address account)`: Returns the account shares.
* `mint(address to, uint256 amount)`: Creates new tokens to the specified address.
* `burn(address from, uint256 amount)`: Destroys tokens from the specified address.
* `transfer(address to, uint256 amount)`: Transfers tokens between addresses.
* `blockAccounts(address[] addresses)`: Blocks multiple accounts at once.
* `unblockAccounts(address[] addresses)`: Unblocks multiple accounts at once.
* `isBlocked(address account)`: Checks if an account is blocked.
* `pause()`: Pauses the contract, halting token transfers.
* `unpause()`: Unpauses the contract, allowing token transfers.
* `setRewardMultiplier(uint256 _rewardMultiplier)`: Sets the reward multiplier.
* `addRewardMultiplier(uint256 _rewardMultiplierIncrement)`: Adds the given amount to the current reward multiplier.
* `approve(address spender, uint256 amount)`: Approves an allowance for a spender.
* `allowance(address owner, address spender)`: Returns the allowance for a spender.
* `transferFrom(address from, address to, uint256 amount)`: Moves tokens from an address to another one using the allowance mechanism.
* `increaseAllowance(address spender, uint256 addedValue)`: Increases the allowance granted to spender by the caller.
* `decreaseAllowance(address spender, uint256 subtractedValue)`: Decreases the allowance granted to spender by the caller.
* `DOMAIN_SEPARATOR()`: Returns the EIP-712 domain separator.
* `nonces(address owner)`: Returns the nonce for the specified address.
* `permit(address owner, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s)`: Implements EIP-2612 permit functionality.

**Private and Internal Functions**

* `_authorizeUpgrade(address newImplementation)`: Internal function to authorize an upgrade.
* `_mint(address to, uint256 amount)`: Internal function to mint tokens to the specified address.
* `_burn(address account, uint256 amount)`: Internal function to burn tokens from the specified address.
* `_beforeTokenTransfer(address from, address to, uint256 amount)`: Hook that is called before any transfer of tokens.
* `_afterTokenTransfer(address from, address to, uint256 amount)`: Hook that is called after any transfer of tokens.
* `_transfer(address from, address to, uint256 amount)`: Internal function to transfer tokens between addresses.
* `_blockAccount(address account)`: Internal function to block account.
* `_unblockAccount(address account)`: Internal function to unblock an account.
* `_setRewardMultiplier(uint256 _rewardMultiplier)`: Internal function to set the reward multiplier.
* `_spendAllowance(address owner, address spender, uint256 amount)`: Internal function to spend an allowance.
* `_useNonce(address owner)`: Increments and returns the current nonce for a given address.
* `_approve(address owner, address spender, uint256 amount)`: Internal function to approve an allowance for a spender.

**Events**

* `Transfer(from indexed addr, to uint256, amount uint256)`: Emitted when transferring tokens.
* `RewardMultiplier(uint256 indexed value)`: Emitted when the reward multiplier has changed.
* `Approval(address indexed owner, address indexed spender, uint256 value)`: Emitted when the allowance of a spender for an owner is set.
* `AccountBlocked(address indexed addr)`: Emitted when an address is blocked.
* `AccountUnblocked(address indexed addr)`: Emitted when an address is removed from the blocklist.
* `Paused(address account)`: Emitted when the pause is triggered by account.
* `Unpaused(address account)`: Emitted when the unpause is triggered by account.
* `Upgraded(address indexed implementation)`: Emitted when the implementation is upgraded.

**Roles**

* `DEFAULT_ADMIN_ROLE`: Grants the ability to grant roles.
* `MINTER_ROLE`: Grants the ability to mint tokens.
* `BURNER_ROLE`: Grants the ability to burn tokens.
* `BLOCKLIST_ROLE`: Grants the ability to manage the blocklist.
* `ORACLE_ROLE`: Grants the ability to update the reward multiplier.
* `UPGRADE_ROLE`: Grants the ability to upgrade the contract.
* `PAUSE_ROLE`: Grants the ability to pause/unpause the contract.